Human immunodeficiency virus 1 envelope glycoprotein 120 V3 glycan-dependent epitope (HIV-1 gp120 V3 glycan epitope)

The HIV-1 Env gp120 V3 glycan-dependent epitope, frequently referred to as the N332-glycan supersite, is a critical antigenic region on the surface of the HIV-1 envelope spike. This epitope is defined by its reliance on a cluster of N-linked glycans, particularly at position N332, and the conserved base of the third variable (V3) loop of the gp120 subunit [Garces et al., 2015, Immunity]. Biologically, these glycans form part of a high-mannose patch that the virus uses to shield itself from host immune detection while maintaining the structural configuration necessary for binding to host co-receptors [Pejchal et al., 2011, Science]. In the context of disease, this site is a primary target for potent broadly neutralizing antibodies (bNAbs) that can prevent the infection of CD4+ T cells and are being investigated for both prevention and treatment of HIV-1 [Sok et al., 2016, Science Immunology]. Therapeutic agents such as PGT121 and 10-1074 bind with high affinity to this glycan-peptide motif, effectively neutralizing a wide range of viral variants by blocking viral entry [Caskey et al., 2017, Nature Medicine]. However, the clinical utility of targeting this epitope is challenged by the virus's ability to undergo rapid mutational escape, often through the loss or shifting of the N332 glycan site [Wagh et al., 2018, PLOS Pathogens].

Other names

N332-glycan supersiteV3-glycan epitopePGT121-like epitope10-1074-like epitopeHigh-mannose patch

Binding to the V3 glycan-dependent epitope sterically blocks the envelope glycoprotein's interaction with host cell receptors and prevents the conformational changes required for viral-cell membrane fusion, while also potentially mediating antibody-dependent cellular cytotoxicity (ADCC) against infected cells.