Identified virulence factors of Haemophilus: IgA1 Protease
Related genes: iga1;
Keywords: IgA1 Protease; Serine protease; Characteristics: Two classes of IgA1 proteases: cleavage at either a prolyl-seryl (type1) or four amino acids away at a prolyl-threoryl bond (type 2).
Display polymorphisms and antigenic variation.
Functions: Interferes with the barrier functions of mucosal IgA antibodies by cleaving secretory IgA1 in the hinge region.
Mechanism: Cleave immunoglobulin A1 at peptide bonds within the hinge region, leaves intact Fabalpha fragments without the Fcalpha or (Fcα)2.SC portions that are required for the activity of secretory IgA.
References: Grundy FJ, et al., 1990. Localization of the cleavage site specificity determinant of Haemophilus influenzae immunoglobulin A1 protease genes. Infect. Immun. 58(2):320-331.
St Geme JW 3rd, et al., 1994. A Haemophilus influenzae IgA protease-like protein promotes intimate interaction with human epithelial cells. Mol. Microbiol. 14(2):217-233.
Rao VK, et al., 1999. Molecular determinants of the pathogenesis of disease due to non-typable Haemophilus influenzae. FEMS Microbiol. Rev. 23(2):99-129.