B-cell receptor specific for Salmonella Typhi Vi capsular polysaccharide (Vi-BCR)

The B-cell receptor specific for Salmonella Typhi Vi capsular polysaccharide is a membrane-bound immunoglobulin complex located on the surface of B lymphocytes that recognizes the Vi (Virulence) capsular antigen of Salmonella enterica serovar Typhi [1]. This receptor is central to the development of protective immunity against typhoid fever, as its engagement by the Vi antigen triggers B-cell activation, proliferation, and differentiation into plasma cells that secrete anti-Vi antibodies [2]. The Vi antigen itself is a linear homopolymer of alpha-1,4-linked N-acetylgalactosaminuronic acid, which acts as a major virulence factor by masking other surface antigens from the host immune system [3]. Vaccines such as the Vi capsular polysaccharide vaccine (ViCPS) and the Typhoid conjugate vaccine (TCV) are designed to target these specific receptors to elicit a robust immune response [1]. While ViCPS induces a T-cell independent response with limited memory, TCVs link the Vi antigen to a carrier protein, which facilitates T-cell help, leading to higher affinity B-cell receptors and long-lasting immunological memory [4]. Monitoring the efficacy of these interventions often involves measuring serum anti-Vi IgG levels as a correlate of protection [2]. References: [1] World Health Organization (2018). Typhoid vaccines: WHO position paper. [2] Voysey, M., et al. (2018). Clinical Infectious Diseases. [3] Jin, C., et al. (2017). Frontiers in Immunology. [4] Pollard, A. J., et al. (2019). The Lancet.

Other names

Vi-specific B-cell receptorSalmonella Typhi Vi antigen receptorVi-polysaccharide-specific BCR

Binding of the Vi capsular polysaccharide antigen to the B-cell receptor induces signal transduction that leads to B-lymphocyte activation, clonal expansion, and the production of protective anti-Vi antibodies [1][2].