V3 glycan region of HIV-1 envelope glycoprotein gp120 (V3 glycan region (no widely used canonical abbreviation beyond "V3 glycan" or "V3-glycan" in immunology literature))

The **V3 glycan region of the HIV-1 envelope glycoprotein gp120** is a conserved, heavily glycosylated structural domain within the variable V3 loop of gp120, a component of the HIV-1 envelope protein complex (Env)[3][6]. The V3 loop is a critical determinant of HIV-1 infectivity and mediates binding to the coreceptor molecules (CCR5 or CXCR4) following initial CD4 receptor engagement[3][6]. The region is structurally notable for its essential N-linked glycan at asparagine 332 (N332), which forms part of a glycan epitope recognized by several classes of broadly neutralizing antibodies (bnAbs), including PGT121/128 and similar mAbs[7][9]. These antibodies can prevent infection by blocking conformational changes required for viral entry into host cells. The glycan shield formed by this and proximal glycans also aids HIV-1 in evading the host immune system[2][4][8]. Despite its variability, structural studies have shown the V3 glycan region’s importance as a target for antibody-mediated neutralization and vaccine design, as well as its frequent mutation and adaptation to escape immune pressure[7][9][3][1].

Other names

V3 loop glycan of HIV-1 Env gp120V3-glycan epitopeN332-glycan epitope (referring to the key glycosylation site)V3 glycan patch

Direct neutralization of HIV-1 by blocking Env-mediated host cell entry (antibody-mediated) Antibody recognition of glycan-dependent epitopes, chiefly involving the N332 glycosylation site and adjacent regions of V3