Project description:SIVmac239Δnef (SIVΔnef) live attenuated vaccine (LAV) induces the best protection among all the vaccine modalities tested in rhesus macaque model of HIV-1 infection. Time-dependent protection is a unique feature of this vaccine: macaques are not protected at 3-5 weeks post vaccination (WPV), whereas immune protection emerges between 15 and 20 WPV. To elucidate the protection mechanisms induced by SIVΔnef vaccine, we longitudinally compared the global gene expression profiles of SIV Gag-CM9+ CD8+ (Gag-specific CD8+) T cells from peripheral blood of Mamu-A*01 rhesus macaques at 3 and 20 WPV using rhesus microarray. We found that gene expression profiles of Gag-specific CD8+ T cells at 20 WPV are qualitatively different from those at 3 WPV. At 20 WPV, the most significant transcriptional changes of Gag-specific CD8+ T cells were genes involved in cell activation, differentiation and maturation toward central memory cells. Our study indicates that a higher quality of SIV-specific CD8+ T cells elicited by SIVΔnef over time may contribute to the maturation of time dependent protection.
Project description:The goal of an effective AIDS vaccine is to generate immunity that will prevent HIV-1 acquisition. Despite limited progress towards this goal, renewed optimism has followed the recent success of the RV144 vaccine trial in Thailand. However, the lack of complete protection in this trial suggests that breakthroughs, where infection occurs despite adequate vaccination, will be a reality for many vaccine candidates. We previously reported that neutralizing antibodies elicited by DNA prime/rAd5 boost vaccination with SIVmac239 Gag/Pol and Env provided protection against pathogenic SIVsmE660 acquisition after repeated mucosal challenge. Here, we report that SIV-specific CD8+ T cells elicited by that vaccine lowered both peak and set-point viral loads in macaques that became infected despite vaccination. These SIV-specific CD8+ T cells showed strong virus inhibitory activity (VIA) and displayed an effector memory (EM) phenotype. VIA correlated with high levels of CD107a mobilization and perforin expression in SIV-specific CD8+ T cells. Remarkably, both the frequency and the number of Gag CM9-specific public clonotypes were strongly correlated with VIA mediated by EM CD8+ T cells. The ability to elicit such virus-specific EM CD8+ T cells might contribute substantially to an efficacious HIV/AIDS vaccine, even after breakthrough infection. Gag CM9-specific EM CD8+ T cells (CD28 low CD95 high tetramer+) from SIV-negative macaques at 12 wks post-DNA/rAd5 immunization were sorted by flow cytometry for microarray studies. RNA samples from strong VIA animals with (n=3) or without (n=6) CM9 peptide stimulation, along with CM9 peptide stimulated samples from weak VIA animals (n=2) were prepared using the Illumina beads station assay and hybridized to the Illumina HumanHT-12 version 4 Expression BeadChip.
Project description:The goal of an effective AIDS vaccine is to generate immunity that will prevent HIV-1 acquisition. Despite limited progress towards this goal, renewed optimism has followed the recent success of the RV144 vaccine trial in Thailand. However, the lack of complete protection in this trial suggests that breakthroughs, where infection occurs despite adequate vaccination, will be a reality for many vaccine candidates. We previously reported that neutralizing antibodies elicited by DNA prime/rAd5 boost vaccination with SIVmac239 Gag/Pol and Env provided protection against pathogenic SIVsmE660 acquisition after repeated mucosal challenge. Here, we report that SIV-specific CD8+ T cells elicited by that vaccine lowered both peak and set-point viral loads in macaques that became infected despite vaccination. These SIV-specific CD8+ T cells showed strong virus inhibitory activity (VIA) and displayed an effector memory (EM) phenotype. VIA correlated with high levels of CD107a mobilization and perforin expression in SIV-specific CD8+ T cells. Remarkably, both the frequency and the number of Gag CM9-specific public clonotypes were strongly correlated with VIA mediated by EM CD8+ T cells. The ability to elicit such virus-specific EM CD8+ T cells might contribute substantially to an efficacious HIV/AIDS vaccine, even after breakthrough infection.
Project description:An attenuated Lassa vaccine in SIV-infected rhesus macaques does not persist or cause renavirus disease but does elicit protective immunity
Project description:Transcriptional profiling of SIV-specific CXCR5+ and CXCR5- CD8+ lymphocytes in rhesus macaques infected with SIVmac251 and SIVE660