Shigella flexneri 2a surface antigens (S. flexneri 2a antigens)

Shigella flexneri 2a surface antigens, primarily the O-specific polysaccharide (O-antigen) component of the lipopolysaccharide (LPS), are critical determinants of bacterial virulence and serotype specificity (PubMed: 25667166). These antigens play a vital role in the pathogenesis of shigellosis by facilitating bacterial attachment to and invasion of the intestinal epithelium, while also providing protection against host innate immune responses such as complement-mediated killing (PubMed: 29158410). Because the O-antigen is highly immunogenic and accessible on the bacterial surface, it serves as the primary target for the development of conjugate vaccines and therapeutic monoclonal antibodies (PubMed: 30245136). Vaccines targeting these antigens, such as Flexyn2a and SF2a-TT, aim to elicit high titers of serum IgG and mucosal IgA antibodies that neutralize the pathogen and prevent infection (PubMed: 31445836). However, the high degree of structural diversity among Shigella serotypes necessitates the inclusion of multiple serotype-specific antigens in a broadly protective vaccine to overcome the lack of cross-reactivity (PubMed: 28838900).

Other names

Shigella flexneri 2a O-antigenShigella flexneri 2a lipopolysaccharideS. flexneri 2a LPSShigella flexneri 2a O-specific polysaccharideShigella flexneri 2a outer membrane antigens

Induction of protective humoral immunity (IgG and IgA) against the O-antigen to prevent bacterial colonization and invasion of the intestinal mucosa.