Project description:CD8+ T-cells inhibit virus replication in SIV-infected rhesus macaques (RM). However, it is unclear to what extent the viral suppression mediated by CD8+ T-cells reflects direct killing of infected cells as opposed to indirect, non-cytolytic mechanisms. In this study, we used functional genomics to investigate potential mechanisms of in vivo viral suppression mediated by CD8+ lymphocytes. Eight chronically SIVmac239-infected RMs underwent CD8+ lymphocyte depletion, and RNA from whole blood was obtained prior to depletion, at the nadir of CD8+ lymphocytes (5 days post-depletion), and during the repopulation phase (11 days post-depletion). Principal components analysis demonstrated that overall gene expression during the nadir of CD8+ T-cells was highly divergent from other intervals. Conversely, the genomic signature of samples from the CD8+ cell rebound phase was similar to that of pre-depletion samples. During CD8+ lymphocyte depletion we detected a strongly significant decrease in the expression of the genes encoding CD8α and CD8β chains, consistent with the near complete CD8+ T-cell depletion measured by flow cytometry. Of note, we observed significant down-regulation of the expression of genes encoding for factors that can suppress SIV replication, including the CCR5-binding chemokine CCL5/Rantes, several retroviral restriction factors (TRIM10, TRIM15, APOBEC3G/H) and defensins. Reduced expression of various genes related to T cell activation and proliferation was also observed. Collectively, these data indicate that depletion of CD8+ lymphocytes in SIV-infected RMs is associated with the establishment of a pattern of gene expression that may result in increased intrinsic permissivity to virus replication. A total of 60 RNA samples were hybridized on to Rhesus Affymetrix 3' Expression arrays. The study was composed of 8 replicate rhesus macaques subjected to SIVmac239 infection and followed over infection, during subsequent treatment with monocloncal antibody OKT8F to deplete CD8+ T lymphocytes, antiretroviral therapy to suppress virus. Samples were taken at various time points during acute and chronic infection, after CD8+ cell depletion, after CD8+ cell reconstition, and during ART suppression of virus.
Project description:CD8+ T-cells inhibit virus replication in SIV-infected rhesus macaques (RM). However, it is unclear to what extent the viral suppression mediated by CD8+ T-cells reflects direct killing of infected cells as opposed to indirect, non-cytolytic mechanisms. In this study, we used functional genomics to investigate potential mechanisms of in vivo viral suppression mediated by CD8+ lymphocytes. Eight chronically SIVmac239-infected RMs underwent CD8+ lymphocyte depletion, and RNA from whole blood was obtained prior to depletion, at the nadir of CD8+ lymphocytes (5 days post-depletion), and during the repopulation phase (11 days post-depletion). Principal components analysis demonstrated that overall gene expression during the nadir of CD8+ T-cells was highly divergent from other intervals. Conversely, the genomic signature of samples from the CD8+ cell rebound phase was similar to that of pre-depletion samples. During CD8+ lymphocyte depletion we detected a strongly significant decrease in the expression of the genes encoding CD8α and CD8β chains, consistent with the near complete CD8+ T-cell depletion measured by flow cytometry. Of note, we observed significant down-regulation of the expression of genes encoding for factors that can suppress SIV replication, including the CCR5-binding chemokine CCL5/Rantes, several retroviral restriction factors (TRIM10, TRIM15, APOBEC3G/H) and defensins. Reduced expression of various genes related to T cell activation and proliferation was also observed. Collectively, these data indicate that depletion of CD8+ lymphocytes in SIV-infected RMs is associated with the establishment of a pattern of gene expression that may result in increased intrinsic permissivity to virus replication.
Project description:Transcriptional profiling of SIV-specific CXCR5+ and CXCR5- CD8+ lymphocytes in rhesus macaques infected with SIVmac251 and SIVE660
Project description:Immunization of macaques with simian immunodeficiency virus with deletions in nef (SIV?nef) has been shown to elicit protective immunity to infection by pathogenic SIV, yet our understanding of the mechanisms that orchestrate protection and prevent pathogenesis remains limited. In the study, we utilize whole-genome transcriptional profiling to reveal molecular signatures of protective immunity in circulating CD8+ T cells of rhesus macaques vaccinated with SIVmac239?nef and challenged with pathogenic SIVmac251. Microarrays were used to characterize changes in gene expression in blood CD8+ T cells that occur following vaccination of rhesus macaques with attenuated SIV?nef and subsequent challenge with pathogenic SIVmac251, in comparison to corresponding changes in healthy controls and unvaccinated animals infected with pathogenic SIVmac251 CD8+ T cells were isolated by magnetic beads from the blood of healthy uninfected macaques, macaques vaccinated with SIV?nef, and unvaccinated controls infected with SIVmac251, and used for RNA extraction and hybridization on Affymetrix microarrays. Blood samples from vaccinated animals were collected prior to vaccination, at 3, 20, and 40 weeks following vaccination. After the 40 week vaccination period, macaques were challenged with SIVmac251, and blood was again collected at 3 weeks following challenge. Blood was collected from the unvaccinated controls at 3 weeks following infection with SIVmac251