Salmonella Paratyphi A flagellin (FliC)

Salmonella Paratyphi A flagellin is the principal structural protein of the flagellar filament, encoded by the fliC gene. In S. Paratyphi A, it is essential for bacterial motility, efficient host cell invasion, and full virulence. Unlike in nontyphoidal Salmonella, flagellin in S. Paratyphi A also has a regulatory role: its absence upregulates expression and secretion of type III secretion system (SPI-1) effectors in a FliZ-dependent manner—a unique linkage in this serovar. The central antigenic domain of flagellin is diverse and immunologically significant, conferring serovar-specificity and serving as a target for recognition by host immunity. This protein is a PAMP, recognized by innate immune receptors such as Toll-like receptor 5 (TLR5), and is a target of vaccine research and diagnostic development. No current drugs specifically inhibit flagellin, but it represents a candidate for antigen-based interventions.

Other names

FliCFlagellin (S. Paratyphi A)Phase 1 flagellin

Vaccine antigen: Used to elicit antibody and T-cell responses that recognize and neutralize flagellated pathogens (active immunization). Adjuvant: May be used to stimulate innate immune receptors (such as TLR5) when introduced exogenously, enhancing immune responses to vaccines.