Variation within serovars of Neisseria gonorrhoeae detected by structural analysis of outer-membrane protein PIB and by pulsed-field gel electrophoresis.

Outer-membrane protein PI is the antigen responsible for serovar specificity of Neisseria gonorrhoeae and is a potential vaccine target. In order to investigate possible hidden variation within a serovar, the sequence of the por genes encoding protein PIB have been obtained from a series of strains, including isolates known to be epidemiologically linked. The inferred amino acid sequences of the PIB molecules of isolates from known sexual contacts were identical, but non-related isolates showed significant heterogeneity in PIB sequence.