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

The Human immunodeficiency virus 1 (HIV-1) envelope glycoprotein gp120 V3 glycan epitope, frequently referred to as the N332 glycan supersite, is a prominent region of vulnerability on the viral surface [5, 7]. This epitope is defined by the base of the third variable loop (V3) and a cluster of conserved N-linked glycans, most notably the high-mannose glycan at position N332 [2, 6]. Biologically, this site is critical for viral infectivity as it facilitates the interaction between the gp120 subunit and host co-receptors, such as CCR5 or CXCR4, which is essential for membrane fusion and entry into CD4+ T cells [7, 17]. Because of its relative conservation and accessibility, it has become a primary target for the development of broadly neutralizing antibodies (bNAbs) and vaccine immunogens [6, 11]. Therapeutic agents targeting this epitope, including monoclonal antibodies such as PGT121 and 10-1074, work by binding the glycan-peptide complex to neutralize the virus and prevent infection [3, 8]. These bNAbs have demonstrated the ability to suppress viremia and protect against viral challenge in clinical and preclinical models [5, 13]. However, the high genetic diversity of HIV-1 leads to significant glycan heterogeneity and the potential for rapid emergence of escape mutants that lack the target glycans or possess altered protein sequences, which remains a major challenge for long-term therapeutic efficacy [9, 14].

Other names

N332 glycan supersiteHigh-mannose patchV3-base glycan epitopegp120 V3-glycan epitopeV3-glycan supersite

Neutralization of HIV-1 virions by binding to the V3-glycan complex, which blocks co-receptor (CCR5 or CXCR4) engagement and inhibits viral entry into host CD4+ T cells [7, 8]. Some antibodies in this class also allosterically modulate CD4 binding [4].