Human B-cell receptor recognizing Streptococcus pneumoniae type 2 capsular polysaccharide (BCR-Spn2-CPS)

The Human B-cell receptor (BCR) or antibody paratope specific for Streptococcus pneumoniae type 2 capsular polysaccharide (CPS) is a specialized immune recognition site essential for defending against pneumococcal disease. These paratopes are formed by the variable regions of immunoglobulin heavy and light chains, often utilizing specific germline genes such as the VH3 family to recognize the complex branched hexasaccharide structure of the Serotype 2 capsule. Upon binding to the CPS on the bacterial surface, these receptors trigger B-cell differentiation into plasma cells or, as secreted antibodies, promote the clearance of the pathogen via opsonophagocytosis. Streptococcus pneumoniae serotype 2 is a highly virulent strain historically associated with invasive disease, and its capsule is a primary target for vaccine-induced immunity. The induction of these specific BCRs is a key therapeutic goal of polyvalent vaccines like PPSV23 and the newer PCV20 conjugate vaccine. Understanding the structural interaction between these human paratopes and the ST2 polysaccharide is critical for the design of next-generation glycoconjugate vaccines and potential passive immunotherapy agents (Source: PubMed: 11544133, 33536233).

Other names

Anti-pneumococcal serotype 2 antibodyAnti-PPS2 antibodyStreptococcus pneumoniae serotype 2-specific B-cell receptorHuman anti-S. pneumoniae type 2 paratopePneumococcal polysaccharide type 2-binding receptor

The paratope of the B-cell receptor or secreted antibody binds specifically to the hexasaccharide repeating units of the Streptococcus pneumoniae type 2 capsular polysaccharide. This binding neutralizes the anti-phagocytic effect of the capsule and facilitates opsonophagocytosis by host immune cells, such as neutrophils and macrophages, through Fc receptor-mediated signaling and complement deposition (Source: PubMed: 15105288, 34103410).