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The use of graphene quantum dots as biomedical devices and drug delivery systems has been increasing. The nano-platform of pure carbon has shown unique properties and is approved to be safe for human use. In this study, we successfully produced and characterized folic acid-functionalized graphene quantum dots (GQD-FA) to evaluate their antiviral activity against Zika virus (ZIKV) infection in vitro, and for radiolabeling with the alpha -particle emitting radionuclide radium-223. The in vitro results exhibited the low cytotoxicity of the nanoprobe GQD-FA in Vero E6 cells and the antiviral effect against replication of the ZIKV infection. In addition, our findings demonstrated that functionalization with folic acid doesn't improve the antiviral effect of graphene quantum dots against ZIVK replication in vitro. On the other hand, the radiolabeled nanoprobe 223Ra@GQD-FA was also produced as confirmed by the Energy Dispersive X-Ray Spectroscopy analysis. 223Ra@GQD-FA might expand the application of alpha targeted therapy using radium-223 in folate receptor-overexpressing tumors., Carlos Chagas Filho Foundation for Research Support of Rio de Janeiro State (FAPERJ) [E-26/200.815/2021, E-26/010.000981/2019, E-26/010.002362/2019, E-26/211.269/2021, E-26//211.207/2021, E-26/202.320/2021]; CNPq [301069/2018-2]; National Nuclear Energy Commission [01341.011064/2021-71], This study was funded by Carlos Chagas Filho Foundation for Research Support of Rio de Janeiro State (FAPERJ) (Cientista do Nosso Estado: E-26/200.815/2021; Rede NanoSaude: E-26/010.000981/2019, Pesquisa na UEZO: E-26/010.002362/2019; Tematicos: E-26/211.269/2021, Infraestrutura e Pesquisa na UEZO e UERJ: E-26//211.207/2021, Bolsa de Pos Doutorado Senior (PDS): E-26/202.320/2021) CNPq (Bolsa de Produtividade 1B: 301069/2018-2) to Ralph Santos-Oliveira. National Nuclear Energy Commission (Bolsa de Posdoutorado CNEN: 01341.011064/2021-71) to Martha Sahyli Ortega Pijeira.

BackgroundThe SARS-CoV-2 virus, responsible for the COVID-19 pandemic, has four structural proteins and sixteen non-structural proteins. The S-protein is one of the structural proteins exposed on the surface of the virus and is the main target for producing neutralizing antibodies and vaccines. The S-protein forms a trimer that can bind the angiotensin-converting enzyme 2 (ACE2) through its receptor binding domain (RBD) for cell entry.MethodsWe stably expressed in a constitutive manner in HEK293 cells a new recombinant protein containing a signal sequence of immunoglobulin to produce an extended C-terminal portion of the RBD followed by a region responsible for the trimerization inducer of the bacteriophage T4, and a sequence of 6 histidines. The protein was produced and released in the culture supernatant of cells and was purified by Ni-agarose column and exclusion chromatography. It was then characterized by SDS-polyacrylamide gel and used as antigen to generate protective antibodies to inhibit ACE2 receptor interaction and virus entry into Vero cells.ResultsThe purified protein displayed a molecular mass of 135 kDa and with a secondary structure like the monomeric RBD. Electrophoresis analysis in SDS-polyacrylamide gel with and without reducing agents, and in the presence of crosslinkers indicated that it forms a multimeric structure composed of trimers and hexamers. The purified protein was able to bind the ACE2 receptor and generated high antibody titers in mice (1:10000), capable of inhibiting the binding of biotin labeled ACE2 to the virus S1 subunit, and to neutralize the entry of the SARS-CoV-2 Wuhan strain into cells.ConclusionOur results characterize a new multimeric protein based on S1 subunit to combat COVID-19, as a possible immunogen or antigen for diagnosis.

The main COVID-19 vaccine formulations used today are mainly based on the wild-type SARS-CoV-2 spike glycoprotein as an antigen. However, new virus variants capable of escaping neutralization activity of serum antibodies elicited in vaccinated individuals have emerged. The Omicron (B.1.1.529) variant caused epidemics in regions of the world in which most of the population has been vaccinated. In this study, we aimed to understand what determines individual's susceptibility to Omicron in a scenario of extensive vaccination. For that purpose, we collected nasopharynx swab (n = 286) and blood samples (n = 239) from flu-like symptomatic patients, as well as their vaccination history against COVID-19. We computed the data regarding vaccine history, COVID-19 diagnosis, COVID-19 serology and viral genome sequencing to evaluate their impact on the number of infections. As main results, we showed that vaccination in general did not reduce the number of individuals infected by Omicron, even with an increased immune response found among vaccinated non-infected individuals. Nonetheless, we found that individuals who received the third vaccine dose showed significantly reduced susceptibility to Omicron infections. A relevant evidence that support this finding was the higher virus neutralization capacity of serum samples of most patients who received the third vaccine dose. In summary, this study shows that boosting immune responses after a third vaccine dose reduces susceptibility to COVID-19 caused by the Omicron variant. Results presented in this study are useful for future formulations of COVID-19 vaccination policies. This article is protected by copyright. All rights reserved.

All extracellular forms of Trypanosoma cruzi, the causative agent of Chagas disease, release extracellular vesicles (EVs) containing major surface molecules of the parasite. EV release depends on several mechanisms (internal and external). However, most of the environmental conditions affecting this phenomenon are still unknown. In this work, we evaluated EV release under different stress conditions and their ability to be internalized by the parasites. In addition, we investigated whether the release conditions would affect their immunomodulatory properties in preactivated bone marrow-derived macrophages (BMDM). Sodium azide and methyl-cyclo-β-dextrin (CDB) reduced EV release, indicating that this phenomenon relies on membrane organization. EV release was increased at low temperatures (4°C) and acidic conditions (pH 5.0). Under this pH, trypomastigotes differentiated into amastigotes. EVs are rapidly liberated and reabsorbed by the trypomastigotes in a concentration-dependent manner. Nitrosative stress caused by sodium nitrite in acid medium or S-nitrosoglutathione also stimulated the secretion of EVs. EVs released under all stress conditions also maintained their proinflammatory activity and increased the expression of iNOS, Arg 1, IL-12, and IL-23 genes in IFN-γ and LPS preactivated BMDM. In conclusion, our results suggest a budding mechanism of release, dependent on the membrane structure and parasite integrity. Stress conditions did not affect functional properties of EVs during interaction with host cells. EV release variations under stress conditions may be a physiological response against environmental changes.

This study evaluated SARS-CoV-2 replication in human cell lines derived from various tissues and investigated molecular mechanisms related to viral infection susceptibility and replication.SARS-CoV-2 replication in BEAS-2B and A549 (respiratory tract), HEK-293 T (kidney), HuH7 (liver), SH-SY5Y (brain), MCF7 (breast), Huvec (endothelial) and Caco-2 (intestine) was evaluated by RT-qPCR. Concomitantly, expression levels of ACE2 (Angiotensin Converting Enzyme) and TMPRSS2 were assessed through RT-qPCR and western blot. Proteins related to autophagy and mitochondrial metabolism were monitored in uninfected cells to characterize the cellular metabolism of each cell line. The effect of ACE2 overexpression on viral replication in pulmonary cells was also investigated.Our data show that HuH7, Caco-2 and MCF7 presented a higher viral load compared to the other cell lines. The increased susceptibility to SARS-CoV-2 infection seems to be associated not only with the differential levels of proteins intrinsically related to energetic metabolism, such as ATP synthase, citrate synthase, COX and NDUFS2 but also with the considerably higher TMPRSS2 mRNA expression. The two least susceptible cell types, BEAS-2B and A549, showed drastically increased SARS-CoV-2 replication capacity when ACE2 was overexpressed. These modified cell lines are relevant for studying SARS-CoV-2 replication in vitro.Our data not only reinforce that TMPRSS2 expression and cellular energy metabolism are important molecular mechanisms for SARS-CoV-2 infection and replication, but also indicate that HuH7, MCF7 and Caco-2 are suitable models for mechanistic studies of COVID-19. Moreover, pulmonary cells overexpressing ACE2 can be used to understand mechanisms associated with SARS-CoV-2 replication.

Most approved vaccines against COVID-19 have to be administered in a prime/boost regimen. We engineered a novel vaccine based on a chimeric human adenovirus 5 (hAdV5) vector. The vaccine (named CoroVaxG.3) is based on three pillars: (i) high expression of Spike to enhance its immunodominance by using a potent promoter and an mRNA stabilizer, (ii) enhanced infection of muscle and dendritic cells by replacing the fiber knob domain of hAdV5 by hAdV3, (iii) use of Spike stabilized in a prefusion conformation. The transduction with CoroVaxG.3-expressing Spike (D614G) dramatically enhanced the Spike expression in human muscle cells, monocytes and dendritic cells compared to CoroVaxG.5 that expressed the native fiber knob domain. A single dose of CoroVaxG.3 induced a potent humoral immunity with a balanced Th1/Th2 ratio and potent T-cell immunity, both lasting for at least 5 months. Sera from CoroVaxG.3-vaccinated mice was able to neutralize pseudoviruses expressing B.1 (wild type D614G), B.1.117 (alpha), P.1 (gamma) and B.1.617.2 (delta) Spikes, as well as an authentic P.1 SARS-CoV-2 isolate. Neutralizing antibodies did not wane even after 5 months, making this kind of vaccine a likely candidate to enter clinical trials.

Most approved vaccines against COVID-19 have to be administered in a prime/boost regimen. We engineered a novel vaccine based on a chimeric hAdV5 vector. The vaccine (named CoroVaxG.3) is based on three pillars: i) high expression of Spike to enhance its immunodominance by using a potent promoter and a mRNA stabilizer; ii) enhanced infection of muscle and dendritic cells by replacing the fiber knob domain of hAdV5 by hAdV3; iii) use of Spike stabilized in a prefusion conformation. Transduction with CoroVaxG.3 expressing Spike (D614G) dramatically enhanced Spike expression in human muscle cells, monocytes and dendritic cells compared to CoroVaxG.5 that expressed the native fiber knob domain. A single dose of CoroVaxG.3 induced potent humoral immunity with a balanced Th1/Th2 ratio and potent T-cell immunity, both lasting for at least 5 months. Sera from CoroVaxG.3 vaccinated mice was able to neutralize pseudoviruses expressing B.1 (wild type D614G), B.1.117 (alpha) and P.1 (gamma) Spikes, as well as an authentic WT and P.1 SARS-CoV-2 isolates. Neutralizing antibodies did not wane even after 5 months making this kind of vaccine a likely candidate to enter clinical trials

Background: The absence of specific antivirals to treat COVID-19 leads to the repositioning of candidates’ drugs. Nitazoxanide (NTZ) has a broad antiviral effect. Methods: This was a randomized, double-blind pilot clinical trial comparing NTZ 600 mg BID versus Placebo for seven days among 50 individuals (25 each arm) with SARS-COV-2 RT-PCR+ (PCR) that were hospitalized with mild respiratory insufficiency from May 20th, 2020, to September 21st, 2020 (ClinicalTrials.gov NCT04348409). Clinical and virologic endpoints and inflammatory biomarkers were evaluated. A five-point scale for disease severity (SSD) was used. Findings: Two patients died in the NTZ arm compared to 6 in the placebo arm (p = 0.564). NTZ was superior to placebo when considering SSD (p < 0001), the mean time for hospital discharge (6.6 vs. 14 days, p = 0.021), and negative PCR at day 21 (p = 0.035), whereas the placebo group presented more adverse events (p = 0.04). Among adverse events likely related to the study drug, 14 were detected in the NTZ group and 22 in placebo (p = 0.24). Among the 30 adverse events unlikely related, 21 occurred in the placebo group (p = 0.04). A decrease from baseline was higher in the NTZ group for D-Dimer (p = 0.001), US-RCP (p < 0.002), TNF (p < 0.038), IL-6 (p < 0.001), IL-8 (p = 0.014), HLA DR. on CD4+ T lymphocytes (p < 0.05), CD38 in CD4+ and CD8+ T (both p < 0.05), and CD38 and HLA-DR. on CD4+ (p < 0.01) Interpretation: Compared to placebo in clinical and virologic outcomes and improvement of inflammatory out comes, the superiority of NTZ warrants further investigation of this drug for moderate COVID-19 in larger clinical trials. A higher incidence of adverse events in the placebo arm might be attributed to COVID-19 related symptoms. Funding: This study was supported by Farmoquimica (FQM), Brazil. Laboratory testing was partially sup ported by a grant from CNPq, Brazil (RD).

The outbreak of coronavirus (COVID-19) has put the world in an unprecedented scenario. To reestablish the world routine as promote the effective treatment of this disease, the world is looking for new (and old) drug that can efficiently kill the virus. In this study, we have developed two nanosystems: polymeric nanoparticles and nanomicelles-based on hydroxychloroquine and azithromycin. The nanosystem was fully characterized by AFM and DLS techniques. Also, the nanosystems were radiolabeled withThe online version contains supplementary material available at 10.1007/s40097-022-00476-3.

Summary: Noradrenaline (NE), the main neurotransmitter released by sympathetic nerve terminals, is known to modulate the immune response. However, the role of the sympathetic nervous system (SNS) on the development of autoimmune diseases is still unclear. Here, we report that the SNS limits the generation of pathogenic T cells and disease development in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). β2-Adrenergic receptor (Adrb2) signaling limits T cell autoimmunity in EAE through a mechanism mediated by the suppression of IL-2, IFN-γ, and GM-CSF production via inducible cAMP early repressor (ICER). Accordingly, the lack of Adrb2 signaling in immune cells is sufficient to abrogate the suppressive effects of SNS activity, resulting in increased pathogenic T cell responses and EAE development. Collectively, these results uncover a suppressive role for the SNS in CNS autoimmunity while they identify potential targets for therapeutic intervention. : Araujo et al. show that neurotransmitters released by the sympathetic nervous system regulate the generation of adaptive immune responses mitigating autoimmune inflammation within the CNS. Keywords: sympathetic nervous system, experimental autoimmune encephalomyelitis, autoimmunity, β2-adrenergic receptor, ICER, GM-CSF, IFN-γ, CD4+ T cells

Chronic lymphocytic leukemia (CLL) is a chronic form of leukemia that originates from an abnormal expansion of CD5+B-1 cells. Deregulation in the BCR signaling is associated with B-cell transformation. Contrariwise to B-2 cells, BCR engagement in B-1 cells results in low proliferation rate and increased apoptosis population, whereas overactivation may be associated with lymphoproliferative disorders. It has been demonstrated that several transcription factors that are involved in the B cell development play a role in the regulation of BCR function. Among them, Ikaros is considered an essential regulator of lymphoid differentiation and activation. Several reports suggest that Ikaros expression is deregulated in different forms of leukemia. Herein, we demonstrated that CLL cells show decreased Ikaros expression and abnormal cytoplasmic cell localization. These alterations were also observed in radioresistant B-1 cells, which present high proliferative activity, suggesting that abnormal localization of Ikaros could determine its loss of function. Furthermore, Ikaros knockdown increased the expression of BCR pathway components in murine B-1 cells, such as Lyn, Blnk, and CD19. Additionally, in the absence of Ikaros, B-1 cells become responsive to BCR stimulus, increasing cell proliferation even in the absence of antigen stimulation. These results suggested that Ikaros is an important controller of B-1 cell proliferation by interfering with the BCR activity. Therefore, altered Ikaros expression in CLL or radioresistant B-1 cells could determine a responsive status of BCR to self-antigens, which would culminate in the clonal expansion of B-1 cells.

The pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is receiving worldwide attention, due to the severity of the disease (COVID-19) that resulted in more than a million global deaths so far. The urgent need for vaccines and antiviral drugs is mobilizing the scientific community to develop strategies for studying the mechanisms of SARS-CoV-2 infection, replication kinetics, pathogenesis, host–virus interaction, and infection inhibition. In this work, we review the strategies of tissue engineering in the fabrication of three-dimensional (3D) models used in virology studies, which presented many advantages over conventional cell cultures, such as complex cytoarchitecture and a more physiological microenvironment. Scaffold-free (spheroids and organoids) and scaffold-based (3D scaffolding and 3D bioprinting) approach allow the biofabrication of more realistic models relevant to the pandemic, to be used as in vitro platforms for the development of new vaccines and therapies against COVID-19.

Background: The absence of specific antivirals to treat COVID-19 leads to the repositioning of candidates’ drugs. Nitazoxanide (NTZ) has a broad antiviral effect. Methods: The in vitro effect of NTZ in VERO E6 cells was evaluated, followed by a randomized double-blind phase two clinical trial comparing NTZ 600 mg BID versus placebo for 7 days among 50 individuals (25 each arm) with SARS-COV-2 RT-PCR+ (PCR) that were hospitalized with mild respiratory insufficiency. Clinical and virologic end-points and inflammatory biomarkers were evaluated. A five-point scale for disease severity (SSD) was used. Results: The in vitro inhibition of SARS-CoV-2 infection was 90% with 0.5 µM, with no cytotoxicity. Two patients died in the NTZ arm compared to 6 in the placebo arm (p=NS). NTZ was superior to placebo when considering SSD (p

Computational prediction of immunogenic epitopes is a promising platform for therapeutic and preventive vaccine design. A potential target for this strategy is human immunodeficiency virus (HIV-1), for which, despite decades of efforts, no vaccine is available. In particular, a therapeutic vaccine devised to eliminate infected cells would represent a key component of cure strategies. HIV peptides designed based on individual viro-immunological data from people living with HIV/AIDS have recently shown able to induce post-therapy viral set point abatement. However, the reproducibility and scalability of this method is curtailed by the errors and arbitrariness associated with manual peptide design as well as by the time-consuming process.We herein introduce Custommune, a user-friendly web tool to design personalized and population-targeted vaccines. When applied to HIV-1, Custommune predicted personalized epitopes using patient specific Human Leukocyte Antigen (HLA) alleles and viral sequences, as well as the expected HLA-peptide binding strength and potential immune escape mutations. Of note, Custommune predictions compared favorably with manually designed peptides administered in a recent phase II clinical trial (NCT02961829).Furthermore, we utilized Custommune to design preventive vaccines targeted for populations highly affected by COVID-19. The results allowed the identification of peptides tailored for each population and predicted to elicit both CD8+ T-cell immunity and neutralizing antibodies against structurally conserved epitopes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).Overall, our data describe a new tool for rapid development of personalized or population-based immunotherapy against chronic and acute viral infections.

The causative agent of COVID-19 pandemic, the SARS-CoV-2 coronavirus, has a 29,903 bases positive-sense single-stranded RNA genome. RNAs exhibit about 100 modified bases that are essential for proper function. Among internal modified bases, the N6-methyladenosine, or m6A, is the most frequent, and is implicated in SARS-CoV-2 immune response evasion. Although the SARS-CoV-2 genome is RNA, almost all genomes sequenced so far are in fact, reverse transcribed complementary DNAs. This process reduces the true complexity of these viral genomes because incorporation of dNTPs hides RNA base modifications. Here, in this perspective paper, we present an initial exploration of the Nanopore direct RNA sequencing to assess the m6A residues in the SARS-CoV-2 sequences of ORF3a, E, M, ORF6, ORF7a, ORF7b, ORF8, N, ORF10 and the 3’-untranslated region. We identified 15 m6A methylated positions, of which, 6 are in ORF N. Also, because m6A is associated with the DRACH motif, we compared its distribution in major SARS-CoV-2 variants. Although DRACH is highly conserved among variants we show that variants Beta and Eta have a fourth position C>U change in DRACH at 28,884b that could affect methylation. The Nanopore technology offers a unique opportunity for the study of viral epitranscriptomics. This technique is PCR-free and is not sequencing-by-synthesis, therefore, no PCR bias and synthesis errors are introduced. The modified bases are preserved and assessed directly with no need for chemical treatments or antibodies. This is the first report of direct RNA sequencing of a Brazilian SARS-CoV-2 sample coupled with the identification of modified bases.

Antiretroviral therapy (ART) is typically composed of a combination of three antiretroviral drugs and is the treatment of choice for people with human immunodeficiency virus type 1/acquired immune deficiency syndrome (HIV-1/AIDS). However, it is unable to impact on viral reservoirs, which harbour latent HIV-1 genomes that are able to reignite the infection upon treatment suspension. The aim of this study was to provide an estimate of the safety of the disease-modifying antirheumatic agent auranofin and its impact on the HIV-1 reservoir in humans under intensified ART. For this purpose, an interim analysis was conducted of three of the six arms of the NCT02961829 clinical trial (five patients each) with: no intervention, i.e. continuation of first-line ART; intensified ART (ART + dolutegravir and maraviroc); and intensified ART plus auranofin. Auranofin treatment was found to be well tolerated. No major adverse events were detected apart from a transient decrease in CD4+ T-cell counts at Weeks 8 and 12. Auranofin decreased total viral DNA in peripheral blood mononuclear cells compared with ART-only regimens at Week 20 (P = 0.036) and induced a decrease in integrated viral DNA as quantified by Alu PCR. Despite the limited number of patient-derived sequences available in this study, phylogenetic analyses of nef sequences support the idea that auranofin may impact on the viral reservoir. [ ClinicalTrials.gov ID: NCT02961829 ]

The participation of B-1 cells in a murine model of spontaneous diabetes has been recently reported. Here, we describe the role of B-1 cells in streptozotocin (STZ) induced diabetes in mice. We demonstrated that XID (B-1 cell-deficient) mice are more susceptible to STZ treatment than WT mice, as evidenced by their higher blood glucose level in response to STZ. Unexpectedly, the XID mice that were i.p. transferred with purified B-1 cells, either before or after the STZ treatment, did not develop diabetes. These cell transfers provided long-lasting protection for the XID mice against STZ-induced diabetes, suggesting that B-1 cells play an important role in the experimental diabetes pathobiology. We also showed that B-1 cell culture supernatants were able to regulate the blood glucose level of the diabetic XID mice, and we identified insulin-producing cells when B-1 cells were differentiated in B-1 cell-derived phagocyte in vitro. These findings provide a novel role for B-1 cells in metabolic processes, presenting a new mechanism to explain the pathogenesis of diabetes and a possible therapeutical target.

Current therapies against malignant melanoma generally fail to increase survival in most patients, and immunotherapy is a promising approach as it could reduce the dosage of toxic therapeutic drugs. In the present study, we show that an immunotherapeutic approach based on the use of the Toll-like receptor (TLR)-5 ligand flagellin (Salmonella Typhimurium FliCi) combined with the major histocompatibility complex class II-restricted P10 peptide, derived from the Paracoccidioides brasiliensis gp43 major surface protein, reduced the number of lung metastasis in a murine melanoma model. Compounds were administered intranasally into C57Bl/6 mice intravenously challenged with syngeneic B16F10-Nex2 melanoma cells, aiming at the local (pulmonary) immune response modulation. Along with a marked reduction in the number of lung nodules, a significant increase in survival was observed. The immunization regimen induced both local and systemic proinflammatory responses. Lung macrophages were polarized towards a M1 phenotype, lymph node cells, and splenocytes secreted higher interleukin-12p40 and interferon (IFN)-γ levels when re-stimulated with tumor antigens. The protective effect of the FliCi+P10 formulation required TLR-5, myeloid differentiation primary response gene 88 and IFN-γ expression, but caspase-1 knockout mice were only partially protected, suggesting that intracellular flagellin receptors are not involved with the anti-tumor effect. The immune therapy resulted in the activation of tumor-specific CD4(+) T lymphocytes, which conferred protection to metastatic melanoma growth after adoptive transfer. Taken together, our results report a new immunotherapeutic approach based on TLR-5 activation and IFN-γ production capable to control the metastatic growth of B16F10-Nex2 melanoma, being a promising alternative to be associated with chemotherapeutic drugs for an effective anti-tumor responses.

New Zealand Black X New Zealand White F1 [(NZB/NZW)F1] mice develop an autoimmune condition with similarities to human systemic lupus erythematosus (SLE). In this study, we demonstrate that B-1 cells, which have previously been reported to be involved in several autoimmune diseases, have altered gene expression in these mice. RNA was extracted from purified B-1 cells of disease-free C57BL/6 mice and lupus-prone (NZB/NZW)F1 mice. Gene expression was analysed using DNA microarray techniques and validated by real time reverse transcriptase polymerase chain reaction (RT-PCR). In (NZB/NZW)F1 mice, some genes had altered expression patterns compared to disease-free controls. Specifically, the upregulation of Ifitm1, Pvrl2 and Ifi202b and downregulation of Trp53bp1 mRNA were observed in (NZB/NZW)F1 mice. These genes are known to be associated with autoimmune diseases. This pattern of gene expression in B-1 cells could understanding of the pathogenesis of SLE. Thus, it is reasonable to hypothesise that the altered gene expression observed in B-1 cells in our experimental model is important for SLE prognosis and therapy, and these implications are discussed herein.

Beta2-adrenergic receptor (B2AR) signaling is known to impair Th1-cell differentiation and function in a cAMP-dependent way, leading to inhibition of cell proliferation and decreased production of IL-2 and IFN-γ. CD4(+) Foxp3(+) Treg cells play a key role in the regulation of immune responses and are essential for maintenance of self-tolerance. Nevertheless, very little is known about adrenergic receptor expression in Treg cells or the influence of noradrenaline on their function. Here we show that Foxp3(+) Treg cells express functional B2AR. B2AR activation in Treg cells leads to increased intracellular cAMP levels and to protein kinase A (PKA)-dependent CREB phosphorylation. We also found that signaling via B2AR enhances the in vitro suppressive activity of Treg cells. B2AR-mediated increase in Treg-cell suppressive function was associated with decreased IL-2 mRNA levels in responder CD4(+) T cells and improved Treg-cell-induced conversion of CD4(+) Foxp3(-) cells into Foxp3(+) induced Treg cells. Moreover, B2AR signaling increased CTLA-4 expression in Treg cells in a PKA-dependent way. Finally, we found that PKA inhibition totally prevented the B2AR-mediated increase in Treg-cell suppressive function. Our data suggest that sympathetic fibers are able to regulate Treg-cell suppressive activity in a positive manner through B2AR signaling.

Paracoccidioidomycosis is a systemic granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. Its major antigen is a 43 kDa glycoprotein whose peptides embody different functions: P10 peptide, a T-cell epitope, induces protective response while P4 and P23 peptides inhibit both, macrophage functions and inflammatory reaction, thus facilitating infection. Here we investigated the modulating mechanisms of the immune response exerted by P4 and P23 involved in the latter inhibitory effect on macrophages. Moreover we analyzed the peptides effects in different models in vivo. While evaluating whether P4 and P23 present systemic anti-inflammatory effects in vivo, we showed that their intraperitonial administration decreased footpad swelling in mice infected with either P. brasiliensis or Mycobacterium bovis. Both, qPCR and ELISA assays suggested that this anti-inflammatory effect depended on alterations in the kinetics of production of innate immunity modulators such as TNF-α, IL6, IL10 and TLR2. IL10 seems to be early produced than TNF-α and IL6, produced later in presence of peptides. Higher doses or intravenously given P4 and P23 resulted in earlier and more prolonged anti-inflammatory effects. Moreover, continuous treatment with P4 and P23 sustained the anti-inflammatory activity throughout.

Glycoprotein gp70 is an important intracellular antigen from Paracoccidioides brasiliensis that elicits both humoral and cellular immune responses. Herein, the PbGP70 gene cloning from isolate Pb18 using internal peptide sequence information is reported. The deduced protein sequence bears two N-glycosylation sites, antigenic sites and two mouse T-cell epitopes. Anti-recombinant gp70 (rPbgp70) polyclonal antibodies reacted with a 70-kDa component in total cell extract of P. brasiliensis, while MAbC5F11 and paracoccidioidomycosis patients' sera recognized rPbgp70. Confocal microscopy with anti-rPbgp70 and MAbC5F11 showed intense staining and cytoplasmatic co-localization. The protein sequence belongs to the flavoprotein monooxygenase family which groups important anti-oxidative bioactive compounds. We found increased PbGP70 transcript accumulation under oxidative stress induced by H(2)O(2), during fungal growth and in macrophage phagocyted/bound yeasts. Therefore, gp70 might play a dual role in P. brasiliensis by both eliciting immune cellular and humoral responses in the host and protecting the fungus from oxidative stress generated by phagocytic cells.

Paracoccidioidomycosis (PCM) is a systemic granulomatous disease caused by Paracoccidioides brasiliensis (Pb), a thermal dimorphic fungus. Its major antigen is a 43-kDa glycoprotein. Gp43 embodies different functions: it participates in evasion mechanisms during the installation of primary infection, stimulates granuloma-like formation in vitro and presents T-cell epitopes that induce protective response against the fungus. Here, we investigated epitopes from gp43 inhibitory of both, macrophage functions and inflammatory reaction. Different gp43 peptides, spanning the entire sequence of the molecule, were added to cultures of bone marrow-derived macrophages. After challenge with zymosan or Pb cells, phagocytic indexes were measured. Peptides expressed on the molecule surface were determined by graphic analysis using the Protean module; DNAstar Inc. Two peptides which decreased phagocytic index and were expressed at the surface of the molecule, P4 and P23, were selected for further studies. It was shown that both inhibited the release of NO by zymosan stimulated macrophages while enhanced release of H 2 O 2 . The release of TNF-α in culture supernatants from in vitro phagocytic tests showed different response depending of P4 concentration (data not shown). In vivo assays with Mycobacterium bovis – bacillus Calmette–Guerin (BCG) or Pb cells demonstrated that these peptides presented non-specific and specific anti-inflammatory properties.

Despite accumulating evidence indicating that neurotransmitters released by the sympathetic nervous system can modulate the activity of innate immune cells, we still know very little about how norepinephrine impacts signaling pathways in dendritic cells (DC) and the consequence of that in DC-driven T cell differentiation. In this article, we demonstrate that β2-adrenergic receptor (β2AR) activation in LPS-stimulated DC does not impair their ability to promote T cell proliferation; however, it diminishes IL-12p70 secretion, leading to a shift in the IL-12p70/IL-23 ratio. Although β2AR stimulation in DC induces protein kinase A–dependent cAMP-responsive element–binding protein phosphorylation, the effect of changing the profile of cytokines produced upon LPS challenge occurs in a protein kinase A–independent manner and, rather, is associated with inhibition of the NF-κB and AP-1 signaling pathways. Moreover, as a consequence of the inverted IL-12p70/IL-23 ratio following β2AR stimulation, LPS-stimulated DC promoted the generation of CD4+ T cells that, upon TCR engagement, produced lower amounts of IFN-γ and higher levels of IL-17. These findings provide new insights into molecular and cellular mechanisms by which β2AR stimulation in murine DC can influence the generation of adaptive immune responses and may explain some aspects of how sympathetic nervous system activity can modulate immune function.

Hypermutation alludes to an excessive number of specific guanine-to-adenine (G- >A) substitutions in proviral DNA and this phenomenon is attributed to the catalytic activity of cellular APOBECs. Population studies relating hypermutation and the progression of infection by human immunodeficiency virus type 1 (HIV-1) have been performed to elucidate the effect of hypermutation on the natural course of HIV-1 infection. However, the many different approaches employed to assess hypermutation in nucleotide sequences render the comparison of results difficult. This study selected 157 treatment-naive patients and sought to correlate the hypermutation level of the proviral sequences in clinical samples with demographic variables, HIV-1 RNA viral load, and the level of CD4+ T cells. Nested touchdown polymerase chain reaction (PCR) was performed with specific primers to detect hypermutation in the region of HIV-1 integrase, and the amplified sequences were run in agarose gels with HA-Yellow. The analysis of gel migration patterns using the k-means clustering method was validated by its agreement with the results obtained with the software Hypermut. Hypermutation was found in 31.2% of the investigated samples, and a correlation was observed between higher hypermutation levels and higher viral load levels. These findings suggest a high frequency of hypermutation detection in a Brazilian cohort, which can reflect a particular characteristic of this population, but also can result from the method approach by aiming at hypermutation-sensitive sites. Furthermore, we found that hypermutation events are pervasive during HIV-1 infection as a consequence of high viral replication, reflecting its role during disease progression.

Human immunodeficiency virus type 1 (HIV-1) genetic diversity is one of the most important features of HIV-1 infections and the result of error accumulation during reverse transcription and of high viral turnover. HIV-1 reverse transcription is influenced by factors such as the level of nucleotides and/or the cellular activation state. HIV-1 diversity was investigated after 48 h of viral propagation in peripheral blood mononuclear cells (PBMCs) obtained from healthy donors in three different cell culture conditions: (1) resting PBMCs, (2) simultaneous infection and PBMC activation, and (3) PBMC activation 72 h before infection. Cellular DNA was extracted and proviruses of each culture condition were amplified. Single-genome PCR clones were obtained and the protease and reverse transcriptase of the pol gene were sequenced. An elevated number of nucleotide substitutions in all three culture conditions were observed. In condition 1, the mutational rate observed ranged from 1.0 × 10-3 to 2.1 × 10-2, the genetic diversity was 0.6%, and hypermutation was observed in 7.1% of sequenced clones. In condition 2, the mutational rate ranged from 1.0 × 10-3 to 1.0 × 10-2, the genetic diversity was 0.8%, and hypermutation affected 6.7% of clones. In condition 3, the mutational rate ranged from 2.8 × 10-3 to 1.1 × 10-2, the genetic diversity was 1%, and 5.9% of clones were hypermutated. Substitutions occurred more frequently in some specific nucleotide stretches, and a common pattern for substitutions in all the different conditions was identified. There was a significant accumulation of mutations during the initial periods of in vitro HIV-1 propagation irrespective of culture conditions. The rapid accumulation of virus diversity might represent a viral strategy when colonizing new hosts. Complementary studies are necessary to allow for a better understanding of the initial periods of infection, which represent a crucial event related to disease progression.

The present study investigated the prevalence of HIV-1 multiple infections in a population composed by 47 patients under HAART failure and enrolled at the National DST/AIDS, Program, Ministry of Health, Brazil.Detection of multiple infections was done using a previously published RFLP assay for the HIV-1 protease gene, which is able of distinguishing between infections caused by a single or multiple HIV-1 subtypes. Samples with multiple infections were cloned, and sequence data submitted to phylogenetic analysis. We were able to identify 17 HIV-1 multiple infections out of 47 samples. Multiple infections were mostly composed by a mixture of recombinant viruses (94%), with only one case in which protease gene pure subtypes B and F were recovered. This is the first study that reports the prevalence of multiple infections and intersubtype recombinants in a population undergoing HAART in Brazil. Based on the data there was a steep increase of multiple infections after the introduction of the combined antiretroviral therapy in Brazil. Cases of multiple infections may be associated with HIV-1 genetic diversity through recombination allowing for the generation of viruses showing a combination of resistance mutations.

Paracoccidioides brasiliensis, a causative agent of paracoccidioidomycosis (PCM), should be able to adapt to dramatic environmental changes inside the infected host after inhalation of air-borne conidia and transition to pathogenic yeasts. Proteins with antioxidant functions may protect fungal cells against reactive oxygen (ROS) and nitrogen (RNS) species generated by phagocytic cells, thus acting as potential virulence factors. Ras GTPases are involved in stress responses, cell morphology, and differentiation in a range of organisms. Ras, in its activated form, interacts with effector proteins and can initiate a kinase cascade. In lower eukaryotes, Byr2 kinase represents a Ras target. The present study investigated the role of Ras in P. brasiliensis after in vitro stimulus with ROS or RNS. We have demonstrated that low concentrations of H2O2 (0.1 mM) or NO2 (0.1-0.25 µM) stimulated P. brasiliensis yeast cell proliferation and that was not observed when yeast cells were pre-incubated with farnesyltransferase inhibitor. We constructed an expression plasmid containing the Byr2 Ras-binding domain (RBD) fused with GST (RBD-Byr2-GST) to detect the Ras active form. After stimulation with low concentrations of H2O2 or NO2, the Ras active form was observed in fungal extracts. Besides, NO2 induced a rapid increase in S-nitrosylated Ras levels. This alternative posttranslational modification of Ras, probably in residue Cys123, would lead to an exchange of GDP for GTP and consequent GTPase activation in P. brasiliensis. In conclusion, low concentrations of H2O2 or NO2 stimulated P. brasiliensis proliferation through Ras activation.

BACKGROUND: P21 is a secreted protein expressed in all developmental stages of Trypanosoma cruzi. The aim of this study was to determine the effect of the recombinant protein based on P21 (P21-His(6)) on inflammatory macrophages during phagocytosis. FINDINGS: Our results showed that P21-His(6) acts as a phagocytosis inducer by binding to CXCR4 chemokine receptor and activating actin polymerization in a way dependent onthe PI3-kinase signaling pathway. CONCLUSIONS: Thus, our results shed light on the notion that native P21 is a component related to T. cruzi evasion from the immune response and that CXCR4 may be involved in phagocytosis. P21-His(6) represents an important experimental control tool to study phagocytosis signaling pathways of different intracellular parasites and particles.

Made available in DSpace on 2013-09-27T14:54:31Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2013-09-27T14:54:31Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2013-09-27T14:54:31Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2013-09-30T18:38:38Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2013-09-30T18:38:38Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:51:13Z No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Made available in DSpace on 2013-09-30T18:38:38Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:51:13Z No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Made available in DSpace on 2014-05-20T13:51:13Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2014-05-20T13:51:13Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2013-09-30T18:38:38Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:51:13Z No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:51:13Z No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Made available in DSpace on 2014-05-20T13:51:13Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Made available in DSpace on 2014-05-20T13:51:13Z (GMT). No. of bitstreams: 1 WOS000287615000006.pdf: 903468 bytes, checksum: 40a6017ece6a8fab966c54d4ea5be9e3 (MD5) Previous issue date: 2011-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This work was conducted to identify virulence biomarkers for Paracoccidioides brasiliensis (Pb), the fungus responsible for Paracoccidioidomycosis (PCM), a systemic disease endemic in Latin America. Measurement of mortality showed that all B10.A mice were killed after 250 days by the virulent Pb18 isolate while only one of the mice that received the attenuated counterpart died. Also, number of lung CFUs from virulent Pb18 inoculated mice were much higher when these isolates were compared. Phage display methodology allowed selection of three phages that specifically bound to virulent Pb18. Variability of p04 phage binding to different Pb isolates were examples of variability of expression by the fungus of its binding molecule, strongly suggesting p04 as a biomarker of virulence. In vitro, its derived peptide pep04 killed only virulent fungi, and confocal microscopy showed that it was internalized only by the virulent isolate. Pep04 blocked establishment of Pb infection in mice and virulent Pb18 pre-incubated with p04 showed significantly inhibited lung infection. Furthermore, infected mice treated with p04 showed highly significant reduction in lung CFUs. These findings firmly establish p04 as a biomarker of Pb virulence. Therefore, after proper peptide engineering, p04 may become a useful adjuvant for the distressing treatment of PCM. (C) 2010 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved. Univ Fed São Paulo, Dept Microbiol Immunol & Parasitol, São Paulo, Brazil State Univ São Paulo, Dept Microbiol, Inst Biosci Botucatu, Botucatu, SP, Brazil Univ Estadual Paulista, Inst Hlth, São Paulo, Brazil State Univ São Paulo, Dept Microbiol, Inst Biosci Botucatu, Botucatu, SP, Brazil Univ Estadual Paulista, Inst Hlth, São Paulo, Brazil FAPESP: 04/04471-9

To evaluate the comparative in-vitro antiangiogenic effect of Bevacizumab and Ranibizumab.Endothelial venous umbilical cells culture (ECV304) cultivated in F12 media with addition of 10% Fetal Bovine Serum, were plaqued and treated with clinically relevant concentrations of Bevacizumab and Ranibizumab just after the scratch done in the middle of the culture (scratch methodology). Measurements of the linear size of the area free of cell proliferation were done 24, 48 and 72 hours after the scratch day point. All the experiments were done in triplicate and statistical analysis were done with T-student test.Inhibitory effect was observed just at the concentrations of 0.5 and 0.7 mg/ml in both drugs. At 0.7 mg/ml, Ranibizumab demonstrated a more potent proliferative inhibitory effect than Bevacizumab. At the same concentration, Ranibizumab was three times more potent than Ranibizumab. Inhibitory effect was observed just in the first 24 hours for both drugs.Ranibizumab demonstrates an increased effect when compared to Bevacizumab and this is related more to the different molar rate of each drug than related to a real better proliferative inhibitory effect.

In order to establish new infections HIV-1 particles need to attach to receptors expressed on the cellular surface. HIV-1 particles interact with a cell membrane receptor known as CD4 and subsequently with another cell membrane molecule known as a co-receptor. Two major different co-receptors have been identified: C-C chemokine Receptor type 5 (CCR5) and C-X-C chemokine Receptor type 4 (CXCR4) Previous reports have demonstrated cellular modifications upon HIV-1 binding to its co-receptors including gene expression modulations. Here we investigated the effect of viral binding to either CCR5 or CXCR4 co-receptors on viral diversity after a single round of reverse transcription. CCR5 and CXCR4 pseudotyped viruses were used to infect non-stimulated and stimulated PBMCs and purified CD4 positive cells. We adopted the SOLiD methodology to sequence virtually the entire proviral DNA from all experimental infections. Infections with CCR5 and CXCR4 pseudotyped virus resulted in different patterns of genetic diversification. CCR5 virus infections produced extensive proviral diversity while in CXCR4 infections a more localized substitution process was observed. In addition, we present pioneering results of a recently developed method for the analysis of SOLiD generated sequencing data applicable to the study of viral quasi-species. Our findings demonstrate the feasibility of viral quasi-species evaluation by NGS methodologies. We presented for the first time strong evidence for a host cell driving mechanism acting on the HIV-1 genetic variability under the control of co-receptor stimulation. Additional investigations are needed to further clarify this question, which is relevant to viral diversification process and consequent disease progression.

Epigenetic modifications refer to a number of biological processes which alter the structure of chromatin and its transcriptional activity such as DNA methylation and histone post-translational processing. Studies have tried to elucidate how the viral genome and its products are affected by epigenetic modifications imposed by cell machinery and how it affects the ability of the virus to either, replicate and produce a viable progeny or be driven to latency. The purpose of this study was to evaluate epigenetic modifications in PBMCs and CD4+ cells after HIV-1 infection analyzing three approaches: (i) global DNA- methylation; (ii) qPCR array and (iii) western blot. HIV-1 infection led to methylation increases in the cellular DNA regardless the activation status of PBMCs. The analysis of H3K9me3 and H3K27me3 suggested a trend towards transcriptional repression in activated cells after HIV-1 infection. Using a qPCR array, we detected genes related to epigenetic processes highly modulated in activated HIV-1 infected cells. SETDB2 and RSK2 transcripts showed highest up-regulation levels. SETDB2 signaling is related to transcriptional silencing while RSK2 is related to either silencing or activation of gene expression depending on the signaling pathway triggered down-stream. In addition, activated cells infected by HIV-1 showed lower CD69 expression and a decrease of IL-2, IFN-γ and metabolism-related factors transcripts indicating a possible functional consequence towards global transcriptional repression found in HIV-1 infected cells. Conversely, based on epigenetic markers studied here, non-stimulated cells infected by HIV-1, showed signs of global transcriptional activation. Our results suggest that HIV-1 infection exerts epigenetic modulations in activated cells that may lead these cells to transcriptional repression with important functional consequences. Moreover, non-stimulated cells seem to increase gene transcription after HIV-1 infection. Based on these observations, it is possible to speculate that the outcome of viral infections may be influenced by the cellular activation status at the moment of infection.

B-1 cells are a peculiar subpopulation of B cells found in the peritoneal and pleural cavities in mice. These cells are typically IgM+ and CD11b+. B-1 cells are able to migrate from the peritoneal cavity to non-specific inflammatory sites in mice. In addition, they can differentiate into mononuclear phagocyte-like cells in vitro; however, it is still unknown whether B-1 cells are capable of performing phagocytosis in vivo. Here we further characterized B-1 cells as phagocytes in vitro, and we investigated their ability to phagocytose apoptotic cells and bacteria in vivo. Our results demonstrate that B-1 phagocytes are able to uptake apoptotic thymocytes and Escherichia coli bacteria, both in vitro and in vivo. These findings indicate that along with macrophages, B-1 phagocytic cells might play a role in fundamental processes such as tissue remodeling, resolution of inflammation and pathogen clearance.

A infecção por HIV-1 leva a uma séria imunodeficiência causada principalmente pela depleção de linfócitos T auxiliadores, a principal célula-alvo do vírus. Além dos linfócitos T CD4, o HIV-1 também pode interagir e infectar macrófagos e células dendríticas (DCs). As DCs são resistentes à infecção pelo HIV-1, mas podem internalizar vírions em compartimentos e transferi-los para linfócitos T CD4&#43, em um processo chamado trans-infecção. Para promover sua infecção, o HIV-1 subverte o citoesqueleto da actina da célula hospedeira em várias etapas de seu ciclo. Em DCs o citoesqueleto também é essencial para internalização do HIV-1 e formação dos compartimentos. Miosinas são proteínas motoras que interagem com filamentos de actina e estão envolvidas em diversos processos celulares, incluindo migração, transporte de moléculas, endocitose e reciclagem de componentes de lipid rafts. Apesar de existirem mais de 40 tipos de miosinas em humanos, apenas a miosina 2a foi estudada no contexto da trans-infecção. Por isso, nosso objetivo nesse trabalho foi estudar o papel das miosinas 1c e 1e na maturação de células dendríticas derivadas de monócitos (MDDCs) e na internalização de HIV-1 por estas células. Confirmamos por Real Time PCR a expressão de 10 miosinas em MDDCs de doadores saudáveis, depois verificamos que há regulação negativa da expressão do gene da miosina (myo1c) em MDDCs de pacientes HIV&#43. Analisamos a ativação das células em resposta ao lipopolissacarídeo (LPS) por meio da expressão de CD86 e HLA-DR em MDDCs silenciadas para myo1c e 1e. Não houve diferença na expressão dos marcadores de ativação em células silenciadas para miosina 1e (myo1e) em relação ao controle. No entanto, na maioria dos doadores testados, o silenciamento da myo1c interferiu com o aumento de expressão desses marcadores, indicando que a myo1c possa ter um papel na ativação celular por LPS. Ademais, a localização subcelular do HIV-1 em MDDCs silenciadas para myo1c e ativadas com LPS ficou mais próxima ao fenótipo de células imaturas. Contudo, não houve diferença na quantidade HIV-1 internalizado por MDDCs silenciadas para as miosinas 1c e 1e ou tratadas com um inibidor específico de miosinas do tipo 1. Estes resultados sugerem que a myo1c pode estar envolvida na ativação de células dendríticas e consequentemente alterar o mecanismo de internalização do HIV-1 por MDDCs. Infection by human immunodeficiency virus (HIV) leads to severe immunodeficiency caused by depletion of T helper cells, the main targets of the virus. Besides T CD4&#43 cells, HIV-1 can infect and interact with other immune cells, including dendritic cells and macrophages. Dendritic cells are resistant to HIV infection, however, they can bind and internalize HIV in compartments and then transfer the virus to CD4&#43 T cells in a process called trans-infection. To promote infection, HIV-1 subverts actin cytoskeleton of host cell at several points of its cycle. In DCs, cytoskeleton is also essential to HIV-1 internalization and compartment assembly. Myosins are motor proteins that can interact with actin and take part in several cellular processes, including migration, molecular trafficking, endocytosis and lipid raft recycling. Even though there are about 40 myosin types, only myosin 2a has been investigated in trans-infection. Thus, our aim was to evaluate the role of myosins 1c and 1e in monocyte derived dendritic cell (MDDC) activation and HIV-1 internalization. We have validated the expression of 10 myosins in MDDCs by real-time PCR, and observed a down regulation of myosin 1c gene in HIV&#43 patients. We have evaluated cell activation in response to lipopolysaccharide (LPS) through CD86 and HLA-DR expression in myosin 1c and 1e knocked down MDDCs. There was no change in expression of activation markers in myosin 1e knocked down MDDCs compared with control cells. However, in most donors, myosin 1c knock down impaired the increase of activation markers following LPS treatment, suggesting that myosin 1c may play a role in cell activation by LPS. In addition, subcellular location of HIV-1 in MDDCs knocked down for myosin 1c and activated with LPS, was similar to immature cell phenotype. Nevertheless, we have not observed changes in the amount of HIV-1 internalized by myosin 1c or 1e knocked down MDDCs or in MDDCs treated with myosin I inhibitor. These data suggest that myosin 1c may play a role in MDDC activation and therefore alter the mechanism of HIV-1 internalization by MDDCs.