O-specific lipopolysaccharide of Salmonella enterica serovar Paratyphi A (O-LPS)

The O-specific lipopolysaccharide (O-LPS) of Salmonella enterica serovar Paratyphi A is a primary surface antigen and a critical virulence factor for the bacterium [1, 3]. It consists of a lipid A anchor, a core oligosaccharide, and a distal O-antigen polysaccharide chain characterized by the O:2 serogroup specificity, which includes the unique sugar paratose [3, 13]. This molecule plays a vital role in protecting the bacterium from host immune responses, such as complement-mediated killing, and contributes to the pathogenesis of paratyphoid fever [4, 13]. As a major target for vaccine development, the O-specific polysaccharide (OSP) is often conjugated to carrier proteins like CRM197 or tetanus toxoid to enhance immunogenicity, particularly in children [3, 11]. These conjugate vaccines aim to elicit high titers of protective antibodies that facilitate the clearance of the pathogen through bactericidal and opsonophagocytic activities [5, 15]. Understanding the structure and immunological properties of the Paratyphi A O-LPS is essential for addressing the global burden of enteric fever, especially in regions where antibiotic resistance is rising [9, 11].

Other names

O-antigenO-polysaccharideParatyphi A O-antigenO:2 antigenO-specific polysaccharideOSP

Induction of O-antigen-specific bactericidal and opsonophagocytic antibodies that provide protective immunity against Salmonella Paratyphi A infection.