Salmonella enterica serovar Paratyphi A O-antigen (O:2) (O:2 LPS)

The Salmonella enterica serovar Paratyphi A O-antigen (O:2) is a surface-exposed polysaccharide component of the lipopolysaccharide (LPS) layer, serving as a primary target for the host immune system (Micoli et al., 2012, PLoS ONE). It is characterized by a repeating oligosaccharide structure containing paratose, which defines the O:2 serogroup specificity (Martin et al., 2016, Vaccine). This antigen is essential for the virulence of Paratyphi A, providing a shield against complement-mediated killing and facilitating environmental survival (Cohen et al., 2014, J Travel Med). In the context of therapeutic development, B-cell receptors (BCRs) and antibodies specific for the O:2 antigen are the primary mediators of protective immunity, making the O:2 LPS a central target for conjugate vaccines (Sahastrabuddhe et al., 2013, Vaccine). Vaccines such as O:2-CRM197 aim to elicit high titers of these specific antibodies to promote opsonophagocytosis and bactericidal activity against the pathogen (Micoli et al., 2012). Furthermore, monoclonal antibodies targeting the O:2 epitope are being investigated for their potential in passive immunization and as diagnostic tools for enteric fever (Wahid et al., 2012, Clin Vaccine Immunol). The interaction between the O:2 antigen and specific B-cell receptors is a critical determinant of vaccine efficacy and the natural history of Paratyphi A infection. Successful targeting of this molecule requires the detoxification of the lipid A component of LPS to prevent systemic inflammatory responses while maintaining the immunogenicity of the O-specific polysaccharide.

Other names

O:2 antigenParatyphi A O-antigenSalmonella Paratyphi A lipopolysaccharideO-specific polysaccharide 2Factor 2 antigen

Induction of protective humoral immunity (antibodies) that facilitate opsonophagocytosis and complement-mediated killing of Salmonella Paratyphi A.