V1V2-specific complement activating serum IgG as a correlate of reduced HIV-1 infection risk in RV144.

Non-neutralizing IgG to the V1V2 loop of HIV-1 gp120 correlates with a decreased risk of HIV-1 infection but the mechanism of protection remains unknown. This V1V2 IgG correlate was identified in RV144 Thai trial vaccine recipients, who were primed with a canarypox vector expressing membrane-bound gp120 (vCP1521) and boosted with vCP1521 plus a mixture gp120 proteins from clade B and clade CRF01_AE (B/E gp120). We sought to determine whether the mechanism of vaccine protection might involve antibody-dependent complement activation. Complement activation was measured as a function of complement component C3d deposition on V1V2-coated beads in the presence of RV144 sera. Variable levels of complement activation were detected two weeks post final boosting in RV144, which is when the V1V2 IgG correlate was identified. The magnitude of complement activation correlated with V1V2-specific serum IgG and was stronger and more common in RV144 than in HIV-1 infected individuals and two related HIV-1 vaccine trials, VAX003 and VAX004, where no protection was seen. After adjusting for gp120 IgA, V1V2 IgG, gender, and risk score, complement activation by case-control plasmas from RV144 correlated inversely with a reduced risk of HIV-1 infection, with odds ratio for positive versus negative response to TH023-V1V2 0.42 (95% CI 0.18 to 0.99, p = 0.048) and to A244-V1V2 0.49 (95% CI 0.21 to 1.10, p = 0.085). These results suggest that complement activity may have contributed in part to modest protection against the acquisition of HIV-1 infection seen in the RV144 trial.

Antibody to HSV gD peptide induced by vaccination does not protect against HSV-2 infection in HSV-2 seronegative women.

BACKGROUND: In the HIV-1 vaccine trial RV144, ALVAC-HIV prime with an AIDSVAX® B/E boost reduced HIV-1 acquisition by 31% at 42 months post first vaccination. The bivalent AIDSVAX® B/E vaccine contains two gp120 envelope glycoproteins, one from the subtype B HIV-1 MN isolate and one from the subtype CRF01_AE A244 isolate. Each envelope glycoprotein harbors a highly conserved 27-amino acid HSV-1 glycoprotein D (gD) tag sequence that shares 93% sequence identity with the HSV-2 gD sequence. We assessed whether vaccine-induced anti-gD antibodies protected females against HSV-2 acquisition in RV144. METHODS: Of the women enrolled in RV144, 777 vaccine and 807 placebo recipients were eligible and randomly selected according to their pre-vaccination HSV-1 and HSV-2 serostatus for analysis. Immunoglobulin G (IgG) and IgA responses to gD were determined by a binding antibody multiplex assay and HSV-2 serostatus was determined by Western blot analysis. Ninety-three percent and 75% of the vaccine recipients had anti-gD IgG and IgA responses two weeks post last vaccination, respectively. There was no evidence of reduction in HSV-2 infection by vaccination compared to placebo recipients over 78 weeks of follow-up. The annual incidence of HSV-2 infection in individuals who were HSV-2 negative at baseline or HSV-1 positive and HSV-2 indeterminate at baseline were 4.38/100 person-years (py) and 3.28/100 py in the vaccine and placebo groups, respectively. Baseline HSV-1 status did not affect subsequent HSV-2 acquisition. Specifically, the estimated odds ratio of HSV-2 infection by Week 78 for female placebo recipients who were baseline HSV-1 positive (n = 422) vs. negative (n = 1120) was 1.14 [95% confidence interval 0.66 to 1.94, p = 0.64)]. No evidence of reduction in the incidence of HSV-2 infection by vaccination was detected. CONCLUSIONS: AIDSVAX® B/E containing gD did not confer protection from HSV-2 acquisition in HSV-2 seronegative women, despite eliciting anti-gD serum antibodies.

Comparison of Antibody Responses Induced by RV144, VAX003, and VAX004 Vaccination Regimens.

The RV144 prime-boost regimen demonstrated efficacy against HIV acquisition while VAX003 and VAX004 did not. Although these trials differed by risk groups, immunization regimens, and immunogens, antibody responses may have contributed to the differences observed in vaccine efficacy. We assessed HIV-specific IgG, both total and subclass, and IgA binding to HIV envelope (Env): gp120 proteins and Cyclic V2 (CycV2) and CycV3 peptides and gp70 V1 V2 scaffolds in these 3 HIV vaccine trials. After two protein immunizations, IgG responses to 92TH023 gp120 (contained in ALVAC-HIV vaccine) were significantly higher in RV144 but responses to other Env were higher in the VAX trials lacking ALVAC-HIV. IgG responses declined significantly between vaccinations. All trials induced antibodies to gp70 V1 V2 but VAX004 responses to 92TH023 gp70 V1 V2 were weak. All CycV2 responses were undetectable in VAX004 while 92TH023 gp70 V1 V2 was detected in both RV144 and VAX003 but MN CycV2 was detected only in VAX003. Multiple protein vaccinations in VAX trials did not improve magnitude or durability of V1 V2 and CycV2 antibodies. Herpes simplex virus glycoprotein D (gD) peptide at the N terminus of AIDSVAX® B/E and B/B gp120 proteins induced antibodies in all trials, although significantly higher in VAX trials. gD peptide induced IgA, IgG1, IgG2, and IgG3 but not IgG4. Multiple protein vaccinations decreased IgG3 and increased IgG4 changing subclass contribution to total IgG. Although confounded by different modes of HIV transmission, higher Env-specific IgA and IgG4 binding antibodies induced in the VAX trials compared to RV144 raises the hypothesis that these differences may have contributed to different vaccine efficacy results.

Tissue memory B cell repertoire analysis after ALVAC/AIDSVAX B/E gp120 immunization of rhesus macaques.

The ALVAC prime/ALVAC + AIDSVAX B/E boost RV144 vaccine trial induced an estimated 31% efficacy in a low-risk cohort where HIV­1 exposures were likely at mucosal surfaces. An immune correlates study demonstrated that antibodies targeting the V2 region and in a secondary analysis antibody-dependent cellular cytotoxicity (ADCC), in the presence of low envelope-specific (Env-specific) IgA, correlated with decreased risk of infection. Thus, understanding the B cell repertoires induced by this vaccine in systemic and mucosal compartments are key to understanding the potential protective mechanisms of this vaccine regimen. We immunized rhesus macaques with the ALVAC/AIDSVAX B/E gp120 vaccine regimen given in RV144, and then gave a boost 6 months later, after which the animals were necropsied. We isolated systemic and intestinal vaccine Env-specific memory B cells. Whereas Env-specific B cell clonal lineages were shared between spleen, draining inguinal, anterior pelvic, posterior pelvic, and periaortic lymph nodes, members of Env­specific B cell clonal lineages were absent in the terminal ileum. Env­specific antibodies were detectable in rectal fluids, suggesting that IgG antibodies present at mucosal sites were likely systemically produced and transported to intestinal mucosal sites.

Challenges and successes for the grantees and the Technical Advisory Group of WHO's influenza vaccine technology transfer initiative.

One of the aims of the WHO Global Action Plan for Influenza Vaccines (GAP) was to transfer influenza vaccine production technology to interested manufacturers and governments in developing countries, to enable greater influenza vaccine manufacturing capacity against any pandemic threat or pandemic. For this objective, the GAP was supported by an independent Technical Advisory Group (TAG) to assist WHO to select vaccine manufacturing proposals for funding and to provide programmatic support for successful grantees. While there were many challenges, for both the TAG and grantees, there were also notable successes with an additional capacity of 338-600 million pandemic vaccine doses being made possible by the programme between 2007 and 2015, and a potential capacity of more than 600 million by 2016/17 with up to one billion doses expected by 2018/19. Seasonal vaccine production was also developed in 4 countries with another 4-5 countries expected to be producing seasonal vaccine by 2018/19. The relatively small WHO investments - in time and funding - made in these companies to develop their own influenza vaccine production facilities have had quite dramatic results.

IgG Antibody Responses to Recombinant gp120 Proteins, gp70V1/V2 Scaffolds, and a CyclicV2 Peptide in Thai Phase I/II Vaccine Trials Using Different Vaccine Regimens.

RV144 correlates of risk analysis showed that IgG antibodies to gp70V1V2 scaffolds inversely correlated with risk of HIV acquisition. We investigated IgG antibody responses in RV135 and RV132, two ALVAC-HIV prime-boost vaccine trials conducted in Thailand prior to RV144. Both trials used ALVAC-HIV (vCP1521) at 0, 1, 3, and 6 months and HIV-1 gp120MNgD and gp120A244gD in alum (RV135) or gp120SF2 and gp120CM235 in MF59 (RV132) at 3 and 6 months. We assessed ELISA binding antibodies to the envelope proteins (Env) 92TH023, A244gD and MNgD, cyclicV2, and gp70V1V2 CaseA2 (subtype B) and 92TH023 (subtype CRF01_AE), and Env-specific IgG1 and IgG3. Antibody responses to gp120 A244gD, MNgD, and gp70V1V2 92TH023 scaffold were significantly higher in RV135 than in RV132. Antibodies to gp70V1V2 CaseA2 were detected only in RV135 vaccine recipients and IgG1 and IgG3 antibody responses to A244gD were significantly higher in RV135. IgG binding to gp70V1V2 CaseA2 and CRF01_AE scaffolds was higher with the AIDSVAX(®)B/E boost but both trials showed similar rates of antibody decline post-vaccination. MF59 did not result in higher IgG antibody responses compared to alum with the antigens tested. However, notable differences in the structure of the recombinant proteins and dosage used for immunizations may have contributed to the magnitude and specificity of IgG induced by the two trials.

Machine learning methods enable predictive modeling of antibody feature:function relationships in RV144 vaccinees.

The adaptive immune response to vaccination or infection can lead to the production of specific antibodies to neutralize the pathogen or recruit innate immune effector cells for help. The non-neutralizing role of antibodies in stimulating effector cell responses may have been a key mechanism of the protection observed in the RV144 HIV vaccine trial. In an extensive investigation of a rich set of data collected from RV144 vaccine recipients, we here employ machine learning methods to identify and model associations between antibody features (IgG subclass and antigen specificity) and effector function activities (antibody dependent cellular phagocytosis, cellular cytotoxicity, and cytokine release). We demonstrate via cross-validation that classification and regression approaches can effectively use the antibody features to robustly predict qualitative and quantitative functional outcomes. This integration of antibody feature and function data within a machine learning framework provides a new, objective approach to discovering and assessing multivariate immune correlates.

Global vaccine supply. The increasing role of manufacturers from middle income countries.

Hallmarks in the remarkable evolution of vaccines and their application include the eradication of smallpox, the development and delivery of the early childhood vaccines and the emergence of recombinant vaccines initiated by the hepatitis B vaccine. Now we enter a most exciting era as vaccines are increasingly produced and delivered in less developed countries. The results are dramatic decreases in childhood morbidity and mortality around the world.

Polyfunctional Fc-effector profiles mediated by IgG subclass selection distinguish RV144 and VAX003 vaccines.

The human phase 2B RV144 ALVAC-HIV vCP1521/AIDSVAX B/E vaccine trial, held in Thailand, resulted in an estimated 31.2% efficacy against HIV infection. By contrast, vaccination with VAX003 (consisting of only AIDSVAX B/E) was not protective. Because protection within RV144 was observed in the absence of neutralizing antibody activity or cytotoxic T cell responses, we speculated that the specificity or qualitative differences in Fc-effector profiles of nonneutralizing antibodies may have accounted for the efficacy differences observed between the two trials. We show that the RV144 regimen elicited nonneutralizing antibodies with highly coordinated Fc-mediated effector responses through the selective induction of highly functional immunoglobulin G3 (IgG3). By contrast, VAX003 elicited monofunctional antibody responses influenced by IgG4 selection, which was promoted by repeated AIDSVAX B/E protein boosts. Moreover, only RV144 induced IgG1 and IgG3 antibodies targeting the crown of the HIV envelope V2 loop, albeit with limited coverage of breakthrough viral sequences. These data suggest that subclass selection differences associated with coordinated humoral functional responses targeting strain-specific protective V2 loop epitopes may underlie differences in vaccine efficacy observed between these two vaccine trials.

Vaccine-induced Env V1-V2 IgG3 correlates with lower HIV-1 infection risk and declines soon after vaccination.

HIV-1-specific immunoglobulin G (IgG) subclass antibodies bind to distinct cellular Fc receptors. Antibodies of the same epitope specificity but of a different subclass therefore can have different antibody effector functions. The study of IgG subclass profiles between different vaccine regimens used in clinical trials with divergent efficacy outcomes can provide information on the quality of the vaccine-induced B cell response. We show that HIV-1-specific IgG3 distinguished two HIV-1 vaccine efficacy studies (RV144 and VAX003 clinical trials) and correlated with decreased risk of HIV-1 infection in a blinded follow-up case-control study with the RV144 vaccine. HIV-1-specific IgG3 responses were not long-lived, which was consistent with the waning efficacy of the RV144 vaccine. These data suggest that specific vaccine-induced HIV-1 IgG3 should be tested in future studies of immune correlates in HIV-1 vaccine efficacy trials.

Plasma IgG to linear epitopes in the V2 and V3 regions of HIV-1 gp120 correlate with a reduced risk of infection in the RV144 vaccine efficacy trial.

Neutralizing and non-neutralizing antibodies to linear epitopes on HIV-1 envelope glycoproteins have potential to mediate antiviral effector functions that could be beneficial to vaccine-induced protection. Here, plasma IgG responses were assessed in three HIV-1 gp120 vaccine efficacy trials (RV144, Vax003, Vax004) and in HIV-1-infected individuals by using arrays of overlapping peptides spanning the entire consensus gp160 of all major genetic subtypes and circulating recombinant forms (CRFs) of the virus. In RV144, where 31.2% efficacy against HIV-1 infection was seen, dominant responses targeted the C1, V2, V3 and C5 regions of gp120. An analysis of RV144 case-control samples showed that IgG to V2 CRF01_AE significantly inversely correlated with infection risk (OR= 0.54, p=0.0042), as did the response to other V2 subtypes (OR=0.60-0.63, p=0.016-0.025). The response to V3 CRF01_AE also inversely correlated with infection risk but only in vaccine recipients who had lower levels of other antibodies, especially Env-specific plasma IgA (OR=0.49, p=0.007) and neutralizing antibodies (OR=0.5, p=0.008). Responses to C1 and C5 showed no significant correlation with infection risk. In Vax003 and Vax004, where no significant protection was seen, serum IgG responses targeted the same epitopes as in RV144 with the exception of an additional C1 reactivity in Vax003 and infrequent V2 reactivity in Vax004. In HIV-1 infected subjects, dominant responses targeted the V3 and C5 regions of gp120, as well as the immunodominant domain, heptad repeat 1 (HR-1) and membrane proximal external region (MPER) of gp41. These results highlight the presence of several dominant linear B cell epitopes on the HIV-1 envelope glycoproteins. They also generate the hypothesis that IgG to linear epitopes in the V2 and V3 regions of gp120 are part of a complex interplay of immune responses that contributed to protection in RV144.

Extended evaluation of the virologic, immunologic, and clinical course of volunteers who acquired HIV-1 infection in a phase III vaccine trial of ALVAC-HIV and AIDSVAX B/E.

BACKGROUND: The Thai Phase III Trial of ALVAC-HIV and AIDSVAX B/E showed an estimated vaccine efficacy (VE) of 31% to prevent acquisition of human immunodeficiency virus (HIV). Here we evaluated the effect of vaccination on disease progression after infection. METHODS: CD4(+) T-cell counts and HIV viral load (VL) were measured serially. The primary analysis evaluated vaccine efficacy (VEP) as the percent reduction (vaccine vs placebo) in cumulative probability of a primary composite endpoint of clinical and CD4(+) count components at prespecified time points after infection. Secondary analyses of biomarker-based endpoints were assessed using marginal mean and linear mixed models. RESULTS: There were 61 endpoints in the modified intent-to-treat cohort (mITT; n = 114). There was no evidence for efficacy at 30, 42, 54, and 60 months in the mITT and per protocol (n = 90) cohorts. Estimated VEP (mITT) was15.8% (-21.9, 41.8) at 60 months postinfection. There was weak evidence of lower VL and higher CD4(+) count at 60 and 66 months in the vaccine group. Lower mucosal VL was observed among vaccine recipients, primarily in semen (P = .04). CONCLUSIONS: Vaccination did not affect the clinical course of HIV disease after infection. A potential vaccine effect on the genital mucosa warrants further study.

Deadly AIDS policy failure by the highest levels of the US government: a personal look back 30 years later for lessons to respond better to future epidemics.

Successful control of any dangerous epidemic requires: (i) early understanding of the epidemiology of the disease and (ii) rapid applications of preventive interventions. Through the lack of both policy and financial support, the United States Centers for Disease Control (CDC) was severely handicapped during the early years of the AIDS epidemic. Senior staff of the Reagan Administration did not understand the essential role of Government in disease prevention. Although CDC clearly documented the dangers of HIV and AIDS early in the epidemic, refusal by the White House to deliver prevention programs then certainly allowed HIV to become more widely seeded. As much of the international health community relies on CDC for up-to-date prevention advice, these actions by the White House surely increased the spread of HIV around the world. To respond better to future epidemics, we need to understand the deadly forces that inhibited CDC at that time.

Risk behaviour and time as covariates for efficacy of the HIV vaccine regimen ALVAC-HIV (vCP1521) and AIDSVAX B/E: a post-hoc analysis of the Thai phase 3 efficacy trial RV 144.

BACKGROUND: The Thai phase 3 HIV vaccine trial RV 144 showed modest efficacy of a vaccine against HIV acquisition. Baseline variables of age, sex, marital status, and risk did not modify vaccine efficacy. We did a post-hoc analysis of the trial's data to investigate behavioural risk and efficacy every 6 months after vaccination. METHODS: RV 144 was a randomised, multicentre, double-blind, placebo-controlled efficacy trial testing the combination of the HIV vaccines ALVAC-HIV (vCP1521) and AIDSVAX B/E to prevent HIV infection or reduce setpoint viral load. Male and female volunteers aged 18-30 years were recruited from the community. In this post-hoc analysis of the modified intention-to-treat population (16,395 participants), HIV risk behaviour was assessed with a self-administered questionnaire at the time of initial vaccination in the trial and every 6 months thereafter for 3 years. We classified participants' behaviour as low, medium, or high risk. Both the acquisition endpoint and the early viral-load endpoint were examined for interactions with risk status over time and temporal effects after vaccination. Multiple proportional hazards regression models with treatment and time-varying risk covariates were analysed. FINDINGS: Risk of acquisition of HIV was low in each risk group, but 9187 (58·2%) participants reported higher-risk behaviour at least once during the study. Participants classified as high or increasing risk at least once during follow-up were compared with those who maintained low-risk or medium-risk behaviour as a time-varying covariate, and the interaction of risk status and acquisition efficacy was significant (p=0·01), with greater benefit in low-risk individuals. Vaccine efficacy seemed to peak early--cumulative vaccine efficacy was estimated to be 60·5% (95% CI 22-80) through the 12 months after initial vaccination--and declined quickly. Vaccination did not seem to affect viral load in either early or late infections. INTERPRETATION: Future HIV vaccine trials should recognise potential interactions between challenge intensity and risk heterogeneity in both population and treatment effects. The regimen tested in the RV 144 phase 3 trial might benefit from extended immunisation schedules. FUNDING: US Army Medical Research and Materiel Command and Division of AIDS, National Institute of Allergy and Infectious Disease, National Institutes of Health.

Magnitude and breadth of the neutralizing antibody response in the RV144 and Vax003 HIV-1 vaccine efficacy trials.

BACKGROUND: A recombinant canarypox vector expressing human immunodeficiency virus type 1 (HIV-1) Gag, Pro, and membrane-linked gp120 (vCP1521), combined with a bivalent gp120 protein boost (AIDSVAX B/E), provided modest protection against HIV-1 infection in a community-based population in Thailand (RV144 trial). No protection was observed in Thai injection drug users who received AIDSVAX B/E alone (Vax003 trial). We compared the neutralizing antibody response in these 2 trials. METHODS: Neutralization was assessed with tier 1 and tier 2 strains of virus in TZM-bl and A3R5 cells. RESULTS: Neutralization of several tier 1 viruses was detected in both RV144 and Vax003. Peak titers were higher in Vax003 and waned rapidly in both trials. The response in RV144 was targeted in part to V3 of gp120.vCP1521 priming plus 2 boosts with gp120 protein was superior to 2 gp120 protein inoculations alone, confirming a priming effect for vCP1521. Sporadic weak neutralization of tier 2 viruses was detected only in Vax003 and A3R5 cells. CONCLUSION: The results suggest either that weak neutralizing antibody responses can be partially protective against HIV-1 in low-risk heterosexual populations or that the modest efficacy seen in RV144 was mediated by other immune responses, either alone or in combination with neutralizing antibodies.

HLA class II restriction of HIV-1 clade-specific neutralizing antibody responses in ethnic Thai recipients of the RV144 prime-boost vaccine combination of ALVAC-HIV and AIDSVAX(®) B/E.

Immune responses to vaccines may be influenced or associated with allelic variants of host genes such as those encoding human leucocyte antigens (HLA). We have molecularly determined the HLA class II DR and DQ gene, allele and haploype profiles in HIV-1 negative ethnic Thai recipients of an HIV-1 prime boost vaccine regimen, designed to induce neutralizing antibody (NAb) responses to HIV-1 CRF01_AE. Non-response to vaccine associated with DRB1*11 (3/32 responders vs. 7/13 non-responders, p(c)=0.027) and DRB1*16:02 (0/32 responders vs. 4/13 non-responders, p(c)=0.078) alleles. Furthermore, vaccine recipients with HLA-DQ heterodimers encoded by DQA1*05:01 and DQB1*03:01 alleles, were much less likely to produce NAb (p=0.009). These data suggest that the lack of response to a vaccine designed to induce clade-specific NAb to HIV-1 is associated with the presence of certain HLA class II alleles and heterodimers in some Southeast Asians.

Safety and reactogenicity of canarypox ALVAC-HIV (vCP1521) and HIV-1 gp120 AIDSVAX B/E vaccination in an efficacy trial in Thailand.

BACKGROUND: A prime-boost vaccination regimen with ALVAC-HIV (vCP1521) administered intramuscularly at 0, 4, 12, and 24 weeks and gp120 AIDSVAX B/E at 12 and 24 weeks demonstrated modest efficacy of 31.2% for prevention of HIV acquisition in HIV-uninfected adults participating in a community-based efficacy trial in Thailand. METHODOLOGY/PRINCIPAL FINDINGS: Reactogenicity was recorded for 3 days following vaccination. Adverse events were monitored every 6 months for 3.5 years, during which pregnancy outcomes were recorded. Of the 16,402 volunteers, 69% of the participants reported an adverse event any time after the first dose. Only 32.9% experienced an AE within 30 days following any vaccination. Overall adverse event rates and attribution of relatedness did not differ between groups. The frequency of serious adverse events was similar in vaccine (14.3%) and placebo (14.9%) recipients (p = 0.33). None of the 160 deaths (85 in vaccine and 75 in placebo recipients, p = 0.43) was assessed as related to vaccine. The most common cause of death was trauma or traffic accident. Approximately 30% of female participants reported a pregnancy during the study. Abnormal pregnancy outcomes were experienced in 17.1% of vaccine and 14.6% (p = 0.13) of placebo recipients. When the conception occurred within 3 months (estimated) of a vaccination, the majority of these abnormal outcomes were spontaneous or elective abortions among 22.2% and 15.3% of vaccine and placebo pregnant recipients, respectively (p = 0.08). Local reactions occurred in 88.0% of vaccine and 61.0% of placebo recipients (p<0.001) and were more frequent after ALVAC-HIV than AIDSVAX B/E vaccination. Systemic reactions were more frequent in vaccine than placebo recipients (77.2% vs. 59.8%, p<0.001). Local and systemic reactions were mostly mild to moderate, resolving within 3 days. CONCLUSIONS/SIGNIFICANCE: The ALVAC-HIV and AIDSVAX B/E vaccine regimen was found to be safe, well tolerated and suitable for potential large-scale use in Thailand. TRIAL REGISTRATION: ClinicalTrials.govNCT00223080.