Splenic memory CD8 T cell signature of enhanced responsiveness to vaccine boost
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ABSTRACT: We addressed the question of primed CD8 T cell responsiveness to boost in a Balb/c mouse model of vaccination against gag of HIV-1, namely intramuscular (i.m.) prime with the Chimpanzee adenovector ChAd3-gag and i.m. boost with Modified Virus Ankara MVA-gag. In this setting, boost was more effective at day(d)100 than at d30 post-prime, as evaluated by multi-lymphoid organ assessment of gag-specific CD8 T cell frequency, CD62L-phenotype and in vivo killing activity at d45 post-boost. RNA-sequencing was used to compare memory signature of gag-specific spleen CD8 T cells at d100 post-prime with those at d30.
Project description:A better understanding of innate responses induced by vaccination is critical for designing optimal vaccines. Here, we studied the diversity and dynamics of the NK cell compartment after prime-boost immunization with the modified vaccinia virus Ankara using cynomolgus macaques as a model. Mass cytometry was used to deeply characterize blood NK cells. The NK cell subphenotype composition was modified by the prime. Certain phenotypic changes induced by the prime were maintained over time and, as a result, the NK cell composition prior to boost differed from that before prime. The key phenotypic signature that distinguished NK cells responding to the boost from those responding to the prime included stronger expression of several cytotoxic, homing, and adhesion molecules, suggesting that NK cells at recall were functionally distinct. Our data reveal potential priming or imprinting of NK cells after the first vaccine injection. This study provides novel insights into prime-boost vaccination protocols that could be used to optimize future vaccines.
Project description:Heterologous prime-boost strategies are of interest for HIV vaccine development. The order of prime-boost components could be important for the induction of T-cell responses. In this phase I/II multi-arm trial, three vaccine candidates were used as prime or boost: MVA HIV-B (coding for Gag, Pol, Nef); HIV LIPO-5 (5 lipopeptides from Gag, Pol, Nef); DNA GTU-MultiHIV B (coding for Rev, Nef, Tat, Gag, Env gp160 clade B). Healthy volunteers (n=92) were randomized to four groups: 1) MVA at weeks (W) 0/8 + LIPO-5 at W20/28 (M/L); 2) LIPO-5 at W0/8 + MVA at W20/28 (L/M); 3) DNA at W0/4/12 + LIPO-5 at W20/28 (G/L); 4) DNA at W0/4/12 + MVA at W20/28 (G/M). Frequency of IFNγ-ELISpot responders at W30 was 33%, 43%, 0% and 74%, respectively. Only MVA-receiving groups were further analyzed. Gene expression profiles of 79 subjects at different timepoints were analyzed by Illumina Whole-Genome Gene Expression BeadChips. Significant whole blood gene expression changes were observed two weeks after the first MVA injection, regardless of its use as prime or boost. An MVA gene signature was identified, including 86 genes mainly related to cell cycle pathways. Three prime-boost strategies led to CD4+ and CD8+ T cell responses and to a whole blood gene expression signature primarily due to their MVA HIV-B component.
Project description:Similar with others, our data proved that antigen-specific CD8+ T cells from mice primed with DNA and boosted by VACV were much more sensitive to antigen stimulation than those from DNA-boost. Since the mechanisms of in vivo tuning of antigen sensitivity (also termed functional avidity) is still not defined, we compared this two vaccination regimen at gene expression level. Results provide important information of which genes were selectively activated by VACV boost vaccination. For example, data shows that the expression levels of genes involved in Cancer and Wnt signaling pathways is more higher in DNA prime-VACV boost regimen that DNA prime-DNA boost vaccination. To obtain sufficient of antigen-specific cells for microarray analysis, the OVA-specific CD8+ T cells from OT-1 mice were adoptively transferred into wild type mice and then immunized by DNA and VACV vaccine encoding OVA. Four week later, mice were scarificed and antigen-specific CD8+ T cells were emriched by CD45.1-PE antibody and anti-PE MicroBeads from splenocytes.Total RNA was extracted by the RNeasy Mini Kit (QIAGEN, Germany). Followed by amplification and biotin labeling, the samples were hybridized using Illumina Total Prep RNA Amplification Kit (Ambion, USA). Mouse WG-6v2 Expression BeadChips were used for analysis of transcriptome.
Project description:Similar with others, our data proved that antigen-specific CD8+ T cells from mice primed with DNA and boosted by VACV were much more sensitive to antigen stimulation than those from DNA-boost. Since the mechanisms of in vivo tuning of antigen sensitivity (also termed functional avidity) is still not defined, we compared this two vaccination regimen at gene expression level. Results provide important information of which genes were selectively activated by VACV boost vaccination. For example, data shows that the expression levels of genes involved in Cancer and Wnt signaling pathways is more higher in DNA prime-VACV boost regimen that DNA prime-DNA boost vaccination.
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:Transcriptional profiling to examine differences resulting from priming of virus-specific CD8 T cells in draining lymph node and in bone marrow, following intradermal injection of modified virus Ankara (MVA)-HIV gag. Transcriptional profiling of mouse pentamer H2kD-AMQMLKETI (HIV-gagP24) CD8 T cells from draining lymph nodes(LN) and bone marrow (BM ) 5 days following intradermal injection of MVA-HIV gag, and compared to naive (CD62L Hi CD44 int) CD8+ T cells from lymph node of naive mice (NTc).
Project description:Transcriptional profiling to examine differences resulting from priming of virus-specific CD8 T cells in draining lymph node and in bone marrow, following intradermal injection of modified virus Ankara (MVA)-HIV gag. Transcriptional profiling of mouse pentamer H2kD-AMQMLKETI (HIV-gagP24) CD8 T cells from draining lymph nodes(LN) and bone marrow (BM ) 5 days following intradermal injection of MVA-HIV gag, and compared to naive (CD62L Hi CD44 int) CD8+ T cells from lymph node of naive mice (NTc). Three-condition experiment, BM, LN and NTc. Experimental replicates: 5 BM, 5 LN, 5 NTc, RNA pooled from 3 independant experiments of 5 mice each.
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: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.