Vibrio cholerae O1 lipopolysaccharide antigen

The Vibrio cholerae O1 lipopolysaccharide antigen (O1 LPS antigen) is a surface carbohydrate structure and the primary serogroup-defining antigen of *V. cholerae* O1, the strain responsible for most cholera pandemics. The O1 LPS antigen comprises a homopolymer of perosamine residues as the O-specific polysaccharide (OSP) attached to the core oligosaccharide and lipid A of the bacterial outer membrane[2][4][5]. It determines O1 serogroup and serotype (Ogawa, Inaba, Hikojima) specificity, crucial for virulence, colonization, and immune recognition[4][7]. The O1 antigen is the main target for protective antibody responses after infection and vaccination, providing the rationale for current vaccine strategies[5][6]. It is also targeted by bacteriophages and subject to phase variation and serotype switching, allowing immune evasion and adaptation within hosts or epidemics[1][7]. Although not a classical drug target for small molecules, it is under active investigation for vaccine development and as a biomarker for immune protection or exposure[6]. Key features: - **Structural class:** O-specific polysaccharide component of LPS, attached to outer membrane lipid A[2][3][4]. - **Virulence:** Essential for host colonization, infectiousness, and protection against bacteriophage predation[1][4]. - **Vaccine target:** Main antigen in current and in-development cholera vaccines[5][6]. - **Serotype specificity:** Variation in O1 antigen determines serotype (Ogawa, Inaba, Hikojima), based on methylation status of terminal perosamine[4][5][7]. - **Immunogenicity:** Induces robust IgG, IgM, and IgA responses, closely correlating with vibriocidal antibody titers, serving as correlates of protection[6]. - **Antigenic variation:** Phase variable genes (e.g., manA, wbeL, rfbT) control biosynthesis and enable intra-strain O1 expression diversity, affecting vaccine efficacy and immune escape potential[1][4][7].

Other names

Vibrio cholerae O1 LPS antigenV. cholerae O1 O-antigenV. cholerae O1 O-specific polysaccharideV. cholerae O1 OSP

Antibody neutralization; Bacteriophage lysis