Salmonella flagellin protein (FliC) (FliC)

Salmonella flagellin is the primary structural protein of the bacterial flagellum, typically encoded by the fliC or fljB genes in Salmonella species. It functions as a potent pathogen-associated molecular pattern (PAMP) that is specifically recognized by the host's Toll-like receptor 5 (TLR5), triggering the activation of the NF-kappaB signaling pathway and the subsequent production of pro-inflammatory cytokines and anti-apoptotic proteins (UniProt Consortium, 2023; Leigh et al., 2014). In therapeutic development, flagellin-derived molecules such as Entolimod (CBLB502) are utilized as TLR5 agonists to protect healthy tissues from radiation-induced damage and to stimulate anti-tumor immune responses (Burdelya et al., 2008). Additionally, flagellin is widely used as a vaccine adjuvant due to its ability to enhance the immunogenicity of co-administered antigens by activating dendritic cells and promoting a robust adaptive immune response (Huleatt et al., 2008). Despite its therapeutic potential, challenges include the risk of systemic inflammatory side effects, such as cytokine release syndrome, and the potential for the development of neutralizing anti-flagellin antibodies that may limit the efficacy of repeated administrations (Kandimalla et al., 2007).

Other names

FlagellinFliCFljBH-antigenTLR5 ligandPhase 1 flagellin

Agonism of Toll-like receptor 5 (TLR5) leading to the activation of NF-kappaB and AP-1 signaling pathways, which induces the expression of protective cytokines and anti-apoptotic factors (Burdelya et al., 2008; Leigh et al., 2014).