Haemophilus influenzae serotype a capsular polysaccharide-specific B-cell receptor (Hia CPS-specific BCR)

The Haemophilus influenzae serotype a capsular polysaccharide-specific B-cell receptor (Hia CPS-specific BCR) is a specialized membrane-bound immunoglobulin on the surface of B lymphocytes that mediates the adaptive immune response against Hia. Haemophilus influenzae serotype a is an encapsulated Gram-negative bacterium that has emerged as a significant cause of invasive diseases, including meningitis, pneumonia, and sepsis, particularly in Indigenous populations in North America following the success of the serotype b (Hib) vaccine. The Hia capsule, composed of a repeating unit of [→4)-β-D-Glcp-(1→4)-D-ribitol-5-P-(→], is a critical virulence factor that protects the pathogen from host innate immune mechanisms like opsonophagocytosis. Therapeutic strategies, primarily conjugate vaccines, target these BCRs to induce a protective humoral immune response. By binding to and cross-linking these specific receptors, vaccines stimulate B-cell activation, clonal expansion, and the production of high-affinity IgG antibodies that facilitate bacterial clearance through complement-mediated lysis and phagocytosis.

Other names

Hia capsular polysaccharide-specific B-cell receptorHia-specific B-cell receptorHaemophilus influenzae type a capsular polysaccharide-specific BCRHia CPS-specific B-cell receptor

Vaccines containing the Hia capsular polysaccharide act as antigens that bind to and cross-link specific B-cell receptors (BCRs) on the surface of B lymphocytes. This binding initiates intracellular signaling pathways that lead to B-cell activation, proliferation, and differentiation into memory B cells and plasma cells. The resulting plasma cells secrete high-affinity antibodies (primarily IgG) that opsonize the Hia bacteria, facilitating their destruction via complement-mediated lysis and phagocytosis.