Vibrio cholerae O1 lipopolysaccharide O-specific polysaccharide (OSP)

The Vibrio cholerae O1 lipopolysaccharide O-specific polysaccharide (OSP) is the primary immunodominant surface antigen of the Gram-negative bacterium responsible for epidemic cholera (Xu et al., 2011, PubMed). It consists of a homopolymer of α(1→2)-linked 4-amino-4,6-dideoxy-D-mannose (D-perosamine) residues, which are acylated with 3-deoxy-L-glycero-tetronic acid (Meeks et al., 2020, NIH). This molecule is a critical component of the bacterial outer membrane, providing structural integrity and acting as a shield against host complement-mediated killing and environmental stressors. In the context of therapeutics, OSP is the central target for all WHO-prequalified oral cholera vaccines (OCVs), which aim to elicit high titers of vibriocidal antibodies and mucosal IgA to prevent intestinal colonization (Wierzba et al., 2015, PubMed). The chemical structure of the OSP determines the serotype of the V. cholerae O1 strain, specifically the Ogawa and Inaba serotypes, which differ by the presence or absence of a single methyl group on the terminal sugar residue (Villeneuve et al., 1999, PubMed). Because immunity to cholera is largely serogroup-specific, the OSP is also the primary focus for rapid diagnostic tests and epidemiological surveillance during outbreaks.

Other names

O-antigenO-specific polysaccharideV. cholerae O1 OSPO-side chainVibrio cholerae O1 LPS

Induction of protective mucosal IgA and serum vibriocidal antibodies that inhibit bacterial motility and attachment to the intestinal epithelium.