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Background: The Antibody Mediated Prevention (AMP) trial evaluated if VRC01, a CD4 binding site broadly neutralizing antibody, could prevent HIV-1 acquisition. To inform our understanding of how prevention efficacy depended on viral env gene charateristics, viral quasis-pecies and neutralization sensitivity of HIV-1 breakthrough infections were analyzed. Methods: The trial evaluated VRC01 in women from sub-Saharan Africa (703/081); and men and transgender persons who have sex with men (704/085), from the Americas. Control samples from Thailand, Kenya and South Africa are being used for calibrating infection timing using sequence data. Rev-env-nef (REN) sequences were generated using Sanger and PacBio Single Molecule Real-Time (SMRT) sequencing platforms. To improve PacBio accuracy and enable quantitation, each viral RNA molecule was labelled with a unique molecular identifier (SMRT-UMI). Rev-env genes from imputed founder viruses were synthesized for pseudovirus production and in vitro sensitivity to VRC01 determined using the TZM-bl assay. Results: Approximately 84 000 unique REN sequences were generated from the first HIV-1 positive visit from 218 infected individuals in both trials, and two to four weeks later from a subset of individuals, providing a median of 174 unique env sequences per participant per time point. In approximately 2/3 of individuals, viral diversity was low, consistent with infection with a single founder virus. Of the 1/3 of individuals with higher viral diversity, consistent with infection with multiple founders, a third had low frequency variants (3 [micro]g/mL) viruses. In some individuals, the unique VRC01 resistance mutations were associated with distinct viral lineages, suggestive of infection with resistant viruses. However, we also found evidence of low frequency resistant mutations, that were likely derived from resistance acquired after infection. Conclusions: SMRT-UMI sequencing allowed a very detailed evaluation of viral populations following infection, including identification of minor founders not detected using conventional approaches. We found evidence of infection with viruses of mixed neutralization phenotypes, and in some cases, low frequency resistance mutations that were likely to be due VRC01 pressure. The study is not yet unblinded., OA03.04LB C.Williamson (1); D.Westfall (2); W. Deng (2); A. Pankow (2); D. Matten (1); B. Murrell (3); T.York (1); A. Gwashu-Nyangiwe (1); M. Rolland (4,5); P. Edlefsen (6); E. Giorgi [...]

Background: HIV-1 Env reference panels are used to guide the clinical development of broadly neutralizing antibodies (bNAbs) but need to be updated periodically as genetic drift may impact neutralization phenotypes. We assessed the neutralization sensitivity of breakthrough viruses from the southern African VRC01 AMP trial (HVTN 703/HPTN 081) as geographically relevant, current subtype C transmitted/founder viruses. Methods: Envelope sequences of breakthrough infections from 30 women in the AMP trial (prior to unblinding) were used to produce transmitted/founder (T/F) pseudotyped viruses. These were tested against 14 bNAbs targeting the CD4bs (n = 4), V3-glycan (n = 3), V2-apex (n = 3), gp120-gp41 interface (n = 2) and the MPER (n = 2) in the TZM-bl neutralization assay. Single bNAb neutralization data was used in the Loewe additive model (CombiNAber) to model the efficacy of bNAb combinations. Weakly neutralizing antibodies targeting normally occluded epitopes on HIV Env (V3, CD4i, V2 and gp41) were included to assess the tier phenotype of the viruses. Results: All breakthrough viruses were of the tier 2 phenotype, typical of T/F viruses. At a concentration of 1 [micro]g/ml at [IC.sub.50], 91% of viruses were neutralized by VRC07-523LS (GMT [IC.sub.50]=0.16) representing the best coverage by a single bNAb. Combinations of two to four bNAbs increased the number of viruses neutralized with the 4 bNAb combination (CAP256-VRC26.25/PGT121/VRC07-523LS/35022) neutralizing 100% of viruses (GMT [IC.sub.50]=0.01). The best-in-class 3 bNAb combination (CAP256-VRC26.25/PGT121/35022) provided 97% coverage (GMT [IC.sub.50]=0.01). Clinically advanced triple combinations such as CAP256-VRC26.25.25/PGT121/VRC07-523LS and/PGDM1400/PGT121/VRC07-523LS both resulted in a coverage of 97% (GMT IC50 = 0.02) against this panel of 30 subtype C breakthrough viruses. Conclusions: Our data confirm the need to use combination bNAbs in passive immunization trials to improve coverage of subtype C viruses. The exposure of a subset of these breakthrough viruses to VRC01 may have affected their phenotype, and this will be investigated when the AMP trial data is unblinded. Overall, these breakthrough viruses represent a unique resource for defining the sensitivity of contemporaneous circulating viral isolates to bNAbs., OA03.05 N.N. Mkhize (1); R.E. Mapengo (1); V. Bekker (1); T. Modise (1); P. Kgagudi (1); B.E. Lambson (1); H. Kaldine (1); R.T. van Dorsten (1); N. Mgodi (2); S. [...]

Background: A key missing element in the development of a successful human immunodeficiency virus (HIV) vaccine is an immunogen that can generate broadly cross-neutralizing antibodies against primary isolates of the virus.Methods: This phase 1 clinical trial employed a DNA prime and subunit envelope protein boost in an attempt to generate cellular and humoral immune responses that might be desirable in a protective HIV vaccine. Priming was performed via intramuscular injection with gag and env DNA adsorbed to polylactide coglycolide microspheres, followed by boosting with a recombinant trimeric envelope (Env) glycoprotein delivered in MF59 adjuvant.Results: The DNA prime and protein boost were generally safe and well-tolerated. Env-specific CD4(+) cellular responses were generated that were predominantly detected after Env protein boosting. Neutralizing antibody responses against the homologous SF162 viral isolate were remarkably strong and were present in the majority of vaccine recipients, including a strong response against CD4-induced epitopes on gp120. Despite the promising potency of this vaccine approach, neutralization breadth against heterologous tier 2 strains of HIV-1 was minimal.Conclusions: Potent neutralization against neutralization-sensitive strains of HIV is achievable in humans through a DNA prime, recombinant oligomeric Env protein boost regimen. Eliciting substantial breadth of neutralization remains an elusive goal.Clinical Trials Registration: NCT00073216. [ABSTRACT FROM AUTHOR]

Background: Recombinant DNA and modified vaccinia virus Ankara (rMVA) vaccines represent a promising approach to an HIV/AIDS vaccine. This Phase 1 clinical trial compared the safety and immunogenicity of a rMVA vaccine administered with and without DNA vaccine primingMethods: GeoVax pGA2/JS7 DNA (D) and MVA/HIV62 (M) vaccines encode noninfectious virus-like particles. Intramuscular needle injections were used to deliver placebo, 2 doses of DNA followed by 2 doses of rMVA (DDMM), one dose of DNA followed by 2 doses of rMVA (DMM), or 3 doses of rMVA (MMM) to HIV-seronegative participants.Results: Local and systemic symptoms were mild or moderate. Immune response rates for CD4 + and CD8 + T cells were highest in the DDMM group and lowest in the MMM group (77% vs 43% CD4 + and 42% vs 17% CD8 +). In contrast, response rates for Env binding and neutralizing Ab were highest in the MMM group. The DMM group had intermediate response rates. A 1/10th-dose DDMM regimen induced similar T cell but reduced Ab response rates compared with the full-dose DDMM.Conclusions: MVA62 was well tolerated and elicited different patterns of T cell and Ab responses when administered alone or in combination with the JS7 DNA vaccine. [ABSTRACT FROM AUTHOR]

BACKGROUND A safe, effective vaccine is essential to eradicating human immunodeficiency virus (HIV) infection. A canarypox-protein HIV vaccine regimen (ALVAC-HIV plus AIDSVAX B/E) showed modest efficacy in reducing infection in Thailand. An analogous regimen using HIV-1 subtype C virus showed potent humoral and cel-lular responses in a phase 1-2a trial in South Africa. Efficacy data and additional safety data were needed for this regimen in a larger population in South Africa. METHODS In this phase 2b-3 trial, we randomly assigned 5404 adults without HIV-1 infection to receive the vaccine (2704 participants) or placebo (2700 participants). The vaccine regimen consisted of injections ofALVAC-HIV at months 0 and 1, followed by four booster injections of ALVAC-HIV plus bivalent subtype C gpl20-MF59 adjuvant at months 3, 6, 12, and 18. The primary efficacy outcome was the occurrence of HIV-1 infection from randomization to 24 months. RESULTS In January 2020, prespecified criteria for nonefficacy were met at an interim analysis; further vaccinations were subsequently halted. The median age of the trial participants was 24 years; 70% of the participants were women. The incidence of adverse events was similar in the vaccine and placebo groups. During the 24-month followup, HIV-1 infection was diagnosed in 138 participants in the vaccine group and in 133 in the placebo group (hazard ratio, 1.02; 95% confidence interval, 0.81 to 1.30; P=0.84). CONCLUSIONS The ALVAC-gpl20 regimen did not prevent HIV-1 infection among participants in South Africa despite previous evidence ofimmunogenicity. (HVTN 702 ClinicalTrials .gov number, NCT02968849.). [ABSTRACT FROM AUTHOR]

Background: HIV type 1 (HIV-1) remains a global health concern, with the greatest burden in sub-Saharan Africa. Despite 40 years of research, no vaccine candidate has shown durable and protective efficacy against HIV-1 acquisition. Although pre-exposure prophylaxis in groups with high vulnerability can be very effective, barriers to its use, such as perceived low acquisition risk, fear of stigma, and concerns about side-effects, remain. Thus, a population-based approach, such as an HIV-1 vaccine, is needed. The current study aimed to evaluate the efficacy and safety of a heterologous HIV-1 vaccine regimen, consisting of a tetravalent mosaic adenovirus 26-based vaccine (Ad26.Mos4.HIV) and aluminium phosphate-adjuvanted clade C glycoprotein (gp) 140, in young women at risk of acquiring HIV-1 in southern Africa., Methods: This randomised, double-blind, phase 2b study enrolled sexually active women without HIV-1 or HIV-2 aged 18-35 years at 23 clinical research sites in Malawi, Mozambique, South Africa, Zambia, and Zimbabwe. Participants were centrally randomly assigned (1:1) to receive intramuscular injections of vaccine or saline placebo in stratified permuted blocks via an interactive web response system. Study participants, study site personnel (except those with primary responsibility for study vaccine preparation and dispensing), and investigators were masked to treatment group allocation. The vaccine regimen consisted of Ad26.Mos4.HIV administered at months 0 and 3 followed by Ad26.Mos4.HIV administered concurrently with aluminium phosphate-adjuvanted clade C gp140 at months 6 and 12. The primary efficacy outcome was vaccine efficacy in preventing laboratory-confirmed HIV-1 acquisition diagnosed between visits at month 7 and month 24 after the first vaccination (VE[7-24]) in the per-protocol population, which included participants who had not acquired HIV-1 4 weeks after the third vaccination, received all planned vaccinations at the first three vaccination visits within the protocol-specified windows, and had no major protocol deviations that could affect vaccine efficacy. Primary safety outcomes were assessed in randomly assigned participants who received one study injection or more based on the actual injection received. The primary safety endpoints were the incidences of unsolicited adverse events (AEs), solicited local and systemic AEs, serious AEs, AEs of special interest, and AEs leading to discontinuation of vaccination. This trial is registered with ClinicalTrials.gov, NCT03060629, and is complete., Findings: Between Nov 3, 2017, and June 30, 2019, 2654 women were randomly assigned, of whom 2636 women (median age of 23 years [IQR 20-25]) were enrolled and received at least one study injection (1313 assigned vaccine, 1323 placebo; 1317 received vaccine, 1319 placebo). Analysis of the primary efficacy outcome in the per-protocol cohort included 1080 women in the vaccine group and 1108 women in the placebo group; the incidence of HIV-1 acquisition per 100 person-years over months 7-24 after the first vaccination was 3·38 (95% CI 2·54-4·41) in the vaccine group and 3·94 (3·04-5·03) in the placebo group, with an estimated VE(7-24) of 14·10% (95% CI -22·00 to 39·51; p=0·40). There were no serious unsolicited AEs, AEs of special interest, or deaths related to the study vaccine. In the vaccine group, 663 (50·3%) of 1317 participants had grade 1 or 2 solicited local AEs and ten (0·8%) of 1317 participants had grade 3 or 4 solicited local AEs. In the placebo group, 305 (23·1%) of 1319 participants had grade 1 or 2 solicited local AEs and three (0·2%) of 1319 participants had grade 3 or 4 solicited local AEs. 863 (65·5%) of 1317 participants in the vaccine group had grade 1 or 2 solicited systemic AEs and 34 (2·6%) of 1317 participants had grade 3 or 4 solicited systemic AEs. 763 (57·8%) of 1319 participants in the placebo group had grade 1 or 2 solicited systemic AEs and 20 (1·5%) of 1319 participants had grade 3 or 4 solicited systemic AEs. Overall, three (0·2%) of 1317 participants in the vaccine group and three (0·2%) of 1319 participants in the placebo group discontinued vaccination due to an unsolicited AE, and three (0·2%) of 1317 participants in the vaccine group and one (0·1%) of 1319 participants in the placebo group discontinued vaccination due to a solicited AE., Interpretation: The heterologous Ad26.Mos4.HIV and clade C gp140 vaccine regimen was safe and well tolerated but did not show efficacy in preventing HIV-1 acquisition in a population of young women in southern Africa at risk of HIV-1., Funding: Division of AIDS at the National Institute of Allergy and Infectious Diseases through the HIV Vaccine Trials Network, Bill & Melinda Gates Foundation, Janssen Vaccines & Prevention, US Army Medical Materiel Development Activity, and Ragon Institute., Competing Interests: Declaration of interests GEG's institution (the South African Medical Research Council) has received funding from the US National Institutes of Health (NIH) and the Bill & Melinda Gates Foundation. KM was a protocol co-chair for the Imbokodo trial. LL is a consultant for Janssen Infectious Diseases. SN, DJS, JvD, WW, JVH, HS, MGP, and FT were employees of Janssen Pharmaceuticals at the time of this study and are stockholders of Johnson & Johnson. AL's institution has received funding from the NIH; outside the submitted work, AL has received consulting fees from Harvard University, and his institution has received funding from Janssen Pharmaceuticals. PM is an employee and stockholder of CureVac. MJM's institution (Fred Hutchinson Cancer Center) has received funding, including for laboratory equipment purchases, from the HIV Vaccine Trials Network (HVTN) Laboratory Center (grant number 5UM1AI068618) and Seattle-Lausanne Clinical Trials Unit; outside the submitted work, her institution has received funding, including for laboratory equipment purchases, from the Scripps Consortium for HIV/AIDS Vaccine Development Subaward, National Institute of Allergy and Infectious Diseases (NIAID) Human Immunology Project Consortium 3, Bill & Melinda Gates Foundation Comprehensive Cellular Vaccine Immune Monitoring Consortium, and Bill & Melinda Gates Foundation Collaboration for AIDS Vaccine Discovery; her institution has received funding, including for laboratory equipment purchases, supporting SARS-CoV-2 vaccine laboratory studies from the COVID-19 Prevention Network (NIAID), Janssen Pharmaceuticals, Infectious Diseases Clinical Research Consortium (NIAID), Sanofi Pasteur, Moderna, and Regeneron; her institution has received funding, including for laboratory equipment purchases, supporting HIV and other vaccine trials and laboratory studies from International AIDS Vaccine Initiative, Janssen Pharmaceuticals, and Vir Biotechnology; and she has participated in scientific advisory boards for the Ragon Institute and Keystone Symposia, and on a board of scientific counsellors for the NIH Vaccine Research Center. GDT's institution (Duke University) has received NIH funding through the HVTN (grant numbers 5UM1AI068614 and 5UM1AI068618); GDT has served as a consultant for and received funding to her institution through Janssen Pharmaceuticals; is a reviewer for the Gilead Research Scholar Program; and has served on the board of scientific counsellors for the NIH Vaccine Research Center. DHB is a co-inventor on HIV vaccine patents that have been licensed to Janssen Pharmaceuticals. SB has received grant funding from Gilead Sciences, Merck, GSK, and ViiV. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: The HVTN 705 Imbokodo trial of 2636 people without HIV and assigned female sex at birth, conducted in southern Africa, evaluated a heterologous HIV-1 vaccine regimen: mosaic adenovirus 26-based vaccine (Ad26.Mos4.HIV) at Months 0, 3, 6, 12 and alum-adjuvanted clade C gp140 at Months 6, 12. Per-protocol vaccine efficacy (VE) against HIV-1 diagnosis from seven to 24 months was 14.1% (95% CI: -22.0% to 39.5%). Immune correlates analysis was performed for markers selected based on prior evidence in efficacy trials and/or nonhuman primate models., Methods: Humoral and cellular immune response markers at Month 7 were evaluated as immune correlates of risk and of protection in a breakthrough case-control cohort (n = 52 cases, 246 non-cases). Primary markers were IgG binding to vaccine-strain gp140, IgG3 binding to diverse Env antigens (IgG3 Env breadth), IgG3 binding to diverse V1V2 antigens (IgG3 V1V2 breadth), antibody-dependent phagocytosis against the vaccine-strain gp140, Env-specific CD4+ and CD8+ T-cell responses, and multi-epitope functions., Findings: No immune markers were statistically significant correlates of risk. IgG3 V1V2 breadth trended toward an inverse association: hazard ratio 0.70 (95% CI: 0.36 to 1.35; p = 0.29) per 10-fold increase and 0.51 (95% CI: 0.21 to 1.24; p = 0.14) in a Cox model with all primary markers. The VE estimate was 11.8% (95% CI: -17.9% to 34.0%) at all IgG3 V1V2 breadth values below 667 weighted geometric mean net MFI; just above this value, the VE estimate sharply increased to 62.6% (95% CI: -17.9% to 89.6%), and further increased to 80.9% (95% CI: -17.9% to 99.5%) at 1471 MFI, the 95th percentile of the marker distribution. Mediation analysis yielded a VE of 35.7% (95% CI: 15.0% to 51.3%) attributable to the vaccine's impact on this marker., Interpretation: The trend in association of greater IgG3 V1V2 antibody breadth with lower likelihood of HIV acquisition is consistent with the identification of antibodies against V1V2 as immune correlates in three other HIV vaccine efficacy trials and suggests that a greater emphasis should be placed on studying this region in the HIV-1 envelope as a vaccine immunogen., Funding: National Institute of Allergy and Infectious Diseases and Janssen Vaccines & Prevention BV., Competing Interests: Declaration of interests TvdK has a patent application with Johnson & Johnson and has stocks in Johnson & Johnson. BK received internal support for the present manuscript from her employer (Los Alamos National Laboratory). In the past 36 months, she received support for attending meetings and/or travel from NIH NIAID and from the Gates foundation. Her institution (LANL) had a patent on this work, although she did not receive any personal funds through this patent and was not involved with the licensing of the design to Johnson & Johnson. DHB has a patent on the mosaic HIV vaccine, but no royalties. FT was an employee of Janssen/Johnson & Johnson at the time the work was conducted and owns stock in Johnson & Johnson. LL received support from Janssen Infectious Diseases BV, Beerse, Belgium for travel expenses to attend HIV conferences and has stock or stock options in Johnson & Johnson. JvD, MGP, WW, TvdK and JHen are employees of Janssen/Johnson & Johnson and hold stock or stock options in Johnson & Johnson. WW has a patent planned, issued, or pending with Johnson & Johnson. SCDR had contracts in the past 36 months to perform immunogenicity testing for Janssen, Sanofi, and Moderna. HS and DJS were employees of Janssen Vaccines & Prevention BV and had stock and/or stock options in Johnson & Johnson at the time the work was conducted. SN was an employee of Janssen Infectious Diseases BV and had stock and/or stock options in Johnson & Johnson at the time the work was conducted. LP was an employee of Janssen Vaccines & Prevention BV at the time the work was conducted. GDT has received consulting fees for a scientific consulting session. All other authors have no potential competing interests to disclose. Funding for the Imbokodo Study and Correlates Group is the same as listed in “Acknowledgments” for the current work., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Current serologic tests for HIV screening and confirmation of infection present challenges to the adoption of HIV vaccines. The detection of vaccine-induced HIV-1 antibodies in the absence of HIV-1 infection, referred to as vaccine-induced seropositivity/seroreactivity, confounds the interpretation of test results, causing misclassification of HIV-1 status with potential affiliated stigmatization. For HIV vaccines to be widely adopted with high community confidence and uptake, tests are needed that are agnostic to the vaccination status of tested individuals (ie, positive only for true HIV-1 infection). Successful development and deployment of such tests will require HIV vaccine developers to work in concert with diagnostic developers. Such tests will need to match today's high-performance standards (accuracy, cost-effectiveness, simplicity) for use in vaccinated and unvaccinated populations, especially in low- and middle-income countries with high HIV burden. Herein, we discuss the challenges and strategies for developing modified serologic HIV tests for concurrent deployment with HIV vaccines., Competing Interests: Potential conflicts of interest. W. C. and O. L. are former and current employees of Janssen Pharmaceutica N.V., respectively, and V. O. M. and M. G. P. are current employees of Janssen Vaccines and Prevention B.V. Both are Johnson & Johnson companies, and the authors may own stock or stock options in them. L. L. is a consultant for Janssen Pharmaceutica N.V. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Broadly neutralizing monoclonal antibodies (mAbs) are being developed for HIV-1 prevention. Hence, these mAbs and licensed oral pre-exposure prophylaxis (PrEP) (tenofovir-emtricitabine) can be concomitantly administered in clinical trials. In 48 US participants (men and transgender persons who have sex with men) who received the HIV-1 mAb VRC01 and remained HIV-free in an antibody-mediated-prevention trial (ClinicalTrials.gov #NCT02716675), we conduct a post-hoc analysis and find that VRC01 clearance is 0.08 L/day faster (p = 0.005), and dose-normalized area-under-the-curve of VRC01 serum concentration over-time is 0.29 day/mL lower (p < 0.001) in PrEP users (n = 24) vs. non-PrEP users (n = 24). Consequently, PrEP users are predicted to have 14% lower VRC01 neutralization-mediated prevention efficacy against circulating HIV-1 strains. VRC01 clearance is positively associated (r = 0.33, p = 0.03) with levels of serum intestinal Fatty Acid Binding protein (I-FABP), a marker of epithelial intestinal permeability, which is elevated upon starting PrEP (p = 0.04) and after months of self-reported use (p = 0.001). These findings have implications for the evaluation of future HIV-1 mAbs and postulate a potential mechanism for mAb clearance in the context of PrEP., (© 2023. The Author(s).)

Background: The phase 2b proof-of-concept Antibody Mediated Prevention (AMP) trials showed that VRC01, an anti-HIV-1 broadly neutralising antibody (bnAb), prevented acquisition of HIV-1 sensitive to VRC01. To inform future study design and dosing regimen selection of candidate bnAbs, we investigated the association of VRC01 serum concentration with HIV-1 acquisition using AMP trial data., Methods: The case-control sample included 107 VRC01 recipients who acquired HIV-1 and 82 VRC01 recipients who remained without HIV-1 during the study. We measured VRC01 serum concentrations with a qualified pharmacokinetic (PK) Binding Antibody Multiplex Assay. We employed nonlinear mixed effects PK modelling to estimate daily-grid VRC01 concentrations. Cox regression models were used to assess the association of VRC01 concentration at exposure and baseline body weight, with the hazard of HIV-1 acquisition and prevention efficacy as a function of VRC01 concentration. We also compared fixed dosing vs. body weight-based dosing via simulations., Findings: Estimated VRC01 concentrations in VRC01 recipients without HIV-1 were higher than those in VRC01 recipients who acquired HIV-1. Body weight was inversely associated with HIV-1 acquisition among both placebo and VRC01 recipients but did not modify the prevention efficacy of VRC01. VRC01 concentration was inversely correlated with HIV-1 acquisition, and positively correlated with prevention efficacy of VRC01. Simulation studies suggest that fixed dosing may be comparable to weight-based dosing in overall predicted prevention efficacy., Interpretation: These findings suggest that bnAb serum concentration may be a useful marker for dosing regimen selection, and operationally efficient fixed dosing regimens could be considered for future trials of HIV-1 bnAbs., Funding: Was provided by the National Institutes of Health, National Institute of Allergy and Infectious Diseases (NIAID) (UM1 AI068614, to the HIV Vaccine Trials Network [HVTN]; UM1 AI068635, to the HVTN Statistical Data and Management Center [SDMC], Fred Hutchinson Cancer Center [FHCC]; 2R37 054165 to the FHCC; UM1 AI068618, to HVTN Laboratory Center, FHCC; UM1 AI068619, to the HPTN Leadership and Operations Center; UM1 AI068613, to the HIV Prevention Trials Network [HPTN] Laboratory Center; UM1 AI068617, to the HPTN SDMC; and P30 AI027757, to the Center for AIDS Research, Duke University (AI P30 AI064518) and University of Washington (P30 AI027757) Centers for AIDS Research; R37AI054165 from NIAID to the FHCC; and OPP1032144 CA-VIMC Bill & Melinda Gates Foundation., Competing Interests: Declaration of interests Kelly E Seaton - support for meetings, HIV Vaccine Trials Network (HVTN). M Julianna McElrath - support for Keystone Symposia. Ian Frank - consulting fees from Gilead, ViiV Health Care and grants or contracts from Moderna, Janssen Therapeutics, Pfizer., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The VRC01 Antibody Mediated Prevention (AMP) efficacy trials conducted between 2016 and 2020 showed for the first time that passively administered broadly neutralizing antibodies (bnAbs) could prevent HIV-1 acquisition against bnAb-sensitive viruses. HIV-1 viruses isolated from AMP participants who acquired infection during the study in the sub-Saharan African (HVTN 703/HPTN 081) and the Americas/European (HVTN 704/HPTN 085) trials represent a panel of currently circulating strains of HIV-1 and offer a unique opportunity to investigate the sensitivity of the virus to broadly neutralizing antibodies (bnAbs) being considered for clinical development. Pseudoviruses were constructed using envelope sequences from 218 individuals. The majority of viruses identified were clade B and C; with clades A, D, F and G and recombinants AC and BF detected at lower frequencies. We tested eight bnAbs in clinical development (VRC01, VRC07-523LS, 3BNC117, CAP256.25, PGDM1400, PGT121, 10-1074 and 10E8v4) for neutralization against all AMP placebo viruses (n = 76). Compared to older clade C viruses (1998-2010), the HVTN703/HPTN081 clade C viruses showed increased resistance to VRC07-523LS and CAP256.25. At a concentration of 1μg/ml (IC80), predictive modeling identified the triple combination of V3/V2-glycan/CD4bs-targeting bnAbs (10-1074/PGDM1400/VRC07-523LS) as the best against clade C viruses and a combination of MPER/V3/CD4bs-targeting bnAbs (10E8v4/10-1074/VRC07-523LS) as the best against clade B viruses, due to low coverage of V2-glycan directed bnAbs against clade B viruses. Overall, the AMP placebo viruses represent a valuable resource for defining the sensitivity of contemporaneous circulating viral strains to bnAbs and highlight the need to update reference panels regularly. Our data also suggests that combining bnAbs in passive immunization trials would improve coverage of global viruses., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2023 Mkhize et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Candidate HIV vaccines are designed to induce antibodies to various components of the HIV virus. An unintended result of these antibodies is that they may also be detected by commercial HIV diagnostic kits designed to detect an immune response to HIV acquisition. This phenomenon is known as Vaccine-Induced Seropositivity/Reactivity (VISP/R). In order to identify the vaccine characteristics associated with VISP/R, we collated the VISP/R results from 8,155 participants from 75 phase 1/2 studies and estimated the odds of VISP/R by multivariable logistic regression and 10-year estimated probability of persistence in relation to vaccine platform, HIV gag and envelope (env) gene inserts, and protein boost. Recipients of viral vectors, protein boosts, and combinations of DNA and viral-vectored vaccines had higher odds of VISP/R compared to those who received DNA-only vaccines (odds ratio, OR = 10.7, 9.1, 6.8, respectively, p<0.001). Recipients of gp140+ env gene insert (OR = 7.079, p<0.001) or gp120 env (OR = 1.508, p<0.001) had higher odds of VISP/R compared to those participants who received no env. Recipients of gp140 protein had higher odds of VISP/R than those that did not receive protein (OR = 25.155, p<0.001), and recipients of gp120 protein, had lower odds of VISP/R than those that did not receive protein (OR = 0.192, p<0.001). VISP/R persisted at 10 years in more recipients of env gene insert or protein compared to those who did not (64% vs 2%). The inclusion of gag gene in a vaccine regimen had modest effects on these odds and was confounded by other covariates. Participants receiving gp140+ gene insert or protein were most often reactive across all serologic HIV tests. Conclusions from this association analysis will provide insight into the possible impact of vaccine design on the HIV diagnostic landscape and vaccinated populations., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: SRW is an Academic Editor at PLoS One; the authors declare no other competing interests., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

The HIV Vaccine Trials Network (HVTN) conducts clinical trials on 4 continents in pursuit of a safe and effective HIV vaccine. Cellular immune responses to vaccination that define vaccine immunogenicity and/or immune correlates of protection can be measured using multiparameter intracellular cytokine staining (ICS) assays. The HVTN cellular immunology laboratory, located in Seattle, WA, conducts ICS assays for vaccine trials according to Good Clinical Laboratory Practices (GCLP). In 2013, the HVTN established a second GCLP compliant cellular immunology laboratory in Cape Town, South Africa to assess vaccine immunogenicity for HVTN trials conducted on the African continent. To ensure ICS readouts in the 2 laboratories were directly comparable, we conducted concordance testing using PBMC from healthy controls and vaccine trial participants. Despite standardized procedures and instrumentation, shared quality control measures and quality assurance oversight, several factors impacted our ability to obtain close agreement in T-cell responses measured in the 2 laboratories. One of these was the type of fetal bovine serum (FBS) used in the assay, which impacted lymphocyte cell viability and background responses. In addition, the differences in supernatant removal technique also significantly affected our ability to detect positive responses to vaccine antigens. Standardization of these factors allowed us to achieve and maintain ICS assay concordance across the 2 laboratories over multiple years, accelerating our efforts to evaluate HIV vaccines. The insights gained in this process are valuable for assay transfer efforts by groups of investigators that need to directly compare data generated in different laboratories around the globe., (©2022 Society for Leukocyte Biology.)

The Antibody Mediated Prevention trials showed that the broadly neutralizing antibody (bnAb) VRC01 prevented acquisition of human immunodeficiency virus-1 (HIV-1) sensitive to VRC01. Using AMP trial data, here we show that the predicted serum neutralization 80% inhibitory dilution titer (PT 80 ) biomarker-which quantifies the neutralization potency of antibodies in an individual's serum against an HIV-1 isolate-can be used to predict HIV-1 prevention efficacy. Similar to the results of nonhuman primate studies, an average PT 80 of 200 (meaning a bnAb concentration 200-fold higher than that required to reduce infection by 80% in vitro) against a population of probable exposing viruses was estimated to be required for 90% prevention efficacy against acquisition of these viruses. Based on this result, we suggest that the goal of sustained PT 80 <200 against 90% of circulating viruses can be achieved by promising bnAb regimens engineered for long half-lives. We propose the PT 80 biomarker as a surrogate endpoint for evaluatinon of bnAb regimens, and as a tool for benchmarking candidate bnAb-inducing vaccines., (© 2022. The Author(s).)

Background: The ALVAC/gp120 + MF59 vaccines in the HIV Vaccine Trials Network (HVTN) 702 efficacy trial did not prevent human immunodeficiency virus-1 (HIV-1) acquisition. Vaccine-matched immunological endpoints that were correlates of HIV-1 acquisition risk in RV144 were measured in HVTN 702 and evaluated as correlates of HIV-1 acquisition., Methods: Among 1893 HVTN 702 female vaccinees, 60 HIV-1-seropositive cases and 60 matched seronegative noncases were sampled. HIV-specific CD4+ T-cell and binding antibody responses were measured 2 weeks after fourth and fifth immunizations. Cox proportional hazards models assessed prespecified responses as predictors of HIV-1 acquisition., Results: The HVTN 702 Env-specific CD4+ T-cell response rate was significantly higher than in RV144 (63% vs 40%, P = .03) with significantly lower IgG binding antibody response rate and magnitude to 1086.C V1V2 (67% vs 100%, P < .001; Pmag < .001). Although no significant univariate associations were observed between any T-cell or binding antibody response and HIV-1 acquisition, significant interactions were observed (multiplicity-adjusted P ≤.03). Among vaccinees with high IgG A244 V1V2 binding antibody responses, vaccine-matched CD4+ T-cell endpoints associated with decreased HIV-1 acquisition (estimated hazard ratios = 0.40-0.49 per 1-SD increase in CD4+ T-cell endpoint)., Conclusions: HVTN 702 and RV144 had distinct immunogenicity profiles. However, both identified significant correlations (univariate or interaction) for IgG V1V2 and polyfunctional CD4+ T cells with HIV-1 acquisition. Clinical Trials Registration . NCT02968849., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

We report a 23% asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) Omicron carriage rate in participants being enrolled into a clinical trial in South Africa, 15-fold higher than in trials before Omicron. We also found lower CD4 + T-cell counts in persons with human immunodeficiency virus (HIV) strongly correlated with increased odds of being SARS-CoV-2 polymerase chain reaction (PCR) positive., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America.)

Since the beginning of the SARS-CoV-2 pandemic, antibody responses and antibody effector functions targeting SARS-CoV-2-infected cells have been understudied. Consequently, the role of these types of antibodies in SARS-CoV-2 disease (COVID-19) and immunity is still undetermined. To provide tools to study these responses, we used plasma from SARS-CoV-2-infected individuals (n = 50) and SARS-CoV-2 naive healthy controls (n = 20) to develop four specific and reproducible flow cytometry-based assays: (i) two assessing antibody binding to, and antibody-mediated NK cell degranulation against, SARS-CoV-2-infected cells and (ii) two assessing antibody binding to, and antibody-mediated NK cell degranulation against, SARS-CoV-2 Spike-transfected cells. All four assays demonstrated the ability to detect the presence of these functional antibody responses in a specific and reproducible manner. Interestingly, we found weak to moderate correlations between the four assays (Spearman rho ranged from 0.50 to 0.74), suggesting limited overlap in the responses captured by the individual assays. Lastly, while we initially developed each assay with multiple dilutions in an effort to capture the full relationship between antibody titers and assay outcome, we explored the relationship between fewer antibody dilutions and the full dilution series for each assay to reduce assay costs and improve assay efficiency. We found high correlations between the full dilution series and fewer or single dilutions of plasma. Use of single or fewer sample dilutions to accurately determine the response rates and magnitudes of the responses allows for high-throughput use of these assays platforms to facilitate assessment of antibody responses elicited by SARS-CoV-2 infection and vaccination in large clinical studies., (© 2022 The Authors. Cytometry Part A published by Wiley Periodicals LLC on behalf of International Society for Advancement of Cytometry.)

Background: The antibody-mediated prevention (AMP) studies (HVTN 703/HPTN 081 and HVTN 704/HPTN 085) are harmonized phase 2b trials to assess HIV prevention efficacy and safety of intravenous infusion of anti-gp120 broadly neutralizing antibody VRC01. Antibodies for other indications can elicit infusion-related reactions (IRRs), often requiring premedication and limiting their application. We report on AMP study IRRs., Methods: From 2016 to 2018, 2699 HIV-uninfected, at-risk men and transgender adults in the Americas and Switzerland (704/085) and 1924 at-risk heterosexual women in sub-Saharan Africa (703/081) were randomized 1:1:1 to VRC01 10 mg/kg, 30 mg/kg, or placebo. Participants received infusions every 8 weeks (n = 10/participant) over 72 weeks, with 104 weeks of follow-up. Safety assessments were conducted before and after infusion and at noninfusion visits. A total of 40,674 infusions were administered., Results: Forty-seven participants (1.7%) experienced 49 IRRs in 704/085; 93 (4.8%) experienced 111 IRRs in 703/081 (P < 0.001). IRRs occurred more frequently in VRC01 than placebo recipients in 703/081 (P < 0.001). IRRs were associated with atopic history (P = 0.046) and with younger age (P = 0.023) in 703/081. Four clinical phenotypes of IRRs were observed: urticaria, dyspnea, dyspnea with rash, and "other." Urticaria was most prevalent, occurring in 25 (0.9%) participants in 704/085 and 41 (2.1%) participants in 703/081. Most IRRs occurred with the initial infusion and incidence diminished through the last infusion. All reactions were managed successfully without sequelae., Conclusions: IRRs in the AMP studies were uncommon, typically mild or moderate, successfully managed at the research clinic, and resolved without sequelae. Analysis is ongoing to explore potential IRR mechanisms., Competing Interests: S.R.W. has received clinical trial funding from Janssen Vaccines. The other authors have no conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Vaccine-induced neutralizing antibodies (nAbs) are key biomarkers considered to be associated with vaccine efficacy. In United States government-sponsored phase 3 efficacy trials of COVID-19 vaccines, nAbs are measured by two different validated pseudovirus-based SARS-CoV-2 neutralization assays, with each trial using one of the two assays. Here we describe and compare the nAb titers obtained in the two assays. We observe that one assay consistently yielded higher nAb titers than the other when both assays were performed on the World Health Organization's anti-SARS-CoV-2 immunoglobulin International Standard, COVID-19 convalescent sera, and mRNA-1273 vaccinee sera. To overcome the challenge this difference in readout poses in comparing/combining data from the two assays, we evaluate three calibration approaches and show that readouts from the two assays can be calibrated to a common scale. These results may aid decision-making based on data from these assays for the evaluation and licensure of new or adapted COVID-19 vaccines., (© 2021. The Author(s).)

BackgroundVRC01, a potent, broadly neutralizing monoclonal antibody, inhibits simian-HIV infection in animal models. The HVTN 104 study assessed the safety and pharmacokinetics of VRC01 in humans. We extend the clinical evaluation to determine intravenously infused VRC01 distribution and protective function at mucosal sites of HIV-1 entry.MethodsHealthy, HIV-1-uninfected men (n = 7) and women (n = 5) receiving VRC01 every 2 months provided mucosal and serum samples once, 4-13 days after infusion. Eleven male and 8 female HIV-seronegative volunteers provided untreated control samples. VRC01 levels were measured in serum, secretions, and tissue, and HIV-1 inhibition was determined in tissue explants.ResultsMedian VRC01 levels were quantifiable in serum (96.2 μg/mL or 1.3 pg/ng protein), rectal tissue (0.11 pg/ng protein), rectal secretions (0.13 pg/ng protein), vaginal tissue (0.1 pg/ng protein), and cervical secretions (0.44 pg/ng protein) from all recipients. VRC01/IgG ratios in male serum correlated with those in paired rectal tissue (r = 0.893, P = 0.012) and rectal secretions (r = 0.9643, P = 0.003). Ex vivo HIV-1Bal26 challenge infected 4 of 21 rectal explants from VRC01 recipients versus 20 of 22 from controls (P = 0.005); HIV-1Du422.1 infected 20 of 21 rectal explants from VRC01 recipients and 12 of 12 from controls (P = 0.639). HIV-1Bal26 infected 0 of 14 vaginal explants of VRC01 recipients compared with 23 of 28 control explants (P = 0.003).ConclusionIntravenous VRC01 distributes into the female genital and male rectal mucosa and retains anti-HIV-1 functionality, inhibiting a highly neutralization-sensitive but not a highly resistant HIV-1 strain in mucosal tissue. These findings lend insight into VRC01 mucosal infiltration and provide perspective on in vivo protective efficacy.FundingNational Institute of Allergy and Infectious Diseases and Bill & Melinda Gates Foundation.

Background: HIV Vaccine Trials Network 703/HIV Prevention Trials Network 081 is a phase 2b randomized, double-blind, placebo-controlled trial to assess the safety and efficacy of passively infused monoclonal antibody VRC01 in preventing HIV acquisition in heterosexual women between the ages of 18 and 50 years at risk of HIV. Participants were enrolled at 20 sites in Botswana, Kenya, Malawi, Mozambique, South Africa, Tanzania, and Zimbabwe. It is one of the 2 Antibody Mediated Prevention efficacy trials, with HIV Vaccine Trials Network 704/HIV Prevention Trials Network 085, evaluating VRC01 for HIV prevention., Methods: Intense community engagement was used to optimize participant recruitment and retention. Participants were randomly assigned to receive intravenous VRC01 10 mg/kg, VRC01 30 mg/kg, or placebo in a 1:1:1 ratio. Infusions were given every 8 weeks with a total of 10 infusions and 104 weeks of follow-up after the first infusion., Results: Between May 2016 and September 2018, 1924 women from sub-Saharan Africa were enrolled. The median age was 26 years (interquartile range: 22-30), and 98.9% were Black. Sexually transmitted infection prevalence at enrollment included chlamydia (16.9%), trichomonas (7.2%), gonorrhea (5.7%), and syphilis (2.2%). External condoms (83.2%) and injectable contraceptives (61.1%) were the methods of contraception most frequently used by participants. In total, through April 3, 2020, 38,490 clinic visits were completed with a retention rate of 96% and 16,807 infusions administered with an adherence rate of 98%., Conclusions: This proof-of-concept, large-scale monoclonal antibody study demonstrates the feasibility of conducting complex trials involving intravenous infusions in high incidence populations in sub-Saharan Africa., Competing Interests: J.R.M. reports an NIH patent for VRC01. The remaining authors have no conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The Antibody-Mediated Prevention trials (HVTN 704/HPTN 085 and HVTN 703/HPTN 081) are the first efficacy trials to evaluate whether VRC01, a broadly neutralizing monoclonal antibody targeting the CD4-binding site of the HIV envelope protein, prevents sexual transmission of HIV-1. HVTN 704/HPTN 085 enrolled 2701 cisgender men and transgender (TG) individuals who have sex with men at 26 sites in Brazil, Peru, Switzerland, and the United States., Methods: Participants were recruited and retained through early, extensive community engagement. Eligible participants were randomized 1:1:1 to 10 mg/kg or 30 mg/kg of VRC01 or saline placebo. Visits occurred monthly, with intravenous (IV) infusions every 8 weeks over 2 years, for a total of 10 infusions. Participants were followed for 104 weeks after first infusion., Results: The median HVTN 704/HPTN 085 participant age was 28 years; 99% were assigned male sex; 90% identified as cisgender men, 5% as TG women and the remaining as other genders. Thirty-two percent were White, 15% Black, and 57% Hispanic/Latinx. Twenty-eight percent had a sexually transmitted infection at enrollment. More than 23,000 infusions were administered with no serious IV administration complications. Overall, retention and adherence to the study schedule exceeded 90%, and the dropout rate was below 10% annually (7.3 per 100 person-years) through week 80, the last visit for the primary end point., Conclusions: HVTN 704/HPTN 085 exceeded accrual and retention expectations. With exceptional safety of IV administration and operational feasibility, it paves the way for future large-scale monoclonal antibody trials for HIV prevention and/or treatment., Competing Interests: P.L.A. has received personal fees and research funds paid to his institution from Gilead Sciences. J.R.M. is an inventor on NIH patent for VRC01. The remaining authors have no conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Whether a broadly neutralizing antibody (bnAb) can be used to prevent human immunodeficiency virus type 1 (HIV-1) acquisition is unclear., Methods: We enrolled at-risk cisgender men and transgender persons in the Americas and Europe in the HVTN 704/HPTN 085 trial and at-risk women in sub-Saharan Africa in the HVTN 703/HPTN 081 trial. Participants were randomly assigned to receive, every 8 weeks, infusions of a bnAb (VRC01) at a dose of either 10 or 30 mg per kilogram (low-dose group and high-dose group, respectively) or placebo, for 10 infusions in total. HIV-1 testing was performed every 4 weeks. The VRC01 80% inhibitory concentration (IC 80 ) of acquired isolates was measured with the TZM-bl assay., Results: Adverse events were similar in number and severity among the treatment groups within each trial. Among the 2699 participants in HVTN 704/HPTN 085, HIV-1 infection occurred in 32 in the low-dose group, 28 in the high-dose group, and 38 in the placebo group. Among the 1924 participants in HVTN 703/HPTN 081, infection occurred in 28 in the low-dose group, 19 in the high-dose group, and 29 in the placebo group. The incidence of HIV-1 infection per 100 person-years in HVTN 704/HPTN 085 was 2.35 in the pooled VRC01 groups and 2.98 in the placebo group (estimated prevention efficacy, 26.6%; 95% confidence interval [CI], -11.7 to 51.8; P = 0.15), and the incidence per 100 person-years in HVTN 703/HPTN 081 was 2.49 in the pooled VRC01 groups and 3.10 in the placebo group (estimated prevention efficacy, 8.8%; 95% CI, -45.1 to 42.6; P = 0.70). In prespecified analyses pooling data across the trials, the incidence of infection with VRC01-sensitive isolates (IC 80 <1 μg per milliliter) per 100 person-years was 0.20 among VRC01 recipients and 0.86 among placebo recipients (estimated prevention efficacy, 75.4%; 95% CI, 45.5 to 88.9). The prevention efficacy against sensitive isolates was similar for each VRC01 dose and trial; VRC01 did not prevent acquisition of other HIV-1 isolates., Conclusions: VRC01 did not prevent overall HIV-1 acquisition more effectively than placebo, but analyses of VRC01-sensitive HIV-1 isolates provided proof-of-concept that bnAb prophylaxis can be effective. (Supported by the National Institute of Allergy and Infectious Diseases; HVTN 704/HPTN 085 and HVTN 703/HPTN 081 ClinicalTrials.gov numbers, NCT02716675 and NCT02568215.)., (Copyright © 2021 Massachusetts Medical Society.)

Background: Experimental human immunodeficiency virus (HIV)-1 vaccines frequently elicit antibodies against HIV-1 that may react with commonly used HIV diagnostic tests, a phenomenon known as vaccine-induced seropositivity/seroreactivity (VISP/VISR). We sought to determine, under clinic conditions, whether a patient-controlled HIV test, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, detected HIV-1 vaccine-induced antibodies., Methods: Plasma assessment of HIV-1 cross-reactivity was examined in end-of-study samples from 57 healthy, HIV-uninfected participants who received a candidate vaccine that has entered Phase 2B and 3 testing. We also screened 120 healthy, HIV-uninfected, unblinded HIV-1 vaccine participants with VISP/VISR for an assessment using saliva. These participants came from 21 different parent vaccine protocols representing 17 different vaccine regimens, all of which contained an HIV-1 envelope immunogen. OraQuick ADVANCE was compared with results from concurrent blood samples using a series of commercial HIV screening immunoassays., Results: Fifty-seven unique participant plasma samples were assayed in vitro, and only 1 (1.8%) was reactive by OraQuick ADVANCE. None of the 120 clinic participants (0%; 95% confidence interval, 0% to 3.7%) tested positive by OraQuick ADVANCE, and all were confirmed to be uninfected by HIV-1 viral ribonucleic acid testing. One hundred eighteen of the 120 (98.3%) participants had a reactive HIV test for VISP/VISR: 77 (64%) had at least 1 reactive fourth-generation HIV-1 diagnostic test ( P  < .0001 vs no reactive OraQuick ADVANCE results), and 41 (34%) only had a reactive test by the less specific third-generation Abbott Prism assay., Conclusions: These data suggest that this widely available patient-controlled test has limited reactivity to HIV-1 antibodies elicited by these candidate HIV-1 vaccines., (© The Author(s) 2020. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Efficacious HIV-1 vaccination requires elicitation of long-lived antibody responses. However, our understanding of how different vaccine types elicit durable antibody responses is lacking. To assess the impact of vaccine type on antibody responses, we measured IgG isotypes against four consensus HIV antigens from 2 weeks to 10 years post HIV-1 vaccination and used mixed effects models to estimate half-life of responses in four human clinical trials. Compared to protein-boosted regimens, half-lives of gp120-specific antibodies were longer but peak magnitudes were lower in Modified Vaccinia Ankara (MVA)-boosted regimens. Furthermore, gp120-specific B cell transcriptomics from MVA-boosted and protein-boosted vaccines revealed a distinct signature at a peak (2 weeks after last vaccination) including CD19, CD40, and FCRL2-5 activation along with increased B cell receptor signaling. Additional analysis revealed contributions of RIG-I-like receptor pathway and genes such as SMAD5 and IL-32 to antibody durability. Thus, this study provides novel insights into vaccine induced antibody durability and B-cell receptor signaling.

Background: Broadly protective pneumococcal vaccines that are affordable for low-resource countries are needed. Streptococcus pneumoniae whole cell vaccine (wSp) is an investigational vaccine that contains killed cells from a nonencapsulated strain of S. pneumoniae (SPn) with aluminum hydroxide adjuvant. Studies in mice demonstrated protection against nasopharyngeal carriage (T-cell-mediated) and invasive pneumococcal disease (antibody-mediated). The aim of this randomized, double-blind, placebo-controlled Phase 1 study was to assess safety, tolerability and immunogenicity of wSp in healthy adults., Methods: Forty-two participants were randomized into 3 dose cohorts to receive 0.1, 0.3, or 0.6 mg of wSp or saline intramuscularly. Participants received a 3-dose vaccination schedule spaced by 4-week intervals. Postvaccination assessments included solicited reactogenicity events through day 7, blood chemistry and hematology assessments at day 7, and adverse events (AEs) through day 84. Participants were monitored for serum antibody and peripheral blood mononuclear cell cytokine responses to pneumococcal antigens. A 6-month telephone follow-up was completed to assess for any additional AEs., Results: wSp was safe and well tolerated. Reactogenicity was acceptable and no untoward safety signals were observed. wSp elicited potentially clinically significant rises (defined arbitrarily as at least a 2-fold rise) in immunoglobulin G responses to multiple pneumococcal antigens, including pneumococcal surface protein A and pneumolysin. Functional antibody responses were observed with the highest dose of wSp (0.6 mg). Increases in T-cell cytokine responses, including interleukin 17A, were also seen among wSp vaccines., Conclusions: wSp was safe and well tolerated in healthy US adults, eliciting pneumococcal antigen-specific antibody and T-cell cytokine responses.

T cell responses have been implicated in reduced risk of HIV acquisition in uninfected persons and control of viral replication in HIV-infected individuals. HIV Gag-specific T cells have been predominantly associated with post-infection control, whereas Env antigens are the target for protective antibodies; therefore, inclusion of both antigens is common in HIV vaccine design. However, inclusion of multiple antigens may provoke antigenic competition, reducing the potential effectiveness of the vaccine. HVTN 084 was a randomized, multicenter, double-blind phase 1 trial to investigate whether adding Env to a Gag/Pol vaccine decreases the magnitude or breadth of Gag/Pol-specific T cell responses. Fifty volunteers each received one intramuscular injection of 1 × 10 10 particle units (PU) of rAd5 Gag/Pol and EnvA/B/C (3:1:1:1 mixture) or 5 × 10 9 PU of rAd5 Gag/Pol. CD4 + T cell responses to Gag/Pol measured 4 weeks after vaccination by cytokine expression were significantly higher in the group vaccinated without Env, whereas CD8 + T cell responses did not differ significantly between the two groups. Mapping of individual epitopes revealed greater breadth of the Gag/Pol-specific T cell response in the absence of Env compared to Env coimmunization. Addition of an Env component to a Gag/Pol vaccine led to reduced Gag/Pol CD4 + T cell response rate and magnitude as well as reduced epitope breadth, confirming the presence of antigenic competition. Therefore, T cell-based vaccine strategies should aim at choosing a minimalist set of antigens to reduce interference of individual vaccine components with the induction of the maximally achievable immune response., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

One of the most successful HIV vaccines to date, the RV144 vaccine tested in Thailand, demonstrated correlates of protection including cross-clade V1V2 immunoglobulin G (IgG) breadth, Env-specific CD4 + T cell polyfunctionality, and antibody-dependent cellular cytotoxicity (ADCC) in vaccinees with low IgA binding. The HIV Vaccine Trials Network (HVTN) 097 trial evaluated this vaccine regimen in South Africa, where clade C HIV-1 predominates. We compared cellular and humoral responses at peak and durability immunogenicity time points in HVTN 097 and RV144 vaccinee samples, and evaluated vaccine-matched and cross-clade immune responses. At peak immunogenicity, HVTN 097 vaccinees exhibited significantly higher cellular and humoral immune responses than RV144 vaccinees. CD4 + T cell responses were more frequent in HVTN 097 irrespective of age and sex, and CD4 + T cell Env-specific functionality scores were higher in HVTN 097. Env-specific CD40L + CD4 + T cells were more common in HVTN 097, with individuals having this pattern of expression demonstrating higher median antibody responses to HIV-1 Env. IgG and IgG3 binding antibody rates and response magnitude to gp120 vaccine- and V1V2 vaccine-matched antigens were higher or comparable in HVTN 097 than in RV144 ADCC, and ADCP functional antibody responses were elicited in HVTN 097. Env-specific IgG and CD4 + Env responses declined significantly over time in both trials. Overall, cross-clade immune responses associated with protection were better than expected in South Africa, suggesting wider applicability of this regimen., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Measurements of HIV exposure could help identify subpopulations at highest risk of acquisition and improve the design of HIV prevention efficacy trials and public health interventions. The HVTN 915 study evaluated the feasibility of self-administered vaginal swabs for detection of HIV virions to assess exposure., Methods: Fifty 18- to 25-year-old sexually active HIV-seronegative women using contraception were enrolled in Soweto, South Africa. Participants self-administered daily vaginal swabs and answered sexual behavior questions through mobile phone for 90 days. Clinician-administered vaginal swabs, behavioral questionnaires, HIV diagnostic testing, and counseling were performed at 8 clinic visits. Glycogen concentrations assessed adherence to swabbing. Y-chromosome DNA (Yc-DNA) assessed the accuracy of reported condom use. HIV exposure was measured by virion polymerase chain reaction in swabs from 41 women who reported unprotected vaginal sex during follow-up., Results: Glycogen was detected in 315/336 (93.8%) participant-collected and in all clinician-collected swabs. Approximately 20/39 daily swabs (51.3%) linked to mobile reports of unprotected sex tested positive for Yc-DNA, whereas 10/187 swabs collected after 3 days of abstinence or protected sex (5.3%) had detectable Yc-DNA. No participant became HIV infected during the study; yet, exposure to HIV was detected by nucleic acids in 2 vaginal swabs from 1 participant, collected less than 1 hour after coitus., Conclusion: There was high adherence to daily vaginal swabbing. Daily mobile surveys had accurate reporting of unprotected sex. Detection of HIV in self-collected vaginal swabs from an uninfected participant demonstrated it was possible to measure HIV exposure, but the detection rate was lower than expected.

Background: The durability and breadth of human immunodeficiency virus type 1 (HIV-1)-specific immune responses elicited through vaccination are important considerations in the development of an effective HIV-1 vaccine. Responses to HIV-1 envelope subunit protein (Env) immunization in humans are often described as short-lived., Methods: We enrolled 16 healthy volunteers who had received priming with an HIV-1 subtype B Env vaccine given with MF59 adjuvant 5-17 years previously and 20 healthy unprimed volunteers. Three booster immunizations with a heterologous subtype C trimeric gp140 protein vaccine were administered to the primed group, and the same subtype C gp140 protein vaccination regimen was administered to the unprimed subjects., Results: Binding antibodies and neutralizing antibodies to tier 1 viral isolates were detected in the majority of previously primed subjects. Remarkably, a single dose of protein boosted binding and neutralizing antibody titers in 100% of primed subjects following this prolonged immunologic rest period, and CD4+ T-cell responses were boosted in 75% of primed individuals., Conclusions: These results demonstrate that HIV-1 protein immunogens can elicit durable memory T- and B-cell responses and that strong tier 1 virus neutralizing responses can be elicited by a single booster dose of protein following a long immunologic rest period. However, we found no evidence that cross-clade boosting led to a significantly broadened neutralizing antibody response., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: VRC01 is an HIV-1 CD4 binding site broadly neutralizing antibody (bnAb) that is active against a broad range of HIV-1 primary isolates in vitro and protects against simian-human immunodeficiency virus (SHIV) when delivered parenterally to nonhuman primates. It has been shown to be safe and well tolerated after short-term administration in humans; however, its clinical and functional activity after longer-term administration has not been previously assessed., Methods and Findings: HIV Vaccine Trials Network (HVTN) 104 was designed to evaluate the safety and tolerability of multiple doses of VRC01 administered either subcutaneously or by intravenous (IV) infusion and to assess the pharmacokinetics and in vitro immunologic activity of the different dosing regimens. Additionally, this study aimed to assess the effect that the human body has on the functional activities of VRC01 as measured by several in vitro assays. Eighty-eight healthy, HIV-uninfected, low-risk participants were enrolled in 6 United States clinical research sites affiliated with the HVTN between September 9, 2014, and July 15, 2015. The median age of enrollees was 27 years (range, 18-50); 52% were White (non-Hispanic), 25% identified as Black (non-Hispanic), 11% were Hispanic, and 11% were non-Hispanic people of diverse origins. Participants were randomized to receive the following: a 40 mg/kg IV VRC01 loading dose followed by five 20 mg/kg IV VRC01 doses every 4 weeks (treatment group 1 [T1], n = 20); eleven 5 mg/kg subcutaneous (SC) VRC01 (treatment group 3 [T3], n = 20); placebo (placebo group 3 [P3], n = 4) doses every 2 weeks; or three 40 mg/kg IV VRC01 doses every 8 weeks (treatment group 2 [T2], n = 20). Treatment groups T4 and T5 (n = 12 each) received three 10 or 30 mg/kg IV VRC01 doses every 8 weeks, respectively. Participants were followed for 32 weeks after their first VRC01 administration and received a total of 249 IV infusions and 208 SC injections, with no serious adverse events, dose-limiting toxicities, nor evidence for anti-VRC01 antibodies observed. Serum VRC01 levels were detected through 12 weeks after final administration in all participants who received all scheduled doses. Mean peak serum VRC01 levels of 1,177 μg/ml (95% CI: 1,033, 1,340) and 420 μg/ml (95% CI: 356, 494) were achieved 1 hour after the IV infusion series of 30 mg/kg and 10 mg/kg doses, respectively. Mean trough levels at week 24 in the IV infusion series of 30 mg/kg and 10 mg/kg doses, respectively, were 16 μg/ml (95% CI: 10, 27) and 6 μg/ml (95% CI: 5, 9) levels, which neutralize a majority of circulating strains in vitro (50% inhibitory concentration [IC50] > 5 μg/ml). Post-infusion/injection serum VRC01 retained expected functional activity (virus neutralization, antibody-dependent cellular cytotoxicity, phagocytosis, and virion capture). The limitations of this study include the relatively small sample size of each VRC01 administration regimen and missing data from participants who were unable to complete all study visits., Conclusions: VRC01 administered as either an IV infusion (10-40 mg/kg) given monthly or bimonthly, or as an SC injection (5 mg/kg) every 2 weeks, was found to be safe and well tolerated. In addition to maintaining drug concentrations consistent with neutralization of the majority of tested HIV strains, VRC01 concentrations from participants' sera were found to avidly capture HIV virions and to mediate antibody-dependent cellular phagocytosis, suggesting a range of anti-HIV immunological activities, warranting further clinical trials., Trial Registration: Clinical Trials Registration: NCT02165267.

Background: It is important to identify vaccine-induced immune responses that predict the preventative efficacy of a human immunodeficiency virus (HIV)-1 vaccine. We assessed T-cell response markers as correlates of risk in the HIV Vaccine Trials Network (HVTN) 505 HIV-1 vaccine efficacy trial., Methods: 2504 participants were randomized to DNA/rAd5 vaccine or placebo, administered at weeks 0, 4, 8, and 24. Peripheral blood mononuclear cells were obtained at week 26 from all 25 primary endpoint vaccine cases and 125 matched vaccine controls, and stimulated with vaccine-insert-matched peptides. Primary variables were total HIV-1-specific CD4+ T-cell magnitude and Env-specific CD4+ polyfunctionality. Four secondary variables were also assessed. Immune responses were evaluated as predictors of HIV-1 infection among vaccinees using Cox proportional hazards models. Machine learning analyses identified immune response combinations best predicting HIV-1 infection., Results: We observed an unexpectedly strong inverse correlation between Env-specific CD8+ immune response magnitude and HIV-1 infection risk (hazard ratio [HR] = 0.18 per SD increment; P = .04) and between Env-specific CD8+ polyfunctionality and infection risk (HR = 0.34 per SD increment; P < .01)., Conclusions: Further research is needed to determine if these immune responses are predictors of vaccine efficacy or markers of natural resistance to HIV-1 infection., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

IL-4 has been called the "prototypic immunoregulatory cytokine." Like many cytokines, it can affect a variety of target cells in multiple ways. IL-4 has an important role in regulating antibody production, hematopoiesis and inflammation, and the development of effector T-cell responses. It is produced only by a subset of activated hematopoietic cells, including T cells and FcεRl+ mast cells and basophils. Based on the different tissue distribution and access to distinct target cells, IL-4 derived from T and FcεRl+ cells may have quite different effects on these immunological processes. In view of this, as well as the clear correlation of aberrant expression with disease, it is of interest to understand the signals that regulate IL-4 expression in a cell-specific manner. Recently, progress has been made in defining the T-cell- and FcεRl-receptor-mediated signals that stimulate IL-4 gene expression. These studies have demonstrated that there are common and cell-specific signaling pathways that regulate production of this cytokine. In this review, we summarize the activities of IL-4 defined both in vitro and in vivo and compare the signals leading to IL-4 expression in cells of both T- and mast-cell lineage.

Background: Anti-HIV-1 broadly neutralizing antibodies (bnAbs) have been developed as potential agents for prevention of HIV-1 infection. The HIV Vaccine Trials Network and the HIV Prevention Trials Network are conducting the Antibody Mediated Prevention (AMP) trials to assess whether, and how, intravenous infusion of the anti-CD4 binding site bnAb, VRC01, prevents HIV-1 infection. These are the first test-of-concept studies to assess HIV-1 bnAb prevention efficacy in humans., Methods: The AMP trials are two parallel phase 2b HIV-1 prevention efficacy trials conducted in two cohorts: 2700 HIV-uninfected men and transgender persons who have sex with men in the United States, Peru, Brazil, and Switzerland; and 1500 HIV-uninfected sexually active women in seven countries in sub-Saharan Africa. Participants are randomized 1:1:1 to receive an intravenous infusion of 10 mg/kg VRC01, 30 mg/kg VRC01, or a control preparation every 8 weeks for a total of 10 infusions. Each trial is designed (1) to assess overall prevention efficacy (PE) pooled over the two VRC01 dose groups vs. control and (2) to assess VRC01 dose and laboratory markers as correlates of protection (CoPs) against overall and genotype- and phenotype-specific infection., Results: Each AMP trial is designed to have 90% power to detect PE > 0% if PE is ≥ 60%. The AMP trials are also designed to identify VRC01 properties (i.e., concentration and effector functions) that correlate with protection and to provide insight into mechanistic CoPs. CoPs are assessed using data from breakthrough HIV-1 infections, including genetic sequences and sensitivities to VRC01-mediated neutralization and Fc effector functions., Conclusions: The AMP trials test whether VRC01 can prevent HIV-1 infection in two study populations. If affirmative, they will provide information for estimating the optimal dosage of VRC01 (or subsequent derivatives) and identify threshold levels of neutralization and Fc effector functions associated with high-level protection, setting a benchmark for future vaccine evaluation and constituting a bridge to other bnAb approaches for HIV-1 prevention., Competing Interests: Conflict of interest statement: All authors have no potential conflicts of interest to declare.

Background: Increasing the breadth of human immunodeficiency virus type 1 (HIV-1) vaccine-elicited immune responses or targeting conserved regions may improve coverage of circulating strains. HIV Vaccine Trials Network 083 tested whether cellular immune responses with these features are induced by prime-boost strategies, using heterologous vectors, heterologous inserts, or a combination of both., Methods: A total of 180 participants were randomly assigned to receive combinations of adenovirus vectors (Ad5 or Ad35) and HIV-1 envelope (Env) gene inserts (clade A or B) in a prime-boost regimen., Results: T-cell responses to heterologous and homologous insert regimens targeted a similar number of epitopes (ratio of means, 1.0; 95% confidence interval [CI], .6-1.6; P = .91), but heterologous insert regimens induced significantly more epitopes that were shared between EnvA and EnvB than homologous insert regimens (ratio of means, 2.7; 95% CI, 1.2-5.7; P = .01). Participants in the heterologous versus homologous insert groups had T-cell responses that targeted epitopes with greater evolutionary conservation (mean entropy [±SD], 0.32 ± 0.1 bits; P = .003), and epitopes recognized by responders provided higher coverage (49%; P = .035). Heterologous vector regimens had higher numbers of total, EnvA, and EnvB epitopes than homologous vector regimens (P = .02, .044, and .045, respectively)., Conclusions: These data demonstrate that vaccination with heterologous insert prime boosting increased T-cell responses to shared epitopes, while heterologous vector prime boosting increased the number of T-cell epitopes recognized., Clinical Trials Registration: NCT01095224., (© The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

Background: Therapeutic vaccination is being studied in eradication and "functional cure" strategies for HIV-1. The Profectus Biosciences multiantigen (MAG) HIV-1 DNA vaccine encodes HIV-1 Gag/Pol, Nef/Tat/Vif, and Envelope, and interleukin-12 (IL-12) and is delivered by electroporation combined with intramuscular injection (IM-EP)., Methods: Sixty-two HIV-1-infected patients on antiretroviral therapy (plasma HIV-1 RNA levels ≤ 200 copies/mL; CD4(+) T-cell counts ≥ 500 cells/mm(3)) were randomly allocated 5:1 to receive vaccine or placebo. At weeks 0, 4, and 12, 4 consecutive cohorts received 3000 μg HIV MAG pDNA with 0, 50, 250, or 1000 μg of IL-12 pDNA by IM-EP. A fifth cohort received HIV MAG pDNA and 1000 μg of IL-12 pDNA by standard IM injection., Results: CD4(+) T cells expressing IL-2 in response to Gag and Pol and interferon-γ responses to Gag, Pol, and Env increased from baseline to week 14 in the low-dose (50-μg) IL-12 arm vs. placebo (P < 0.05; intracellular cytokine staining). The total increase in the IL-2-expressing CD4 T-cell responses to any antigen was also higher in the low-dose IL-12 arm vs. placebo (P = 0.04). Cytokine responses by CD8 T cells to HIV antigens were not increased in any vaccine arm relative to placebo., Conclusions: HIV-1 MAG/low-dose IL-12 DNA vaccine delivered by IM-EP augmented CD4(+) but not CD8(+) T-cell responses to multiple HIV-1 antigens.