Salmonella enterica serovar Enteritidis core-O-polysaccharide (SE COPS)

Salmonella enterica serovar Enteritidis core-O-polysaccharide (COPS) is a complex carbohydrate structure located on the outer membrane of the bacterium, representing the combined core oligosaccharide and the O-specific polysaccharide (O-antigen) chain of the lipopolysaccharide (LPS) molecule (Simon et al., 2011). The O-antigen portion consists of repeating units of mannose, rhamnose, and galactose, with a characteristic tyvelose side chain that defines the O9 serogroup specificity (Liu et al., 2014). Biologically, COPS is essential for maintaining the structural integrity of the bacterial outer membrane and serves as a primary defense mechanism against host innate immunity, particularly the complement system (MacLennan et al., 2014). In the field of vaccinology, COPS is a major therapeutic target for preventing invasive non-typhoidal Salmonella (iNTS) infections and foodborne gastroenteritis (Micoli et al., 2018). It is typically developed as a glycoconjugate vaccine, where the COPS is chemically linked to a carrier protein like CRM197 or tetanus toxoid to induce a robust, T-cell dependent antibody response (Tennant et al., 2016). These antibodies facilitate the clearance of the pathogen through opsonophagocytosis and serum bactericidal activity.

Other names

Salmonella Enteritidis O-antigenGroup D1 O-antigenSalmonella Enteritidis LPS O-side chainO9 antigenSE COPS

Induction of protective humoral immunity, specifically opsonophagocytic and bactericidal antibodies against the O-antigen