HIV-1 Envelope-specific B-cell receptor (non-V3-glycan epitopes) (HIV Env BCR)

This target refers to the population of B-cell receptors (BCRs) on the surface of B lymphocytes that specifically recognize epitopes on the HIV-1 Envelope (Env) protein other than the V3-glycan patch, such as the CD4 binding site (CD4bs), the V1/V2 apex, or the membrane-proximal external region (MPER) (Jardine et al., 2013, Science). In the context of modern HIV vaccine design, these BCRs are the primary targets of germline-targeting immunogens, which are engineered to bind and activate rare precursor B cells capable of evolving into broadly neutralizing antibodies (bNAbs) (Schief et al., 2023, Science). These immunogens are often presented on multivalent nanoparticle scaffolds, such as ferritin or lumazine synthase, to enhance B-cell signaling and mimic the repetitive structure of viral surfaces (Leggat et al., 2022, Nature Immunology). The clinical objective of targeting these receptors is to overcome the high genetic diversity of HIV-1 by eliciting antibodies that target conserved regions of the viral spike. Research into these BCRs often involves monitoring the immune response not only to the intended Env epitope but also to the protein scaffold itself, as anti-scaffold responses can compete with the desired anti-HIV response (IAVI G001 Trial, NCT03547245). Understanding the interaction between these receptors and engineered immunogens is critical for the iterative design of sequential vaccination strategies aimed at preventing HIV-1 infection.

Other names

Non-V3-glycan Env-specific BCRsCD4 binding site B-cell receptorsMPER-specific B-cell receptorsApex-specific B-cell receptorsHIV-1 Env-reactive B-cell receptorsAnti-scaffold B-cell receptors

Vaccine-mediated engagement of specific germline B-cell receptors to trigger clonal expansion and initiate the somatic hypermutation process required for the development of broadly neutralizing antibodies (bNAbs).