3BNC117

3BNC117 is a human monoclonal antibody that functions as a broadly neutralizing antibody (bnAb) against HIV-1. It targets the CD4 binding site on the HIV-1 envelope glycoprotein gp120, blocking the virus’s ability to attach to the CD4 receptor on host cells. The antibody was isolated from an HIV-1–infected donor and has been studied for its breadth of neutralization across diverse HIV-1 strains, including many primary isolates.

Mechanistically, 3BNC117 neutralizes virus by binding to a conserved region of gp120 critical for receptor engagement, thereby preventing viral entry. Its breadth and potency have made it a leading candidate in passive immunization strategies. Like other bnAbs, viral escape can occur, often through mutations in the targeted epitope, highlighting the rationale for combination strategies with other bnAbs or vaccines to broaden coverage.

Clinical development and findings have explored 3BNC117 as a potential therapeutic and preventive agent. In early human studies, it was generally well tolerated and capable of reducing plasma HIV-1 RNA levels in viremic individuals. In some trials, administration of 3BNC117 delayed viral rebound during analytical treatment interruption in a subset of participants. These results support continued investigation of 3BNC117 for HIV treatment, prevention, and as part of combination antibody regimens.

Future directions include developing longer-acting formulations, improving breadth through antibody engineering, and combining 3BNC117 with other bnAbs or therapeutic modalities to enhance efficacy and durability. While not approved as a stand-alone therapy, 3BNC117 remains a prominent tool in HIV-1 bnAb research.