# Vaccine elicitation of HIV-1 neutralizing antibodies against both V2 apex and fusion peptide in rhesus macaques

## TL;DR

A new HIV vaccine design successfully induces antibodies that neutralize multiple virus strains in monkeys.

## Contribution

A dual-epitope vaccine elicits cross-strain neutralizing antibodies against both the fusion peptide and V2 apex of HIV-1 in rhesus macaques.

## Key findings

- Macaques immunized with the dual-epitope vaccine showed >1,000-fold higher autologous tier 2-neutralizing titers than wild-type Env trimers.
- FP- and V2 apex-directed monoclonal antibodies isolated from immunized macaques exhibited heterologous neutralization.
- The vaccine demonstrates proof of concept for eliciting antibodies against multiple HIV-1 Env vulnerabilities simultaneously.

## Abstract

Broadly neutralizing antibodies (bNAbs) targeting multiple sites of HIV-1 Env vulnerability can be induced by infection, but simultaneous elicitation of bNAbs against multiple epitopes has not been achieved by vaccination. In this study, we designed a dual-epitope vaccine targeting both the fusion peptide (FP) and the V2 apex and evaluated its capacity to induce bNAbs against both epitopes in rhesus macaques. This vaccine combined an FP conjugate with a cocktail of engineered Env trimers with enhanced V2 apex recognition and increased antigen retention in lymph nodes. Macaque immunization with the dual-epitope vaccine elicited >1,000-fold higher autologous tier 2-neutralizing titers than wild-type Env trimers and enhanced heterologous neutralization. Both FP- and V2 apex-monoclonal antibodies were isolated from immunized macaques and showed heterologous neutralization with genetic and structural signatures similar to well-characterized FP and V2 apex bNAbs. These results demonstrate proof of concept for simultaneous vaccine elicitation of neutralizing antibodies against multiple sites of Env vulnerability.

Duan et al. demonstrate that a dual-epitope HIV-1 vaccine, comprising an FP conjugate and V2 apex-modified Env trimers, elicits potent serum neutralizing activity with cross-strain breadth in all immunized NHPs. Both FP-directed and V2 apex-directed monoclonal antibodies were isolated and showed cross-strain-tier 2 neutralization.