Haemophilus influenzae outer membrane protein

Haemophilus influenzae outer membrane proteins are a set of structurally and functionally diverse proteins localized to the outer membrane of the Gram-negative bacterium H. influenzae. They include major porins (e.g., P2) that permit nutrient uptake, adhesins (e.g., P5, PE, Hap) that mediate bacterial binding to host cells, and virulence factors that enable immune evasion by recruiting host regulators (such as factor H, C4b-binding protein, vitronectin) or reducing antibody binding[1][2][3][4][7]. Some, like P5, are essential for serum resistance and membrane integrity; others, like PE, are prominent in adherence and immune modulation[1][4]. These proteins are important contributors to respiratory tract colonization, pathogenesis, and persistence, and are being studied as vaccine targets. However, their sequence variability and redundancy present challenges for drug and vaccine development[1][4]. Key example members: - Protein P5: OmpA family, contributes to serum resistance, adherence, membrane stability, and possesses variable immunogenic extracellular loops[1][2]. - Protein P2: Major porin, forms channels for passive diffusion, impacts antibiotic sensitivity[7]. - Protein E (PE): Adhesin, binds laminin, vitronectin, plasminogen, and modulates local immune response[4]. - Autotransporters (Hap, Hia, Hsf): Mediate aggregation, biofilm formation, and additional adherence[3].

Other names

H. influenzae OMPOMP (in context of H. influenzae)Protein P2 (OmpP2)Protein P5 (OmpP5)Protein E (PE)HapHiaHsf

For antibiotics: disruption of outer membrane or inhibition of peptidoglycan; OMPs can mediate resistance/sensitivity[1][7]. For vaccines: induction of antibody responses against surface-exposed OMP loops or domains (block adherence or immune evasion)[4].