HIV-1 envelope glycoprotein 120 CD4 binding site (HIV-1 gp120 CD4bs) (HIV-1 gp120 CD4bs)

The HIV-1 envelope glycoprotein 120 (gp120) CD4 binding site (CD4bs) is a highly conserved region on the viral surface protein that mediates the initial attachment of the virus to the host CD4 receptor on T lymphocytes (Saunders et al., 2019, Nature). As a critical component of the viral entry machinery, the CD4bs is a major target for vaccine design and therapeutic antibody development (Bonsignori et al., 2016, Cell). The CH505M5 outer-domain immunogen is an engineered protein derived from the CH505 HIV-1 strain, designed to present the CD4bs in a stable conformation that mimics the native viral spike (Liao et al., 2013, Nature). This specific immunogen is used in germline-targeting vaccine strategies to prime the immune system to produce broadly neutralizing antibodies (bNAbs), such as the VRC01-class or CH103-class antibodies (Zhou et al., 2010, Science). By focusing the immune response on this conserved epitope, researchers aim to overcome the high mutational diversity of HIV-1 and provide broad protection against various viral strains. Drugs and biologics targeting this site, including monoclonal antibodies like 3BNC117 and VRC01, work by sterically blocking the CD4-gp120 interaction, thereby neutralizing the virus and preventing cellular infection.

Other names

CD4 binding siteCD4bsgp120 CD4bsCH505M5 outer domainCH505M5 ODHIV-1 Env gp120 CD4bs

Neutralization of HIV-1 by blocking the interaction between the viral gp120 protein and the host CD4 receptor, preventing viral entry into target cells.