Salmonella Paratyphi A lipopolysaccharide O:2 antigen (O:2 antigen)

Salmonella Paratyphi A lipopolysaccharide O:2 antigen is a key surface-exposed polysaccharide found on the outer membrane of Salmonella enterica serovar Paratyphi A [Bio-Rad, FEMS Microbiology Reviews]. This bacterium is a major cause of paratyphoid fever, a systemic febrile illness similar to typhoid fever that is prevalent in South and Southeast Asia [Vaccines for AMR, NIH]. The O:2 antigen is a part of the lipopolysaccharide (LPS) molecule and is distinguished by the presence of paratose, a 3,6-dideoxyhexose sugar that defines the O2 serogroup [Coalition Against Typhoid, FEMS Microbiology Reviews]. It plays a vital role in bacterial pathogenesis by contributing to serum resistance and protecting the organism from the host's innate immune system [Bio-Rad, NIH]. As a highly immunogenic component, it is the primary target for the development of paratyphoid conjugate vaccines [Vaccines for AMR, NIH]. These vaccines aim to induce high titers of anti-O:2 IgG antibodies, which provide protection through complement-mediated bactericidal activity and opsonophagocytosis [NIH]. Currently, several bivalent vaccines combining this antigen with the S. Typhi Vi antigen are in clinical development to provide broad protection against enteric fever [NIH].

Other names

Salmonella Paratyphi A O-antigenO2 antigenParatyphi A O-specific polysaccharideO-SPSalmonella enterica serovar Paratyphi A LPSGroup A O-antigen

Induction of protective serum IgG antibodies that provide bactericidal activity and facilitate opsonophagocytosis of Salmonella Paratyphi A [NIH, Vaccines for AMR].