Project description:Recently, several neutralizing anti-HIV antibodies have been isolated from memory B cells of HIV-infected individuals. However, despite extensive evidence of B-cell dysfunction in HIV disease, little is known about the cells from which these rare HIV-specific antibodies originate. Accordingly, HIV envelope gp140 and CD4 or co-receptor (CoR) binding site (bs) mutant probes were used to evaluate HIV-specific responses in the peripheral blood B cells of individuals at various stages of infection. In contrast to non-HIV responses, HIV-specific responses against gp140 were enriched within abnormal B cells, namely activated and exhausted memory subsets, which are largely absent in the blood of uninfected individuals. Responses against the CoRbs (a poorly-neutralizing epitope) arose early whereas those against the CD4bs (a well-characterized neutralizing epitope) were delayed and infrequent. Enrichment of the HIV-specific response within resting memory B cells, the predominant subset in uninfected individuals, did occur in certain infected individuals who maintained low levels of plasma viremia and immune activation with or without antiretroviral therapy. These findings were corroborated by transcriptional profiles. Taken together, our findings provide valuable insight into virus-specific B-cell responses in HIV infection and demonstrate that memory B-cell abnormalities may contribute to the ineffectiveness of the antibody response in infected individuals. HIV-specific responses against gp140 were enriched within abnormal B cells, namely activated (AM) and exhausted (tissue-like; TLM) memory subsets, which are largely absent in the blood of uninfected individuals. These responses are highest during the early stage of HIV infection, significantly decreased following the initiation of antiretroviral therapy (ART), and most importantly, enriched in normal resting memory B cells (RM) when HIV viremia and immune activation are controlled either naturally or as a result of ART. These HIV-specific B cells (AM and TLM) and resting memory B cells (RM) were sorted from peripheral blood mononuclear cells (PBMCs) of 6 HIV infected individuals. In addition, gp140-specific IgG+ B cells were sorted from individuals with either a strong (n= 6) or weak (n= 6) pro-resting memory profile. TaqMan gene expression assay was performed on these HIV-specific B cells and B cell subset. The array consisted of 29 genes.

Project description:High levels of HIV-1 replication during the chronic phase of infection are usually associated with rapid disease progression (RP). However, a minority of HIV-infected individuals remain asymptomatic and show persistently high CD4+ T cell counts despite high viremia for many years (viremic non progressors, VNP). The latter profile is reminiscent of the non-pathogenic model of SIV infection in natural hosts such as the sooty mangabey. We used various genomic approaches to examine 66 RP and 6 VNP defined according to strict criteria. RP were characterized by depletion of protective HLA alleles, enrichment of HLA alleles associated with disease progression, and a characteristic transcriptome profile of CD4+ and CD8+ T cells similar to that observed in pathogenic SIV infection of rhesus macaque. In contrast, VNPs presented lower expression of interferon stimulated genes than RP, and shared with SIV-infected sooty mangabeys a common profile of regulation of a set of genes that includes CASP1, CD38, LAG3, TNFSF13B, SOCS1 and EEF1D. The estimated 8% of RP and 0.1% of VNP in human cohorts represent two subsets of HIV-infected individuals whose analysis may inform our understanding of HIV pathogenesis. Selection criteria rapid progressors (RP): HIV seroconversion window <1 year WITH documented negative and positive serology or biological proof of primary infection. AND One of A) or B) A) >2 CD4+ T cell counts below 350 cells/µl within 3 years of seroconversion AND no subsequent rise of CD4+ T cells above 350 cells/µl in the absence of ART. B) ART initiated within 3 years of seroconversion AND CD4+ T cell count within 1 month of ART-start <350 cells/µl. Selection criteria viremic non progressors (VNP): > 3 years of follow-up AND median HIV viremia from >3 measurements >100'000 viral RNA copies/ml AND HIV viremia consistently above 10’000 copies/ml AND CD4+ T cell count above 350 cells/µl AND no ART during follow-up. Selection criteria elite/viremic controllers (EC): see Casado et al. 2010. Host and viral genetic correlates of clinical definitions of HIV-1 disease progression. PLoS ONE 5:e11079. Total RNA from 41 samples obtained from CD4 T cells from HIV infected individuals to identify associations between gene expression and different distinct patterns of disease progression Total RNA from 38 samples obtained from CD8 T cells from HIV infected individuals to identify associations between gene expression and different distinct

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