O-specific polysaccharide of Vibrio cholerae O1 (O-SP)

The O-specific polysaccharide (O-SP) of Vibrio cholerae O1 is the distal carbohydrate polymer of the O-antigen domain of V. cholerae lipopolysaccharide (LPS), covalently linked to the core oligosaccharide and lipid A in the bacterial outer membrane. In O1 strains, O-SP consists of a homopolymer of α-(1→2)-linked 4-amino-4,6-dideoxy-D-mannopyranose (perosamine) residues, in which the amino group is acylated with 3-deoxy-L-glycero-tetronic acid. The O-SP's terminal perosamine may be methylated (Ogawa serotype) or unmethylated (Inaba serotype), producing specific B-cell epitopes. O-SP is key for defining serogroup O1 and for classification into Ogawa and Inaba serotypes. This polysaccharide is the dominant target for vibriocidal antibodies and is the principal antigen in cholera immunity acquired after infection or vaccination. O-SP, while not a classical therapeutic target like an enzyme or receptor, is a critical vaccine antigen, and manipulation of its structure (e.g., via vaccine design) is a leading strategy for cholera prevention.

Other names

O-antigen of Vibrio cholerae O1O1 O-antigen polysaccharideO-specific antigen of Vibrio cholerae O1O-SP of V. cholerae O1O1 O-SP

Induction of protective humoral immune response, especially vibriocidal antibodies targeting O-SP on bacterial surface, leading to bacterial clearance by the immune system