Examination of a surface exposed epitope on the protein IA molecule of Neisseria gonorrhoeae

Proteolytic cleavage of purified PIA of strain 7122 transparent phenotype (0-) (serotype 1, serogroup I) resulted in two, four, and five fragments using (TPCK)-trypsin, alpha-PI A was subsequently cleaved into smaller fragments. Immunoblot experiments using a monoclonal antibody (MoAb) specific for a surface exposed epitope of PI A of strain 7122, as assessed by coagglutination, Western blot, and immunofluorescence assay revealed that all cleavage fragments 2≥ 15K were reactive with the MoAb after incubation with peroxidase conjugated goat anti-mouse IgG, whereas controls using normal mouse serum showed no nonspecific binding. These data indicate that whereas purified protein I is susceptible to proteolytic cleavage, the epitope domain is relatively protease resistant.