Priming with DNA Expressing Trimeric HIV V1V2 Alters the Immune Hierarchy Favoring the Development of V2-Specific Antibodies in Rhesus Macaques

Abstract

The RV144 vaccine trial revealed a correlation between reduced risk of HIV infection and the level of non-neutralizing antibody (Ab) responses targeting specific epitopes in the second variable domain (V2) of the HIV gp120 envelope (Env) protein, suggesting this region as a target for vaccine development. To favor induction of V2-specific Abs, we developed a vaccine regimen that included priming with DNA expressing an HIV V1V2 trimeric scaffold immunogen followed by booster immunizations with a combination of DNA and protein in rhesus macaques. Priming vaccination with DNA expressing the HIV recombinant subtype CRF01_AE V1V2 scaffold induced higher and broader V2-specific Ab responses than vaccination with DNA expressing CRF01_AE gp145 Env. Abs recognizing the V2 peptide that was reported as a critical target in RV144 developed only after the priming immunization with V1V2 DNA. The V2-specific Abs showed several non-neutralizing Fc-mediated functions, including ADCP and C1q binding. Importantly, robust V2-specific Abs were maintained upon boosting with gp145 DNA and gp120 protein co-immunization. In conclusion, priming with DNA expressing the trimeric V1V2 scaffold alters the hierarchy of humoral immune responses to V2 region epitopes, providing a method for more efficient induction and maintenance of V2-specific Env Abs associated with reduced risk of HIV infection. IMPORTANCE The aim of this work has been to design and test a vaccine regimen focusing the immune response to targets associated with infection prevention. We demonstrated that priming with a DNA vaccine expressing only the HIV Env V1V2 region induces Ab responses targeting the critical region in V2 associated with protection. This work shows that V1V2 scaffold DNA priming immunization provides a method to focus immune responses to the desired target region, in the absence of immune interference by other epitopes. This induced immune responses with improved recognition of epitopes important for protective immunity, namely, V2-specific humoral immune responses inversely correlating with HIV risk of infection in the RV144 trial.

Control of SARS-CoV-2 infection after Spike DNA or Spike DNA+Protein co-immunization in rhesus macaques

“…Expression of Spike DNA plasmids was analyzed upon transient transfection of HEK293T clone17 cells using the Calcium Phosphate DNA co-precipitation and DNA (1 microG DNA/ 60 mm plate) as described [32,63]. After 48 hours, supernatants and cells were harvested, and the cells were lysed in 1 ml of hypertonic N1 lysis buffer as described.…”

Control of SARS-CoV-2 infection after Spike DNA or Spike DNA+Protein co-immunization in rhesus macaques

“…Expression of Spike DNA plasmids was analyzed upon transient transfection of HEK293T clone17 cells using the Calcium Phosphate DNA co-precipitation and DNA (1 microG DNA/60 mm plate) as described [32,63]. After 48 hours, supernatants and cells were harvested, and the cells were lysed in 1 ml of hypertonic N1 lysis buffer as described.…”

Vaccination with immune complexes modulates the elicitation of functional antibodies against HIV-1

“…To this end, an uncleaved prefusion-optimized (UFO) gp140 Env trimer of CRF01_AE A244 with V3 truncation (UFO-BG.ΔV3) and A244 V1V2 on a trimeric 2J9C scaffold (V1V2-2J9C) were examined as uncomplexed proteins (UC) or in complex with mAb 2158 (IC) for immunogenicity in rabbits. A V1V2-2J9C DNA vaccine previously shown to promote the targeting of Ab responses to the V2 apex ( 27 ) was also incorporated for a co-immunization regimen. The data demonstrated that V1V2-specific Abs with distinct binding profiles were produced in the groups immunized with DNA and UFO-BG.ΔV3 UC or IC vaccines versus DNA and V1V2-2J9C UC and IC vaccines.…”