Shigella dysenteriae type 1 O-antigen lipopolysaccharide (SD1 O-LPS)

Shigella dysenteriae type 1 O-antigen lipopolysaccharide is a primary surface component and virulence factor of the Gram-negative bacterium responsible for epidemic bacillary dysentery. The O-antigen consists of a repeating tetrasaccharide unit [→3)-alpha-L-Rha p-(1→3)-alpha-L-Rha p-(1→2)-alpha-D-Gal p-(1→3)-alpha-D-GlcNAc p-(1→] which is essential for the bacterium's ability to survive the host's gastrointestinal environment and evade the innate immune system (PubMed: 25631135, NIH: PMC4324225). As a major target for protective immunity, it is the focus of numerous glycoconjugate vaccine strategies designed to elicit long-lasting bactericidal antibody responses (PubMed: 10417353). Beyond its role as an immunogen, the Lipid A moiety of the LPS molecule acts as a potent endotoxin, contributing to the severe inflammatory response and systemic complications associated with Shiga bacillus infections (StatPearls: NBK482338). Therapeutic interventions often involve targeting this structure either through neutralization by antibodies or disruption of the membrane by cationic antimicrobial peptides.

Other names

Shigella dysenteriae serotype 1 O-specific polysaccharideShigella dysenteriae type 1 O-antigenS. dysenteriae type 1 LPSShiga bacillus O-antigen

Vaccines targeting this antigen induce O-antigen-specific serum IgG antibodies that provide protective immunity by facilitating bacterial opsonization and complement-mediated killing. Antibiotics like polymyxins bind to the Lipid A component of the lipopolysaccharide to disrupt the bacterial outer membrane.