Outer membrane protein P2 (OMP P2)

Outer membrane protein P2 (OMP P2) is the most abundant surface protein of Non-typeable Haemophilus influenzae (NTHi), representing approximately 50% of the total membrane protein content (UniProt: P20149). It functions primarily as a homotrimeric porin, enabling the passive diffusion of small molecules, monoatomic ions, and certain antibiotics such as beta-lactams across the bacterial outer membrane (PubMed: 2361271). OMP P2 is a major immunogen and a primary target for the host's bactericidal antibody response, making it a prominent subject of vaccine research (PubMed: 2843467). NTHi is a leading opportunistic pathogen associated with respiratory conditions, including acute otitis media in children and acute exacerbations of chronic obstructive pulmonary disease (COPD) in adults (PMC: 2168175). While its abundance and surface exposure make it a promising vaccine candidate, the protein exhibits high sequence heterogeneity in its surface-exposed loops, which often restricts immune protection to specific bacterial strains (PubMed: 11889073). Current therapeutic strategies focus on identifying conserved epitopes within the P2 molecule, such as loop 6, to develop mucosal and systemic vaccines with broader protective efficacy (PMC: 2634458).

Other names

OmpP2Porin P2Major outer membrane proteinNTHi P2Non-typeable Haemophilus influenzae outer membrane protein P2

As a porin, OMP P2 facilitates the entry of beta-lactam antibiotics into the bacterial periplasm via passive diffusion; when utilized as a vaccine antigen, it aims to stimulate the production of bactericidal and mucosal antibodies to neutralize the pathogen.