Immunoglobulin A1 protease types of Neisseria gonorrhoeae and their relationship to auxotype and serovar.

Immunoglobulin A1 (IgA1) proteases are extracellular bacterial proteolytic enzymes which correlate with virulence in several species of human pathogens. We report that Neisseria gonorrhoeae produced two distinct types of IgA1 protease, each of which cleaved a different peptide bond in the hinge region of human IgA1. The type of IgA1 protease produced correlated with both nutritional auxotype and outer membrane protein I serovar in this organism. Gonococcal type 1 IgA1 protease was produced primarily by N. gonorrhoeae strains which require arginine, hypoxanthine, and uracil (AHU) and which belong to the protein IA-1 or IA-2 serovar. Most isolates of other auxotypes and serovars produced type 2 IgA1 protease. Although both the AHU auxotype and protein IA serogroup were found to be associated with disseminated gonococcal infection, there was no direct correlation of IgA1 protease type with disseminated or with uncomplicated gonorrhea.