Purification and antigenic relatedness of proteins II of Neisseria gonorrhoeae.

Gonococcal proteins II from three strains were purified by chromatofocusing, and antisera was raised against them. These antisera were examined by immunoblotting to explore the antigenic relatedness of proteins II of seven different strains. The strongest reactions of the antisera were with the homologous proteins II. The antiserum against the proteins II of one strain also reacted with the proteins II present in all of the heterologous strains, whereas the antisera against the proteins II of two other strains showed little cross-reactivity with heterologous proteins II. Monoclonal antibodies produced against the three proteins II of strain F62 were specific for homologous proteins II and recognized epitopes unique to each individual protein II. These studies confirm the extensive intra- and interstrain variability in the antigenic structure of these proteins.