ABSTRACT: 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: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: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:An efficacious vaccine to HIV-1 remains elusive. We tested two vaccine regimens based on prime-boosting with two chimpanzee-origin adenovirus (Ad) vectors (SAdV) of serotypes SAdV24 and SAdV23 or two distinct human serotype Ad vectors (HAdV), i.e., HAdV5 and HAdV26, expressing Gag and gp160 of SIVmac239 for induction of protection against repeated low dose rectal SIVmac251 challenges in Indian rhesus macaques (RMs). Animals were rendered seropositive to the HAdV vectors prior to vaccination. In RMs with non-controller genotypes, the SAdV vectors achieved significant reduction in viral acquisition. In RMs with controller genotypes, both vaccine regimens reduced set-point and peak viral loads and accelerated viral clearance. In SAdV-vaccinated RMs resistance against infection correlated with levels of circulating envelope (Env)-specific antibody (Ab) titers. In both vaccine groups CD8+T cells controlled viral loads upon infection. Circulating CD4+ and CD8+ T cells showed significant changes in their transcriptome over time following vaccination, which differed between the vaccine groups. T cells from SIV-resistant RMs had unique transcriptional profiles indicating that both follicular T helper (TFH) cell responses and highly activated CD8+ T cells may play a role in protection. Our results demonstrate that SAdV-based candidate AIDS vaccines provide protection from virus acquisition and replication in a stringent SIV challenge model in RMs and may thus outperform HIV-1 vaccines that have undergone large-scale clinical efficacy testing in humans.
Project description:The primary objective of this study was to evaluate response to a SIV DNA-based vaccine that was adminstered via vivo electroporation (EP) in rhesus macaques to further understand the molecular correlates of protection against SIV. In this study, rhesus macaques were immunized with a DNA vaccine including individual plasmids encoding SIV gag, env, and pol alone, or in combination with a molecular adjuvant, plasmid DNA expressing the chemokine ligand 5 (RANTES), followed by EP. At eight month post-vaccination, animals were challenged with SIV. Standard immunological assays, flow-based activation analysis without ex vivo restimulation and high-throughput gene expression analysis were performed to determine the host response to each vaccine regimen. The overall study was designed to evaluate the response to a SIV-DNA vaccination administered to animals via intramuscular electroporation. Chinese rhesus macaques were divided into three treatment groups (n=6 animals per group): Control (no vaccination), DNA vaccine alone (pCSIVgag, pCSIVpol, pCSIVenv), DNA vaccine with RANTES adjuvant (pCSIVgag, pCSIVpol, pCSIVenv, pmacRANTES). Eight months following the last vaccination, animals were infected with 25 MID of SIVmac251 and response to infection was monitored. RNA for microarray analysis was isolated from fresh PBMCs that were isolated from individual animals and treated overnight with a pool of overlapping SIV pol peptides or mock treated. Samples for microarray analysis were taken longitudinally at 8 months post-vaccination (pre-SIV challenge; biological n=5-6 per group for each treatment; technical n=2 for each sample) and at day 10 post-SIV challenge (n=5-6 per group for each treatment; technical n=2 for each sample).
Project description:The primary objective of this study was to evaluate response to a SIV DNA-based vaccine that was adminstered via vivo electroporation (EP) in rhesus macaques to further understand the molecular correlates of protection against SIV. In this study, rhesus macaques were immunized with a DNA vaccine including individual plasmids encoding SIV gag, env, and pol alone, or in combination with a molecular adjuvant, plasmid DNA expressing the chemokine ligand 5 (RANTES), followed by EP. At eight month post-vaccination, animals were challenged with SIV. Standard immunological assays, flow-based activation analysis without ex vivo restimulation and high-throughput gene expression analysis were performed to determine the host response to each vaccine regimen.
Project description:Successful development of HIV-vaccination strategies will also depend on the ability to use novel approaches to analyse and integrate immunogenicity data generated in vaccine trials. The ANRS VAC 18 trial evaluated the immunogenicity of HIV-LIPO-5 vaccine (5 HIV peptides coupled to a palmytoil tail) administered at W0, 4, 12 and 24 in healthy volunteers. 62-69% of vaccinees developed HIV-specific ELISpot responses by W26. Here we present extensive immunogenicity assessments in a subset of vaccinees using ELISpot, lymphoproliferation, intracellular cytokine staining (ICS), cytokine multiplex and transcriptomic analyses. Peripheral blood mononuclear cells from volunteers collected before and following vaccinations were stimulated with HIV LIPO 5 vaccine, Gag peptides contained or not in the vaccine as controls. Different time points and stimulation conditions were compared, using false discovery rate to control for test multiplicity. 74% and 30% of vaccinees had cultured ELISpot and lymphoproliferation responses at W14, respectively. Ex-vivo ICS showed mainly single IL-2 producing cells. Secretion of IFN-γ, TNF-α, IL-5, and IL-13 increased significantly in response to Gag stimulation after culture at W14 compared to W0. An induction of metallothionein genes was consistently detected after HIV-LIPO-5 stimulation at W0 and W14 related to the adjuvant effect of the lipid tail. After vaccination (W14), significant probes increased substantially (>1200 probes) including IFN-γ, CXCL9, IL2RA, TNFAIP6, CCL3L1 and IL-6 W14 (fold change > 100%). In conclusion, HIV LIPO-5 vaccination elicited memory precursor responses with a Th1 and Th2 profile. The signature profile before vaccination provides information about the adjuvant effect of the lipid tail. Consistently with cytokine responses, vaccination is associated with a modulation in gene expression. This combined approach allowed to identify new signatures of HIV vaccine response and indicates that HIV-LIPO-5 could be further developed as a prime component of heterologous prime boost strategies. PBMC mRNA of 12 healthy volunteers, stimulate in four different conditions (HIV-LIPO-5, Gag+, Gag-, NS) during 6 and 24 hours before and after vaccination (week 0 and week 14)
Project description:The generation of CD8+ T-cell memory is an important aim of immunization. While several distinct subsets of CD8+ T-cell memory have been described, the lineage relationships between effector (EFF), effector memory (EM) and central memory (CM) T cells remain contentious. Specifically, there is contradictory experimental evidence to support both the linear (Naive>EFF>EM>CM) and progressive differentiation (Naive>CM>EM>EFF) models. In this study, we applied a systems biology approach to examine global transcriptional relationships between the three major CD8+ T cell subsets arising endogenously as a result of vaccination with three different prime-boost vaccine regimens. Differential gene expression analysis and principle component analysis revealed that central memory cells were more closely related to naive T cells than both effector memory and effector cells. When the transcriptional relationships between subsets were enriched in an unbiased fashion with known global transcriptional changes that result when T-cells repeatedly encounter antigen, our analysis favored a model whereby cumulative antigenic stimulation drives differentiation specifically from Naive > CM > EM > EFF. These findings provide an insight into the lineage relationship between mature CD8+ T-cell subsets and will help in the rational design of vaccines aimed at generating effective immune responses against infections and cancer. Effector (EFF), effector memory (EM), central memory (CM) and naive CD8+ T cells from mice spleen. Memory subset arise endogenously as a result of vaccination with three different prime-boost vaccine regimens: DNA-rAd5, rAd5-rAd5 and rAd5-rLCMV.
Project description:Using whole-blood transcriptional profiling, we investigated differences in the host response to vaccination and challenge in a rhesus macaque AIDS vaccine trial. Samples were collected from animals prior to and after vaccination with live irradiated vaccine cells secreting the modified endoplasmic reticulum chaperone gp96-Ig loaded with SIV peptides, either alone or in combination with a SIV-gp120 protein boost. Additional samples were collected following multiple low-dose rectal challenge with SIVmac251. Animals in the boosted group had a 73% reduced risk of infection. Surprisingly, few changes in gene expression were observed during the vaccination phase. Focusing on post-challenge comparisons, in particular for protected animals, we identified a host response signature of protection comprised of strong interferon signaling after the first challenge, which then largely abated after further challenges. We also identified a host response signature, comprised of early macrophage-mediated inflammatory responses, in animals with undetectable viral load five days after the first challenge, but which had unusually high viral titers after subsequent challenges. Statistical analysis showed that prime-boost vaccination significantly lowered the probability of infection in a time-consistent manner throughout several challenges. Given that humoral responses in the prime-boost group were highly significant pre-challenge correlates of protection, the strong innate signaling after the first challenge suggests that interferon signaling enhances vaccine-induced antibody responses and is an important contributor to protection from infection during repeated low-dose exposure to SIV. 36 Indian-origin outbred, young adult, male and female rhesus macaques divided into thre vaccination groups of 12 animals each. Groups were balanced for Mamu-A*01 (three in each group), Mamu-B*08 (one in each group), and for susceptible and resistant TRIM5α alleles. There were no Mamu-B*17+ animals. The prime group (PG) received Gp96 SIV Ig vaccine 292 cells that were transfected with plasmids encoding gp96-Ig, SIVmac251 rev-tat-nef, Gag and gp160 (35). They were injected intraperitoneally with 107 irradiated gp96SIVIg vaccine cells in HBSS, which secrete 10 μg of gp96SIVIg per 24 h. For the prime-boost group (PBG), 100 g of rSIVgp120 protein was added to the vaccine cells. The control group received 292-gp96 Ig cells not transfected with SIV antigens. After a 32-week vaccination phase, which consisted of priming in weeks 0, 6, and 25 and (for the PBG only) additional boosts in weeks 6 and 25, all animals were subject to up to seven weekly low-dose intrarectal challenges starting at 33-week with SIVmac251 at a dosage of 120 TCID50. Whenever an animal had detectable viral load (>50 copies/ml of plasma) at 5 days post challenge, it was considered viremic, further challenges were suspended, and only viral load screening continued on a weekly basis. Whole blood samples (preserved in PAXgene tubes) were collected 2 weeks prior to the first prime, 1 week after the first prime, 2 weeks before and 1 week after the third prime, 1 week before the first challenge, for newly infected animals five days into the corresponding study week and from viremic animals four days into the study week (also denoted as challenge 2 and challenge 3). Total RNA was isolated from Paxgene tubes using Paxgene Blood RNeasy Mini Kits (Qiagen) following the manufacturer’s protocol. RNA quality was assessed on an Agilent 2100 Bioanalyzer using the nanochip format, and only intact RNA was used for microarray analyses.
Project description:The Canarypox/gp120/Alum vaccines decreased the risk of HIV acquisition in humans. We demonstrate here the efficacy of this vaccine regimen also in the SIVmac251 macaque model when we used the alum but not the MF59 adjuvant. Analysis of innate and adaptive cell responses, envelope antibodies Fc profiles and glycoforms demonstrated a lower inflammatory response with alum than MF59. Alum elicited mucosal V2 peptide-specific IgG associated with vaccine efficacy whereas the MF59 induced mucosal V2 peptide-specific IgG associated with increased risk of infection. Alum modulated the expression of 12 genes, 7 of which are part of the RAS pathway, that correlates with vaccine efficacy and were linked to innate responses that preserve mucosal integrity and adaptive mucosal antibody response to V2. Thus, activation of the RAS pathway, preservation of mucosal integrity and mucosal antibody to V2 in concert, reduce the risk of SIVmac251 acquisition. Fifty-four (54) rhesus macaques were randomized into two vaccination groups. One group (n=27) was primed twice with ALVAC-SIV (at week 0 and week 4) and boosted twice with ALVAC-SIV/gp120 in MF59 adjuvant (at week 12 and week 24). The second group (n=27) was primed twice with ALVAC-SIV (at week 0 and week 4) and boosted twice with ALVAC-SIV/gp120 in Alum adjuvant (at week 12 and week 24). Blood samples were taken pre-vaccination, 24 hours after the first prime (post-1st imunization at week 0) and 24 hours after the first boost (post-3rd immunization at week 12). All the samples were taken before SIV challenge. Blood samples were conserved in PAXgene tubes. RNA was extracted and hybridized to Illumina beadchips. technical replicate: P162_P382_post1st, P162_P382_post1st_rep1
Project description:CD4 T cells promote innate and adaptive immune responses, but how vaccine-elicited CD4 T cells contribute to immune protection remains unclear. Here we evaluated whether induction of virus-specific CD4 T cells by vaccination would protect mice against infection with chronic lymphocytic choriomeningitis virus (LCMV). Immunization with vaccines that selectively induced CD4 T cell responses resulted in catastrophic inflammation and mortality following challenge with a persistent form of LCMV. Immunopathology required antigen-specific CD4 T cells and was associated with a cytokine storm, generalized inflammation, and multi-organ system failure. Virus-specific CD8 T cells or antibodies abrogated the pathology. These data demonstrate that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger lethal immunopathology. Splenic GP66-specific CD4 T cells from mice immunized with either a LMwt vaccine (sham) or LMgp61 vaccine (CD4 vaccine) were purified by FACS on day 8 post-infection with LCMV clone 13