Human immunodeficiency virus 1 envelope glycoprotein 120 V3 loop N332 glycan-dependent epitope (gp120 V3 N332 epitope)

The HIV-1 envelope glycoprotein 120 (gp120) V3 loop N332 glycan-dependent epitope, commonly known as the N332 supersite, is a critical region of vulnerability on the surface of the HIV-1 virus (Sok et al., 2016). This epitope is centered around a highly conserved N-linked glycan at position N332, located at the base of the third variable (V3) loop of the gp120 subunit (Walker et al., 2011). It is a primary target for several potent broadly neutralizing antibodies (bNAbs), such as PGT121 and 10-1074, which are capable of recognizing both the carbohydrate shield and the underlying protein structure (Caskey et al., 2017). In the viral life cycle, this region is involved in the attachment and entry process into host CD4+ T cells, though its primary role in the glycan shield is to protect the virus from immune detection. Therapeutic interventions targeting this site, particularly through passive immunization with bNAbs, have demonstrated the ability to significantly reduce viral loads and provide protection against infection in clinical settings (Stephenson et al., 2021). However, the high mutation rate of HIV-1 can lead to the loss or shifting of the N332 glycan, resulting in viral escape and therapeutic resistance (Wagh et al., 2018). Consequently, this epitope remains a central focus for both the development of long-acting antibody therapies and the design of immunogens for a preventative HIV vaccine (Sanders & Moore, 2017).

Other names

N332 glycan supersiteV3-glycan epitopePGT121-binding site10-1074-binding sitegp120 V3-base glycan epitopeHIV-1 Env N332 supersite

Broadly neutralizing antibodies (bNAbs) target this epitope by binding to the N332 glycan and the surrounding V3 loop peptide, which sterically blocks the envelope trimer from interacting with the CD4 receptor or CCR5/CXCR4 co-receptors, thereby preventing viral entry into host cells (Walker et al., 2011; Sok et al., 2016).