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Competing Interests: Declaration of competing interest All authors have nothing to disclose related to this work

Background: Dyspnea is a complex symptom of chronic obstructive pulmonary disease (COPD) which is not strongly correlated with lung function measures. Long-acting bronchodilators (LAB) may reduce this dyspnea, but some patients report persistent chronic dyspnea despite this treatment. This study aims to assess residual reversibility and clinical response after short-acting bronchodilator (SAB) in COPD patients already treated by LAB and reporting persistent dyspnea., Methods: COPD patients with a persistent dyspnea (modified Medical Research Council scale (mMRC) ≥1) despite current stable treatment with at least one LAB were included. Spirometry, plethysmography and impulse oscillometry (IOS) were performed at peak effect of their LAB and repeat 45 min after the intake of two SAB (400 µg of salbutamol and 80 µg of ipratropium). Dyspnea improvement was assessed at 45 min after SAB through a comparative two-sided VAS (-100 mm for maximal improvement; +100 mm for maximal degradation)., Results: Twenty-two COPD patients were analyzed, mainly men (59.1 %) with a mean age of 60.6 years and a median FEV1 of 54 % of predicted values. Fifty percent of patients reported a severe basal dyspnea (mMRC ≥2). After SAB, spirometric and plethysmographic measurements were statistically improved. For IOS measurement, reactance at 5 Hz (X5) and area of reactance (AX) were also improved. Fifty percent of patients reported a clinically relevant improvement of their resting dyspnea. However, no correlation was found between dyspnea improvement and functional measures., Conclusions: Fifty percent of COPD patients regularly treated with one or two LAB still report a relevant improvement of resting dyspnea after the adjunctive intake of double short-acting bronchodilators. Physiological mechanisms associated with this improvement remain to be determined., Clinical Trial Registration: NCT02928744., Competing Interests: Declaration of Competing Interest OLR reports personal fees from AstraZeneca, Boehringer Ingelheim and GlaxoSmithKline, and non-financial supports from AstraZeneca, Boehringer Ingelheim, Chiesi, Correvio, GlaxoSmithKline, Mayoli, MSD, Mylan, Novartis, Pfizer, PulmonX, Santelys Association, Vertex and Zambon, unrelated to the submitted work. MP reports non-financial supports from Boehringer Ingelheim, GlaxoSmithKline, Sanofi Aventis France and Sysmed, unrelated to the submitted work. HS reports non-financial support from GlaxoSmithKline, LVL médical, Oxyvie, unrelated to the submitted work. NB reports personal fees from AstraZeneca, and non-financial support from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKlein, Novartis, Santelys association, SOS oxygène and Teva, unrelated to the submitted work. PD reports personnal fees and non-financial support from ALK, AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Menarini, Novartis, Sanofi and Stallergènes, unrelated to the submitted work. TP reports grants from AstraZeneca, personal fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline and Novartis, and congress support from AstraZeneca, GlaxoSmithKlein, Novartis and Chiesi, unrelated to the submitted work., (Copyright © 2023 SPLF and Elsevier Masson SAS. All rights reserved.)

Background: The COVID-19 pandemic brought unprecedented global disruption to both healthcare providers and patients with respiratory allergies. There are limited real-life data on the impact of the COVID-19 pandemic on the risk perception of patients with allergy treated with allergen immunotherapy (AIT)., Objective: To understand the risk perception of allergic patients treated with sublingual immunotherapy (SLIT) before and during the pandemic, and their attitudes towards COVID-19 infection and vaccination., Methods: This was a non-interventional, cross-sectional survey conducted from October to November 2021 in France. Adult patients, who had been prescribed and had received a Stallergenes SLIT (liquid or liquid and tablets) before the pandemic (from August 1, 2018 to March 10, 2020) and during the pandemic (from March 11, 2020 to August 31, 2021), were identified from the Stallergenes named-patient products (NPP) database. Patients completed an online questionnaire. Data were analyzed descriptively., Results: A total of 5258 patients from all over France completed the questionnaire. Mean (±SD) age of the respondents was 39.3 (±13.0) years and 66.9% were female. Some of them (11.8%) were obese (BMI >30 kg/m 2 ). Main allergic diseases were rhinitis (80.0% of patients) with or without conjunctivitis, and asthma (39.0%). More than half of the patients experienced moderate to severe (58.0%) and persistent allergic rhinitis profile (70.4%). Most patients were poly-allergic (72.7%), mostly to house dust mites (61.9%), grass pollens (61.5%), tree pollens (57.8%), and cat dander (37.2%). Only 14.1% of patients experienced an aggravation of their allergy symptoms during lockdown and 14.8% were infected with COVID-19, with hospitalization required for 1.8%. Only 3.1% of patients reported their SLIT initiation as being postponed due to the pandemic. SLIT was changed, temporarily interrupted or permanently discontinued during the pandemic in 21.9% of patients. Changes mainly concerned the maintenance dose for SLIT-liquid (63.2%). SLIT modification was due to COVID-19 infection in only 4.2%. Most patients did not feel vulnerable (53.1%), anxious (55.2%), at risk to present severe symptoms of COVID-19 (77.1%), or at risk to transmit coronavirus (80.4%). However, greater anxiety was reported in patients with allergic asthma (33.6%) or other respiratory disorders (50.4%). Patients who felt vulnerable partly assigned their vulnerability to their allergic disease (59.3%). Suffering from an allergic disease did not make patients feel more vulnerable to side effects of COVID-19 vaccine for 79.6% of them., Conclusion: Overall, most patients with allergy and under SLIT were not strongly concerned by the COVID-19 infection. SLIT did not have a negative impact on the COVID-19 symptoms., Competing Interests: PD reports personal support by Stallergenes Greer for the present manuscript; receiving consulting fees from ALK-Abello, Astra Zeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Viatris, Menarini, and Stallergenes Greer; payments or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from ALK-Abello, Astra Zeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Viatris, Menarini, Novartis, Procter & Gamble, and Stallergenes Greer; and support for attending meetings and/or travel from ALK-Abello, Astra Zeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Viatris, Menarini, Novartis, Procter & Gamble, and Stallergenes Greer. SS reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from DBV Technologies, Thermo Fisher Scientific, and ALK-Greer; and support for attending meetings and/or travel from Sanofi, ALK-Greer, and Stallergenes Greer. CR reports support by Stallergenes Greer (to Asthme & Allergies) for the present manuscript; grants and contracts by ALK, AstraZeneca, GSK, and Chiesi; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Stallergenes Greer, ALK, AstraZeneca, GSK, and Novartis; and support for attending meetings and/or travel from Stallergenes Greer, ALK, and GSK. GWC reports receiving consulting fees from AstraZeneca, Glaxo Smith Kline, Hal Allergy, Menarini, Sanofi, and Stallergenes; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from AstraZeneca, Glaxo Smith Kline, Hal Allergy, Menarini, Sanofi, and Stallergenes; and support for attending meetings and/or travel by AstraZeneca, Glaxo Smith Kline, Hal Allergy, Menarini, Sanofi, and Stallergenes. PD reports receiving medical writing support from Stallergenes Greer for the present manuscript; institutional grants or contracts from ALK-Abelló, AstraZeneca, GlaxoSmithKline, Menarini, Puressentiel, Stallergenes Greer, ThermoFisher Scientific, Viatris; and support for attending meetings and/or travel from ALK and Stallergenes Greer., (© 2024 The Author(s).)

Purpose: Asthma is a frequent chronic inflammatory bronchial disease affecting more than 300 million patients worldwide, 70% of whom are secondary to allergy. The diversity of asthmatic endotypes contributes to their complexity. The inter-relationship between allergen and other exposure and the airway microbiome adds to the phenotypic diversity and defines the natural course of asthma. Here, we compared the mouse models of house dust mite (HDM)-induced allergic asthma. Allergic sensitization was performed via various routes and associated with outcomes., Methods: Mice were sensitized with HDM via the oral, nasal or percutaneous routes. Lung function, barrier integrity, immune response and microbiota composition were analyzed., Results: Severe impairment of respiratory function was observed in the mice sensitized by the nasal and cutaneous paths. It was associated with epithelial dysfunction characterized by an increased permeability secondary to junction protein disruption. Such sensitization paths induced a mixed eosinophilic and neutrophilic inflammatory response with high interleukin (IL)-17 airway secretion. In contrast, orally sensitized mice showed a mild impairment of respiratory function. Epithelial dysfunction was mild with increased mucus production, but preserved epithelial junctions. Regarding lung microbiota, sensitization provoked a significant loss of diversity. At the genus level, Cutibacterium , Acinetobacter , Streptococcus and Lactobacillus were found to be modulated according to the sensitization pathway. An increase in theanti-inflammatory microbiota metabolites was observed in the oral-sensitization group., Conclusions: Our study highlights the strong impact of the sensitization route on the pathophysiology and the critical phenotypic diversity of allergic asthma in a mouse model., Competing Interests: There are no financial or other issues that might lead to conflict of interest., (Copyright © 2023 The Korean Academy of Asthma, Allergy and Clinical Immunology • The Korean Academy of Pediatric Allergy and Respiratory Disease.)

Animal models are essential to understanding COVID-19 pathophysiology and for preclinical assessment of drugs and other therapeutic or prophylactic interventions. We explored the small, cheap, and transparent zebrafish larva as a potential host for SARS-CoV-2. Bath exposure, as well as microinjection in the coelom, pericardium, brain ventricle, or bloodstream, resulted in a rapid decrease of SARS-CoV-2 RNA in wild-type larvae. However, when the virus was inoculated in the swim bladder, viral RNA stabilized after 24 h. By immunohistochemistry, epithelial cells containing SARS-CoV-2 nucleoprotein were observed in the swim bladder wall. Our data suggest an abortive infection of the swim bladder. In some animals, several variants of concern were also tested with no evidence of increased infectivity in our model. Low infectivity of SARS-CoV-2 in zebrafish larvae was not due to the host type I interferon response, as comparable viral loads were detected in type I interferon-deficient animals. A mosaic overexpression of human ACE2 was not sufficient to increase SARS-CoV-2 infectivity in zebrafish embryos or in fish cells in vitro . In conclusion, wild-type zebrafish larvae appear mostly non-permissive to SARS-CoV-2, except in the swim bladder, an aerial organ sharing similarities with the mammalian lung., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Laghi, Rezelj, Boucontet, Frétaud, Da Costa, Boudinot, Salinas, Lutfalla, Vignuzzi and Levraud.)

Background: Invariant chain (CD74, Ii) is a multifunctional protein expressed in antigen presenting cells. It assists the ER exit of various cargos and serves as a receptor for the macrophage migration inhibitory factor. The newly translated Ii chains trimerize, a structural feature that is not readily understood in the context of its MHCII chaperoning function. Two segments of Ii, the luminal C-terminal region (TRIM) and the transmembrane domain (TM), have been shown to participate in the trimerization process but their relative importance and impact on the assembly with MHCII molecules remains debated. Here, we addressed the requirement of these domains in the trimerization of human Ii as well as in the oligomerization with MHCII molecules. We used site-directed mutagenesis to generate series of Ii and DR mutants. These were transiently transfected in HEK293T cells to test their cell surface expression and analyse their interactions by co-immunoprecipitations., Results: Our results showed that the TRIM domain is not essential for Ii trimerization nor for intracellular trafficking with MHCII molecules. We also gathered evidence that in the absence of TM, TRIM allows the formation of multi-subunit complexes with HLA-DR. Similarly, in the absence of TRIM, Ii can assemble into high-order structures with MHCII molecules., Conclusions: Altogether, our data show that trimerization of Ii through either TM or TRIM sustains nonameric complex formation with MHCII molecules., (© 2021. The Author(s).)

Porcine reproductive and respiratory syndrome (PRRS) has an extensive impact on pig production. The causative virus (PRRSV) is divided into two species, PRRSV-1 (European origin) and PRRSV-2 (North American origin). Within PRRSV-1, PRRSV-1.3 strains, such as Lena, are more pathogenic than PRRSV-1.1 strains, such as Flanders 13 (FL13). To date, the molecular interactions of PRRSV with primary lung mononuclear phagocyte (MNP) subtypes, including conventional dendritic cells types 1 (cDC1) and 2 (cDC2), monocyte-derived DCs (moDC), and pulmonary intravascular macrophages (PIM), have not been thoroughly investigated. Here, we analyze the transcriptome profiles of in vivo FL13-infected parenchymal MNP subpopulations and of in vitro FL13- and Lena-infected parenchymal MNP. The cell-specific expression profiles of in vivo sorted cells correlated with their murine counterparts (AM, cDC1, cDC2, moDC) with the exception of PIM. Both in vivo and in vitro , FL13 infection altered the expression of a low number of host genes, and in vitro infection with Lena confirmed the higher ability of this strain to modulate host response. Machine learning (ML) and gene set enrichment analysis (GSEA) unraveled additional relevant genes and pathways modulated by FL13 infection that were not identified by conventional analyses. GSEA increased the cellular pathways enriched in the FL13 data set, but ML allowed a more complete comprehension of functional profiles during FL13 in vitro infection. Data indicates that cellular reprogramming differs upon Lena and FL13 infection and that the latter might keep antiviral and inflammatory macrophage/DC functions silent. Although the slow replication kinetics of FL13 likely contribute to differences in cellular gene expression, the data suggest distinct mechanisms of interaction of the two viruses with the innate immune system during early infection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Crisci, Moroldo, Vu Manh, Mohammad, Jourdren, Urien, Bouguyon, Bordet, Bevilacqua, Bourge, Pezant, Pléau, Boulesteix, Schwartz, Bertho and Giuffra.)

Host miRNAs are known to modulate the cell response to virus infections. We characterized the miRNA-targeted transcriptome of porcine alveolar macrophages (PAMs) at early times after infection with a subtype 1.1 strain of PRRSV (Porcine Reproductive and Respiratory Syndrome Virus). We performed the immunoprecipitation of RISC (RNA-induced Silencing Complex) followed by microarray analysis of the RISC-bound miRNA targets (RIP-Chip) to evaluate the relative enrichment or depletion of expressed genes in RISC. The miRNA-mediated regulation occurred early after PRRSV infection and decreased fast (1,241 and 141 RISC-bound genes at 7 h and 10 h post-infection, respectively); it affected several cell functions with evidence of miRNA buffering of upregulated interferon-related genes. Eight miRNAs were highly enriched in RISC of both control and infected cells with no evidence of differential expression. Although miR-335-5p was the miRNA with most predicted targets among enriched RISC-bound genes, no effects on surface markers, cytokine expression and PRRSV replication were detected upon miR-335-5p mimics of primary PAMs. Our results do not point to specific miRNA-driven mechanisms regulating the early response to infection with this PRRSV 1.1 strain and indicate that the miRNome expressed by steady-state PAMs reacts promptly to counterbalance PRRSV infection by a pervasive modulation of host functions.

Classical HLA class II molecules are highly polymorphic heterodimeric transmembrane proteins encoded by a polygenic cluster on chromosome 6. Polymorphic residues in the membrane-distal domains ensure that a large collection of microbial peptides can be bound in the human population. Still, the HLA-DR, -DP and -DQ isotypes show a high degree of conservation in their overall tertiary and quaternary structures, in line with their common function in T cell receptor activation. Interestingly, the primary structure of the intracellular domains are highly divergent between isotypes and they also show allotypic variations. The functional impact of these differences remains to be fully appreciated. Here, we address the role of the MHC class II cytoplasmic tails in intracellular trafficking. First, the emphasis will be on the interplay between the cytoplasmic domains of classical human MHC class II molecules and those of the invariant chain chaperone (CD74) isoforms. Then, we will examine the importance of the highly conserved β-chain cytoplasmic lysine residue in the ubiquitin-driven trafficking of MHC class II molecules. These considerations should help understand the potential functional impact of sequence variations that may arise in the cytoplasmic tails and transmembrane domains of MHC class II molecules., (Copyright © 2018. Published by Elsevier Inc.)

Innate lymphoid cells (ILCs) are important mediators of the immune response and homeostasis in barrier tissues of mammals. However, the existence and function of ILCs in other vertebrates are poorly understood. Here, we use single-cell RNA sequencing to generate a comprehensive atlas of zebrafish lymphocytes during tissue homeostasis and after immune challenge. We profiled 14,080 individual cells from the gut of wild-type zebrafish, as well as of rag1 -deficient zebrafish that lack T and B cells, and discovered populations of ILC-like cells. We uncovered a rorc -positive subset of ILCs that could express cytokines associated with type 1, 2, and 3 responses upon immune challenge. Specifically, these ILC-like cells expressed il22 and tnfa after exposure to inactivated bacteria or il13 after exposure to helminth extract. Cytokine-producing ILC-like cells express a specific repertoire of novel immune-type receptors, likely involved in recognition of environmental cues. We identified additional novel markers of zebrafish ILCs and generated a cloud repository for their in-depth exploration., (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

The current paradigm in the pathogenesis of several hemolytic red blood cell disorders is that reduced cellular deformability is a key determinant of splenic sequestration of affected red cells. Three distinct features regulate cellular deformability: membrane deformability, surface area-to-volume ratio (cell sphericity), and cytoplasmic viscosity. By perfusing normal human spleens ex vivo, we had previously showed that red cells with increased sphericity are rapidly sequestered by the spleen. Here, we assessed the retention kinetics of red cells with decreased membrane deformability but without marked shape changes. A controlled decrease in membrane deformability (increased membrane rigidity) was induced by treating normal red cells with increasing concentrations of diamide. Following perfusion, diamide-treated red blood cells (RBCs) were rapidly retained in the spleen with a mean clearance half-time of 5.9 minutes (range, 4.0-13.0). Splenic clearance correlated positively with increased membrane rigidity ( r = 0.93; P < .0001). To determine to what extent this increased retention was related to mechanical blockade in the spleen, diamide-treated red cells were filtered through microsphere layers that mimic the mechanical sensing of red cells by the spleen. Diamide-treated red cells were retained in the microsphilters (median, 7.5%; range, 0%-38.6%), although to a lesser extent compared with the spleen (median, 44.1%; range, 7.3%-64.0%; P < .0001). Taken together, these results have implications for understanding the sensitivity of the human spleen to sequester red cells with altered cellular deformability due to various cellular alterations and for explaining clinical heterogeneity of RBC membrane disorders., (© 2018 by The American Society of Hematology.)

Porcine Reproductive and Respiratory Syndrome virus (PRRSV) is an arterivirus responsible for highly contagious infection and huge economic losses in pig industry. Two species, PRRSV-1 and PRRSV-2 are distinguished, PRRSV-1 being more prevalent in Europe. PRRSV-1 can further be divided in subtypes. PRRSV-1.3 such as Lena are more pathogenic than PRRSV-1.1 such as Lelystad or Flanders13. PRRSV-1.3 viruses trigger a higher Th1 response than PRRSV-1.1, although the role of the cellular immune response in PRRSV clearance remains ill defined. The pathogenicity as well as the T cell response inductions may be differentially impacted according to the capacity of the virus strain to infect and/or activate DCs. However, the interactions of PRRSV with in vivo -differentiated-DC subtypes such as conventional DC1 (cDC1), cDC2, and monocyte-derived DCs (moDC) have not been thoroughly investigated. Here, DC subpopulations from Lena in vivo infected pigs were analyzed for viral genome detection. This experiment demonstrates that cDC1, cDC2, and moDC are not infected in vivo by Lena. Analysis of DC cytokines production revealed that cDC1 are clearly activated in vivo by Lena. In vitro comparison of 3 Europeans strains revealed no infection of the cDC1 and cDC2 and no or little infection of moDC with Lena, whereas the two PRRSV-1.1 strains infect none of the 3 DC subtypes. In vitro investigation of T helper polarization and cytokines production demonstrate that Lena induces a higher Th1 polarization and IFNγ secretion than FL13 and LV. Altogether, this work suggests an activation of cDC1 by Lena associated with a Th1 immune response polarization.

Ischemic myocardial injury results in sterile cardiac inflammation that leads to tissue repair, two processes controlled by mononuclear phagocytes. Despite global burden of cardiovascular diseases, we do not understand the functional contribution to pathogenesis of specific cardiac mononuclear phagocyte lineages, in particular dendritic cells. To address this limitation, we used detailed lineage tracing and genetic studies to identify bona fide murine and human CD103 + conventional dendritic cell (cDC)1s, CD11b + cDC2s, and plasmacytoid DCs (pDCs) in the heart of normal mice and immunocompromised NSG mice reconstituted with human CD34 + cells, respectively. After myocardial infarction (MI), the specific depletion of cDCs, but not pDCs, improved cardiac function and prevented adverse cardiac remodeling. Our results showed that fractional shortening measured after MI was not influenced by the absence of pDCs. Interestingly, however, depletion of cDCs significantly improved reduction in fractional shortening. Moreover, fibrosis and cell areas were reduced in infarcted zones. This correlated with reduced numbers of cardiac macrophages, neutrophils, and T cells, indicating a blunted inflammatory response. Accordingly, mRNA levels of proinflammatory cytokines IL-1β and IFN-γ were reduced. Collectively, our results demonstrate the unequivocal pathological role of cDCs following MI., (Copyright © 2018 by The American Association of Immunologists, Inc.)

Membrane-associated RING-CH-1 (March1) is a member of the March family of E3 ubiquitin ligases. March1 downregulates cell surface expression of MHC II and CD86 by targeting them to lysosomal degradation. Given the key roles of MHC class II and CD86 in T cell activation and to get further insights into the development of allergic inflammation, we asked whether March1 deficiency exacerbates or attenuates features of allergic asthma in mice. Herein, we used an acute model of allergy to compare the asthmatic phenotype of March1-deficient and -sufficient mice immunized with ovalbumin (OVA) and later challenged by intranasal instillation of OVA in the lungs. We found that eosinophilic inflammation in airways and lung tissue was similar between WT and March1 -/- allergic mice, whereas neutrophilic inflammation was significant only in March1 -/- mice. Airway hyperresponsiveness as well as levels of IFN- γ , IL-13, IL-6, and IL-10 was lower in the lungs of asthmatic March1 -/- mice compared to WT, whereas lung levels of TNF- α , IL-4, and IL-5 were not significantly different. Interestingly, in the serum, levels of total and ova-specific IgE were reduced in March1-deficient mice as compared to WT mice. Taken together, our results demonstrate a role of March1 E3 ubiquitin ligase in modulating allergic responses.

Background: In the agenda towards malaria eradication, assessment of both malaria exposure and efficacy of anti-vectorial and therapeutic strategies is a key component of management and the follow-up of field interventions. The simultaneous use of several antigens (Ags) as serological markers has the potential for accurate evaluation of malaria exposure. Here we aimed to measure the longitudinal evolution of the background levels of immunity in an urban setting in confirmed clinical cases of malaria., Methods: A retrospective serological cross-sectional study on was carried out using 234 samples taken from 2010 to 2013 in peri-urban sentinel facility of Cote d'Ivoire. Antibody responses to recombinant proteins or BSA-peptides, 8 Plasmodium falciparum (PfAMA1, PfMSP4, PfMSP1, PfEMP1-DBL1α1-PF13, PfLSA1-41, PfLSA3-NR2, PfGLURP and PfCSP), one P. malariae (PmCSP) and one Anopheles gambiae salivary (gSG6-P1) antigens were measured using magnetic bead-based multiplex immunoassay (MBA). Total anti- P. falciparum IgG responses against schizont lysate from african 07/03 strain (adapted to culture) and 3D7 strain was measured by ELISA., Results: High prevalence (7-93%) and levels of antibody responses to most of the antigens were evidenced. However, analysis showed only marginal decreasing trend of Ab responses from 2010 to 2013 that did not parallel the reduction of clinical malaria prevalence following the implementation of intervention in this area. There was a significant inverse correlation between Ab responses and parasitaemia (P<10-3, rho = 0.3). The particular recruitment of asymptomatic individuals in 2011 underlined a high background level of immunity almost equivalent to symptomatic patients, possibly obscuring observable yearly variations., Conclusion: The use of cross-sectional clinical malaria surveys and MBA can help to identify endemic sites where control measures have unequal impact providing relevant information about population immunity and possible decrease of transmission. However, when immunity is substantially boosted despite observable clinical decline, a larger cohort including asymptomatic recruitment is needed to monitor the impact of control measures on level of immunity.

Ubiquitination was recently identified as a central process in the pathogenesis and development of numerous inflammatory diseases, such as obesity, atherosclerosis, and asthma. Treatment with proteasomal inhibitors led to severe side effects because ubiquitination is heavily involved in a plethora of cellular functions. Thus, new players regulating ubiquitination processes must be identified to improve therapies for inflammatory diseases. In addition to their role in adaptive immunity, endosomal MHC class II (MHCII) molecules were shown to modulate innate immune responses by fine tuning the TLR4 signaling pathway. However, the role of MHCII ubiquitination by membrane associated ring-CH-type finger 1 (MARCH1) E3 ubiquitin ligase in this process remains to be assessed. In this article, we demonstrate that MARCH1 is a key inhibitor of innate inflammation in response to bacterial endotoxins. The higher mortality of March1 -/- mice challenged with a lethal dose of LPS was associated with significantly stronger systemic production of proinflammatory cytokines and splenic NK cell activation; however, we did not find evidence that MARCH1 modulates LPS or IL-10 signaling pathways. Instead, the mechanism by which MARCH1 protects against endotoxic shock rests on its capacity to promote the transition of monocytes from Ly6C Hi to Ly6C +/- Moreover, in competitive bone marrow chimeras, March1 -/- monocytes and polymorphonuclear neutrophils outcompeted wild-type cells with regard to bone marrow egress and homing to peripheral organs. We conclude that MARCH1 exerts MHCII-independent effects that regulate the innate arm of immunity. Thus, MARCH1 might represent a potential new target for emerging therapies based on ubiquitination reactions in inflammatory diseases., (Copyright © 2017 by The American Association of Immunologists, Inc.)

Variant Creutzfeldt-Jakob disease (vCJD) is a human prion disease resulting from the consumption of meat products contaminated by the agent causing bovine spongiform encephalopathy. Evidence supporting the presence of a population of silent carriers that can potentially transmit the disease through blood transfusion is increasing. The development of a blood-screening assay for both symptomatic vCJD patients and asymptomatic carriers is urgently required. We show that a diagnostic assay combining plasminogen-bead capture and protein misfolding cyclic amplification (PMCA) technologies consistently detected minute amounts of abnormal prion protein from French and British vCJD cases in the required femtomolar range. This assay allowed the blinded identification of 18 patients with clinical vCJD among 256 plasma samples from the two most affected countries, with 100% sensitivity [95% confidence interval (CI), 81.5 to 100%], 99.2% analytical specificity (95% CI, 95.9 to 100%), and 100% diagnostic specificity (95% CI, 96.5 to 100%). This assay also allowed the detection of silent carriage of prions 1.3 and 2.6 years before the clinical onset in two blood donors who later developed vCJD. These data provide a key step toward the validation of this PMCA technology as a blood-based diagnostic test for vCJD and support its potential for detecting presymptomatic patients, a prerequisite for limiting the risk of vCJD transmission through blood transfusion., (Copyright © 2016, American Association for the Advancement of Science.)

Real time analysis of viral infection is now feasible with the emergence of viral mutants encoding reporter genes (such as fluorescent proteins or Luciferase). The development of reverse genetic approaches in the virology field has contributed significantly to improve our knowledge on viral dissemination in mammals using intravital imaging technologies. In this context, zebra fish recently appeared as a promizing tool to study infectiology and viruses responsible for human diseases such as Herpes, Flu, hepatitis and chikungunya infections. This small vertebrate is optically transparent during the early stages of development, and has been particularly useful to study the tropism of fluorescent viruses, spreading mechanisms as well as viral persistence at cellular resolution. The size of this small organism is compatible with imaging of the whole larva using a dissecting microscope. Genome editing technology has contributed important tools that are now being exploited for the characterization of the host pathogen interaction in vivo, mainly focused on the conserved features of antiviral innate immunity.

Polyamines are small, positively charged molecules derived from ornithine and synthesized through an intricately regulated enzymatic pathway. Within cells, they are abundant and play several roles in diverse processes. We find that polyamines are required for the life cycle of the RNA viruses chikungunya virus (CHIKV) and Zika virus (ZIKV). Depletion of spermidine and spermine via type I interferon signaling-mediated induction of spermidine/spermine N1-acetyltransferase (SAT1), a key catabolic enzyme in the polyamine pathway, restricts CHIKV and ZIKV replication. Polyamine depletion restricts these viruses in vitro and in vivo, due to impairment of viral translation and RNA replication. The restriction is released by exogenous replenishment of polyamines, further supporting a role for these molecules in virus replication. Thus, SAT1 and, more broadly, polyamine depletion restrict viral replication and suggest promising avenues for antiviral therapies., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Bunyaviruses represent a growing threat to humans and livestock globally. The receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely unidentified and poorly characterized. DC-SIGN is a C-type lectin highly expressed on dermal dendritic cells that has been found to act as an authentic entry receptor for many phleboviruses (Bunyaviridae), including Rift Valley fever virus (RVFV), Toscana virus (TOSV) and Uukuniemi virus (UUKV). We found that these phleboviruses can exploit another C-type lectin, L-SIGN, for infection. L-SIGN shares 77% sequence homology with DC-SIGN and is expressed on liver sinusoidal endothelial cells. L-SIGN is required for UUKV binding but not for virus internalization. An endocytosis-defective mutant of L-SIGN was still able to mediate virus uptake and infection, indicating that L-SIGN acts as an attachment receptor for phleboviruses rather than an endocytic receptor. Our results point out a fundamental difference in the use of the C-type lectins L-SIGN and DC-SIGN by UUKV to enter cells, although both proteins are closely related in terms of molecular structure and biological function. This study sheds new light on the molecular mechanisms by which phleboviruses target the liver and also highlights the added complexity in virus-receptor interactions beyond attachment., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Type II diabetes regroups different physiological anomalies that ultimately lead to low-grade chronic inflammation, insulin resistance and loss of pancreatic β-cells. Obesity is one of the best examples of such a condition that can develop into Metabolic Syndrome, causing serious health problems of great socio-economic consequences. The pathological outcome of obesity has a genetic basis and depends on the delicate balance between pro- and anti-inflammatory effectors of the immune system. The causal link between obesity and inflammation is well established. While innate immunity plays a key role in the development of a pro-inflammatory state in obese adipose tissues, it has now become clear that adaptive immune cells are also involved and participate in the cascade of events that lead to metabolic perturbations. The efficacy of some immunotherapeutic protocols in reducing the symptoms of obesity-driven metabolic syndrome in mice implicated all arms of the immune response. Recently, the production of pathogenic immunoglobulins and pro-inflammatory cytokines by B and T lymphocytes suggested an auto-immune basis for the establishment of a non-healthy obese state. Understanding the cellular landscape of obese adipose tissues and how immune cells sustain chronic inflammation holds the key to the development of targeted therapies. In this review, we emphasize the role of antigen-presenting cells and MHC molecules in obese adipose tissue and the general contribution of the adaptive arm of the immune system in inflammation-induced insulin resistance., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Regulatory T (Treg) cells expressing Foxp3 transcripton factor are essential for immune homeostasis. They arise in the thymus as a separate lineage from conventional CD4(+)Foxp3(-) T (Tconv) cells. Here, we show that the thymic development of Treg cells depends on the expression of their endogenous cognate self-antigen. The formation of these cells was impaired in mice lacking this self-antigen, while Tconv cell development was not negatively affected. Thymus-derived Treg cells were selected by self-antigens in a specific manner, while autoreactive Tconv cells were produced through degenerate recognition of distinct antigens. These distinct modes of development were associated with the expression of T cell receptor of higher functional avidity for self-antigen by Treg cells than Tconv cells, a difference subsequently essential for the control of autoimmunity. Our study documents how self-antigens define the repertoire of thymus-derived Treg cells to subsequently endow this cell type with the capacity to undermine autoimmune attack., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Phagocytes restrict the germination of Aspergillus fumigatus conidia and prevent the establishment of invasive pulmonary aspergillosis in immunecompetent mice. Here we report that immunecompetent mice recovering from a primary A. fumigatus challenge are protected against a secondary lethal challenge. Using RAGγc knock-out mice we show that this protection is independent of T, B and NK cells. In protected mice, lung phagocytes are recruited more rapidly and are more efficient in conidial phagocytosis and killing. Protection was also associated with an enhanced expression of CXCR2 and Dectin-1 on bone marrow phagocytes. We also show that protective lung cytokine and chemokine responses are induced more rapidly and with enhanced dynamics in protected mice. Our findings support the hypothesis that following a first encounter with a non-lethal dose of A. fumigatus conidia, the innate immune system is primed and can mediate protection against a secondary lethal infection.

Plasmodium falciparum resistance to artemisinins, the most potent and fastest acting anti-malarials, threatens malaria elimination strategies. Artemisinin resistance is due to mutation of the PfK13 propeller domain and involves an unconventional mechanism based on a quiescence state leading to parasite recrudescence as soon as drug pressure is removed. The enhanced P. falciparum quiescence capacity of artemisinin-resistant parasites results from an increased ability to manage oxidative damage and an altered cell cycle gene regulation within a complex network involving the unfolded protein response, the PI3K/PI3P/AKT pathway, the PfPK4/eIF2α cascade and yet unidentified transcription factor(s), with minimal energetic requirements and fatty acid metabolism maintained in the mitochondrion and apicoplast. The detailed study of these mechanisms offers a way forward for identifying future intervention targets to fend off established artemisinin resistance.

CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cell therapy is a promising approach for the treatment of autoimmune diseases. To be effective, Treg cells should be in an activated state in the target tissue. This can be achieved by systemic administration of Ag-specific Treg cells, which are difficult to produce in conditions that can be translated to the clinic. In this paper, we propose an alternative approach consisting of in situ injection of preactivated polyclonal Treg cells that would exert bystander suppression in the target tissue. We show that polyclonal Treg cells suppressed uveitis in mice as efficiently as Ag-specific Treg cells but only when preactivated and administered in the vitreous. Uveitis control was correlated with an increase of IL-10 and a decrease of reactive oxygen species produced by immune cell infiltrates in the eye. Thus, our results reveal a new mechanism of Treg cell-mediated suppression and a new Treg cell therapy approach., (Copyright © 2016 by The American Association of Immunologists, Inc.)