Human B-cell receptor recognizing Streptococcus pneumoniae serotype 3 capsular polysaccharide (Anti-PPS3 BCR)

The Human B-cell receptor (BCR) recognizing Streptococcus pneumoniae serotype 3 (Sp3) capsular polysaccharide is a specialized immune receptor responsible for identifying one of the most virulent pneumococcal strains (Luck et al., 2020). Serotype 3 is distinguished by its thick, mucoid capsule composed of repeating cellobiuronic acid units, which allows the bacteria to evade phagocytosis (Kolarich et al., 2009). The paratopes of these BCRs, often encoded by specific immunoglobulin gene segments like VH3-15, provide the structural basis for high-affinity binding to the polysaccharide epitopes (Zhou et al., 2015). In a therapeutic context, these receptors are the primary targets for pneumococcal vaccines, such as PCV13 and PPSV23, which aim to stimulate the expansion of B-cell clones expressing these specific paratopes (Poolman et al., 2011). Activation of these BCRs leads to the secretion of opsonizing antibodies that mark the bacteria for destruction by the innate immune system (Sun et al., 2014). Understanding the molecular interaction between these paratopes and the Sp3 capsule is critical for overcoming the challenges of low immunogenicity and high disease burden associated with this specific serotype (Choi et al., 2016).

Other names

Anti-pneumococcal polysaccharide serotype 3 antibody paratopeAnti-PPS3 B-cell receptorVH3-15 anti-Sp3 BCRHuman anti-pneumococcal serotype 3 capsular polysaccharide antibody

Vaccine-derived polysaccharide antigens bind to the paratopes of these B-cell receptors, initiating signal transduction that leads to B-cell proliferation, isotype switching, and the generation of memory B cells and plasma cells secreting protective antibodies (Poolman et al., 2011).