Shigella lipopolysaccharide antigen (Shigella LPS)

Shigella lipopolysaccharide (LPS) antigens are essential structural components located on the outer membrane of Shigella bacteria, the primary cause of bacillary dysentery (Morona et al., 2003). The LPS molecule consists of three distinct regions: the membrane-anchored Lipid A, a core oligosaccharide, and the highly variable O-specific polysaccharide, or O-antigen (Raetz & Whitfield, 2002). The O-antigen is the dominant surface feature recognized by the human immune system and determines the serotype specificity of the organism (Phalipon et al., 2008). In the context of infection, LPS contributes to bacterial fitness and protection against host complement-mediated killing while inducing a robust inflammatory response (Mattock & Blocker, 2017). As a therapeutic target, the O-antigen is the primary focus for vaccine candidates, such as Flexyn2a and SF2a-TT15, which aim to elicit protective IgG and IgA antibodies (Cohen et al., 2022). Because immunity is largely serotype-specific, pharmaceutical development focuses on multivalent formulations to provide broad protection against prevalent strains like S. flexneri and S. sonnei (Mani et al., 2016).

Other names

Shigella O-antigenShigella O-polysaccharideShigella somatic antigenShigella endotoxin

Vaccines targeting Shigella lipopolysaccharide antigens work by inducing the production of serotype-specific antibodies, primarily IgG and secretory IgA, which bind to the O-antigen to neutralize the bacteria and facilitate opsonophagocytosis (Cohen et al., 2022). Monoclonal antibodies targeting these antigens provide passive immunity by directly binding to the bacterial surface, preventing epithelial cell invasion and promoting clearance by immune cells (Phalipon et al., 2008).