Human immunodeficiency virus type 1 envelope glycoprotein gp120 V1V2 apex (HIV-1 gp120 V1V2 apex)

The V1V2 apex of the HIV-1 gp120 envelope glycoprotein is a critical structural component located at the distal tip of the viral spike [1, 4]. It consists of the first and second variable loops (V1 and V2) and is characterized by a dense glycan shield, particularly the conserved N-linked glycan at position N160 [4, 6]. This region plays a dual role: it stabilizes the trimeric envelope complex in a closed, prefusion state to shield conserved epitopes from the immune system, and it undergoes significant conformational changes upon receptor binding to facilitate viral entry [1, 2]. As one of the few conserved sites of vulnerability on the otherwise highly variable envelope, the V2 apex is a primary target for broadly neutralizing antibodies (bNAbs) such as PG9, PG16, and PGT145 [4, 7]. These antibodies typically possess long, anionic loops that penetrate the glycan shield to contact the underlying protein backbone [6, 11]. Therapeutic strategies focusing on this region include the development of passive antibody therapies and rationally designed immunogens for vaccines aimed at eliciting similar broad-spectrum protection [9, 15].

Other names

V2 apexV1V2 glycan regionV1V2 domainV1V2 loopV2-apex epitopeV1V2 glycan shield

Neutralization of viral entry by stabilizing the prefusion trimer conformation and blocking the structural rearrangements required for CD4 and coreceptor binding.