Flagellin type B (FliC) (FliC)

Flagellin type B (FliC) is the primary structural subunit of the flagellar filament in Pseudomonas aeruginosa, a major opportunistic pathogen. It is a multifunctional protein responsible for bacterial motility, chemotaxis, and initial attachment to host surfaces, which are critical steps for establishing infection [UniProt P02968]. The FliC protein is organized into domains D0, D1, D2, and D3; while D0 and D1 are highly conserved and responsible for Toll-like receptor 5 (TLR5) recognition, the D2 and D3 domains are hypervariable and project outward from the filament surface, serving as major targets for the host's adaptive immune response [PubMed: 15153205, PubMed: 11113294]. In clinical settings, Flagellin B is a key virulence factor involved in the pathogenesis of cystic fibrosis and hospital-acquired infections, as it triggers potent pro-inflammatory responses through the TLR5 and NLRC4 inflammasome pathways [PubMed: 22434327]. As a therapeutic target, the D2 subunit/domain is primarily utilized in the development of subunit vaccines and neutralizing antibodies aimed at inhibiting bacterial movement and promoting opsonophagocytosis [PubMed: 24391942]. However, the significant sequence diversity within the D2 domain across different Pseudomonas strains presents a challenge for achieving broad-spectrum efficacy [PubMed: 28863240].

Other names

Pseudomonas flagellin BB-type flagellinFliC type BFlagellar filament structural proteinD2 domain of flagellin B

Neutralization of motility and colonization through antibody binding; induction of protective immunity; activation of TLR5-mediated cytokine production for adjuvant effects.