83 results on '"Porrot F"'
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2. Broadly neutralizing antibodies suppress post-transcytosis HIV-1 infectivity
- Author
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Lorin, V., primary, Malbec, M., additional, Eden, C., additional, Bruel, T., additional, Porrot, F., additional, Seaman, M.S., additional, Schwartz, O., additional, and Mouquet, H., additional
- Published
- 2017
- Full Text
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3. La réponse immunitaire cellulaire contre la protéine gag du VIH-1
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Buseyne, Florence, Mcchesney, M, Porrot, F, Sansonnetti, P, Blanche, S, Rivière, Y, Virologie et Immunologie Cellulaire, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Hôpital de l'Institut Pasteur [Paris], Institut Pasteur [Paris], CHU Necker - Enfants Malades [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), and Institut Pasteur [Paris] (IP)
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[SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology ,[SDV.BA]Life Sciences [q-bio]/Animal biology ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,[SDV.IMM]Life Sciences [q-bio]/Immunology ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,[SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie ,[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,[SDV.BC]Life Sciences [q-bio]/Cellular Biology ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 1992
4. Gag-specific cytotoxic T lymphocytes from human immunodeficiency virus type 1-infected individuals: Gag epitopes are clustered in three regions of the p24gag protein
- Author
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Buseyne, F, primary, McChesney, M, additional, Porrot, F, additional, Kovarik, S, additional, Guy, B, additional, and Rivière, Y, additional
- Published
- 1993
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5. Inactivation in vitro du VIH par des solutions antiseptiques de digluconate de chlorhexidine
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Henin, Y., primary, Porrot, F., additional, and Destouesse, F., additional
- Published
- 1993
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6. Inaktivierung des AIDS-Erregers HIV-1-Virus durch das Kontrazeptivum a-gen 53 n.
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Hénin, Y., Maréchal, V., Porrot, F., and Chermann, J. C.
- Published
- 1988
7. Erratum: Broadly neutralizing antibodies suppress post-transcytosis HIV-1 infectivity
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Lorin, V., Malbec, M., Eden, C., Bruel, T., Porrot, F., Seaman, M.S., Schwartz, O., and Mouquet, H.
- Abstract
Correction to: Mucosal Immunology advance online publication, 14 December 2016; doi:10.1038/mi.2016.106 Although Supplementary Movies 1–4 did not appear with the article when it was originally published, they are now accessible along with the other Supplementary Information. The publisher regrets the error.
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- 2017
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8. Mechanisms of Tecovirimat Antiviral Activity and Poxvirus Resistance.
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Vernuccio R, León AM, Poojari C, Buchrieser J, Selverian C, Jaleta Y, Meola A, Guivel-Benhassine F, Porrot F, Haouz A, Chevreuil M, Raynal B, Mercer J, Simon-Loriere E, Chandran K, Schwartz O, Hub J, and Guardado-Calvo P
- Abstract
Mpox is a zoonotic disease endemic in central and west Africa. However, since 2022, human-adapted mpox virus (MPXV) strains are causing large outbreaks spreading outside these regions, leading the World Health Organization to declare public health emergency twice. Tecovirimat, the most widely used drug to treat these infections, blocks viral egress through a poorly understood mechanism. Tecovirimat-resistant strains, all with mutations in the viral phospholipase F13, pose public health concerns. Herein, we report the structure of an F13 homodimer, both alone and in complex with tecovirimat. We demonstrate that tecovirimat acts as a molecular glue, inducing the dimerization of the phospholipase. F13 escape mutations in MPXV clinical isolates are at the dimer interface and prevent drug-induced dimerization in solution and cells. These findings, which decipher tecovirimat's mode of action, will allow better monitoring of poxvirus outbreaks and pave the way for developing more potent and resilient therapeutics.
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- 2024
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9. Broad sarbecovirus neutralization by combined memory B cell antibodies to ancestral SARS-CoV-2.
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Planchais C, Fernández I, Chalopin B, Bruel T, Rosenbaum P, Beretta M, Dimitrov JD, Conquet L, Donati F, Prot M, Porrot F, Planas D, Staropoli I, Guivel-Benhassine F, Baquero E, van der Werf S, Haouz A, Simon-Lorière E, Montagutelli X, Maillère B, Rey FA, Guardado-Calvo P, Nozach H, Schwartz O, and Mouquet H
- Abstract
Antibodies play a pivotal role in protecting from SARS-CoV-2 infection, but their efficacy is challenged by the continuous emergence of viral variants. In this study, we describe two broadly neutralizing antibodies cloned from the memory B cells of a single convalescent individual after infection with ancestral SARS-CoV-2. Cv2.3194, a resilient class 1 anti-RBD antibody, remains active against Omicron sub-variants up to BA.2.86. Cv2.3132, a near pan-Sarbecovirus neutralizer, targets the heptad repeat 2 membrane proximal region. When combined, Cv2.3194 and Cv2.3132 form a complementary SARS-CoV-2 neutralizing antibody cocktail exhibiting a local dose-dependent synergy. Thus, remarkably robust neutralizing memory B cell antibodies elicited in response to ancestral SARS-CoV-2 infection can withstand viral evolution and immune escape. The cooperative effect of such antibody combination may confer a certain level of protection against the latest SARS-CoV-2 variants., Competing Interests: The Institut Pasteur has pending patent applications on “Human neutralizing monoclonal antibodies against SARS-CoV-2 and their use thereof” (PCT/EP2022/058777, WO/2022/228827A1) in which C.P., I.F., T.B., X.M., F.A.R., O.S., and H.M. are inventors, and on “Combined antibodies against Sarbecoviruses and their use thereof” (EP23305528.4, PCT/IB2022/000108) in which C.P., T.B., O.S., and H.M. are inventors, both being licensed by the biotech company SpikImm. H.M. is a scientific consultant for SpikImm, and received consulting fees., (© 2024 The Authors.)
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- 2024
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10. Distinct evolution of SARS-CoV-2 Omicron XBB and BA.2.86/JN.1 lineages combining increased fitness and antibody evasion.
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Planas D, Staropoli I, Michel V, Lemoine F, Donati F, Prot M, Porrot F, Guivel-Benhassine F, Jeyarajah B, Brisebarre A, Dehan O, Avon L, Bolland WH, Hubert M, Buchrieser J, Vanhoucke T, Rosenbaum P, Veyer D, Péré H, Lina B, Trouillet-Assant S, Hocqueloux L, Prazuck T, Simon-Loriere E, and Schwartz O
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- Humans, Antibodies, Neutralizing, Epithelial Cells, Exercise, SARS-CoV-2 genetics, COVID-19
- Abstract
The unceasing circulation of SARS-CoV-2 leads to the continuous emergence of novel viral sublineages. Here, we isolate and characterize XBB.1, XBB.1.5, XBB.1.9.1, XBB.1.16.1, EG.5.1.1, EG.5.1.3, XBF, BA.2.86.1 and JN.1 variants, representing >80% of circulating variants in January 2024. The XBB subvariants carry few but recurrent mutations in the spike, whereas BA.2.86.1 and JN.1 harbor >30 additional changes. These variants replicate in IGROV-1 but no longer in Vero E6 and are not markedly fusogenic. They potently infect nasal epithelial cells, with EG.5.1.3 exhibiting the highest fitness. Antivirals remain active. Neutralizing antibody (NAb) responses from vaccinees and BA.1/BA.2-infected individuals are markedly lower compared to BA.1, without major differences between variants. An XBB breakthrough infection enhances NAb responses against both XBB and BA.2.86 variants. JN.1 displays lower affinity to ACE2 and higher immune evasion properties compared to BA.2.86.1. Thus, while distinct, the evolutionary trajectory of these variants combines increased fitness and antibody evasion., (© 2024. The Author(s).)
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- 2024
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11. Beta-variant recombinant booster vaccine elicits broad cross-reactive neutralization of SARS-CoV-2 including Omicron variants.
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Planas D, Peng L, Zheng L, Guivel-Benhassine F, Staropoli I, Porrot F, Bruel T, Bhiman JN, Bonaparte M, Savarino S, de Bruyn G, Chicz RM, Moore PL, Schwartz O, and Sridhar S
- Abstract
Background: SARS-CoV-2 Omicron lineage contains variants with multiple sequence mutations relative to the ancestral strain particularly in the viral spike gene. These mutations are associated inter alia with loss of neutralization sensitivity to sera generated by immunization with vaccines targeting ancestral strains or prior infection with circulating (non-Omicron) variants. Here we present a comparison of vaccine formulation elicited cross neutralization responses using two different assay readouts from a subpopulation of a Phase II/III clinical trial., Methods: Human sera from a Phase II/III trial (NCT04762680) was collected and evaluated for neutralizing responses to SARS-CoV-2 spike antigen protein vaccines formulated with AS03 adjuvant, following a primary series of two-doses of ancestral strain vaccine in individuals who were previously unvaccinated or as an ancestral or variant strain booster vaccine among individuals previously vaccinated with the mRNA BNT162b2 vaccine., Results: We report that a neutralizing response to Omicron BA.1 is induced by the two-dose primary series in 89% of SARS-CoV-2-seronegative individuals. A booster dose of each vaccine formulation raises neutralizing antibody titers that effectively neutralizes Omicron BA.1 and BA.4/5 variants. Responses are highest after the monovalent Beta variant booster and similar in magnitude to human convalescent plasma titers., Conclusion: The findings of this study suggest the possibility to generate greater breadth of cross-neutralization to more recently emerging viral variants through use of a diverged spike vaccine in the form of a Beta variant booster vaccine., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Lingyi Zheng reports a relationship with Sanofi, Swiftwater, PA, USA that includes: employment. Stephen Savarino reports a relationship with Sanofi, Swiftwater, PA, USA that includes: employment. Saranya Sridhar has patent pending to Assignee. Roman M Chicz has patent pending to Assignee. Guy de Bruyn has patent pending to Asignee. Stephen Savarino has patent pending to Assignee. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)
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- 2024
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12. High fusion and cytopathy of SARS-CoV-2 variant B.1.640.1.
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Bolland W, Michel V, Planas D, Hubert M, Staropoli I, Guivel-Benhassine F, Porrot F, N'Debi M, Rodriguez C, Fourati S, Prot M, Planchais C, Hocqueloux L, Simon-Lorière E, Mouquet H, Prazuck T, Pawlotsky J-M, Bruel T, Schwartz O, and Buchrieser J
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- Humans, Africa, Pandemics, Spike Glycoprotein, Coronavirus physiology, Giant Cells virology, COVID-19 virology, SARS-CoV-2 physiology
- Abstract
SARS-CoV-2 variants with undetermined properties have emerged intermittently throughout the COVID-19 pandemic. Some variants possess unique phenotypes and mutations which allow further characterization of viral evolution and Spike functions. Around 1,100 cases of the B.1.640.1 variant were reported in Africa and Europe between 2021 and 2022, before the expansion of Omicron. Here, we analyzed the biological properties of a B.1.640.1 isolate and its Spike. Compared to the ancestral Spike, B.1.640.1 carried 14 amino acid substitutions and deletions. B.1.640.1 escaped binding by some anti-N-terminal domain and anti-receptor-binding domain monoclonal antibodies, and neutralization by sera from convalescent and vaccinated individuals. In cell lines, infection generated large syncytia and a high cytopathic effect. In primary airway cells, B.1.640.1 replicated less than Omicron BA.1 and triggered more syncytia and cell death than other variants. The B.1.640.1 Spike was highly fusogenic when expressed alone. This was mediated by two poorly characterized and infrequent mutations located in the Spike S2 domain, T859N and D936H. Altogether, our results highlight the cytopathy of a hyper-fusogenic SARS-CoV-2 variant, supplanted upon the emergence of Omicron BA.1. (This study has been registered at ClinicalTrials.gov under registration no. NCT04750720.)IMPORTANCEOur results highlight the plasticity of SARS-CoV-2 Spike to generate highly fusogenic and cytopathic strains with the causative mutations being uncharacterized in previous variants. We describe mechanisms regulating the formation of syncytia and the subsequent consequences in a primary culture model, which are poorly understood., Competing Interests: The authors declare no conflict of interest.
- Published
- 2024
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13. Neutralizing Antibody Levels as a Correlate of Protection Against SARS-CoV-2 Infection: A Modeling Analysis.
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Lingas G, Planas D, Péré H, Porrot F, Guivel-Benhassine F, Staropoli I, Duffy D, Chapuis N, Gobeaux C, Veyer D, Delaugerre C, Le Goff J, Getten P, Hadjadj J, Bellino A, Parfait B, Treluyer JM, Schwartz O, Guedj J, Kernéis S, and Terrier B
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- Humans, Antibodies, Neutralizing, Prospective Studies, SARS-CoV-2, COVID-19
- Abstract
Although anti-severe acute respiratory syndrome-coronavirus 2 antibody kinetics have been described in large populations of vaccinated individuals, we still poorly understand how they evolve during a natural infection and how this impacts viral clearance. For that purpose, we analyzed the kinetics of both viral load and neutralizing antibody levels in a prospective cohort of individuals during acute infection with alpha variant. Using a mathematical model, we show that the progressive increase in neutralizing antibodies leads to a shortening of the half-life of both infected cells and infectious viral particles. We estimated that the neutralizing activity reached 90% of its maximal level within 11 days after symptom onset and could reduce the half-life of both infected cells and circulating virus by a 6-fold factor, thus playing a key role to achieve rapid viral clearance. Using this model, we conducted a simulation study to predict in a more general context the protection conferred by pre-existing neutralization titers, due to either vaccination or prior infection. We predicted that a neutralizing activity, as measured by 50% effective dose > 10
3 , could reduce by 46% the risk of having viral load detectable by standard polymerase chain reaction assays and by 98% the risk of having viral load above the threshold of infectiousness. Our model shows that neutralizing activity could be used to define correlates of protection against infection and transmission., (© 2023 The Authors. Clinical Pharmacology & Therapeutics published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)- Published
- 2024
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14. TMPRSS2 is a functional receptor for human coronavirus HKU1.
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Saunders N, Fernandez I, Planchais C, Michel V, Rajah MM, Baquero Salazar E, Postal J, Porrot F, Guivel-Benhassine F, Blanc C, Chauveau-Le Friec G, Martin A, Grzelak L, Oktavia RM, Meola A, Ahouzi O, Hoover-Watson H, Prot M, Delaune D, Cornelissen M, Deijs M, Meriaux V, Mouquet H, Simon-Lorière E, van der Hoek L, Lafaye P, Rey F, Buchrieser J, and Schwartz O
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- Humans, Bronchi cytology, Bronchi virology, Common Cold drug therapy, Common Cold virology, Membrane Fusion, SARS-CoV-2, Single-Domain Antibodies pharmacology, Single-Domain Antibodies therapeutic use, Species Specificity, Virus Internalization, Betacoronavirus metabolism, Receptors, Virus metabolism, Serine Endopeptidases metabolism, Spike Glycoprotein, Coronavirus metabolism
- Abstract
Four endemic seasonal human coronaviruses causing common colds circulate worldwide: HKU1, 229E, NL63 and OC43 (ref.
1 ). After binding to cellular receptors, coronavirus spike proteins are primed for fusion by transmembrane serine protease 2 (TMPRSS2) or endosomal cathepsins2-9 . NL63 uses angiotensin-converting enzyme 2 as a receptor10 , whereas 229E uses human aminopeptidase-N11 . HKU1 and OC43 spikes bind cells through 9-O-acetylated sialic acid, but their protein receptors remain unknown12 . Here we show that TMPRSS2 is a functional receptor for HKU1. TMPRSS2 triggers HKU1 spike-mediated cell-cell fusion and pseudovirus infection. Catalytically inactive TMPRSS2 mutants do not cleave HKU1 spike but allow pseudovirus infection. Furthermore, TMPRSS2 binds with high affinity to the HKU1 receptor binding domain (Kd 334 and 137 nM for HKU1A and HKU1B genotypes) but not to SARS-CoV-2. Conserved amino acids in the HKU1 receptor binding domain are essential for binding to TMPRSS2 and pseudovirus infection. Newly designed anti-TMPRSS2 nanobodies potently inhibit HKU1 spike attachment to TMPRSS2, fusion and pseudovirus infection. The nanobodies also reduce infection of primary human bronchial cells by an authentic HKU1 virus. Our findings illustrate the various evolution strategies of coronaviruses, which use TMPRSS2 to either directly bind to target cells or prime their spike for membrane fusion and entry., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2023
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15. Sotrovimab therapy elicits antiviral activities against Omicron BQ.1.1 and XBB.1.5 in sera of immunocompromised patients.
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Bruel T, Vrignaud LL, Porrot F, Staropoli I, Planas D, Guivel-Benhassine F, Puech J, Prot M, Munier S, Bolland WH, Soulié C, Zafilaza K, Lusivika-Nzinga C, Meledge ML, Dorival C, Molino D, Péré H, Yordanov Y, Simon-Lorière E, Veyer D, Carrat F, Schwartz O, Marcelin AG, and Martin-Blondel G
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- Humans, Prospective Studies, Antiviral Agents pharmacology, Antiviral Agents therapeutic use, Antibodies, Monoclonal, Humanized therapeutic use, Immunocompromised Host
- Abstract
Antibodies effective against the recent Omicron sublineages are missing. By taking advantage of a multi-centric prospective cohort of immunocompromised individuals treated for mild-to-moderate COVID-19, Bruel et al. show that administration of 500 mg of sotrovimab induces serum neutralization and antibody-dependent cellular cytotoxicity of BQ.1.1 and XBB.1.5. Therefore, sotrovimab may remain a therapeutic option against these variants., Competing Interests: Declaration of interest T.B. and O.S. have a pending patent application for an anti-RBD mAb not used in this study (PCT/FR2021/070522)., (Copyright © 2023 Elsevier Inc. All rights reserved.)
- Published
- 2023
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16. IFITM1 inhibits trophoblast invasion and is induced in placentas associated with IFN-mediated pregnancy diseases.
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Degrelle SA, Buchrieser J, Dupressoir A, Porrot F, Loeuillet L, Schwartz O, and Fournier T
- Abstract
Interferon-induced transmembrane proteins (IFITMs) are restriction factors that block many viruses from entering cells. High levels of type I interferon (IFN) are associated with adverse pregnancy outcomes, and IFITMs have been shown to impair the formation of syncytiotrophoblast. Here, we examine whether IFITMs affect another critical step of placental development, extravillous cytotrophoblast (EVCT) invasion. We conducted experiments using in vitro / ex vivo models of EVCT, mice treated in vivo with the IFN-inducer poly (I:C), and human pathological placental sections. Cells treated with IFN-β demonstrated upregulation of IFITMs and reduced invasive abilities. Transduction experiments confirmed that IFITM1 contributed to the decreased cell invasion. Similarly, migration of trophoblast giant cells, the mouse equivalent of human EVCTs, was significantly reduced in poly (I:C)-treated mice. Finally, analysis of CMV- and bacterial-infected human placentas revealed upregulated IFITM1 expression. These data demonstrate that high levels of IFITM1 impair trophoblast invasion and could explain the placental dysfunctions associated with IFN-mediated disorders., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)
- Published
- 2023
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17. Complement-dependent mpox-virus-neutralizing antibodies in infected and vaccinated individuals.
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Hubert M, Guivel-Benhassine F, Bruel T, Porrot F, Planas D, Vanhomwegen J, Wiedemann A, Burrel S, Marot S, Palich R, Monsel G, Diombera H, Gallien S, Lopez-Zaragoza JL, Vindrios W, Taieb F, Fernandes-Pellerin S, Delhaye M, Laude H, Arowas L, Ungeheuer MN, Hocqueloux L, Pourcher V, Prazuck T, Marcelin AG, Lelièvre JD, Batéjat C, Lévy Y, Manuguerra JC, and Schwartz O
- Subjects
- Humans, Antibodies, Viral, Vaccinia virus, Antibodies, Neutralizing, Complement System Proteins, Smallpox Vaccine, Smallpox prevention & control, Mpox (monkeypox)
- Abstract
Mpox virus (MPXV) caused a multi-country outbreak in non-endemic areas in 2022. Following historic success of smallpox vaccination with vaccinia virus (VACV)-based vaccines, the third generation modified vaccinia Ankara (MVA)-based vaccine was used as prophylaxis for MPXV, but its effectiveness remains poorly characterized. Here, we applied two assays to quantify neutralizing antibodies (NAbs) in sera from control, MPXV-infected, or MVA-vaccinated individuals. Various levels of MVA NAbs were detected after infection, historic smallpox, or recent MVA vaccination. MPXV was minimally sensitive to neutralization. However, addition of complement enhanced detection of responsive individuals and NAb levels. Anti-MVA and -MPXV NAbs were observed in 94% and 82% of infected individuals, respectively, and 92% and 56% of MVA vaccinees, respectively. NAb titers were higher in individuals born before 1980, highlighting the impact of historic smallpox vaccination on humoral immunity. Altogether, our results indicate that MPXV neutralization is complement dependent and uncover mechanisms underlying vaccine effectiveness., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)
- Published
- 2023
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18. Antiviral activities of sotrovimab against BQ.1.1 and XBB.1.5 in sera of treated patients.
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Bruel T, Vrignaud LL, Porrot F, Staropoli I, Planas D, Guivel-Benhassine F, Puech J, Prot M, Munier S, Henry-Bolland W, Soulié C, Zafilaza K, Lusivika-Nzinga C, Meledge ML, Dorival C, Molino D, Péré H, Yordanov Y, Simon-Lorière E, Veyer D, Carrat F, Schwartz O, Marcelin AG, and Martin-Blondel G
- Abstract
Background: Monoclonal antibodies (mAbs) targeting the spike of SARS-CoV-2 prevent severe COVID-19. Omicron subvariants BQ.1.1 and XBB.1.5 evade neutralization of therapeutic mAbs, leading to recommendations against their use. Yet, the antiviral activities of mAbs in treated patients remain ill-defined., Methods: We investigated neutralization and antibody-dependent cellular cytotoxicity (ADCC) of D614G, BQ.1.1 and XBB.1.5 in 320 sera from 80 immunocompromised patients with mild-to-moderate COVID-19 prospectively treated with mAbs (sotrovimab, n=29; imdevimab/casirivimab, n=34; cilgavimab/tixagevimab, n=4) or anti-protease (nirmatrelvir/ritonavir, n=13). We measured live-virus neutralization titers and quantified ADCC with a reporter assay., Findings: Only Sotrovimab elicits serum neutralization and ADCC against BQ.1.1 and XBB.1.5. As compared to D614G, sotrovimab neutralization titers of BQ.1.1 and XBB.1.5 are reduced (71- and 58-fold, respectively), but ADCC levels are only slightly decreased (1.4- and 1-fold, for BQ.1.1 and XBB.1.5, respectively)., Interpretation: Our results show that sotrovimab is active against BQ.1.1 and XBB.1.5 in treated individuals, suggesting that it may be a valuable therapeutic option., Competing Interests: Declaration of interest T.B. and O.S. have a pending patent application for an anti-RBD mAb not used in this study (PCT/FR2021/070522). All other authors declare no conflicts of interest.
- Published
- 2023
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19. Resistance of Omicron subvariants BA.2.75.2, BA.4.6, and BQ.1.1 to neutralizing antibodies.
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Planas D, Bruel T, Staropoli I, Guivel-Benhassine F, Porrot F, Maes P, Grzelak L, Prot M, Mougari S, Planchais C, Puech J, Saliba M, Sahraoui R, Fémy F, Morel N, Dufloo J, Sanjuán R, Mouquet H, André E, Hocqueloux L, Simon-Loriere E, Veyer D, Prazuck T, Péré H, and Schwartz O
- Subjects
- Humans, Antibodies, Viral, Antiviral Agents, Breakthrough Infections, Spike Glycoprotein, Coronavirus genetics, Antibodies, Neutralizing, BNT162 Vaccine, COVID-19 immunology, COVID-19 prevention & control, SARS-CoV-2 genetics
- Abstract
Convergent evolution of SARS-CoV-2 Omicron BA.2, BA.4, and BA.5 lineages has led to the emergence of several new subvariants, including BA.2.75.2, BA.4.6. and BQ.1.1. The subvariant BQ.1.1 became predominant in many countries in December 2022. The subvariants carry an additional and often redundant set of mutations in the spike, likely responsible for increased transmissibility and immune evasion. Here, we established a viral amplification procedure to easily isolate Omicron strains. We examined their sensitivity to 6 therapeutic monoclonal antibodies (mAbs) and to 72 sera from Pfizer BNT162b2-vaccinated individuals, with or without BA.1/BA.2 or BA.5 breakthrough infection. Ronapreve (Casirivimab and Imdevimab) and Evusheld (Cilgavimab and Tixagevimab) lose antiviral efficacy against BA.2.75.2 and BQ.1.1, whereas Xevudy (Sotrovimab) remaine weakly active. BQ.1.1 is also resistant to Bebtelovimab. Neutralizing titers in triply vaccinated individuals are low to undetectable against BQ.1.1 and BA.2.75.2, 4 months after boosting. A BA.1/BA.2 breakthrough infection increases these titers, which remains about 18-fold lower against BA.2.75.2 and BQ.1.1, than against BA.1. Reciprocally, a BA.5 breakthrough infection increases more efficiently neutralization against BA.5 and BQ.1.1 than against BA.2.75.2. Thus, the evolution trajectory of novel Omicron subvariants facilitates their spread in immunized populations and raises concerns about the efficacy of most available mAbs., (© 2023. The Author(s).)
- Published
- 2023
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20. Longitudinal analysis of serum neutralization of SARS-CoV-2 Omicron BA.2, BA.4, and BA.5 in patients receiving monoclonal antibodies.
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Bruel T, Stéfic K, Nguyen Y, Toniutti D, Staropoli I, Porrot F, Guivel-Benhassine F, Bolland WH, Planas D, Hadjadj J, Handala L, Planchais C, Prot M, Simon-Lorière E, André E, Baele G, Cuypers L, Mouthon L, Mouquet H, Buchrieser J, Sève A, Prazuck T, Maes P, Terrier B, Hocqueloux L, and Schwartz O
- Subjects
- Humans, Antibodies, Monoclonal therapeutic use, Antibody-Dependent Cell Cytotoxicity, Antiviral Agents therapeutic use, SARS-CoV-2, COVID-19
- Abstract
The emergence of Omicron sublineages impacts the therapeutic efficacy of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibodies (mAbs). Here, we evaluate neutralization and antibody-dependent cellular cytotoxicity (ADCC) activities of 6 therapeutic mAbs against Delta, BA.2, BA.4, and BA.5. The Omicron subvariants escape most antibodies but remain sensitive to bebtelovimab and cilgavimab. Consistent with their shared spike sequence, BA.4 and BA.5 display identical neutralization profiles. Sotrovimab is the most efficient at eliciting ADCC. We also analyze 121 sera from 40 immunocompromised individuals up to 6 months after infusion of Ronapreve (imdevimab + casirivimab) or Evusheld (cilgavimab + tixagevimab). Sera from Ronapreve-treated individuals do not neutralize Omicron subvariants. Evusheld-treated individuals neutralize BA.2 and BA.5, but titers are reduced. A longitudinal evaluation of sera from Evusheld-treated patients reveals a slow decay of mAb levels and neutralization, which is faster against BA.5. Our data shed light on antiviral activities of therapeutic mAbs and the duration of effectiveness of Evusheld pre-exposure prophylaxis., Competing Interests: Declaration of interests T.B., C.P., H.M., and O.S. have a pending patent application for an anti-RBD mAb not used in this study (PCT/FR2021/070522)., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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21. Resistance of Omicron subvariants BA.2.75.2, BA.4.6 and BQ.1.1 to neutralizing antibodies.
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Planas D, Bruel T, Staropoli I, Guivel-Benhassine F, Porrot F, Maes P, Grzelak L, Prot M, Mougari S, Planchais C, Puech J, Saliba M, Sahraoui R, Fémy F, Morel N, Dufloo J, Sanjuán R, Mouquet H, André E, Hocqueloux L, Simon-Loriere E, Veyer D, Prazuck T, Péré H, and Schwartz O
- Abstract
Convergent evolution of SARS-CoV-2 Omicron BA.2, BA.4 and BA.5 lineages has led to the emergence of several new subvariants, including BA.2.75.2, BA.4.6. and BQ.1.1. The subvariants BA.2.75.2 and BQ.1.1 are expected to become predominant in many countries in November 2022. They carry an additional and often redundant set of mutations in the spike, likely responsible for increased transmissibility and immune evasion. Here, we established a viral amplification procedure to easily isolate Omicron strains. We examined their sensitivity to 6 therapeutic monoclonal antibodies (mAbs) and to 72 sera from Pfizer BNT162b2-vaccinated individuals, with or without BA.1/BA.2 or BA.5 breakthrough infection. Ronapreve (Casirivimab and Imdevimab) and Evusheld (Cilgavimab and Tixagevimab) lost any antiviral efficacy against BA.2.75.2 and BQ.1.1, whereas Xevudy (Sotrovimab) remained weakly active. BQ.1.1 was also resistant to Bebtelovimab. Neutralizing titers in triply vaccinated individuals were low to undetectable against BQ.1.1 and BA.2.75.2, 4 months after boosting. A BA.1/BA.2 breakthrough infection increased these titers, which remained about 18-fold lower against BA.2.75.2 and BQ.1.1, than against BA.1. Reciprocally, a BA.5 breakthrough infection increased more efficiently neutralization against BA.5 and BQ.1.1 than against BA.2.75.2. Thus, the evolution trajectory of novel Omicron subvariants facilitated their spread in immunized populations and raises concerns about the efficacy of most currently available mAbs.
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- 2022
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22. IRF8 regulates efficacy of therapeutic anti-CD20 monoclonal antibodies.
- Author
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Grzelak L, Roesch F, Vaysse A, Biton A, Legendre R, Porrot F, Commère PH, Planchais C, Mouquet H, Vignuzzi M, Bruel T, and Schwartz O
- Subjects
- Humans, Interferon Regulatory Factors genetics, Interferon Regulatory Factors metabolism, RNA, Rituximab pharmacology, Rituximab therapeutic use, Antigens, CD20, Antineoplastic Agents
- Abstract
Anti-CD20 monoclonal antibodies such as Rituximab, Ofatumumab, and Obinutuzumab are widely used to treat lymphomas and autoimmune diseases. They act by depleting B cells, mainly through Fc-dependent effectors functions. Some patients develop resistance to treatment but the underlying mechanisms are poorly understood. Here, we performed a genome-wide CRISPR/Cas9 screen to identify genes regulating the efficacy of anti-CD20 antibodies. We used as a model the killing of RAJI B cells by Rituximab through complement-dependent-cytotoxicity (CDC). As expected, the screen identified MS4A1, encoding CD20, the target of Rituximab. Among other identified genes, the role of Interferon Regulatory Factor 8 (IRF8) was validated in two B-cell lines. IRF8 KO also decreased the efficacy of antibody-dependent cellular cytotoxicity and phagocytosis (ADCC and ADCP) induced by anti-CD20 antibodies. We further show that IRF8 is necessary for efficient CD20 transcription. Levels of IRF8 and CD20 RNA or proteins correlated in normal B cells and in hundreds of malignant B cells. Therefore, IRF8 regulates CD20 expression and controls the depleting capacity of anti-CD20 antibodies. Our results bring novel insights into the pathways underlying resistance to CD20-targeting immunotherapies., (© 2022 Wiley-VCH GmbH.)
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- 2022
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23. Neutralising antibody responses to SARS-CoV-2 omicron among elderly nursing home residents following a booster dose of BNT162b2 vaccine: A community-based, prospective, longitudinal cohort study.
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Bruel T, Pinaud L, Tondeur L, Planas D, Staropoli I, Porrot F, Guivel-Benhassine F, Attia M, Pelleau S, Woudenberg T, Duru C, Koffi AD, Castelain S, Fernandes-Pellerin S, Jolly N, De Facci LP, Roux E, Ungeheuer MN, Van Der Werf S, White M, Schwartz O, and Fontanet A
- Abstract
Background: The protective immunity against omicron following a BNT162b2 Pfizer booster dose among elderly individuals (ie, those aged >65 years) is not well characterised., Methods: In a community-based, prospective, longitudinal cohort study taking place in France in which 75 residents from three nursing homes were enrolled, we selected 38 residents who had received a two-dose regimen of mRNA vaccine and a booster dose of Pfizer BNT162b2 vaccine. We excluded individuals that did not receive three vaccine doses or did not have available sera samples. We measured anti-S IgG antibodies and neutralisation capacity in sera taken 56 (28-68) and 55 (48-64) days (median (range)) after the 2
nd and 3rd vaccine doses, respectively. Antibodies targeting the SARS-CoV-2 Spike protein were measured with the S-Flow assay as binding antibody units per milliliter (BAU/mL). Neutralising activities in sera were measured as effective dilution 50% (ED50) with the S-Fuse assay using authentic isolates of delta and omicron BA.1., Findings: Among the 38 elderly individuals recruited to the cohort study between November 23rd , 2020 and April 29th , 2021, with median age of 88 (range 72-101) years, 30 (78.95%) had been previously infected with SARS-CoV-2. After three vaccine doses, serum neutralising activity was lower against omicron BA.1 (median ED50 of 774.5, range 15.0-34660.0) than the delta variant (median ED50 of 4972.0, range 213.7-66340.0), and higher among previously infected (ie, convalescent; median ED50 against omicron: 1088.0, range 32.6-34660.0) compared with infection-naive residents (median ED50 against omicron: 188.4, range 15.0-8918.0). During the French omicron wave in December 2021-January 2022, 75% (6/8) of naive residents were infected, compared to 25% (7/30) of convalescent residents ( P =0.0114). Anti-Spike antibody levels and neutralising activity against omicron BA.1 after a third BNT162b2 booster dose were lower in those with breakthrough BA.1 infection ( n =13) compared with those without ( n =25), with a median of 1429.9 (range 670.9-3818.3) BAU/mL vs 2528.3 (range 695.4-8832.0) BAU/mL ( P =0.029) and a median ED50 of 281.1 (range 15.0-2136.0) vs 1376.0 (range 32.6-34660.0) ( P =0.0013), respectively., Interpretation: This study shows that elderly individuals who received three vaccine doses elicit neutralising antibodies against the omicron BA.1 variant of SARS-CoV-2. Elderly individuals who had also been previously infected showed higher neutralising activity compared with naive individuals. Yet, breakthrough infections with omicron occurred. Individuals with breakthrough infections had significantly lower neutralising titers compared to individuals without breakthrough infection. Thus, a fourth dose of vaccine may be useful in the elderly population to increase the level of neutralising antibodies and compensate for waning immunity., Funding: Institut Pasteur, Fondation pour la Recherche Médicale (FRM), European Health Emergency Preparedness and Response Authority (HERA), Agence nationale de recherches sur le sida et les hépatites virales - Maladies Infectieuses Emergentes (ANRS-MIE), Agence nationale de la recherche (ANR), Assistance Publique des Hôpitaux de Paris (AP-HP) and Fondation de France., Competing Interests: SvdW is a member of the Data Safety Monitoring Board of the DISCOVERY trial and the EU-solidact trial, and an associate editor within the Eurosurveillance journal. MW and SP declare a pending patent (US 63/057.471), SvdW declares issued patents (EP1697507, EP1694829, PCT/EP2020055939, US16/809.717 and WO20211176099), and a provisional patent (US63003855). All the other authors declare no competing interests., (© 2022 The Authors.)- Published
- 2022
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24. Serum neutralization of SARS-CoV-2 Omicron sublineages BA.1 and BA.2 in patients receiving monoclonal antibodies.
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Bruel T, Hadjadj J, Maes P, Planas D, Seve A, Staropoli I, Guivel-Benhassine F, Porrot F, Bolland WH, Nguyen Y, Casadevall M, Charre C, Péré H, Veyer D, Prot M, Baidaliuk A, Cuypers L, Planchais C, Mouquet H, Baele G, Mouthon L, Hocqueloux L, Simon-Loriere E, André E, Terrier B, Prazuck T, and Schwartz O
- Subjects
- Antibodies, Monoclonal therapeutic use, Antibodies, Monoclonal, Humanized, Antibodies, Neutralizing therapeutic use, Antibodies, Viral, Humans, Membrane Glycoproteins genetics, Neutralization Tests, Spike Glycoprotein, Coronavirus, Viral Envelope Proteins, SARS-CoV-2, COVID-19 Drug Treatment
- Abstract
The severe acute respiratory syndrome coronavirus 2 Omicron BA.1 sublineage has been supplanted in many countries by the BA.2 sublineage. BA.2 differs from BA.1 by about 21 mutations in its spike. In this study, we first compared the sensitivity of BA.1 and BA.2 to neutralization by nine therapeutic monoclonal antibodies (mAbs). In contrast to BA.1, BA.2 was sensitive to cilgavimab, partly inhibited by imdevimab and resistant to adintrevimab and sotrovimab. We then analyzed sera from 29 immunocompromised individuals up to 1 month after administration of Ronapreve (casirivimab and imdevimab) and/or Evusheld (cilgavimab and tixagevimab) antibody cocktails. All treated individuals displayed elevated antibody levels in their sera, which efficiently neutralized the Delta variant. Sera from Ronapreve recipients did not neutralize BA.1 and weakly inhibited BA.2. Neutralization of BA.1 and BA.2 was detected in 19 and 29 out of 29 Evusheld recipients, respectively. As compared to the Delta variant, neutralizing titers were more markedly decreased against BA.1 (344-fold) than BA.2 (nine-fold). We further report four breakthrough Omicron infections among the 29 individuals, indicating that antibody treatment did not fully prevent infection. Collectively, BA.1 and BA.2 exhibit noticeable differences in their sensitivity to therapeutic mAbs. Anti-Omicron neutralizing activity of Ronapreve and, to a lesser extent, that of Evusheld is reduced in patients' sera., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)
- Published
- 2022
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25. Identification of DAXX as a restriction factor of SARS-CoV-2 through a CRISPR/Cas9 screen.
- Author
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Mac Kain A, Maarifi G, Aicher SM, Arhel N, Baidaliuk A, Munier S, Donati F, Vallet T, Tran QD, Hardy A, Chazal M, Porrot F, OhAinle M, Carlson-Stevermer J, Oki J, Holden K, Zimmer G, Simon-Lorière E, Bruel T, Schwartz O, van der Werf S, Jouvenet N, Nisole S, Vignuzzi M, and Roesch F
- Subjects
- CRISPR-Cas Systems, Co-Repressor Proteins genetics, Co-Repressor Proteins metabolism, Humans, Interferons metabolism, Molecular Chaperones genetics, Molecular Chaperones metabolism, Proteasome Endopeptidase Complex metabolism, COVID-19, SARS-CoV-2
- Abstract
Interferon restricts SARS-CoV-2 replication in cell culture, but only a handful of Interferon Stimulated Genes with antiviral activity against SARS-CoV-2 have been identified. Here, we describe a functional CRISPR/Cas9 screen aiming at identifying SARS-CoV-2 restriction factors. We identify DAXX, a scaffold protein residing in PML nuclear bodies known to limit the replication of DNA viruses and retroviruses, as a potent inhibitor of SARS-CoV-2 and SARS-CoV replication in human cells. Basal expression of DAXX is sufficient to limit the replication of SARS-CoV-2, and DAXX over-expression further restricts infection. DAXX restricts an early, post-entry step of the SARS-CoV-2 life cycle. DAXX-mediated restriction of SARS-CoV-2 is independent of the SUMOylation pathway but dependent on its D/E domain, also necessary for its protein-folding activity. SARS-CoV-2 infection triggers the re-localization of DAXX to cytoplasmic sites and promotes its degradation. Mechanistically, this process is mediated by the viral papain-like protease (PLpro) and the proteasome. Together, these results demonstrate that DAXX restricts SARS-CoV-2, which in turn has evolved a mechanism to counteract its action., (© 2022. The Author(s).)
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- 2022
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26. Fusogenicity and neutralization sensitivity of the SARS-CoV-2 Delta sublineage AY.4.2.
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Saunders N, Planas D, Bolland WH, Rodriguez C, Fourati S, Buchrieser J, Planchais C, Prot M, Staropoli I, Guivel-Benhassine F, Porrot F, Veyer D, Péré H, Robillard N, Saliba M, Baidaliuk A, Seve A, Hocqueloux L, Prazuck T, Rey FA, Mouquet H, Simon-Lorière E, Bruel T, Pawlotsky JM, and Schwartz O
- Subjects
- Antibodies, Monoclonal, Humanized, Antibodies, Viral, Humans, Spike Glycoprotein, Coronavirus genetics, Viral Envelope Proteins, COVID-19, SARS-CoV-2 genetics
- Abstract
Background: SARS-CoV-2 lineages are continuously evolving. As of December 2021, the AY.4.2 Delta sub-lineage represented 20 % of sequenced strains in the UK and had been detected in dozens of countries. It has since then been supplanted by Omicron. The AY.4.2 spike displays three additional mutations (T95I, Y145H and A222V) in the N-terminal domain when compared to the original Delta variant (B.1.617.2) and remains poorly characterized., Methods: We compared the Delta and the AY.4.2 spikes, by assessing their binding to antibodies and ACE2 and their fusogenicity. We studied the sensitivity of an authentic AY.4.2 viral isolate to neutralizing antibodies., Findings: The AY.4.2 spike exhibited similar binding to all the antibodies and sera tested, and similar fusogenicity and binding to ACE2 than the ancestral Delta spike. The AY.4.2 virus was slightly less sensitive than Delta to neutralization by a panel of monoclonal antibodies; noticeably, the anti-RBD Imdevimab showed incomplete neutralization. Sensitivity of AY.4.2 to sera from vaccinated individuals was reduced by 1.3 to 3-fold, when compared to Delta., Interpretation: Our results suggest that mutations in the NTD remotely impair the efficacy of anti-RBD antibodies. The spread of AY.4.2 was not due to major changes in spike fusogenicity or ACE2 binding, but more likely to a partially reduced neutralization sensitivity., Funding: The work was funded by Institut Pasteur, Fondation pour la Recherche Médicale, Urgence COVID-19 Fundraising Campaign of Institut Pasteur, ANRS, the Vaccine Research Institute, Labex IBEID, ANR/FRM Flash Covid PROTEO-SARS-CoV-2 and IDISCOVR., Competing Interests: Declaration of interests C.P., H.M., O.S, T.B., F.R. have a pending patent application for an anti-RBD mAb not used in the present study (PCT/FR2021/070522)., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)
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- 2022
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27. Considerable escape of SARS-CoV-2 Omicron to antibody neutralization.
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Planas D, Saunders N, Maes P, Guivel-Benhassine F, Planchais C, Buchrieser J, Bolland WH, Porrot F, Staropoli I, Lemoine F, Péré H, Veyer D, Puech J, Rodary J, Baele G, Dellicour S, Raymenants J, Gorissen S, Geenen C, Vanmechelen B, Wawina-Bokalanga T, Martí-Carreras J, Cuypers L, Sève A, Hocqueloux L, Prazuck T, Rey FA, Simon-Loriere E, Bruel T, Mouquet H, André E, and Schwartz O
- Subjects
- Adult, Antibodies, Monoclonal immunology, BNT162 Vaccine administration & dosage, BNT162 Vaccine immunology, Belgium, COVID-19 immunology, COVID-19 transmission, ChAdOx1 nCoV-19 administration & dosage, ChAdOx1 nCoV-19 immunology, Convalescence, Female, Humans, Male, Mutation, Neutralization Tests, Phylogeny, SARS-CoV-2 classification, SARS-CoV-2 genetics, SARS-CoV-2 isolation & purification, Travel, Antibodies, Neutralizing immunology, Antibodies, Viral immunology, COVID-19 virology, Immune Evasion immunology, Immunization, Secondary, SARS-CoV-2 immunology
- Abstract
The SARS-CoV-2 Omicron variant was first identified in November 2021 in Botswana and South Africa
1-3 . It has since spread to many countries and is expected to rapidly become dominant worldwide. The lineage is characterized by the presence of around 32 mutations in spike-located mostly in the N-terminal domain and the receptor-binding domain-that may enhance viral fitness and enable antibody evasion. Here we isolated an infectious Omicron virus in Belgium from a traveller returning from Egypt. We examined its sensitivity to nine monoclonal antibodies that have been clinically approved or are in development4 , and to antibodies present in 115 serum samples from COVID-19 vaccine recipients or individuals who have recovered from COVID-19. Omicron was completely or partially resistant to neutralization by all monoclonal antibodies tested. Sera from recipients of the Pfizer or AstraZeneca vaccine, sampled five months after complete vaccination, barely inhibited Omicron. Sera from COVID-19-convalescent patients collected 6 or 12 months after symptoms displayed low or no neutralizing activity against Omicron. Administration of a booster Pfizer dose as well as vaccination of previously infected individuals generated an anti-Omicron neutralizing response, with titres 6-fold to 23-fold lower against Omicron compared with those against Delta. Thus, Omicron escapes most therapeutic monoclonal antibodies and, to a large extent, vaccine-elicited antibodies. However, Omicron is neutralized by antibodies generated by a booster vaccine dose., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2022
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28. SARS-CoV-2 Alpha, Beta, and Delta variants display enhanced Spike-mediated syncytia formation.
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Rajah MM, Hubert M, Bishop E, Saunders N, Robinot R, Grzelak L, Planas D, Dufloo J, Gellenoncourt S, Bongers A, Zivaljic M, Planchais C, Guivel-Benhassine F, Porrot F, Mouquet H, Chakrabarti LA, Buchrieser J, and Schwartz O
- Subjects
- Animals, Caco-2 Cells, Cell Line, Chlorocebus aethiops, Giant Cells drug effects, Giant Cells metabolism, HEK293 Cells, Humans, SARS-CoV-2 drug effects, SARS-CoV-2 genetics, Vero Cells, Virus Replication drug effects, Angiotensin-Converting Enzyme 2 metabolism, Antibodies, Monoclonal pharmacology, Giant Cells virology, Mutation, SARS-CoV-2 physiology, Spike Glycoprotein, Coronavirus genetics
- Abstract
Severe COVID-19 is characterized by lung abnormalities, including the presence of syncytial pneumocytes. Syncytia form when SARS-CoV-2 spike protein expressed on the surface of infected cells interacts with the ACE2 receptor on neighboring cells. The syncytia forming potential of spike variant proteins remain poorly characterized. Here, we first assessed Alpha (B.1.1.7) and Beta (B.1.351) spread and fusion in cell cultures, compared with the ancestral D614G strain. Alpha and Beta replicated similarly to D614G strain in Vero, Caco-2, Calu-3, and primary airway cells. However, Alpha and Beta formed larger and more numerous syncytia. Variant spike proteins displayed higher ACE2 affinity compared with D614G. Alpha, Beta, and D614G fusion was similarly inhibited by interferon-induced transmembrane proteins (IFITMs). Individual mutations present in Alpha and Beta spikes modified fusogenicity, binding to ACE2 or recognition by monoclonal antibodies. We further show that Delta spike also triggers faster fusion relative to D614G. Thus, SARS-CoV-2 emerging variants display enhanced syncytia formation., (© 2021 The Authors.)
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- 2021
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29. Release of infectious virus and cytokines in nasopharyngeal swabs from individuals infected with non-alpha or alpha SARS-CoV-2 variants: an observational retrospective study.
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Monel B, Planas D, Grzelak L, Smith N, Robillard N, Staropoli I, Goncalves P, Porrot F, Guivel-Benhassine F, Guinet ND, Rodary J, Puech J, Euzen V, Bélec L, Orvoen G, Nunes L, Moulin V, Fourgeaud J, Wack M, Imbeaud S, Campagne P, Duffy D, Santo JPD, Bruel T, Péré H, Veyer D, and Schwartz O
- Subjects
- Adult, Aged, Antibodies, Viral metabolism, COVID-19 pathology, COVID-19 virology, Female, Humans, Immunoglobulin A metabolism, Immunoglobulin G metabolism, Male, Middle Aged, Retrospective Studies, Cytokines metabolism, Nasopharynx virology, SARS-CoV-2 isolation & purification
- Abstract
Background: The dynamics of SARS-CoV-2 alpha variant shedding and immune responses at the nasal mucosa remain poorly characterised., Methods: We measured infectious viral release, antibodies and cytokines in 426 PCR+ nasopharyngeal swabs from individuals harboring non-alpha or alpha variants., Findings: With both lineages, viral titers were variable, ranging from 0 to >10
6 infectious units. Rapid antigenic diagnostic tests were positive in 94% of samples with infectious virus. 68 % of individuals carried infectious virus within two days after onset of symptoms. This proportion decreased overtime. Viable virus was detected up to 14 days. Samples containing anti-spike IgG or IgA did not generally harbor infectious virus. Ct values were slightly but not significantly lower with alpha. This variant was characterized by a fast decrease of infectivity overtime and a marked release of 13 cytokines (including IFN-b, IP-10 and IL-10)., Interpretation: The alpha variant displays modified viral decay and cytokine profiles at the nasopharyngeal mucosae during symptomatic infection., Funding: This retrospective study has been funded by Institut Pasteur, ANRS, Vaccine Research Institute, Labex IBEID, ANR/FRM and IDISCOVR, Fondation pour la Recherche Médicale., Competing Interests: Declaration of Competing Interest L.G., I.S., T.B., F.G.-B., and O.S. have a patent US 63/020,063 entitled “S-Flow: a FACS-based assay for serological analysis of SARS-CoV2 infection” pending. The other authors have no conflict of interests to disclose., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)- Published
- 2021
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30. Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization.
- Author
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Planas D, Veyer D, Baidaliuk A, Staropoli I, Guivel-Benhassine F, Rajah MM, Planchais C, Porrot F, Robillard N, Puech J, Prot M, Gallais F, Gantner P, Velay A, Le Guen J, Kassis-Chikhani N, Edriss D, Belec L, Seve A, Courtellemont L, Péré H, Hocqueloux L, Fafi-Kremer S, Prazuck T, Mouquet H, Bruel T, Simon-Lorière E, Rey FA, and Schwartz O
- Subjects
- Antibodies, Monoclonal, Humanized immunology, Antibodies, Neutralizing blood, Antibodies, Viral blood, COVID-19 epidemiology, COVID-19 Vaccines administration & dosage, Epitopes chemistry, Epitopes genetics, Epitopes immunology, France, Humans, India epidemiology, Male, Middle Aged, Neutralization Tests, Spike Glycoprotein, Coronavirus chemistry, Spike Glycoprotein, Coronavirus genetics, Antibodies, Neutralizing immunology, Antibodies, Viral immunology, COVID-19 immunology, COVID-19 virology, COVID-19 Vaccines immunology, Convalescence, Immune Evasion immunology, Spike Glycoprotein, Coronavirus immunology
- Abstract
The SARS-CoV-2 B.1.617 lineage was identified in October 2020 in India
1-5 . Since then, it has become dominant in some regions of India and in the UK, and has spread to many other countries6 . The lineage includes three main subtypes (B1.617.1, B.1.617.2 and B.1.617.3), which contain diverse mutations in the N-terminal domain (NTD) and the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein that may increase the immune evasion potential of these variants. B.1.617.2-also termed the Delta variant-is believed to spread faster than other variants. Here we isolated an infectious strain of the Delta variant from an individual with COVID-19 who had returned to France from India. We examined the sensitivity of this strain to monoclonal antibodies and to antibodies present in sera from individuals who had recovered from COVID-19 (hereafter referred to as convalescent individuals) or who had received a COVID-19 vaccine, and then compared this strain with other strains of SARS-CoV-2. The Delta variant was resistant to neutralization by some anti-NTD and anti-RBD monoclonal antibodies, including bamlanivimab, and these antibodies showed impaired binding to the spike protein. Sera collected from convalescent individuals up to 12 months after the onset of symptoms were fourfold less potent against the Delta variant relative to the Alpha variant (B.1.1.7). Sera from individuals who had received one dose of the Pfizer or the AstraZeneca vaccine had a barely discernible inhibitory effect on the Delta variant. Administration of two doses of the vaccine generated a neutralizing response in 95% of individuals, with titres three- to fivefold lower against the Delta variant than against the Alpha variant. Thus, the spread of the Delta variant is associated with an escape from antibodies that target non-RBD and RBD epitopes of the spike protein., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2021
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31. Sensitivity of infectious SARS-CoV-2 B.1.1.7 and B.1.351 variants to neutralizing antibodies.
- Author
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Planas D, Bruel T, Grzelak L, Guivel-Benhassine F, Staropoli I, Porrot F, Planchais C, Buchrieser J, Rajah MM, Bishop E, Albert M, Donati F, Prot M, Behillil S, Enouf V, Maquart M, Smati-Lafarge M, Varon E, Schortgen F, Yahyaoui L, Gonzalez M, De Sèze J, Péré H, Veyer D, Sève A, Simon-Lorière E, Fafi-Kremer S, Stefic K, Mouquet H, Hocqueloux L, van der Werf S, Prazuck T, and Schwartz O
- Subjects
- COVID-19 Vaccines immunology, Convalescence, Cross Reactions, Humans, Neutralization Tests, Sensitivity and Specificity, Vaccination, Antibodies, Neutralizing immunology, Antibodies, Viral immunology, COVID-19 immunology, SARS-CoV-2 immunology
- Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.7 and B.1.351 variants were first identified in the United Kingdom and South Africa, respectively, and have since spread to many countries. These variants harboring diverse mutations in the gene encoding the spike protein raise important concerns about their immune evasion potential. Here, we isolated infectious B.1.1.7 and B.1.351 strains from acutely infected individuals. We examined sensitivity of the two variants to SARS-CoV-2 antibodies present in sera and nasal swabs from individuals infected with previously circulating strains or who were recently vaccinated, in comparison with a D614G reference virus. We utilized a new rapid neutralization assay, based on reporter cells that become positive for GFP after overnight infection. Sera from 58 convalescent individuals collected up to 9 months after symptoms, similarly neutralized B.1.1.7 and D614G. In contrast, after 9 months, convalescent sera had a mean sixfold reduction in neutralizing titers, and 40% of the samples lacked any activity against B.1.351. Sera from 19 individuals vaccinated twice with Pfizer Cominarty, longitudinally tested up to 6 weeks after vaccination, were similarly potent against B.1.1.7 but less efficacious against B.1.351, when compared to D614G. Neutralizing titers increased after the second vaccine dose, but remained 14-fold lower against B.1.351. In contrast, sera from convalescent or vaccinated individuals similarly bound the three spike proteins in a flow cytometry-based serological assay. Neutralizing antibodies were rarely detected in nasal swabs from vaccinees. Thus, faster-spreading SARS-CoV-2 variants acquired a partial resistance to neutralizing antibodies generated by natural infection or vaccination, which was most frequently detected in individuals with low antibody levels. Our results indicate that B1.351, but not B.1.1.7, may increase the risk of infection in immunized individuals.
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- 2021
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32. Syncytia formation by SARS-CoV-2-infected cells.
- Author
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Buchrieser J, Dufloo J, Hubert M, Monel B, Planas D, Rajah MM, Planchais C, Porrot F, Guivel-Benhassine F, Van der Werf S, Casartelli N, Mouquet H, Bruel T, and Schwartz O
- Published
- 2021
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33. Syncytia formation by SARS-CoV-2-infected cells.
- Author
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Buchrieser J, Dufloo J, Hubert M, Monel B, Planas D, Rajah MM, Planchais C, Porrot F, Guivel-Benhassine F, Van der Werf S, Casartelli N, Mouquet H, Bruel T, and Schwartz O
- Subjects
- Angiotensin-Converting Enzyme 2 genetics, Angiotensin-Converting Enzyme 2 metabolism, Animals, Antigens, Differentiation genetics, Antigens, Differentiation metabolism, COVID-19 metabolism, COVID-19 virology, Cell Fusion, Cell Line, Chlorocebus aethiops, Giant Cells metabolism, HEK293 Cells, Humans, Membrane Proteins genetics, Membrane Proteins metabolism, RNA-Binding Proteins genetics, RNA-Binding Proteins metabolism, Serine Endopeptidases genetics, Serine Endopeptidases metabolism, Spike Glycoprotein, Coronavirus metabolism, Vero Cells virology, COVID-19 pathology, Giant Cells virology, Host-Pathogen Interactions, SARS-CoV-2
- Abstract
Severe cases of COVID-19 are associated with extensive lung damage and the presence of infected multinucleated syncytial pneumocytes. The viral and cellular mechanisms regulating the formation of these syncytia are not well understood. Here, we show that SARS-CoV-2-infected cells express the Spike protein (S) at their surface and fuse with ACE2-positive neighboring cells. Expression of S without any other viral proteins triggers syncytia formation. Interferon-induced transmembrane proteins (IFITMs), a family of restriction factors that block the entry of many viruses, inhibit S-mediated fusion, with IFITM1 being more active than IFITM2 and IFITM3. On the contrary, the TMPRSS2 serine protease, which is known to enhance infectivity of cell-free virions, processes both S and ACE2 and increases syncytia formation by accelerating the fusion process. TMPRSS2 thwarts the antiviral effect of IFITMs. Our results show that SARS-CoV-2 pathological effects are modulated by cellular proteins that either inhibit or facilitate syncytia formation., (© 2020 The Authors.)
- Published
- 2020
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34. Antibody Neutralization of HIV-1 Crossing the Blood-Brain Barrier.
- Author
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Lorin V, Danckaert A, Porrot F, Schwartz O, Afonso PV, and Mouquet H
- Subjects
- Cell Line, Endothelial Cells virology, HIV Infections virology, HIV-1 immunology, Humans, Transcytosis, Virion immunology, Antibodies, Neutralizing immunology, Blood-Brain Barrier immunology, Blood-Brain Barrier virology, HIV Antibodies immunology, HIV Infections immunology
- Abstract
HIV-1 can cross the blood-brain barrier (BBB) to penetrate the brain and infect target cells, causing neurocognitive disorders as a result of neuroinflammation and brain damage. Here, we examined whether antibodies targeting the HIV-1 envelope glycoproteins interfere with the transcytosis of virions across the human BBB endothelium. We found that although the viral envelope spike gp160 is required for optimal endothelial cell endocytosis, no anti-gp160 antibodies blocked the BBB transcytosis of HIV-1 in vitro Instead, both free viruses and those in complex with antibodies transited across endothelial cells in the BBB model, as observed by confocal microscopy. HIV-1 infectious capacity was considerably altered by the transcytosis process but still detectable, even in the presence of nonneutralizing antibodies. Only virions bound by neutralizing antibodies lacked posttranscytosis infectivity. Overall, our data support the role of neutralizing antibodies in protecting susceptible brain cells from HIV-1 infection despite their inability to inhibit viral BBB endocytic transport. IMPORTANCE HIV-1 can cross the blood-brain barrier (BBB) to penetrate the brain and infect target cells, causing neurocognitive disorders as a result of neuroinflammation and brain damage. The HIV-1 envelope spike gp160 is partially required for viral transcytosis across the BBB endothelium. But do antibodies developing in infected individuals and targeting the HIV-1 gp160 glycoproteins block HIV-1 transcytosis through the BBB? We addressed this issue and discovered that anti-gp160 antibodies do not block HIV-1 transport; instead, free viruses and those in complex with antibodies can transit across BBB endothelial cells. Importantly, we found that only neutralizing antibodies could inhibit posttranscytosis viral infectivity, highlighting their ability to protect susceptible brain cells from HIV-1 infection., (Copyright © 2020 Lorin et al.)
- Published
- 2020
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35. A comparison of four serological assays for detecting anti-SARS-CoV-2 antibodies in human serum samples from different populations.
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Grzelak L, Temmam S, Planchais C, Demeret C, Tondeur L, Huon C, Guivel-Benhassine F, Staropoli I, Chazal M, Dufloo J, Planas D, Buchrieser J, Rajah MM, Robinot R, Porrot F, Albert M, Chen KY, Crescenzo-Chaigne B, Donati F, Anna F, Souque P, Gransagne M, Bellalou J, Nowakowski M, Backovic M, Bouadma L, Le Fevre L, Le Hingrat Q, Descamps D, Pourbaix A, Laouénan C, Ghosn J, Yazdanpanah Y, Besombes C, Jolly N, Pellerin-Fernandes S, Cheny O, Ungeheuer MN, Mellon G, Morel P, Rolland S, Rey FA, Behillil S, Enouf V, Lemaitre A, Créach MA, Petres S, Escriou N, Charneau P, Fontanet A, Hoen B, Bruel T, Eloit M, Mouquet H, Schwartz O, and van der Werf S
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, COVID-19, COVID-19 Testing, Cohort Studies, Coronavirus Infections epidemiology, Coronavirus Infections immunology, Enzyme-Linked Immunosorbent Assay methods, Female, Flow Cytometry methods, France epidemiology, Healthy Volunteers, Humans, Immunoprecipitation methods, Luciferases, Male, Middle Aged, Neutralization Tests, Pandemics, Pneumonia, Viral epidemiology, Pneumonia, Viral immunology, SARS-CoV-2, Seroepidemiologic Studies, Spike Glycoprotein, Coronavirus immunology, Translational Research, Biomedical, Young Adult, Antibodies, Viral blood, Betacoronavirus immunology, Clinical Laboratory Techniques methods, Coronavirus Infections diagnosis, Pneumonia, Viral diagnosis, Serologic Tests methods
- Abstract
It is of paramount importance to evaluate the prevalence of both asymptomatic and symptomatic cases of SARS-CoV-2 infection and their differing antibody response profiles. Here, we performed a pilot study of four serological assays to assess the amounts of anti-SARS-CoV-2 antibodies in serum samples obtained from 491 healthy individuals before the SARS-CoV-2 pandemic, 51 individuals hospitalized with COVID-19, 209 suspected cases of COVID-19 with mild symptoms, and 200 healthy blood donors. We used two ELISA assays that recognized the full-length nucleoprotein (N) or trimeric spike (S) protein ectodomain of SARS-CoV-2. In addition, we developed the S-Flow assay that recognized the S protein expressed at the cell surface using flow cytometry, and the luciferase immunoprecipitation system (LIPS) assay that recognized diverse SARS-CoV-2 antigens including the S1 domain and the carboxyl-terminal domain of N by immunoprecipitation. We obtained similar results with the four serological assays. Differences in sensitivity were attributed to the technique and the antigen used. High anti-SARS-CoV-2 antibody titers were associated with neutralization activity, which was assessed using infectious SARS-CoV-2 or lentiviral-S pseudotype virus. In hospitalized patients with COVID-19, seroconversion and virus neutralization occurred between 5 and 14 days after symptom onset, confirming previous studies. Seropositivity was detected in 32% of mildly symptomatic individuals within 15 days of symptom onset and in 3% of healthy blood donors. The four antibody assays that we used enabled a broad evaluation of SARS-CoV-2 seroprevalence and antibody profiling in different subpopulations within one region., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2020
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36. Atlastin Endoplasmic Reticulum-Shaping Proteins Facilitate Zika Virus Replication.
- Author
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Monel B, Rajah MM, Hafirassou ML, Sid Ahmed S, Burlaud-Gaillard J, Zhu PP, Nevers Q, Buchrieser J, Porrot F, Meunier C, Amraoui S, Chazal M, Salles A, Jouvenet N, Roingeard P, Blackstone C, Amara A, and Schwartz O
- Subjects
- Antiviral Agents pharmacology, Cytopathogenic Effect, Viral, GTP Phosphohydrolases genetics, GTP-Binding Proteins, Gene Knockout Techniques, HeLa Cells, Humans, Membrane Proteins, Viral Nonstructural Proteins genetics, Viral Nonstructural Proteins metabolism, Virus Release, Zika Virus drug effects, Endoplasmic Reticulum metabolism, GTP Phosphohydrolases metabolism, Virus Replication physiology, Zika Virus physiology, Zika Virus Infection metabolism, Zika Virus Infection virology
- Abstract
The endoplasmic reticulum (ER) is the site for Zika virus (ZIKV) replication and is central to the cytopathic effects observed in infected cells. ZIKV induces the formation of ER-derived large cytoplasmic vacuoles followed by "implosive" cell death. Little is known about the nature of the ER factors that regulate flavivirus replication. Atlastins (ATL1, -2, and -3) are dynamin-related GTPases that control the structure and the dynamics of the ER membrane. We show here that ZIKV replication is significantly decreased in the absence of ATL proteins. The appearance of infected cells is delayed, the levels of intracellular viral proteins and released virus are reduced, and the cytopathic effects are strongly impaired. We further show that ATL3 is recruited to viral replication sites and interacts with the nonstructural viral proteins NS2A and NS2B3. Thus, proteins that shape and maintain the ER tubular network ensure efficient ZIKV replication. IMPORTANCE Zika virus (ZIKV) is an emerging virus associated with Guillain-Barré syndrome, and fetal microcephaly as well as other neurological complications. There is no vaccine or specific antiviral treatment against ZIKV. We found that endoplasmic reticulum (ER)-shaping atlastin proteins (ATL1, -2, and -3), which induce ER membrane fusion, facilitate ZIKV replication. We show that ATL3 is recruited to the viral replication site and colocalize with the viral proteins NS2A and NS2B3. The results provide insights into host factors used by ZIKV to enhance its replication., (Copyright © 2019 American Society for Microbiology.)
- Published
- 2019
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37. IFITM proteins inhibit placental syncytiotrophoblast formation and promote fetal demise.
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Buchrieser J, Degrelle SA, Couderc T, Nevers Q, Disson O, Manet C, Donahue DA, Porrot F, Hillion KH, Perthame E, Arroyo MV, Souquere S, Ruigrok K, Dupressoir A, Heidmann T, Montagutelli X, Fournier T, Lecuit M, and Schwartz O
- Subjects
- Animals, Female, Fetal Resorption immunology, Gene Products, env immunology, Humans, Mice, Poly I-C pharmacology, Pregnancy, Pregnancy Proteins immunology, Trophoblasts drug effects, Antigens, Differentiation immunology, Apoptosis Regulatory Proteins immunology, Cell Fusion, Fetal Death etiology, Interferon Type I immunology, Intracellular Signaling Peptides and Proteins immunology, RNA-Binding Proteins immunology, Trophoblasts immunology
- Abstract
Elevated levels of type I interferon (IFN) during pregnancy are associated with intrauterine growth retardation, preterm birth, and fetal demise through mechanisms that are not well understood. A critical step of placental development is the fusion of trophoblast cells into a multinucleated syncytiotrophoblast (ST) layer. Fusion is mediated by syncytins, proteins deriving from ancestral endogenous retroviral envelopes. Using cultures of human trophoblasts or mouse cells, we show that IFN-induced transmembrane proteins (IFITMs), a family of restriction factors blocking the entry step of many viruses, impair ST formation and inhibit syncytin-mediated fusion. Moreover, the IFN inducer polyinosinic:polycytidylic acid promotes fetal resorption and placental abnormalities in wild-type but not in Ifitm- deleted mice. Thus, excessive levels of IFITMs may mediate the pregnancy complications observed during congenital infections and other IFN-induced pathologies., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2019
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38. HIV Fusion in Dendritic Cells Occurs Mainly at the Surface and Is Limited by Low CD4 Levels.
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Chauveau L, Donahue DA, Monel B, Porrot F, Bruel T, Richard L, Casartelli N, and Schwartz O
- Subjects
- Cells, Cultured, Dendritic Cells metabolism, HIV Infections metabolism, Humans, Toll-Like Receptor 7 metabolism, CD4 Antigens metabolism, Cell Fusion, Dendritic Cells virology, HIV Infections virology, HIV-1 physiology, Receptors, HIV metabolism, Virus Replication
- Abstract
HIV-1 poorly infects monocyte-derived dendritic cells (MDDCs). This is in large part due to SAMHD1, which restricts viral reverse transcription. Pseudotyping HIV-1 with vesicular stomatitis virus G protein (VSV-G) strongly enhances infection, suggesting that earlier steps of viral replication, including fusion, are also inefficient in MDDCs. The site of HIV-1 fusion remains controversial and may depend on the cell type, with reports indicating that it occurs at the plasma membrane or, conversely, in an endocytic compartment. Here, we examined the pathways of HIV-1 entry in MDDCs. Using a combination of temperature shift and fusion inhibitors, we show that HIV-1 fusion mainly occurs at the cell surface. We then asked whether surface levels or intracellular localization of CD4 modulates HIV-1 entry. Increasing CD4 levels strongly enhanced fusion and infection with various HIV-1 isolates, including reference and transmitted/founder strains, but not with BaL, which uses low CD4 levels for entry. Overexpressing coreceptors did not facilitate viral infection. To further study the localization of fusion events, we generated CD4 mutants carrying heterologous cytoplasmic tails (LAMP1 or Toll-like receptor 7 [TLR7]) to redirect the molecule to intracellular compartments. The intracellular CD4 mutants did not facilitate HIV-1 fusion and replication in MDDCs. Fusion of an HIV-2 isolate with MDDCs was also enhanced by increasing surface CD4 levels. Our results demonstrate that MDDCs are inefficiently infected by various HIV-1 and HIV-2 strains, in part because of low CD4 levels. In these cells, viral fusion occurs mainly at the surface, and probably not after internalization. IMPORTANCE Dendritic cells (DCs) are professional antigen-presenting cells inducing innate and adaptive immune responses. DCs express the HIV receptor CD4 and are potential target cells for HIV. There is debate about the sensitivity of DCs to productive HIV-1 and HIV-2 infection. The fusion step of the viral replication cycle is inefficient in DCs, and the underlying mechanisms are poorly characterized. We show that increasing the levels of CD4 at the plasma membrane allows more HIV fusion and productive infection in DCs. We further demonstrate that HIV fusion occurs mainly at the cell surface and not in an intracellular compartment. Our results help us understand why DCs are poorly sensitive to HIV infection., (Copyright © 2017 American Society for Microbiology.)
- Published
- 2017
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39. Zika virus induces massive cytoplasmic vacuolization and paraptosis-like death in infected cells.
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Monel B, Compton AA, Bruel T, Amraoui S, Burlaud-Gaillard J, Roy N, Guivel-Benhassine F, Porrot F, Génin P, Meertens L, Sinigaglia L, Jouvenet N, Weil R, Casartelli N, Demangel C, Simon-Lorière E, Moris A, Roingeard P, Amara A, and Schwartz O
- Subjects
- Astrocytes cytology, Astrocytes physiology, Cells, Cultured, Endoplasmic Reticulum metabolism, Epithelial Cells cytology, Epithelial Cells physiology, Fibroblasts cytology, Fibroblasts physiology, Humans, Membrane Proteins metabolism, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-akt metabolism, RNA-Binding Proteins metabolism, SEC Translocation Channels metabolism, Signal Transduction, Astrocytes virology, Cell Death, Cytopathogenic Effect, Viral, Epithelial Cells virology, Fibroblasts virology, Vacuoles metabolism, Zika Virus pathogenicity
- Abstract
The cytopathic effects of Zika virus (ZIKV) are poorly characterized. Innate immunity controls ZIKV infection and disease in most infected patients through mechanisms that remain to be understood. Here, we studied the morphological cellular changes induced by ZIKV and addressed the role of interferon-induced transmembrane proteins (IFITM), a family of broad-spectrum antiviral factors, during viral replication. We report that ZIKV induces massive vacuolization followed by "implosive" cell death in human epithelial cells, primary skin fibroblasts and astrocytes, a phenomenon which is exacerbated when IFITM3 levels are low. It is reminiscent of paraptosis, a caspase-independent, non-apoptotic form of cell death associated with the formation of large cytoplasmic vacuoles. We further show that ZIKV-induced vacuoles are derived from the endoplasmic reticulum (ER) and dependent on the PI3K/Akt signaling axis. Inhibiting the Sec61 ER translocon in ZIKV-infected cells blocked vacuole formation and viral production. Our results provide mechanistic insight behind the ZIKV-induced cytopathic effect and indicate that IFITM3, by acting as a gatekeeper for incoming virus, restricts virus takeover of the ER and subsequent cell death., (© 2017 Institut Pasteur.)
- Published
- 2017
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40. SUN2 Silencing Impairs CD4 T Cell Proliferation and Alters Sensitivity to HIV-1 Infection Independently of Cyclophilin A.
- Author
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Donahue DA, Porrot F, Couespel N, and Schwartz O
- Subjects
- Cells, Cultured, Gene Silencing, Humans, Intracellular Signaling Peptides and Proteins genetics, Membrane Proteins genetics, CD4-Positive T-Lymphocytes physiology, CD4-Positive T-Lymphocytes virology, Cell Proliferation, Cyclophilin A metabolism, HIV-1 growth & development, Intracellular Signaling Peptides and Proteins metabolism, Membrane Proteins metabolism
- Abstract
Linker of nucleoskeleton and cytoskeleton (LINC) complexes connect the nucleus to the cytoskeleton in eukaryotic cells. We previously reported that the overexpression of SUN2, an inner nuclear membrane protein and LINC complex component, inhibits HIV infection between the steps of reverse transcription and nuclear import in a capsid-specific manner. We also reported that SUN2 silencing does not modulate HIV infection in several cell lines. Silencing of SUN2 was recently reported to decrease HIV infection of CD4 T cells, an effect which was suggested to result from modulation of cyclophilin A (CypA)-dependent steps of HIV infection. We confirm here that HIV infection of primary CD4 T cells is compromised in the absence of endogenous SUN2, and we extend these findings to additional viral strains. However, we find that CypA is not required for the decreased infection observed in SUN2-silenced cells and, conversely, that endogenous SUN2 is not required for the well-documented positive modulation of HIV infection by CypA. In contrast, CD4 T cells lacking SUN2 exhibit a considerable defect in proliferative capacity and display reduced levels of activation markers and decreased viability. Additionally, SUN2-silenced CD4 T cells that become infected support reduced levels of viral protein expression. Our results demonstrate that SUN2 is required for the optimal activation and proliferation of primary CD4 T cells and suggest that the disruption of these processes explains the contribution of endogenous SUN2 to HIV infection in primary lymphocytes. IMPORTANCE Linker of nucleoskeleton and cytoskeleton (LINC) complexes connect the nucleus to the cytoskeleton. We previously reported that the overexpression of the LINC complex protein SUN2 inhibits HIV infection by targeting the viral capsid and blocking infection before the virus enters the nucleus. A recent report showed that the depletion of endogenous SUN2 in primary CD4 T cells results in decreased HIV infection and that this involves cyclophilin A (CypA), a host protein that interacts with the capsid of HIV to promote infection. We confirm that HIV infection is reduced in CD4 T cells lacking SUN2, but we find no role for CypA. Instead, SUN2 silencing results in CD4 T cells with decreased viability and much lower proliferation rates. Our results show that SUN2 is required for optimal CD4 T cell activation and proliferation and explain the reduced level of HIV infection in the absence of SUN2., (Copyright © 2017 American Society for Microbiology.)
- Published
- 2017
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41. Natural mutations in IFITM3 modulate post-translational regulation and toggle antiviral specificity.
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Compton AA, Roy N, Porrot F, Billet A, Casartelli N, Yount JS, Liang C, and Schwartz O
- Subjects
- Animals, Cell Line, Genome, Humans, Interferon Inducers immunology, Mutation, Protein Transport physiology, Ubiquitination genetics, Viruses immunology, Evolution, Molecular, Host-Pathogen Interactions, Immunity, Innate, Membrane Proteins genetics, Primates genetics, RNA-Binding Proteins genetics
- Abstract
The interferon-induced transmembrane (IFITM) proteins protect host cells from diverse virus infections. IFITM proteins also incorporate into HIV-1 virions and inhibit virus fusion and cell-to-cell spread, with IFITM3 showing the greatest potency. Here, we report that amino-terminal mutants of IFITM3 preventing ubiquitination and endocytosis are more abundantly incorporated into virions and exhibit enhanced inhibition of HIV-1 fusion. An analysis of primate genomes revealed that IFITM3 is the most ancient antiviral family member of the IFITM locus and has undergone a repeated duplication in independent host lineages. Some IFITM3 genes in nonhuman primates, including those that arose following gene duplication, carry amino-terminal mutations that modify protein localization and function. This suggests that "runaway" IFITM3 variants could be selected for altered antiviral activity. Furthermore, we show that adaptations in IFITM3 result in a trade-off in antiviral specificity, as variants exhibiting enhanced activity against HIV-1 poorly restrict influenza A virus. Overall, we provide the first experimental evidence that diversification of IFITM3 genes may boost the antiviral coverage of host cells and provide selective functional advantages., (© 2016 The Authors.)
- Published
- 2016
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42. CD4-mimetic sulfopeptide conjugates display sub-nanomolar anti-HIV-1 activity and protect macaques against a SHIV162P3 vaginal challenge.
- Author
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Ariën KK, Baleux F, Desjardins D, Porrot F, Coïc YM, Michiels J, Bouchemal K, Bonnaffé D, Bruel T, Schwartz O, Le Grand R, Vanham G, Dereuddre-Bosquet N, and Lortat-Jacob H
- Subjects
- Administration, Intravaginal, Animals, Anti-HIV Agents administration & dosage, Anti-HIV Agents chemistry, CD4-Positive T-Lymphocytes virology, Drug Stability, Female, Gels administration & dosage, HIV Infections prevention & control, HIV Infections transmission, HIV-1 pathogenicity, Heparitin Sulfate chemistry, Humans, Macaca fascicularis, Molecular Mimicry, Peptides pharmacokinetics, Simian Immunodeficiency Virus genetics, Simian Immunodeficiency Virus pathogenicity, Vagina virology, Anti-HIV Agents pharmacology, CD4 Antigens chemistry, HIV-1 drug effects, Peptides chemistry, Peptides pharmacology, Simian Acquired Immunodeficiency Syndrome prevention & control
- Abstract
The CD4 and the cryptic coreceptor binding sites of the HIV-1 envelope glycoprotein are key to viral attachment and entry. We developed new molecules comprising a CD4 mimetic peptide linked to anionic compounds (mCD4.1-HS
12 and mCD4.1-PS1), that block the CD4-gp120 interaction and simultaneously induce the exposure of the cryptic coreceptor binding site, rendering it accessible to HS12 - or PS1- mediated inhibition. Using a cynomolgus macaque model of vaginal challenge with SHIV162P3, we report that mCD4.1-PS1, formulated into a hydroxyethyl-cellulose gel provides 83% protection (5/6 animals). We next engineered the mCD4 moiety of the compound, giving rise to mCD4.2 and mCD4.3 that, when conjugated to PS1, inhibited cell-free and cell-associated HIV-1 with particularly low IC50 , in the nM to pM range, including some viral strains that were resistant to the parent molecule mCD4.1. These chemically defined molecules, which target major sites of vulnerability of gp120, are stable for at least 48 hours in conditions replicating the vaginal milieu (37 °C, pH 4.5). They efficiently mimic several large gp120 ligands, including CD4, coreceptor or neutralizing antibodies, to which their efficacy compares very favorably, despite a molecular mass reduced to 5500 Da. Together, these results support the development of such molecules as potential microbicides.- Published
- 2016
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43. SUN2 Overexpression Deforms Nuclear Shape and Inhibits HIV.
- Author
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Donahue DA, Amraoui S, di Nunzio F, Kieffer C, Porrot F, Opp S, Diaz-Griffero F, Casartelli N, and Schwartz O
- Subjects
- Cell Nucleus pathology, HEK293 Cells, HeLa Cells, Humans, Interferons metabolism, Intracellular Signaling Peptides and Proteins biosynthesis, Membrane Proteins biosynthesis, Species Specificity, Virus Replication, HIV Infections virology, HIV-1 physiology, HIV-2 physiology, Intracellular Signaling Peptides and Proteins physiology, Membrane Proteins physiology
- Abstract
Unlabelled: In a previous screen of putative interferon-stimulated genes, SUN2 was shown to inhibit HIV-1 infection in an uncharacterized manner. SUN2 is an inner nuclear membrane protein belonging to the linker of nucleoskeleton and cytoskeleton complex. We have analyzed here the role of SUN2 in HIV infection. We report that in contrast to what was initially thought, SUN2 is not induced by type I interferon, and that SUN2 silencing does not modulate HIV infection. However, SUN2 overexpression in cell lines and in primary monocyte-derived dendritic cells inhibits the replication of HIV but not murine leukemia virus or chikungunya virus. We identified HIV-1 and HIV-2 strains that are unaffected by SUN2, suggesting that the effect is specific to particular viral components or cofactors. Intriguingly, SUN2 overexpression induces a multilobular flower-like nuclear shape that does not impact cell viability and is similar to that of cells isolated from patients with HTLV-I-associated adult T-cell leukemia or with progeria. Nuclear shape changes and HIV inhibition both mapped to the nucleoplasmic domain of SUN2 that interacts with the nuclear lamina. This block to HIV replication occurs between reverse transcription and nuclear entry, and passaging experiments selected for a single-amino-acid change in capsid (CA) that leads to resistance to overexpressed SUN2. Furthermore, using chemical inhibition or silencing of cyclophilin A (CypA), as well as CA mutant viruses, we implicated CypA in the SUN2-imposed block to HIV infection. Our results demonstrate that SUN2 overexpression perturbs both nuclear shape and early events of HIV infection., Importance: Cells encode proteins that interfere with viral replication, a number of which have been identified in overexpression screens. SUN2 is a nuclear membrane protein that was shown to inhibit HIV infection in such a screen, but how it blocked HIV infection was not known. We show that SUN2 overexpression blocks the infection of certain strains of HIV before nuclear entry. Mutation of the viral capsid protein yielded SUN2-resistant HIV. Additionally, the inhibition of HIV infection by SUN2 involves cyclophilin A, a protein that binds the HIV capsid and directs subsequent steps of infection. We also found that SUN2 overexpression substantially changes the shape of the cell's nucleus, resulting in many flower-like nuclei. Both HIV inhibition and deformation of nuclear shape required the domain of SUN2 that interacts with the nuclear lamina. Our results demonstrate that SUN2 interferes with HIV infection and highlight novel links between nuclear shape and viral infection., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)
- Published
- 2016
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44. Vpr Enhances Tumor Necrosis Factor Production by HIV-1-Infected T Cells.
- Author
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Roesch F, Richard L, Rua R, Porrot F, Casartelli N, and Schwartz O
- Subjects
- Cell Line, DNA-Binding Proteins metabolism, Humans, MAP Kinase Kinase Kinases metabolism, NF-kappa B metabolism, T-Lymphocytes immunology, T-Lymphocytes metabolism, Tumor Necrosis Factor-alpha metabolism, Gene Expression Regulation immunology, HIV-1 immunology, T-Lymphocytes virology, Tumor Necrosis Factor-alpha immunology, vpr Gene Products, Human Immunodeficiency Virus immunology
- Abstract
Unlabelled: The HIV-1 accessory protein Vpr displays different activities potentially impacting viral replication, including the arrest of the cell cycle in the G2 phase and the stimulation of apoptosis and DNA damage response pathways. Vpr also modulates cytokine production by infected cells, but this property remains partly characterized. Here, we investigated the effect of Vpr on the production of the proinflammatory cytokine tumor necrosis factor (TNF). We report that Vpr significantly increases TNF secretion by infected lymphocytes. De novo production of Vpr is required for this effect. Vpr mutants known to be defective for G2 cell cycle arrest induce lower levels of TNF secretion, suggesting a link between these two functions. Silencing experiments and the use of chemical inhibitors further implicated the cellular proteins DDB1 and TAK1 in this activity of Vpr. TNF secreted by HIV-1-infected cells triggers NF-κB activity in bystander cells and allows viral reactivation in a model of latently infected cells. Thus, the stimulation of the proinflammatory pathway by Vpr may impact HIV-1 replication in vivo., Importance: The role of the HIV-1 accessory protein Vpr remains only partially characterized. This protein is important for viral pathogenesis in infected individuals but is dispensable for viral replication in most cell culture systems. Some of the functions described for Vpr remain controversial. In particular, it remains unclear whether Vpr promotes or instead prevents proinflammatory and antiviral immune responses. In this report, we show that Vpr promotes the release of TNF, a proinflammatory cytokine associated with rapid disease progression. Using Vpr mutants or inhibiting selected cellular genes, we show that the cellular proteins DDB1 and TAK1 are involved in the release of TNF by HIV-infected cells. This report provides novel insights into how Vpr manipulates TNF production and helps clarify the role of Vpr in innate immune responses and inflammation., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
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45. SAMHD1 Limits HIV-1 Antigen Presentation by Monocyte-Derived Dendritic Cells.
- Author
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Ayinde D, Bruel T, Cardinaud S, Porrot F, Prado JG, Moris A, and Schwartz O
- Subjects
- CD8-Positive T-Lymphocytes immunology, Cells, Cultured, Humans, Monomeric GTP-Binding Proteins, SAM Domain and HD Domain-Containing Protein 1, T-Lymphocytes, Cytotoxic immunology, Antigen Presentation, Dendritic Cells immunology, HIV Antigens immunology, HIV-1 immunology
- Abstract
Unlabelled: Monocyte-derived dendritic cells (MDDC) stimulate CD8 cytotoxic T lymphocytes (CTL) by presenting endogenous and exogenous viral peptides via major histocompatibility complex class I (MHC-I) molecules. MDDC are poorly susceptible to HIV-1, in part due to the presence of SAMHD1, a cellular enzyme that depletes intracellular deoxynucleoside triphosphates (dNTPs) and degrades viral RNA. Vpx, an HIV-2/SIVsm protein absent from HIV-1, antagonizes SAMHD1 by inducing its degradation. The impact of SAMHD1 on the adaptive cellular immune response remains poorly characterized. Here, we asked whether SAMHD1 modulates MHC-I-restricted HIV-1 antigen presentation. Untreated MDDC or MDDC pretreated with Vpx were exposed to HIV-1, and antigen presentation was examined by monitoring the activation of an HIV-1 Gag-specific CTL clone. SAMHD1 depletion strongly enhanced productive infection of MDDC as well as endogenous HIV-1 antigen presentation. Time-lapse microscopy analysis demonstrated that in the absence of SAMHD1, the CTL rapidly killed infected MDDC. We also report that various transmitted/founder (T/F) HIV-1 strains poorly infected MDDC and, as a consequence, did not stimulate CTL. Vesicular stomatitis virus glycoprotein (VSV-G) pseudotyping of T/F alleviated a block in viral entry and induced antigen presentation only in the absence of SAMHD1. Furthermore, by using another CTL clone that mostly recognizes incoming HIV-1 antigens, we demonstrate that SAMHD1 does not influence exogenous viral antigen presentation. Altogether, our results demonstrate that the antiviral activity of SAMHD1 impacts antigen presentation by DC, highlighting the link that exists between restriction factors and adaptive immune responses., Importance: Upon viral infection, DC may present antigens derived from incoming viral material in the absence of productive infection of DC or from newly synthesized viral proteins. In the case of HIV, productive infection of DC is blocked at an early postentry step. This is due to the presence of SAMHD1, a cellular enzyme that depletes intracellular levels of dNTPs and inhibits viral reverse transcription. We show that the depletion of SAMHD1 in DCs strongly stimulates the presentation of viral antigens derived from newly produced viral proteins, leading to the activation of HIV-1-specific cytotoxic T lymphocytes (CTL). We further show in real time that the enhanced activation of CTL leads to killing of infected DCs. Our results indicate that the antiviral activity of SAMHD1 not only impacts HIV replication but also impacts antigen presentation by DC. They highlight the link that exists between restriction factors and adaptive immune responses.
- Published
- 2015
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46. HIV-2 infects resting CD4+ T cells but not monocyte-derived dendritic cells.
- Author
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Chauveau L, Puigdomenech I, Ayinde D, Roesch F, Porrot F, Bruni D, Visseaux B, Descamps D, and Schwartz O
- Subjects
- Cells, Cultured, Humans, Viral Regulatory and Accessory Proteins metabolism, CD4-Positive T-Lymphocytes virology, Dendritic Cells virology, HIV-2 physiology, Virus Internalization, Virus Replication
- Abstract
Background: Human Immunodeficiency Virus-type 2 (HIV-2) encodes Vpx that degrades SAMHD1, a cellular restriction factor active in non-dividing cells. HIV-2 replicates in lymphocytes but the susceptibility of monocyte-derived dendritic cells (MDDCs) to in vitro infection remains partly characterized., Results: Here, we investigated HIV-2 replication in primary CD4+ T lymphocytes, both activated and non-activated, as well as in MDDCs. We focused on the requirement of Vpx for productive HIV-2 infection, using the reference HIV-2 ROD strain, the proviral clone GL-AN, as well as two primary HIV-2 isolates. All HIV-2 strains tested replicated in activated CD4+ T cells. Unstimulated CD4+ T cells were not productively infected by HIV-2, but viral replication was triggered upon lymphocyte activation in a Vpx-dependent manner. In contrast, MDDCs were poorly infected when exposed to HIV-2. HIV-2 particles did not potently fuse with MDDCs and did not lead to efficient viral DNA synthesis, even in the presence of Vpx. Moreover, the HIV-2 strains tested were not efficiently sensed by MDDCs, as evidenced by a lack of MxA induction upon viral exposure. Virion pseudotyping with VSV-G rescued fusion, productive infection and HIV-2 sensing by MDDCs., Conclusion: Vpx allows the non-productive infection of resting CD4+ T cells, but does not confer HIV-2 with the ability to efficiently infect MDDCs. In these cells, an entry defect prevents viral fusion and reverse transcription independently of SAMHD1. We propose that HIV-2, like HIV-1, does not productively infect MDDCs, possibly to avoid triggering an immune response mediated by these cells.
- Published
- 2015
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47. IFITM proteins incorporated into HIV-1 virions impair viral fusion and spread.
- Author
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Compton AA, Bruel T, Porrot F, Mallet A, Sachse M, Euvrard M, Liang C, Casartelli N, and Schwartz O
- Subjects
- Antigens, Differentiation genetics, CD4-Positive T-Lymphocytes metabolism, CD4-Positive T-Lymphocytes virology, Cell Line, Cell Membrane genetics, Cell Membrane metabolism, Cell Membrane virology, Gene Products, gag genetics, Gene Products, gag metabolism, HIV Infections genetics, HIV-1 genetics, Host-Pathogen Interactions, Humans, Membrane Proteins genetics, RNA-Binding Proteins genetics, Virion genetics, Antigens, Differentiation metabolism, HIV Infections metabolism, HIV Infections virology, HIV-1 physiology, Membrane Proteins metabolism, RNA-Binding Proteins metabolism, Virion physiology, Virus Internalization
- Abstract
The interferon-induced transmembrane (IFITM) proteins protect cells from diverse virus infections by inhibiting virus-cell fusion. IFITM proteins also inhibit HIV-1 replication through mechanisms only partially understood. We show that when expressed in uninfected lymphocytes, IFITM proteins exert protective effects during cell-free virus infection, but this restriction can be overcome upon HIV-1 cell-to-cell spread. However, when present in virus-producing lymphocytes, IFITM proteins colocalize with viral Env and Gag proteins and incorporate into nascent HIV-1 virions to limit entry into new target cells. IFITM in viral membranes is associated with impaired virion fusion, offering additional and more potent defense against virus spread. Thus, IFITM proteins act additively in both productively infected cells and uninfected target cells to inhibit HIV-1 spread, potentially conferring these proteins with greater breadth and potency against enveloped viruses., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
48. Broadly neutralizing antibodies that inhibit HIV-1 cell to cell transmission.
- Author
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Malbec M, Porrot F, Rua R, Horwitz J, Klein F, Halper-Stromberg A, Scheid JF, Eden C, Mouquet H, Nussenzweig MC, and Schwartz O
- Subjects
- CD4-Positive T-Lymphocytes immunology, CD4-Positive T-Lymphocytes virology, Coculture Techniques, Dendritic Cells cytology, Dendritic Cells immunology, HEK293 Cells, HeLa Cells, Humans, Inhibitory Concentration 50, Microscopy, Fluorescence, Time Factors, Virion physiology, Antibodies, Neutralizing immunology, HIV physiology, HIV Antibodies immunology, HIV Infections drug therapy, HIV Infections immunology
- Abstract
The neutralizing activity of anti-HIV-1 antibodies is typically measured in assays where cell-free virions enter reporter cell lines. However, HIV-1 cell to cell transmission is a major mechanism of viral spread, and the effect of the recently described broadly neutralizing antibodies (bNAbs) on this mode of transmission remains unknown. Here we identify a subset of bNAbs that inhibit both cell-free and cell-mediated infection in primary CD4(+) lymphocytes. These antibodies target either the CD4-binding site (NIH45-46 and 3BNC60) or the glycan/V3 loop (10-1074 and PGT121) on HIV-1 gp120 and act at low concentrations by inhibiting multiple steps of viral cell to cell transmission. These antibodies accumulate at virological synapses and impair the clustering and fusion of infected and target cells and the transfer of viral material to uninfected T cells. In addition, they block viral cell to cell transmission to plasmacytoid DCs and thereby interfere with type-I IFN production. Thus, only a subset of bNAbs can efficiently prevent HIV-1 cell to cell transmission, and this property should be considered an important characteristic defining antibody potency for therapeutic or prophylactic antiviral strategies.
- Published
- 2013
- Full Text
- View/download PDF
49. HIV-1 Nef promotes the localization of Gag to the cell membrane and facilitates viral cell-to-cell transfer.
- Author
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Malbec M, Sourisseau M, Guivel-Benhassine F, Porrot F, Blanchet F, Schwartz O, and Casartelli N
- Subjects
- Cell Line, Humans, Virus Internalization, Cell Membrane virology, HIV-1 physiology, Virus Assembly, Virus Release, gag Gene Products, Human Immunodeficiency Virus metabolism, nef Gene Products, Human Immunodeficiency Virus metabolism
- Abstract
Background: Newly synthesized HIV-1 particles assemble at the plasma membrane of infected cells, before being released as free virions or being transferred through direct cell-to-cell contacts to neighboring cells. Localization of HIV-1 Gag precursor at the cell membrane is necessary and sufficient to trigger viral assembly, whereas the GagPol precursor is additionally required to generate a fully matured virion. HIV-1 Nef is an accessory protein that optimizes viral replication through partly defined mechanisms. Whether Nef modulates Gag and/or GagPol localization and assembly at the membrane and facilitates viral cell-to-cell transfer has not been extensively characterized so far., Results: We report that Nef increases the total amount of Gag proteins present in infected cells, and promotes Gag localization at the cell membrane. Moreover, the processing of p55 into p24 is improved in the presence of Nef. We also examined the effect of Nef during HIV-1 cell-to-cell transfer. We show that without Nef, viral transfer through direct contacts between infected cells and target cells is impaired. With a nef-deleted virus, the number of HIV-1 positive target cells after a short 2h co-culture is reduced, and viral material transferred to uninfected cells is less matured. At later time points, this defect is associated with a reduction in the productive infection of new target cells., Conclusions: Our results highlight a previously unappreciated role of Nef during the viral replication cycle. Nef promotes HIV-1 Gag membrane localization and processing, and facilitates viral cell-to-cell transfer.
- Published
- 2013
- Full Text
- View/download PDF
50. SAMHD1 restricts HIV-1 cell-to-cell transmission and limits immune detection in monocyte-derived dendritic cells.
- Author
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Puigdomènech I, Casartelli N, Porrot F, and Schwartz O
- Subjects
- Cells, Cultured, Coculture Techniques, GTP-Binding Proteins biosynthesis, Humans, Interferon Type I metabolism, Monomeric GTP-Binding Proteins genetics, Myxovirus Resistance Proteins, RNA Interference, RNA, Small Interfering, SAM Domain and HD Domain-Containing Protein 1, Viral Regulatory and Accessory Proteins physiology, Virus Replication, Dendritic Cells immunology, Dendritic Cells virology, HIV-1 physiology, Monomeric GTP-Binding Proteins metabolism, T-Lymphocytes virology
- Abstract
SAMHD1 is a viral restriction factor expressed in dendritic cells and other cells, inhibiting infection by cell-free human immunodeficiency virus type 1 (HIV-1) particles. SAMHD1 depletes the intracellular pool of deoxynucleoside triphosphates, thus impairing HIV-1 reverse transcription and productive infection in noncycling cells. The Vpx protein from HIV-2 or simian immunodeficiency virus (SIVsm/SIVmac) antagonizes the effect of SAMHD1 by triggering its degradation. A large part of HIV-1 spread occurs through direct contacts between infected cells and bystander target cells. Here, we asked whether SAMHD1 impairs direct HIV-1 transmission from infected T lymphocytes to monocyte-derived dendritic cells (MDDCs). HIV-1-infected lymphocytes were cocultivated with MDDCs that have been pretreated or not with Vpx or with small interfering RNA against SAMHD1. We show that in the cocultures, SAMHD1 significantly inhibits productive cell-to-cell transmission to target MDDCs and prevents the type I interferon response and expression of the interferon-stimulated gene MxA. Therefore, SAMHD1, by controlling the sensitivity of MDDCs to HIV-1 infection during intercellular contacts, impacts their ability to sense the virus and to trigger an innate immune response.
- Published
- 2013
- Full Text
- View/download PDF
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