Vibrio cholerae O1 O-specific polysaccharide and O139 capsular polysaccharide (OSP/CPS)

Vibrio cholerae O1 O-specific polysaccharide (OSP) and O139 capsular polysaccharide (CPS) are the primary surface antigens and protective targets of the bacterium responsible for epidemic cholera. The O1 serogroup, which includes Ogawa and Inaba serotypes, possesses an OSP composed of a perosamine homopolymer, while the O139 serogroup features a unique hexasaccharide CPS that is structurally identical to its O-antigen. These polysaccharides are critical for bacterial virulence, providing resistance to serum killing and facilitating intestinal colonization by the pathogen. In the context of therapeutics, they serve as the essential components of oral cholera vaccines (OCVs), which induce mucosal IgA and serum vibriocidal antibodies. These antibodies mediate protection by agglutinating bacteria, inhibiting motility, and triggering complement-mediated lysis. Modern vaccine development focuses on OSP-protein conjugates to enhance immunogenicity and provide long-lasting memory, particularly against the O139 serogroup which has shown lower immunogenicity in some whole-cell formulations.

Other names

Vibrio cholerae O-antigenCholera O-specific polysaccharideV. cholerae O1 OSPV. cholerae O139 CPSO1/O139 surface polysaccharidesVibrio cholerae OSP epitopes

Induction of vibriocidal antibodies (IgM, IgG) and mucosal IgA that bind to OSP/CPS epitopes on the bacterial surface, leading to complement-mediated bacteriolysis, bacterial agglutination, and inhibition of motility to prevent intestinal colonization.