Germline B cell receptors specific for HIV-1 Envelope CD4 binding site epitopes (VRC01-class glBCRs)

Germline B cell receptors (BCRs) specific for the HIV-1 Envelope (Env) CD4 binding site (CD4bs) are the naive, unmutated precursors of broadly neutralizing antibodies (bnAbs) such as VRC01 [1, 2]. These receptors are the primary targets of germline-targeting vaccine strategies, which aim to initiate the development of bnAbs in HIV-uninfected individuals [1, 3]. Because native HIV-1 Env has negligible affinity for these germline precursors, engineered immunogens like the eOD-GT8 60mer nanoparticle are designed to specifically bind and activate B cells expressing these receptors [2, 4]. Once activated, these B cells undergo somatic hypermutation and affinity maturation in germinal centers, a process that must be further guided by sequential booster immunogens to eventually produce mature, broad-spectrum neutralizing antibodies [1, 5]. This approach represents a paradigm shift in vaccinology, moving from traditional whole-antigen exposure to the precise manipulation of specific B cell lineages to overcome the extreme diversity of HIV-1 [3, 5]. Successful priming of these receptors has been demonstrated in human clinical trials (e.g., IAVI G001), marking a significant milestone in HIV vaccine development [1].

Other names

VRC01-class germline B cell receptorsVRC01-class precursorsglVRC01-class BCRsInferred germline (iGL) B cell receptorsCD4 binding site-specific germline B cell receptors

Germline-targeting immunogens bind to and activate rare naive B cells expressing specific germline BCRs, initiating somatic hypermutation and affinity maturation toward broadly neutralizing antibodies [1, 2].