Adaptive NK Cells Rapidly Expand during Acute HIV Infection and Persist Despite Early Initiation of Antiretroviral Therapy.

HIV is associated with NK cell dysfunction and expansion of adaptive-like NK cells that persist despite antiretroviral therapy (ART). We investigated the timing of NK cell perturbations during acute HIV infection and the impact of early ART initiation. PBMCs and plasma were obtained from people with HIV (PWH; all men who have sex with men; median age, 26.0 y) diagnosed during Fiebig stages I, II, III, or IV/V. Participants initiated ART a median of 3 d after diagnosis, and immunophenotyping was performed at diagnosis and longitudinally after ART. Anti-CMV Abs were assessed by ELISA. Samples from matched HIV-uninfected males were also analyzed. Proportions of adaptive NK cells (A-NKs; defined as Fcε-Receptor-1γ-) were expanded at HIV diagnosis at all Fiebig stages (pooled median 66% versus 25% for controls; p < 0.001) and were not altered by early ART initiation. Abs to CMV immediate early protein were elevated in PWH diagnosed in Fiebig stages III and IV/V (p < 0.03 for both). Proportions of A-NKs defined as either Fcε-Receptor-1γ- or NKG2C+/CD57+ were significantly associated with HIV DNA levels at diagnosis (p = 0.046 and 0.029, respectively) and trended toward an association after 48 wk of ART. Proportions of activated HLA-DR+/CD38+ NK cells remained elevated in PWH despite early ART initiation. NK cell activation and A-NK expansion occur very early after HIV transmission, before T cell activation, and are not altered by ART initiation during acute infection. A-NKs may contribute to HIV control and thus be useful for HIV cure.

Innate immune cell activation after HIV-1 vaccine administration is associated with increased antibody production.

The RV144 Thai phase III clinical trial's canarypox-protein HIV vaccine regimen showed modest efficacy in reducing infection. We therefore sought to determine the effects of vaccine administration on innate cell activation and subsequent associations with vaccine-induced immune responses. RV306 was a randomized, double-blind clinical trial in HIV-uninfected Thai adults that tested delayed boosting following the RV144 regimen. PBMC collected from RV306 participants prior to and 3 days after the last boost were used to investigate innate immune cell activation. Our analysis showed an increase in CD38+ mucosal associated invariant T (MAIT) cells, CD38+ invariant natural killer T (iNKT) cells, CD38+ γδ T cells, CD38+, CD69+ and HLA-DR+ NK cells 3 days after vaccine administration. An increase in CD14-CD16+ non-classical monocytes and CD14+CD16+ intermediate monocytes accompanied by a decrease in CD14+CD16- classical monocytes was also associated with vaccine administration. Inclusion of ALVAC-HIV in the boost did not further increase MAIT, iNKT, γδ T, and NK cell activation or increase the proportion of non-classical monocytes. Additionally, NK cell activation 3 days after vaccination was positively associated with antibody titers of HIV Env-specific total IgG and IgG1. Vδ1 T cell activation 3 days after vaccine administration was associated with HIV Env-specific IgG3 titers. Finally, we observed trending associations between MAIT cell activation and Env-specific IgG3 titers and between NK cell activation and TH023 pseudovirus neutralization titers. Our study identifies a potential role for innate cells, specifically NK, MAIT, and γδ T cells, in promoting antibody responses following HIV-1 vaccine administration.

Distinct mucosal and systemic immunological characteristics in transgender women potentially relating to HIV acquisition.

Transgender women (TGW) are disproportionally affected by HIV infection, with a global estimated prevalence of 19.9%, often attributed to behavioral risk factors, with less known about biological factors. We evaluated potential biological risk factors for HIV acquisition in TGW at the sites of viral entry by assessing immune parameters of the neovaginal surface and gut mucosa. The neovagina in TGW, compared with the vagina in cisgender women (CW), shows distinct cell composition and may pose a more inflammatory environment, evidenced by increased CD4+ T cell activation and higher levels of soluble markers of inflammation (C-reactive protein, soluble CD30). Increased inflammation may be driven by microbiome composition, as shown by a greater abundance of Prevotella and a higher Shannon Diversity Index. In addition, we have observed higher frequency of CD4+CCR5+ target cells and decreased DNA methylation of the CCR5 gene in the gut mucosa of TGW compared with CW and men who have sex with men, which was inversely correlated with testosterone levels. The rectal microbiome composition in TGW appears to favor a proinflammatory milieu as well as mucosal barrier disruption. Thus, it is possible that increased inflammation and higher frequencies of CCR5-expressing target cells at sites of mucosal viral entry may contribute to increased risk of HIV acquisition in TGW, with further validation in larger studies warranted.

Additional boosting to the RV144 vaccine regimen increased Fc-mediated effector function magnitude but not durability.

OBJECTIVES: The RV144 vaccine trial resulted in a decreased risk of HIV acquisition that was associated with a nonneutralizing antibody response. The objective of this study was to determine the impact of an additional boost to the RV144 vaccine regimen on antibody effector function and durability. DESIGN: RV306 was a randomized, double-blind late boosting of the RV144 prime-boost regimen in HIV-uninfected Thai adults (NCT01931358). This analysis included study participants who received the RV144 vaccine regimen and received no additional boost (group 1) or were boosted with ALVAC-HIV and AIDSVAX (group 2) or only AIDSVAX alone (group 3) 24 weeks after completing the RV144 series. METHODS: Plasma samples from RV306 study participants were used to measure antibody-dependent cellular phagocytosis (ADCP), antibody-dependent neutrophil phagocytosis (ADNP), antibody-dependent complement deposition (ADCD), antibody-dependent cellular cytotoxicity (ADCC), trogocystosis, and gp120-specifc IgG subclasses. RESULTS: Additional boosting increased the magnitude of all Fc-mediated effector functions 2 weeks following the additional boost compared with 2 weeks after completing the RV144 regimen. However, only trogocytosis remained higher 24-26 weeks after the last vaccination for the study participants receiving an additional boost compared with those that did not receive an additional boost. The additional boost increased IgG1 and IgG4 but decreased IgG3 gp-120 specific antibodies compared with 2 weeks after completing the RV144 regimen. CONCLUSION: Additional boosting of RV144 improved the magnitude but not the durability of some Fc-mediated effector functions that were associated with vaccine efficacy, with trogocytosis being the most durable.

ALVAC-HIV and AIDSVAX B/E vaccination induce improved immune responses compared with AIDSVAX B/E vaccination alone.

The RV144 phase III vaccine trial demonstrated that ALVAC-HIV and AIDSVAX B/E administration over 6 months resulted in 31% efficacy in preventing HIV acquisition, while administration of AIDSVAX B/E alone in both VAX003 and VAX004 studies failed to show efficacy. In this study, we aimed to understand the impact of ALVAC-HIV on the development of cellular, humoral, and functional immune responses compared to the administration of AIDSVAX B/E alone. ALVAC-HIV in combination with 3 doses of AIDSVAX B/E significantly increased CD4+ HIV-specific T cell responses, polyfunctionality, and proliferation compared with 3 doses of AIDSVAX B/E alone. Additionally, Env-specific plasmablasts and A244-specific memory B cells were identified with a significantly higher magnitude in the group that received ALVAC-HIV. Subsequently, data revealed increased magnitude of plasma IgG binding to and avidity for HIV Env in participants who received ALVAC-HIV compared with 3 doses of AIDSVAX B/E alone. Lastly, levels of the Fc-mediated effector functions antibody-dependent cellular cytotoxicity, NK cell activation, and trogocytosis were significantly increased in participants who received ALVAC-HIV compared with those receiving AIDSVAX B/E alone. Taken together, these results suggest that ALVAC-HIV plays an essential role in developing cellular and humoral immune responses to protein-boosted regimens relative to protein alone.

Viral vector delivered immunogen focuses HIV-1 antibody specificity and increases durability of the circulating antibody recall response.

The modestly efficacious HIV-1 vaccine regimen (RV144) conferred 31% vaccine efficacy at 3 years following the four-shot immunization series, coupled with rapid waning of putative immune correlates of decreased infection risk. New strategies to increase magnitude and durability of protective immunity are critically needed. The RV305 HIV-1 clinical trial evaluated the immunological impact of a follow-up boost of HIV-1-uninfected RV144 recipients after 6-8 years with RV144 immunogens (ALVAC-HIV alone, AIDSVAX B/E gp120 alone, or ALVAC-HIV + AIDSVAX B/E gp120). Previous reports demonstrated that this regimen elicited higher binding, antibody Fc function, and cellular responses than the primary RV144 regimen. However, the impact of the canarypox viral vector in driving antibody specificity, breadth, durability and function is unknown. We performed a follow-up analysis of humoral responses elicited in RV305 to determine the impact of the different booster immunogens on HIV-1 epitope specificity, antibody subclass, isotype, and Fc effector functions. Importantly, we observed that the ALVAC vaccine component directly contributed to improved breadth, function, and durability of vaccine-elicited antibody responses. Extended boosts in RV305 increased circulating antibody concentration and coverage of heterologous HIV-1 strains by V1V2-specific antibodies above estimated protective levels observed in RV144. Antibody Fc effector functions, specifically antibody-dependent cellular cytotoxicity and phagocytosis, were boosted to higher levels than was achieved in RV144. V1V2 Env IgG3, a correlate of lower HIV-1 risk, was not increased; plasma Env IgA (specifically IgA1), a correlate of increased HIV-1 risk, was elevated. The quality of the circulating polyclonal antibody response changed with each booster immunization. Remarkably, the ALVAC-HIV booster immunogen induced antibody responses post-second boost, indicating that the viral vector immunogen can be utilized to selectively enhance immune correlates of decreased HIV-1 risk. These results reveal a complex dynamic of HIV-1 immunity post-vaccination that may require careful balancing to achieve protective immunity in the vaccinated population. Trial registration: RV305 clinical trial (ClinicalTrials.gov number, NCT01435135). ClinicalTrials.gov Identifier: NCT00223080.

Risk Factors for HIV sero-conversion in a high incidence cohort of men who have sex with men and transgender women in Bangkok, Thailand.

BACKGROUND: We measured Human Immunodeficiency (HIV) incidence, retention, and assessed risk factors for seroconversion among two previously unreported cohorts of men who have sex with men (MSM) and Transgender Women (TGW) in Bangkok, Thailand between 2017 and 2019. METHODS: We conducted an 18-month prospective cohort study of HIV-uninfected Thai cisgender men and TGW aged between 18 and 35 years who reported sex with men in the past six months and at least one additional risk factor for HIV infection. HIV and syphilis testing and computer-based behavioral questionnaires were administered at each visit. We utilized Poisson regression to calculate HIV incidence rates. A survival random forest model identified the most predictive risk factors for HIV sero-conversion and then used in a survival regression tree model to elucidate hazard ratios for individuals with groups of selected risk factors. Cox proportional hazards (pH) regression evaluated the strength of association between individual covariates and risk of sero-conversion. FINDINGS: From April 2017-October 2019, 1,184 participants were screened, 167 were found ineligible, and 1,017 enrolled. Over the 18-month study, visit retention was 93·4% (95% CI 91·6%-94·8%) and HIV incidence was 3·73 per 100 person-years (95% CI 2·79-5·87). Utilizing survival regression tree modeling, those who were 18-20 years of age, reported sexual attraction to mostly or only men, and had five or more lifetime sexual partners were 4·9 times more likely to seroconvert compared to other cohort participants. Factors associated with HIV incidence utilizing Cox pH regression included sexual attraction to mostly or only men (adjusted hazard ratio (aHR) 14·9 (95% CI 20·1-107·9), younger age (18-19 years, aHR 10·88 (95% CI 4·12-28·7), five or greater lifetime sexual partners (aHR 2·0, 95%CI 1·1-3·6), inconsistent condom use with casual partners (aHR 2·43, 95% CI 1·3-4·5), and prior HIV testing (adjusted HR 2·0, 95% CI 1·1-3·5). INTERPRETATION: Interpretation HIV incidence remains high among Bangkok-based MSM and TGW. These key populations expressed high interest in participating in efficacy evaluation of future prevention strategies and had high retention in this 18 month study. FUNDING: Funding US National Institute of Allergy and Infectious Diseases (NIAID), Division of AIDS Interagency Agreements (DAIDS) and U.S. Department of the Army.

Determinants of suboptimal CD4+ T cell recovery after antiretroviral therapy initiation in a prospective cohort of acute HIV-1 infection.

INTRODUCTION: Up to 30% of individuals treated with antiretroviral therapy (ART) during chronic HIV fail to recover CD4 counts to >500 cells/mm3 despite plasma viral suppression. We investigated the frequency and associations of suboptimal CD4 recovery after ART started during acute HIV infection (AHI). METHODS: Participants who started ART in Fiebig I to V AHI with ≥48 weeks of continuous documented HIV-RNA < 50 copies/mL were stratified by CD4 count at latest study visit to suboptimal immune recovery (SIR; CD4 < 350 cells/mm3 ), intermediate immune recovery (IIR; 350 ≤ CD4 < 500) and complete immune recovery (CIR; CD4 ≥ 500). Clinical and laboratory parameters were assessed at pre-ART baseline and latest study visit. Additional inflammatory and neurobehavioral endpoints were examined at baseline and 96 weeks. RESULTS: Of 304 participants (96% male, median 26 years old) evaluated after median 144 (range 60 to 420) weeks of ART initiated at median 19 days (range 1 to 62) post-exposure, 3.6% (n = 11) had SIR and 14.5% (n = 44) had IIR. Pre-ART CD4 count in SIR compared to CIR participants was 265 versus 411 cells/mm3 (p = 0.002). Individuals with SIR or IIR had a slower CD4 rate of recovery compared to those with CIR. Timing of ART initiation by Fiebig stage did not affect CD4 count during treatment. Following ART, the CD8+ T cell count (p = 0.001) and CD4/CD8 ratio (p = 0.047) were lower in SIR compared to CIR participants. Compared to the CIR group at week 96, the combined SIR and IIR groups had higher sCD14 (p = 0.008) and lower IL-6 (p = 0.04) in plasma, without differences in neuropsychological or psychiatric indices. CONCLUSIONS: Despite immediate and sustained treatment in AHI, suboptimal CD4 recovery occurs uncommonly and is associated with low pre-ART CD4 count as well as persistent low CD8 count and CD4/CD8 ratio during treatment.

Abundant HIV-infected cells in blood and tissues are rapidly cleared upon ART initiation during acute HIV infection.

The timing and location of the establishment of the viral reservoir during acute HIV infection remain unclear. Using longitudinal blood and tissue samples obtained from HIV-infected individuals at the earliest stage of infection, we demonstrate that frequencies of infected cells reach maximal values in gut-associated lymphoid tissue and lymph nodes as early as Fiebig stage II, before seroconversion. Both tissues displayed higher frequencies of infected cells than blood until Fiebig stage III, after which infected cells were equally distributed in all compartments examined. Initiation of antiretroviral therapy (ART) at Fiebig stages I to III led to a profound decrease in the frequency of infected cells to nearly undetectable level in all compartments. The rare infected cells that persisted were preferentially found in the lymphoid tissues. Initiation of ART at later stages (Fiebig stages IV/V and chronic infection) induced only a modest reduction in the frequency of infected cells. Quantification of HIV DNA in memory CD4+ T cell subsets confirmed the unstable nature of most of the infected cells at Fiebig stages I to III and the emergence of persistently infected cells during the transition to Fiebig stage IV. Our results indicate that although a large pool of cells is infected during acute HIV infection, most of these early targets are rapidly cleared upon ART initiation. Therefore, infected cells present after peak viremia have a greater ability to persist.

Late boosting of the RV144 regimen with AIDSVAX B/E and ALVAC-HIV in HIV-uninfected Thai volunteers: a double-blind, randomised controlled trial.

BACKGROUND: The RV144 phase 3 vaccine trial in Thailand demonstrated that ALVAC-HIV (vCP1521) and AIDSVAX B/E administration over 6 months resulted in a 31% efficacy in preventing HIV acquisition. In this trial, we assessed the immunological effect of an additional vaccine boost to the RV144 regimen at varying intervals between the priming vaccine series and the boost. METHODS: RV306 is a double-blind, placebo-controlled, randomised clinical trial done at three clinical sites in Thailand. Eligible volunteers were HIV-uninfected individuals aged 20-40 years who were at low risk for HIV infection and in good health. A randomisation schedule was centrally generated with fixed sized strata for Research Institute for Health Sciences Chiang Mai and combined Bangkok clinics. Participants were randomly assigned to one of five groups and then further randomly assigned to either vaccine or placebo. All participants received the primary RV144 vaccine series at months 0, 1, 3, and 6. Group 1 received no additional boost, group 2 received additional AIDSVAX B/E and ALVAC-HIV (vCP1521) or placebo at month 12, group 3 received AIDSVAX B/E alone or placebo at month 12, group 4a received AIDSVAX B/E and ALVAC-HIV or placebo at month 15, and group 4b received AIDSVAX B/E and ALVAC-HIV or placebo at month 18. Primary outcomes were safety and tolerability of these vaccination regimens and cellular and humoral immune responses compared between the RV144 series alone and regimens with late boosts at different timepoints. Safety and tolerability outcomes were assessed by evaluating local and systemic reactogenicity and adverse events in all participants. This trial is registered at ClinicalTrials.gov (NCT01931358); clinical follow-up is now complete. FINDINGS: Between Oct 28, 2013, and April 29, 2014, 367 participants were enrolled, of whom 27 were assigned active vaccination in group 1, 102 in group 2, 101 in group 3, 52 in group 4a, 51 in group 4b, and 34 combined placebo across all the groups. No vaccine-related serious adverse events were recorded. Occurrence and severity of local and systemic reactogenicity were similar across active groups. Groups with late boosts (groups 2, 3, 4a, and 4b) had increased peak plasma IgG-binding antibody levels against gp70 V1V2 relative to group 1 vaccine recipients with no late boost (gp70 V1V2 92TH023 adjusted p<0·02 for each; gp70 V1V2 CaseA2 adjusted p<0·0001 for each). Boosting at month 12 (groups 2 and 3) did not increase gp120 responses compared with the peak responses after the RV144 priming regimen at month 6; however, boosting at month 15 (group 4a) improved responses to gp120 A244gD- D11 (p=0·0003), and boosting at month 18 (group 4b) improved responses to both gp120 A244gD- D11 (p<0·0001) and gp120 MNgD- D11 (p=0·0016). Plasma IgG responses were significantly lower among vaccine recipients boosted at month 12 (pooled groups 2 + 3) than at month 15 (group 4a; adjusted p<0·0001 for each, except for gp70 V1V2 CaseA2, p=0·0142) and at month 18 (group 4b; all adjusted p<0·001). Boosting at month 18 versus month 15 resulted in a significantly higher plasma IgG response to gp120 antigens (all adjusted p<0·01) but not gp70 V1V2 antigens. CD4 functionality and polyfunctionality scores after stimulation with HIV-1 Env peptides (92TH023) increased with delayed boosting. Groups with late boosts had increased functionality and polyfunctionality scores relative to vaccine recipients with no late boost (all adjusted p<0·05, except for the polyfunctionality score in group 1 vs group 4b, p<0·01). INTERPRETATION: Taken together, these results suggest that additional boosting of the RV144 regimen with longer intervals between the primary vaccination series and late boost improved immune responses and might improve the efficacy of preventing HIV acquisition. FUNDING: US National Institute of Allergy and Infectious Diseases and US Department of the Army.

Pattern and Frequency of Seroreactivity to Routinely Used Serologic Tests in Early-Treated Infants With HIV.

BACKGROUND: Previous studies have shown low frequencies of seroreactivity to HIV diagnostic assays for infected infants treated with antiretroviral therapy (ART) early in infection. METHODS: Fifty-eight HIV-infected infants treated with ART at a median age of 1.9 months (range: 0.2-5.4) for up to 4 years of life were assessed for seroreactivity to 4 routinely used HIV clinical immunoassays (IA): Second-generation (2ndG) IA and 2 rapid diagnostic tests (RDT), based on third-generation principles, measuring antibody only and a fourth-generation (4thG) antigen/antibody IA. HIV Western blot assay was also performed to assess HIV-specific antibodies. RESULTS: The 2ndG IA demonstrated the highest frequency of seroreactivity in children (69%) followed by the 4thG IA (40%) and the RDT (26%) after one year of ART. Infants initiating ART during ages 3-6 months (N = 15) showed a greater frequency (range: 53%-93%) and breadth (median and range: 3 [1-4]) of reactivity across the assays compared with those treated within 3 months (N = 43):16%-61% and breadth (1 [0-4]). The 4thG IA showed significantly reduced reactivity relative to the 2ndG IA at one (P = 0.016) and 3 (P = 0.004) years of ART. Western blot profiles following 3 years of ART showed the highest frequency of reactivity to HIV Gag p24 (76%) and lowest reactivity to Env gp120 and gp41, with only 24% of children confirmed positive by the assay. CONCLUSIONS: These results suggest that the use of 4thG IA and RDT test combination algorithms with limited HIV antigen breadth may not be adequate for diagnosis of HIV-infected children following early treatment.

Dynamics of Human Immunodeficiency Virus-1 Genetic Diversification During Acute Infection.

We analyzed human immunodeficiency virus envelope diversity in 98 acute infections. The within-host genetic diversity, divergence from transmitted/founder (T/F) strain, and the observed frequency of multiple T/F infections increased with Fiebig stage. These data identify rapid viral dynamics during acute infection with implications for clinical trials conducted in this setting.

Decreased Seroreactivity in Individuals Initiating Antiretroviral Therapy during Acute HIV Infection.

Antiretroviral therapy (ART) during acute HIV infection (AHI) interrupts viral dynamics and may delay the emergence of serological markers targeted by current HIV screening and confirmatory assays, thus creating challenges for correctly classifying HIV infection status. The performance of three HIV antigen/antibody combination (HIV Ag/Ab Combo) assays (the Bio-Rad GS, Abbott Architect, and Bio-Rad BioPlex 2200 assays) was evaluated with samples collected from RV254/South East Asia Research Collaboration in HIV 010 (RV254/SEARCH010) study (Bangkok, Thailand) participants at weeks 12 and 24 following the initiation of ART at Fiebig stage I (FI) (n = 23), FII (n = 39), or FIII/IV (n = 22). Supplemental, confirmatory testing was performed by the Geenius HIV 1/2 and HIV-1 Western blot assays (Bio-Rad). Samples from 30 untreated, HIV-1-infected individuals demonstrated robust HIV Ag/Ab Combo assay reactivity with well-developed HIV-1 Western blotting profiles by 24 weeks after infection. In contrast, 52.2% of samples from individuals initiating ART at FI, 7.7% of samples from individuals initiating ART at FII, and 4.5% of samples from individuals initiating ART at FIII/IV were nonreactive by the HIV Ag/Ab Combo assays, with 36.4 to 39.1% of samples having low signal-to-cutoff (S/CO) results by the Architect and BioPlex assays (S/CO < 10). Seroreversion from a reactive to a nonreactive status was observed in 10 individuals initiating ART at FII and 3 individuals initiating ART at FIII/IV. The Geenius and HIV-1 Western blot assay results were negative or indeterminate for 73.9% and 69.6% of individuals, respectively, treated at FI; 50.0% and 26.3% of individuals, respectively, treated at FII; and 54.5% and 40.9% of individuals, respectively, treated at FIII/IV. Virologic suppression of HIV-1 by ART during AHI impedes seroconversion to biomarkers of infection, limiting the utility of HIV Ag/Ab Combo and supplemental, confirmatory assays for infection status determination.

Characterization of Cellular Immune Responses in Thai Individuals With and Without HIV-Associated Neurocognitive Disorders.

HIV-associated neurocognitive disorder (HAND) remains a challenge despite antiretroviral therapy (ART), and has been linked to monocyte/macrophage (M/M) migration to the brain. Due to the potential impact of T cell effector mechanisms in eliminating activated/HIV-infected M/M, T cell activation may play a role in the development of HAND. We sought to investigate the relationship between cognition and both CD8+ T cell activation (HLA-DR+/CD38+) and HIV-specific CD8+ T cell responses at the time of HIV diagnosis and 12 months postinitiation of ART. CD8+ T cell activation was increased in HAND compared to cognitive normal (NL) individuals and correlated directly with plasma viral load and inversely with the cognitive status. In addition, Gag-specific cytolytic activity (CD107a/b+) was decreased in HAND compared with NL individuals and correlated with their neurological testing, suggesting a potential role of cytotoxic CD8+ T cells in the mechanism of HAND development.

Characterization of HIV-1 gp120 antibody specificities induced in anogenital secretions of RV144 vaccine recipients after late boost immunizations.

Sexual transmission is the principal driver of the human immunodeficiency virus (HIV) pandemic. Understanding HIV vaccine-induced immune responses at mucosal surfaces can generate hypotheses regarding mechanisms of protection, and may influence vaccine development. The RV144 (ClinicalTrials.gov NCT00223080) efficacy trial showed protection against HIV infections but mucosal samples were not collected, therefore, the contribution of mucosal antibodies to preventing HIV-1 acquisition is unknown. Here, we report the generation, magnitude and persistence of antibody responses to recombinant gp120 envelope and antigens including variable one and two loop scaffold antigens (gp70V1V2) previously shown to correlate with risk in RV144. We evaluated antibody responses to gp120 A244gD and gp70V1V2 92TH023 (both CRF01_AE) and Case A2 (subtype B) in cervico-vaginal mucus (CVM), seminal plasma (SP) and rectal secretions (RS) from HIV-uninfected RV144 vaccine recipients, who were randomized to receive two late boosts of ALVAC-HIV/AIDSVAX®B/E, AIDSVAX®B/E, or ALVAC-HIV alone at 0 and 6 months. Late vaccine boosting increased IgG geometric mean titers (GMT) to gp120 A244gD in AIDSVAX®B/E and ALVAC-HIV/AIDSVAX®B/E CVM (28 and 17 fold, respectively), followed by SP and RS. IgG to gp70V1V2 92TH023 increased in AIDSVAX®B/E and ALVAC-HIV/AIDSVAX®B/E CVM (11-17 fold) and SP (2 fold) two weeks post first boost. IgG to Case A2 was only detected in AIDSVAX®B/E and ALVAC-HIV/AIDSVAX®B/E CVM. Mucosal IgG to gp120 A244gD (CVM, SP, RS), gp70V1V2 92TH023 (CVM, SP), and Case A2 (CVM) correlated with plasma IgG levels (p<0.001). Although the magnitude of IgG responses declined after boosting, anti-gp120 A244gD IgG responses in CVM persisted for 12 months post final vaccination. Further studies in localization, persistence and magnitude of envelope specific antibodies (IgG and dimeric IgA) in anogenital secretions will help determine their role in preventing mucosal HIV acquisition.

Acute HIV infection detection and immediate treatment estimated to reduce transmission by 89% among men who have sex with men in Bangkok.

INTRODUCTION: Antiretroviral treatment (ART) reduces HIV transmission. Despite increased ART coverage, incidence remains high among men who have sex with men (MSM) in many places. Acute HIV infection (AHI) is characterized by high viral replication and increased infectiousness. We estimated the feasible reduction in transmission by targeting MSM with AHI for early ART. METHODS: We recruited a cohort of 88 MSM with AHI in Bangkok, Thailand, who initiated ART immediately. A risk calculator based on viral load and reported behaviour, calibrated to Thai epidemiological data, was applied to estimate the number of onwards transmissions. This was compared with the expected number without early interventions. RESULTS: Forty of the MSM were in 4th-generation AHI stages 1 and 2 (4thG stage 1, HIV nucleic acid testing (NAT)+/4thG immunoassay (IA)-/3rdG IA-; 4thG stage 2, NAT+/4thG IA+/3rdG IA-) while 48 tested positive on third-generation IA but had negative or indeterminate western blot (4thG stage 3). Mean plasma HIV RNA was 5.62 log10 copies/ml. Any condomless sex in the four months preceding the study was reported by 83.7%, but decreased to 21.2% by 24 weeks on ART. After ART, 48/88 (54.6%) attained HIV RNA <50 copies/ml by week 8, increasing to 78/87 (89.7%), and 64/66 (97%) at weeks 24 and 48, respectively. The estimated number of onwards transmissions in the first year of infection would have been 27.3 (95% credible interval: 21.7-35.3) with no intervention, 8.3 (6.4-11.2) with post-diagnosis behaviour change only, 5.9 (4.4-7.9) with viral load reduction only and 3.1 (2.4-4.3) with both. The latter was associated with an 88.7% (83.8-91.1%) reduction in transmission. CONCLUSIONS: Disproportionate HIV transmission occurs during AHI. Diagnosis of AHI with early ART initiation can substantially reduce onwards transmission.

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.

Initiation of Antiretroviral Therapy During Acute HIV-1 Infection Leads to a High Rate of Nonreactive HIV Serology.

BACKGROUND: Third- and fourth-generation immunoassays (IAs) are widely used in the diagnosis of human immunodeficiency virus (HIV) infection. Antiretroviral therapy (ART) during acute HIV infection (AHI) may impact HIV-specific antibodies, with failure to develop antibody or seroreversion. We report on the ability of diagnostic tests to detect HIV-specific antibodies in Thai participants initiating ART during AHI. METHODS: Participants with detectable plasma HIV RNA but nonreactive HIV-specific immunoglobulin G, enrolled in an AHI study, were offered immediate initiation of ART. Participants were tested at initiation and at 12 and 24 weeks following treatment using standard second-, third-, and fourth-generation IAs and Western blot (WB). RESULTS: Participants (N = 234) initiating ART at a median of 19 days (range, 1-62 days) from HIV exposure demonstrated different frequencies of reactivity prior to and following 24 weeks of ART depending on the IA. Third-generation IA nonreactivity prior to ART was 48%, which decreased to 4% following ART (P < .001). Fourth-generation IA nonreactivity was 18% prior to ART and 17% following ART (P = .720). Negative WB results were observed in 89% and 12% of participants prior to and following 24 weeks of ART, respectively (P < .001). Seroreversion to nonreactivity during ART was observed to at least one of the tests in 20% of participants, with fourth-generation IA demonstrating the highest frequency (11%) of seroreversion. CONCLUSIONS: HIV-specific antibodies may fail to develop and, when detected, may decline when ART is initiated during AHI. Although fourth-generation IA was the most sensitive at detecting AHI prior to ART, third-generation IA was the most sensitive during treatment. CLINICAL TRIALS REGISTRATION: NCT00796146 and NCT00796263.

Initiation of ART during early acute HIV infection preserves mucosal Th17 function and reverses HIV-related immune activation.

Mucosal Th17 cells play an important role in maintaining gut epithelium integrity and thus prevent microbial translocation. Chronic HIV infection is characterized by mucosal Th17 cell depletion, microbial translocation and subsequent immune-activation, which remain elevated despite antiretroviral therapy (ART) correlating with increased mortality. However, when Th17 depletion occurs following HIV infection is unknown. We analyzed mucosal Th17 cells in 42 acute HIV infection (AHI) subjects (Fiebig (F) stage I-V) with a median duration of infection of 16 days and the short-term impact of early initiation of ART. Th17 cells were defined as IL-17+ CD4+ T cells and their function was assessed by the co-expression of IL-22, IL-2 and IFNγ. While intact during FI/II, depletion of mucosal Th17 cell numbers and function was observed during FIII correlating with local and systemic markers of immune-activation. ART initiated at FI/II prevented loss of Th17 cell numbers and function, while initiation at FIII restored Th17 cell numbers but not their polyfunctionality. Furthermore, early initiation of ART in FI/II fully reversed the initially observed mucosal and systemic immune-activation. In contrast, patients treated later during AHI maintained elevated mucosal and systemic CD8+ T-cell activation post initiation of ART. These data support a loss of Th17 cells at early stages of acute HIV infection, and highlight that studies of ART initiation during early AHI should be further explored to assess the underlying mechanism of mucosal Th17 function preservation.

A novel acute HIV infection staging system based on 4th generation immunoassay.

BACKGROUND: Fourth generation (4thG) immunoassay (IA) is becoming the standard HIV screening method but was not available when the Fiebig acute HIV infection (AHI) staging system was proposed. Here we evaluated AHI staging based on a 4thG IA (4thG staging). FINDINGS: Screening for AHI was performed in real-time by pooled nucleic acid testing (NAT, n=48,828 samples) and sequential enzyme immunoassay (EIA, n=3,939 samples) identifying 63 subjects with non-reactive 2nd generation EIA (Fiebig stages I (n=25), II (n=7), III (n=29), IV (n=2)). The majority of samples tested (n=53) were subtype CRF_01AE (77%). NAT+ subjects were re-staged into three 4thG stages: stage 1 (n=20; 4th gen EIA-, 3rd gen EIA-), stage 2 (n=12; 4th gen EIA+, 3rd gen EIA-), stage 3 (n=31; 4th gen EIA+, 3rd gen EIA+, Western blot-/indeterminate). 4thG staging distinguishes groups of AHI subjects by time since presumed HIV exposure, pattern of CD8+ T, B and natural killer cell absolute numbers, and HIV RNA and DNA levels. This staging system further stratified Fiebig I subjects: 18 subjects in 4thG stage 1 had lower HIV RNA and DNA levels than 7 subjects in 4thG stage 2. CONCLUSIONS: Using 4th generation IA as part of AHI staging distinguishes groups of patients by time since exposure to HIV, lymphocyte numbers and HIV viral burden. It identifies two groups of Fiebig stage I subjects who display different levels of HIV RNA and DNA, which may have implication for HIV cure. 4th generation IA should be incorporated into AHI staging systems.