Human immunodeficiency virus type 1 envelope glycoprotein gp120 V3 glycan base region (HIV-1 gp120 V3 glycan base)

The HIV-1 Env gp120 V3 glycan base region, frequently termed the V3-glycan supersite, represents a critical target for broadly neutralizing antibodies (bNAbs) on the surface of the HIV-1 envelope glycoprotein (Julien et al., 2013). This site is located at the base of the third variable (V3) loop of the gp120 subunit and is characterized by a dense cluster of N-linked glycans, with the glycan at asparagine 332 (N332) serving as a central anchor for antibody recognition (Walker et al., 2011). Biologically, this region is essential for the structural stability of the envelope trimer and plays a role in the conformational transitions required for viral entry into host cells. Therapeutic agents targeting this region, such as the monoclonal antibodies PGT121 and 10-1074, work by binding to these conserved glycans and the underlying protein surface, thereby sterically blocking the virus from infecting CD4+ T cells (Sok et al., 2014). Clinical development of these bNAbs has shown promise in reducing viral loads in infected individuals and providing protection in animal models. However, the high genetic variability of HIV-1 allows the virus to escape neutralization by shifting or deleting glycosylation sites, which poses a significant challenge for long-term efficacy (Garces et al., 2015). Consequently, this region is a primary focus for structure-based vaccine design, aiming to elicit antibodies that can overcome such viral diversity.

Other names

V3-glycan supersiteN332-glycan supersitegp120 V3 baseV3-loop base region

Broadly neutralizing antibodies bind to the conserved N332 glycan and the surrounding protein surface at the base of the V3 loop, sterically hindering the envelope trimer's ability to undergo conformational changes required for CD4 binding and coreceptor engagement, thereby preventing viral fusion and entry (Sok et al., 2014; Garces et al., 2015).