Human immunodeficiency virus type 1 envelope glycoprotein gp120 V3 glycan loop epitope (V3 glycan supersite)

The HIV-1 Env gp120 V3 glycan loop epitope, commonly known as the V3 glycan supersite, is a critical region of vulnerability on the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 [1, 12]. This epitope is centered around the base of the third variable (V3) loop and is defined by a cluster of high-mannose N-linked glycans, particularly the highly conserved glycan at asparagine 332 (N332) [1, 4]. Biologically, the V3 loop is essential for viral entry as it mediates the interaction with host cell coreceptors, CCR5 or CXCR4, following CD4 binding [7, 16]. The V3 glycan supersite is a primary target for potent broadly neutralizing antibodies (bNAbs) such as 10-1074 and PGT121, which are being investigated for both HIV-1 prevention and treatment [5, 10]. These antibodies neutralize the virus by physically blocking coreceptor engagement or inducing allosteric changes that prevent membrane fusion [1, 8]. However, the therapeutic utility of targeting this site is challenged by the virus's ability to rapidly evolve escape mutants that shift or remove key glycosylation sites, necessitating the use of combination antibody regimens [8, 16].

Other names

V3 glycan patchN332 glycan supersiteHigh-mannose patchV3/N332-glycan epitopeN332-supersite

Broadly neutralizing antibodies (bNAbs) target this epitope to inhibit viral entry by blocking the interaction between the gp120 V3 loop and host coreceptors (CCR5 or CXCR4) or by allosterically interfering with CD4 binding. Additionally, these antibodies can mediate the clearance of infected cells through Fc-mediated effector functions such as antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP).