Boosting of ALVAC-SIV Vaccine-Primed Macaques with the CD4-SIVgp120 Fusion Protein Elicits Antibodies to V2 Associated with a Decreased Risk of SIVmac251 Acquisition.
ABSTRACT: The recombinant ALVAC vaccine coupled with the monomeric gp120/alum protein have decreased the risk of HIV and SIV acquisition. Ab responses to the V1/V2 regions have correlated with a decreased risk of virus acquisition in both humans and macaques. We hypothesized that the breadth and functional profile of Abs induced by an ALVAC/envelope protein regimen could be improved by substituting the monomeric gp120 boost, with the full-length single-chain (FLSC) protein. FLSC is a CD4-gp120 fusion immunogen that exposes cryptic gp120 epitopes to the immune system. We compared the immunogenicity and relative efficiency of an ALVAC-SIV vaccine boosted either with bivalent FLSC proteins or with monomeric gp120 in alum. FLSC was superior to monomeric gp120 in directing Abs to the C3 ?2 helix, the V5 loop, and the V3 region that contains the putative CCR5 binding site. In addition, FLSC boosting elicited significantly higher binding Abs to V2 and increased both the Ab-dependent cellular cytotoxicity activity and the breadth of neutralizing Abs. However, the FLSC vaccine regimen demonstrated only a trend in vaccine efficacy, whereas the monomeric gp120 regimen significantly decreased the risk of SIVmac251 acquisition. In both vaccine regimens, anti-V2 Abs correlated with a decreased risk of virus acquisition but differed with regard to systemic or mucosal origin. In the FLSC regimen, serum Abs to V2 correlated, whereas in the monomeric gp120 regimen, V2 Abs in rectal secretions, the site of viral challenge, were associated with efficacy.
Project description:A recombinant vaccine containing Aventis Pasteur's canarypox vector (ALVAC)-HIV and gp120 alum decreased the risk of HIV acquisition in the RV144 vaccine trial. The substitution of alum with the more immunogenic MF59 adjuvant is under consideration for the next efficacy human trial. We found here that an ALVAC-simian immunodeficiency virus (SIV) and gp120 alum (ALVAC-SIV + gp120) equivalent vaccine, but not an ALVAC-SIV + gp120 MF59 vaccine, was efficacious in delaying the onset of SIVmac251 in rhesus macaques, despite the higher immunogenicity of the latter adjuvant. Vaccine efficacy was associated with alum-induced, but not with MF59-induced, envelope (Env)-dependent mucosal innate lymphoid cells (ILCs) that produce interleukin (IL)-17, as well as with mucosal IgG to the gp120 variable region 2 (V2) and the expression of 12 genes, ten of which are part of the RAS pathway. The association between RAS activation and vaccine efficacy was also observed in an independent efficacious SIV-vaccine approach. Whether RAS activation, mucosal ILCs and antibodies to V2 are also important hallmarks of HIV-vaccine efficacy in humans will require further studies.
Project description:The recombinant Canarypox ALVAC-HIV/gp120/alum vaccine regimen was the first to significantly decrease the risk of HIV acquisition in humans, with equal effectiveness in both males and females. Similarly, an equivalent SIV-based ALVAC vaccine regimen decreased the risk of virus acquisition in Indian rhesus macaques of both sexes following intrarectal exposure to low doses of SIVmac251. Here, we demonstrate that the ALVAC-SIV/gp120/alum vaccine is also efficacious in female Chinese rhesus macaques following intravaginal exposure to low doses of SIVmac251 and we confirm that CD14+ classical monocytes are a strong correlate of decreased risk of virus acquisition. Furthermore, we demonstrate that the frequency of CD14+ cells and/or their gene expression correlates with blood Type 1 CD4+ T helper cells, ?4?7+ plasmablasts, and vaginal cytocidal NKG2A+ cells. To better understand the correlate of protection, we contrasted the ALVAC-SIV vaccine with a NYVAC-based SIV/gp120 regimen that used the identical immunogen. We found that NYVAC-SIV induced higher immune activation via CD4+Ki67+CD38+ and CD4+Ki67+?4?7+ T cells, higher SIV envelope-specific IFN-? producing cells, equivalent ADCC, and did not decrease the risk of SIVmac251 acquisition. Using the systems biology approach, we demonstrate that specific expression profiles of plasmablasts, NKG2A+ cells, and monocytes elicited by the ALVAC-based regimen correlated with decreased risk of virus acquisition.
Project description:We compare the immunogenicity of ALVAC- or NYVAC- based SIVmac251 vaccine regimens combined with gp120/alum boosts and their relative efficacy in a cohort of 65 female rhesus macaques. Both NYVAC- and ALVAC-based regimens induced equivalent titers of serum binding antibodies to gp120, whereas NYVAC elicited significantly higher envelope specific T cell responses. Surprisingly, however, only the ALVAC-based regimen was able to significantly decrease the risk of SIVmac251 acquisition following repeated low-dose intravaginal challenges. The risk of virus acquisition was associated negatively with the frequency of classical monocytes and positively with non-classical. The systems biology approach used to investigate the molecular basis of the different vaccine efficacies demonstrated specific expression profiles elicited by the ALVAC-based regimen that correlate with efficacy. Overall design: A total of 65 female rhesus macaques were randomized into five groups: ALVAC-SIV/gp120 (20 animals), NYVAC-SIV/gp120 (20 animals), ALVAC-control (10 animals), NYVAC-control (10 animals), and naïve (5 animals). The animals in the ALVAC-SIV/gp120 and NYVAC-SIV/gp120 groups were immunized at weeks 0, 4, 12, and 24 with ALVAC-SIV (vCP180) or NYVAC-SIV (VP1071) carrying the identical Env-Gag-Pol genes, respectively. At weeks 12 and 24, the animals from these groups received an alum-formulated gp120 protein boost. The animals in the ALVAC-control and NYVAC-control groups were immunized at weeks 0, 4, 12, and 24 with empty ALVAC-SIV (vCP180) or NYVAC-SIV (VP1071) vectors, respectively. At weeks 12 and 24, the animals from these groups received alum. technical replicate: P168_A06015_w0.6h, P168_A06015_w0.6h_rep1 technical replicate: P168_A06028_w0.6h_rep1, P168_A06028_w0.6h_rep2 technical replicate: P168_A06082_w0.0h, P168_A06082_w0.0h_rep1 technical replicate: P168_A06083_w0.24h, P168_A06083_w0.24h_rep1
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:Immunization with recombinant ALVAC/gp120 alum vaccine provided modest protection from human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) acquisition in humans and macaques. Vaccine-mediated protection was associated with the elicitation of IgG against the envelope V2 loop and of envelope-specific CD4+ T cell responses. We hypothesized that the simultaneous expression of the costimulatory molecule CD40L (CD154) by the ALVAC-HIV vector could increase both protective humoral and cellular responses. We engineered an ALVAC-SIV coexpressing CD40L with SIVmac251 (ALVAC-SIV/CD40L) gag, pol, and env genes. We compared its immunogenicity in macaques with that of a canonical ALVAC-SIV, with both given as a vector-prime/gp120 in alum boost strategy. The ALVAC-SIV/CD40L was superior to the ALVAC-SIV regimen in inducing binding and tier 1 neutralizing antibodies against the gp120. The increase in humoral responses was associated with the expression of the membrane-bound form of the CD40L by CD4+ T cells in lymph nodes. Unexpectedly, the ALVAC-SIV/CD40L vector had a blunting effect on CD4+ Th1 helper responses and instead favored the induction of myeloid-derived suppressor cells, the immune-suppressive interleukin-10 (IL-10) cytokine, and the down-modulatory tryptophan catabolism. Ultimately, this strategy failed to protect macaques from SIV acquisition. Taken together, these results underlie the importance of balanced vaccine-induced activating versus suppressive immune responses in affording protection from HIV.IMPORTANCE CD40-CD40 ligand (CD40L) interaction is crucial for inducing effective cytotoxic and humoral responses against pathogens. Because of its immunomodulatory function, CD40L has been used to enhance immune responses to vaccines, including candidate vaccines for HIV. The only successful vaccine ever tested in humans utilized a strategy combining canarypox virus-based vector (ALVAC) together with an envelope protein (gp120) adjuvanted in alum. This strategy showed limited efficacy in preventing HIV-1/SIV acquisition in humans and macaques. In both species, protection was associated with vaccine-induced antibodies against the HIV envelope and CD4+ T cell responses, including type 1 antiviral responses. In this study, we tested whether augmenting CD40L expression by coexpressing it with the ALVAC vector could increase the protective immune responses. Although coexpression of CD40L did increase humoral responses, it blunted type 1 CD4+ T cell responses against the SIV envelope protein and failed to protect macaques from viral infection.
Project description:The ALVAC-HIV clade B/AE and equivalent SIV-based/gp120 + Alum vaccines successfully decreased the risk of virus acquisition in humans and macaques. Here, we tested the efficacy of HIV clade B/C ALVAC/gp120 vaccine candidates + MF59 or different doses of Aluminum hydroxide (Alum) against SHIV-Cs of varying neutralization sensitivity in macaques. Low doses of Alum induced higher mucosal V2-specific IgA that increased the risk of Tier 2 SHIV-C acquisition. High Alum dosage, in contrast, elicited serum IgG to V2 that correlated with a decreased risk of Tier 1 SHIV-C acquisition. MF59 induced negligible mucosal antibodies to V2 and an inflammatory profile with blood C-reactive Protein (CRP) levels correlating with neutralizing antibody titers. MF59 decreased the risk of Tier 1 SHIV-C acquisition. The relationship between vaccine efficacy and the neutralization profile of the challenge virus appear to be linked to the different immunological spaces created by MF59 and Alum via CXCL10 and IL-1?, respectively.
Project description:We contrasted innate and adaptive immune responses of HIV vaccine candidates of varying efficacy in macaques that shared the ALVAC+gp120 protein boost with an ALVAC, DNA or Ad26 prime modality. The vaccine efficacies of the DNA/ALVAC+gp120 and ALVAC/ALVAC+gp120 vaccine regimens, both protective, were associated with qualitative temporal-spatial differences in the innate CD14+ and CD16+ cells in blood and tissues. The activation of hypoxia and the inflammasome in CD14+ DR+ CD16- classical monocytes and CD4+ Th2 responses correlated with a decreased risk of SIVmac251 acquisition. CD4+ Th2 cells, in turn, correlated with mucosal NKp44+ cells and mucosal protective antibodies to V2. In contrast, the Ad26/ALVAC+gp120 vaccine resulted in increased de novo differentiated CX3CR1+ CD163+ macrophages in lymph nodes, increased CD4+ Th17 cells in blood and rectal mucosa, and a lack vaccine efficacy. These data posit that the engagement of classical monocytes and inflammasome activation is central for the elicitation of protective innate and adaptive responses by the ALVAC-based HIV vaccine platform. Overall design: Twenty four (24) rhesus macaques were randomized to two vaccination groups. One group (n=12) was primed once with Ad26 (at week 0) and boosted twice with ALVAC-SIV/gp120 in Alum adjuvant (at week 12 and week 24). The second group (n=12) was primed twice with DNA (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 boost (week 12), 2 weeks after the first boost (week 14), 24 hours after the second boost (week 24) and 1 week after the second boost (week 15). All the samples were taken before SIV challenge. One animal (R270) who received the Ad26/ALVAC+gp120 vaccine was not included in the transcriptomic study because of a lack of blood samples. Blood samples were conserved in PAXgene tubes. RNA was extracted and hybridized to Illumina beadchips.
Project description:The recombinant canarypox vector, ALVAC-HIV, together with human immunodeficiency virus (HIV) gp120 envelope glycoprotein, has protected 31.2% of Thai individuals from HIV acquisition in the RV144 HIV vaccine trial. This outcome was unexpected, given the limited ability of the vaccine components to induce CD8(+) T-cell responses or broadly neutralizing antibodies. We vaccinated macaques with an immunization regimen intended to mimic the RV144 trial and exposed them intrarectally to a dose of the simian immunodeficiency virus SIV(mac251) that transmits few virus variants, similar to HIV transmission to humans. Vaccination induced anti-envelope antibodies in all vaccinees and CD4(+) and CD8(+) T-cell responses. Three of the 11 macaques vaccinated with ALVAC-SIV/gp120 were protected from SIV(mac251) acquisition, but the result was not significant. The remaining vaccinees were infected and progressed to disease. The magnitudes of vaccine-induced SIV(mac251)-specific T-cell responses and binding antibodies were not significantly different between protected and infected animals. However, sera from protected animals had higher avidity antibodies to gp120, recognized the variable envelope regions V1/V2, and reduced SIV(mac251) infectivity in cells that express high levels of ?(4)?(7) integrins, suggesting a functional role of antibodies to V2. The current results emphasize the utility of determining the titer of repeated mucosal challenge in the preclinical evaluation of HIV vaccines.
Project description:The human papillomavirus pseudovirions (HPV-PsVs) approach is an effective gene-delivery system that can prime or boost an immune response in the vaginal tract of nonhuman primates and mice. Intravaginal vaccination with HPV-PsVs expressing SIV genes, combined with an i.m. gp120 protein injection, induced humoral and cellular SIV-specific responses in macaques. Priming systemic immune responses with i.m. immunization with ALVAC-SIV vaccines, followed by intravaginal HPV-PsV-SIV/gp120 boosting, expanded and/or recruited T cells in the female genital tract. Using a stringent repeated low-dose intravaginal challenge with the highly pathogenic SIVmac251, we show that although these regimens did not demonstrate significant protection from virus acquisition, they provided control of viremia in a number of animals. High-avidity Ab responses to the envelope gp120 V1/V2 region correlated with delayed SIVmac251 acquisition, whereas virus levels in mucosal tissues were inversely correlated with antienvelope CD4(+) T cell responses. CD8(+) T cell depletion in animals with controlled viremia caused an increase in tissue virus load in some animals, suggesting a role for CD8(+) T cells in virus control. This study highlights the importance of CD8(+) cells and antienvelope CD4(+) T cells in curtailing virus replication and antienvelope V1/V2 Abs in preventing SIVmac251 acquisition.
Project description:Qualitative differences in the innate and adaptive responses elicited by different HIV vaccine candidates have not been thoroughly investigated. We tested the ability of the Aventis Pasteur live recombinant canarypox vector (ALVAC)-SIV, DNA-SIV and Ad26-SIV vaccine prime modalities together with two ALVAC-SIV?+?gp120 protein boosts to reduce the risk of SIVmac251 acquisition in rhesus macaques. We found that the DNA and ALVAC prime regimens were effective, but the Ad26 prime was not. The activation of hypoxia and the inflammasome in CD14+CD16- monocytes, gut-homing CCR5-negative CD4+ T helper 2 (TH2) cells and antibodies to variable region 2 correlated with a decreased risk of SIVmac251 acquisition. By contrast, signal transducer and activator of transcription 3 activation in CD16+ monocytes was associated with an increased risk of virus acquisition. The Ad26 prime regimen induced the accumulation of CX3CR1+CD163+ macrophages in lymph nodes and of long-lasting CD4+ TH17 cells in the gut and lungs. Our data indicate that the selective engagement of monocyte subsets following a vaccine prime influences long-term immunity, uncovering an unexpected association of CD14+ innate monocytes with a reduced risk of SIVmac251 acquisition.