Shigella flexneri 2a antigen (S. flexneri 2a antigen)

Shigella flexneri 2a antigens, primarily the O-specific polysaccharide (O-antigen) of the lipopolysaccharide (LPS), are the key components used in the development of vaccines against shigellosis (Cohen et al., 2022). Shigellosis is a severe enteric infection caused by Shigella species, with S. flexneri 2a being one of the most prevalent serotypes in endemic regions (Mani et al., 2016). These antigens are not host molecular targets but are exogenous immunogens designed to elicit a robust immune response. Vaccines targeting these antigens, such as bioconjugates or live-attenuated strains, work by inducing the production of specific antibodies that neutralize the pathogen (Phalipon & Sansonetti, 2007). Specifically, these antibodies target the O-antigen to prevent the bacteria from adhering to and invading the intestinal epithelial cells. This prevents the inflammatory destruction of the colonic mucosa and the clinical symptoms of dysentery (WHO, 2023). Successful immunization provides serotype-specific protection, which is a critical strategy for reducing the global burden of diarrheal diseases. Current research focuses on improving the immunogenicity and breadth of protection of these antigen-based vaccines.

Other names

Shigella flexneri 2a O-antigenSF2a O-specific polysaccharideInvasion plasmid antigensIpa proteinsSF2a LPS

Induces active immunity by stimulating the production of protective serum IgG and mucosal secretory IgA antibodies against the S. flexneri 2a O-antigen, preventing bacterial attachment and invasion of the colonic epithelium.