B-cell receptor (BCR) specific for Vi polysaccharide (Vi-BCR)

The B-cell receptor (BCR) specific for Vi polysaccharide epitopes is a specialized membrane-bound immunoglobulin on B lymphocytes that recognizes the Vi capsular polysaccharide of Salmonella enterica serovar Typhi (PubMed: 28254443). This receptor plays a critical role in the host's adaptive immune response by identifying the pathogen's protective capsule, which is a major virulence factor. Upon binding to Vi epitopes, the BCR initiates intracellular signaling cascades that drive the differentiation of B cells into antibody-secreting plasma cells and memory B cells (PubMed: 29158497). In vaccinology, this receptor is the primary target for Vi-based vaccines, including plain polysaccharide and conjugate formulations (PubMed: 30245167). While plain polysaccharide vaccines stimulate these BCRs in a T-cell independent manner, conjugate vaccines facilitate T-cell help, leading to superior immunogenicity and long-term protection (WHO Position Paper on Typhoid Vaccines, 2018). Understanding the interaction between the Vi antigen and its specific BCR is fundamental to the development of effective strategies against typhoid fever (PubMed: 25444812).

Other names

Vi-antigen-specific B-cell receptorVi-capsular-polysaccharide-specific BCRSalmonella Typhi Vi-specific BCRVi-specific immunoglobulin receptor

The Vi polysaccharide antigen binds to and cross-links specific B-cell receptors, initiating intracellular signaling pathways (such as Lyn/Syk and PLCγ2) that lead to B-cell activation, clonal expansion, and the secretion of anti-Vi antibodies that neutralize Salmonella Typhi.