Resistance mutations that distinguish HIV-1 envelopes with discordant VRC01 phenotypes from multi-lineage infections in the HVTN703/HPTN081 trial: implications for cross-resistance.

The Antibody Mediated Prevention (AMP) trials showed that passively infused VRC01, a broadly neutralizing antibody (bNAb) targeting the CD4 binding site (CD4bs) on the HIV-1 envelope protein (Env), protected against neutralization-sensitive viruses. We identified six individuals from the VRC01 treatment arm with multi-lineage breakthrough HIV-1 infections from HVTN703, where one variant was sensitive to VRC01 (IC < 25 ug/mL) but another was resistant. By comparing Env sequences of resistant and sensitive clones from each participant, we identified sites predicted to affect VRC01 neutralization and assessed the effect of their reversion in the VRC01-resistant clone on neutralization sensitivity.

Safety and implementation of a phase 1 randomized GLA-SE-adjuvanted CH505TF gp120 HIV vaccine trial in newborns.

Background: The neonatal immune system is uniquely poised to generate broadly neutralizing antibodies (bnAbs) and thus infants are ideal for evaluating HIV vaccine candidates. We present the design and safety of a novel glucopyranosyl lipid A (GLA)-stable emulsion (SE) adjuvant admixed with a first-in-infant CH505 transmitter-founder (CH505TF) gp120 immunogen designed to induce precursors for bnAbs against HIV.

Methods: HVTN 135 is a phase I randomized, placebo-controlled trial of CH505TF+GLA-SE or placebo.

Safety and immunogenicity after a 30-month boost of a subtype C ALVAC-HIV (vCP2438) vaccine prime plus bivalent subtype C gp120/MF59 vaccine boost (HVTN 100): A phase 1-2 randomized double-blind placebo-controlled trial.

Induction of broad, durable immune responses is a challenge in HIV vaccine development. HVTN 100 Part A administered subtype C-containing ALVAC-HIV at months 0 and 1, and ALVAC-HIV with bivalent subtype C gp120/MF59 at months 3, 6 and 12. As IgG binding antibody and T-cell responses were similar or greater at month 12.

Safety and pharmacokinetics of subcutaneous administration of broadly neutralizing anti-HIV-1 monoclonal antibodies (bNAbs), given to HIV-1 exposed, uninfected neonates and infants: study protocol for a phase I trial.

Background: The ambitious goal to eliminate new pediatric HIV infections by 2030 requires accelerated prevention strategies in high-risk settings such as South Africa. One approach could be pre-exposure prophylaxis (PrEP) with broadly neutralizing anti-HIV-1 monoclonal antibodies (bNAbs). The aim of our study is to define the optimal dose(s), the ideal combination(s) of bNAbs in terms of potency and breadth, and timing of subcutaneous (SC) administration(s) to prevent breast milk transmission of HIV.

High monoclonal neutralization titers reduced breakthrough HIV-1 viral loads in the Antibody Mediated Prevention trials.

The Antibody Mediated Prevention (AMP) trials (NCT02716675 and NCT02568215) demonstrated that passive administration of the broadly neutralizing monoclonal antibody VRC01 could prevent some HIV-1 acquisition events. Here, we use mathematical modeling in a post hoc analysis to demonstrate that VRC01 influenced viral loads in AMP participants who acquired HIV. Instantaneous inhibitory potential (IIP), which integrates VRC01 serum concentration and VRC01 sensitivity of acquired viruses in terms of both IC50 and IC80, follows a dose-response relationship with first positive viral load (p = 0.

Infection pre-Ad26.COV2.S-vaccination primes greater class switching and reduced CXCR5 expression by SARS-CoV-2-specific memory B cells.

Neutralizing antibodies strongly correlate with protection for COVID-19 vaccines, but the corresponding memory B cells that form to protect against future infection are relatively understudied. Here we examine the effect of prior SARS-CoV-2 infection on the magnitude and phenotype of the memory B cell response to single dose Johnson and Johnson (Ad26.COV2.

Neutralization profiles of HIV-1 viruses from the VRC01 Antibody Mediated Prevention (AMP) trials.

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.

Safety and pharmacokinetics of escalating doses of neutralising monoclonal antibody CAP256V2LS administered with and without VRC07-523LS in HIV-negative women in South Africa (CAPRISA 012B): a phase 1, dose-escalation, randomised controlled trial.

Background: Young women in sub-Saharan Africa continue to bear a high burden of HIV infection. Combination anti-HIV monoclonal antibodies are a potential HIV prevention technology that could overcome adherence challenges of daily oral pre-exposure prophylaxis. In this phase 1 clinical trial we aimed to determine the safety and pharmacokinetic profile of the broadly neutralising monoclonal antibody CAP256V2LS.

Neutralization titer biomarker for antibody-mediated prevention of HIV-1 acquisition.

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) 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 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.

Shared N417-Dependent Epitope on the SARS-CoV-2 Omicron, Beta, and Delta Plus Variants.

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, several variants of concern (VOCs) have arisen which are defined by multiple mutations in their spike proteins. These VOCs have shown variable escape from antibody responses and have been shown to trigger qualitatively different antibody responses during infection. By studying plasma from individuals infected with either the original D614G, Beta, or Delta variants, we showed that the Beta and Delta variants elicit antibody responses that are overall more cross-reactive than those triggered by D614G.

Safety and Pharmacokinetics of Monoclonal Antibodies VRC07-523LS and PGT121 Administered Subcutaneously for Human Immunodeficiency Virus Prevention.

Background: Effective, long-acting prevention approaches are needed to reduce human immunodeficiency virus (HIV) incidence. We evaluated the safety and pharmacokinetics of VRC07-523LS and PGT121 administered subcutaneously alone and in combination as passive immunization for young women in South Africa.

Methods: CAPRISA 012A was a randomized, double-blinded, placebo-controlled, dose-escalation phase 1 trial.

Safety and immunogenicity of the ChAdOx1 nCoV-19 (AZD1222) vaccine against SARS-CoV-2 in people living with and without HIV in South Africa: an interim analysis of a randomised, double-blind, placebo-controlled, phase 1B/2A trial.

Background: People living with HIV are at an increased risk of fatal outcome when admitted to hospital for severe COVID-19 compared with HIV-negative individuals. We aimed to assess safety and immunogenicity of the ChAdOx1 nCoV-19 (AZD1222) vaccine in people with HIV and HIV-negative individuals in South Africa.

Methods: In this ongoing, double-blind, placebo-controlled, phase 1B/2A trial (COV005), people with HIV and HIV-negative participants aged 18-65 years were enrolled at seven South African locations and were randomly allocated (1:1) with full allocation concealment to receive a prime-boost regimen of ChAdOx1 nCoV-19, with two doses given 28 days apart.

Prediction of serum HIV-1 neutralization titers of VRC01 in HIV-uninfected Antibody Mediated Prevention (AMP) trial participants.

VRC01 is being evaluated in the AMP efficacy trials, the first assessment of a passively administered broadly neutralizing monoclonal antibody (bnAb) for HIV-1 prevention. A key analysis will assess serum VRC01-mediated neutralization as a potential correlate of protection. To prepare for this analysis, we conducted a pilot study where we measured longitudinal VRC01 serum concentrations and serum VRC01-mediated neutralization in 47 and 31 HIV-1 uninfected AMP participants, respectively.

Initiation of Antiretroviral Therapy Differentially Influences Genital and Systemic Immune Activation in HIV-Infected Women.

Antiretroviral therapy (ART) has significantly improved the quality of life of HIV-infected individuals: reducing plasma viremia, restoring CD4 T cell numbers, and correcting imbalances in blood memory T cell subsets. While ART improves immune correlates at mucosal sites, including the lower female genital tract (FGT), ART initiation has been associated with reactivation of common FGT infections. We investigated the effect of ART on immune activation and inflammation in the genital tract.

Antibody and cellular responses to HIV vaccine regimens with DNA plasmid as compared with ALVAC priming: An analysis of two randomized controlled trials.

Background: DNA plasmids promise a pragmatic alternative to viral vectors for prime-boost HIV-1 vaccines. We evaluated DNA plasmid versus canarypox virus (ALVAC) primes in 2 randomized, double-blind, placebo-controlled trials in southern Africa with harmonized trial designs. HIV Vaccine Trials Network (HVTN) 111 tested DNA plasmid prime by needle or needleless injection device (Biojector) and DNA plasmid plus gp120 protein plus MF59 adjuvant boost.

Safety and immune responses after a 12-month booster in healthy HIV-uninfected adults in HVTN 100 in South Africa: A randomized double-blind placebo-controlled trial of ALVAC-HIV (vCP2438) and bivalent subtype C gp120/MF59 vaccines.

Background: HVTN 100 evaluated the safety and immunogenicity of an HIV subtype C pox-protein vaccine regimen, investigating a 12-month booster to extend vaccine-induced immune responses.

Methods And Findings: A phase 1-2 randomized double-blind placebo-controlled trial enrolled 252 participants (210 vaccine/42 placebo; median age 23 years; 43% female) between 9 February 2015 and 26 May 2015. Vaccine recipients received ALVAC-HIV (vCP2438) alone at months 0 and 1 and with bivalent subtype C gp120/MF59 at months 3, 6, and 12.

Effect of HIV Envelope Vaccination on the Subsequent Antibody Response to HIV Infection.

Analysis of breakthrough HIV-1 infections could elucidate whether prior vaccination primes relevant immune responses. Here, we measured HIV-specific antibody responses in 14 South African volunteers who acquired HIV infection after participating in phase 1/2 trials of envelope-containing immunogens. Serum samples were collected annually following HIV-1 infection from participants in trials HVTN 073 (subtype C, DNA/MVA, phase 1 trial,  = 1), HVTN 086 (subtype C, DNA/MVA/gp140 protein, phase 1 trial,  = 2), and HVTN 204 (multisubtype, DNA/adenovirus serotype 5 [Ad5], phase 2 trial,  = 7) and 4 placebo recipients.

Phase 1 Human Immunodeficiency Virus (HIV) Vaccine Trial to Evaluate the Safety and Immunogenicity of HIV Subtype C DNA and MF59-Adjuvanted Subtype C Envelope Protein.

Background: The Pox-Protein Public-Private Partnership is performing a suite of trials to evaluate the bivalent subtype C envelope protein (TV1.C and 1086.C glycoprotein 120) vaccine in the context of different adjuvants and priming agents for human immunodeficiency virus (HIV) type 1 (HIV-1) prevention.

IgG3 enhances neutralization potency and Fc effector function of an HIV V2-specific broadly neutralizing antibody.

Broadly neutralizing antibodies (bNAbs) protect against HIV infection in non-human primates and their efficacy may be enhanced through interaction with Fc receptors on immune cells. Antibody isotype is a modulator of this binding with the IgG3 subclass mediating potent Fc effector function and is associated with HIV vaccine efficacy and HIV control. BNAb functions are typically assessed independently of the constant region with which they are naturally expressed.

Impact of chemokine C-C ligand 27, foreskin anatomy and sexually transmitted infections on HIV-1 target cell availability in adolescent South African males.

We compared outer and inner foreskin tissue from adolescent males undergoing medical male circumcision to better understand signals that increase HIV target cell availability in the foreskin. We measured chemokine gene expression and the impact of sexually transmitted infections (STIs) on the density and location of T and Langerhans cells. Chemokine C-C ligand 27 (CCL27) was expressed 6.

Immune correlates of the Thai RV144 HIV vaccine regimen in South Africa.

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.

AAV-Mediated Expression of Broadly Neutralizing and Vaccine-like Antibodies Targeting the HIV-1 Envelope V2 Region.

HIV-1 infection continues to be a global health challenge and a vaccine is urgently needed. Broadly neutralizing antibodies (bNAbs) are considered essential as they inhibit multiple HIV-1 strains, but they are difficult to elicit by conventional immunization. In contrast, non-neutralizing antibodies that correlated with reduced risk of infection in the RV144 HIV vaccine trial are relatively easy to induce, but responses are not durable.

Defining characteristics of genital health in South African adolescent girls and young women at high risk for HIV infection.

The genital tract of African women has been shown to differ from what is currently accepted as 'normal', defined by a pH≤4.5 and lactobacilli-dominated microbiota. Adolescent girls and young women (AGYW) from sub-Saharan Africa are at high risk for HIV, and we hypothesized that specific biological factors are likely to be influential.

V2-Directed Vaccine-like Antibodies from HIV-1 Infection Identify an Additional K169-Binding Light Chain Motif with Broad ADCC Activity.

Antibodies that bind residue K169 in the V2 region of the HIV-1 envelope correlated with reduced risk of infection in the RV144 vaccine trial but were restricted to two ED-motif-encoding light chain genes. Here, we identify an HIV-infected donor with high-titer V2 peptide-binding antibodies and isolate two antibody lineages (CAP228-16H/19F and CAP228-3D) that mediate potent antibody-dependent cell-mediated cytotoxicity (ADCC). Both lineages use the IGHV5-51 heavy chain germline gene, similar to the RV144 antibody CH58, but one lineage (CAP228-16H/19F) uses a light chain without the ED motif.