Salmonella enterica serovar Typhimurium O:4 O-antigen polysaccharide (S. Typhimurium O:4 O-Ag)

The Salmonella enterica serovar Typhimurium O:4 O-antigen polysaccharide is a critical component of the bacterial outer membrane's lipopolysaccharide (LPS) and serves as a primary immunodominant surface antigen (Source: 1.1.3, 1.1.4). It consists of a repeating tetrasaccharide unit with a backbone of mannose, rhamnose, and galactose, where the presence of the dideoxyhexose sugar abequose linked to mannose confers the O:4 serogroup specificity (Source: 1.1.3, 1.2.3). This polysaccharide plays a vital role in bacterial pathogenesis by providing resistance to the bactericidal effects of host serum and shielding other surface structures, such as flagella and the type III secretion system, from immune recognition (Source: 1.2.1, 1.2.2). S. Typhimurium is a leading cause of foodborne gastroenteritis and life-threatening invasive nontyphoidal salmonellosis (iNTS), particularly in children and immunocompromised individuals in sub-Saharan Africa (Source: 1.2.4, 1.4.2). Due to its high immunogenicity, the O:4 O-antigen is a major target for the development of glycoconjugate and GMMA-based vaccines designed to elicit protective antibody responses (Source: 1.3.2, 1.3.4). These therapeutic strategies aim to induce high-titer IgG antibodies that promote bacterial clearance through opsonization and complement-mediated killing (Source: 1.3.1, 1.3.3).

Other names

O4 antigenGroup B O-antigenSalmonella Typhimurium O-polysaccharideS. Typhimurium LPS O-antigenO-antigen side chain of lipopolysaccharide

Induction of protective humoral immunity, specifically O-antigen-specific IgG and IgM antibodies that facilitate complement-mediated bactericidal activity and opsonophagocytosis.