Immune system (Salmonella Typhi, Paratyphi A, and Paratyphi B antigens)

This entry refers to the collective antigenic components derived from inactivated Salmonella enterica serovars Typhi, Paratyphi A, and Paratyphi B, which are used to stimulate a host immune response. Rather than targeting a specific molecular receptor or enzyme, these antigens act as immunogens that trigger a broad cascade of innate and adaptive immune pathways (WHO, 2018). The primary biological function is the induction of active immunity against enteric fevers, including typhoid and paratyphoid, by priming the immune system to recognize bacterial O and H antigens (CDC, 2024). Historically administered as the TAB vaccine, these whole-cell inactivated preparations were effective but associated with significant systemic reactogenicity, such as fever and inflammation (PubMed, 1945). In modern clinical practice, these have largely been replaced by more refined targets, such as the Vi capsular polysaccharide or live-attenuated strains, which offer better safety profiles and targeted efficacy (StatPearls, 2023).

Other names

TAB vaccine antigensSalmonella enterica serovar Typhi antigensSalmonella enterica serovar Paratyphi antigensInactivated Salmonella antigensTyphoid-paratyphoid A and B vaccine antigens

The antigens from inactivated Salmonella Typhi, Paratyphi A, and Paratyphi B are processed by antigen-presenting cells (APCs), which then present them to T and B lymphocytes. This process induces the production of specific serum antibodies (agglutinins) against the somatic (O) and flagellar (H) antigens of the bacteria, providing active immunity to prevent infection by the corresponding live pathogens (StatPearls, 2023; PubMed, 1945).