Serology of Neisseria gonorrhoeae: coagglutination serogroups WI and WII/III correspond to different outer membrane protein I molecules

Abstract

The 125I-labeled tryptic peptides of the outer membrane protein I of 33 previously characterized serological reference strains of N. gonorrhoeae were investigated by peptide maps in relation to their coagglutination W serogroup. Serogroup WI strains tended to have lower molecular weight protein I molecules than did WII strains, and WIII strains had the highest molecular weight protein I molecules, although the serogroup could not be predicted from the molecular weight of the protein I molecules for a given strain. All 13 strains belonging to serogroup WI were found to have 11 peptides in common, as judged by their migration with respect to one another and to the internal marker valine in the peptide maps. Common peptides isolated from a given strain were found to comigrate with the corresponding common peptides from other strains in the same serogroup under various electrophoresis conditions. The 20 strains belonging to serogroups WII and WIII were all found to have 10 common peptides by the same criteria. When common peptides from serogroup WI were compared with the common peptides of serogroups WII and WIII, only 3 of these peptides appeared to be similar. Thus, 2 different outer membrane protein I molecules seem to exist which are mutually exclusive. Protein IA molecules contain the antigens recognized as serogroup WI, and protein IB molecules contain the antigens that characterize serogroups WII and WIII.