Major pilin PilA (Nontypeable Haemophilus influenzae) (PilA)

Nontypeable Haemophilus influenzae (NTHi) PilA is the major structural subunit of the Type IV Pilus (T4P), a critical surface appendage used by the bacterium for host colonization and environmental adaptation. It plays a fundamental role in mediating adherence to the respiratory epithelium and is essential for the formation and structural integrity of bacterial biofilms, which protect NTHi from host immune clearance and antibiotic treatment. Beyond adhesion, PilA facilitates 'twitching motility'—a form of surface movement—and is involved in natural transformation by mediating the uptake of exogenous DNA. Because NTHi is a primary pathogen in pediatric otitis media and a major cause of exacerbations in patients with Chronic Obstructive Pulmonary Disease (COPD), PilA has emerged as a high-priority target for vaccine development. Current therapeutic strategies focus on generating antibodies against highly conserved regions of PilA to block bacterial attachment and disrupt biofilm-mediated persistence in the middle ear and lower airways.

Other names

Type IV pilin PilAMajor pilin subunitT4P major subunitPilA protein

Vaccine-induced antibodies bind to the PilA subunit to neutralize the function of Type IV pili, thereby preventing bacterial adherence to host respiratory epithelium and inhibiting the formation of protective biofilms.