Recapitulation of HIV-1 Neutralization Breadth in Plasma by the Combination of Two Broadly Neutralizing Antibodies from Different Lineages in the Same SHIV-Infected Rhesus Macaque.

Viral infection generally induces polyclonal neutralizing antibody responses. However, how many lineages of antibody responses can fully represent the neutralization activities in sera has not been well studied. Using the newly designed stable HIV-1 Env trimer as hook, we isolated two distinct broadly neutralizing antibodies (bnAbs) from Chinese rhesus macaques infected with SHIV for 5 years. One lineage of neutralizing antibodies (JT15 and JT16) targeted the V2-apex in the Env trimers, similar to the J038 lineage bnAbs identified in our previous study. The other lineage neutralizing antibody (JT18) targeted the V3 crown region in the Env, which strongly competed with human 447-52D. Each lineage antibody neutralized a different set of viruses. Interestingly, when the two neutralizing antibodies from different lineages isolated from the same macaque were combined, the mixture had a neutralization breath very similar to that from the cognate sera. Our study demonstrated that a minimum of two different neutralizing antibodies can fully recapitulate the serum neutralization breadth. This observation can have important implications in AIDS vaccine design.