Preliminary observations on the protective action of a cytoplasmic immunogen of Neisseria gonorrhoeae.

A non-toxic protein, termed beta(-t), consisting of lysine, aspartic acid, threonine, serine, glutamic acid, glycine, and alanine (1.2:1.3:1.3:3:2.2:7:1) was isolated, by the polyacrylamide gel electrophoresis, from an isoelectric toxic proteinaceous fraction beta(+1) of the type 1 cytoplasm of N. gonorrhoeae. The beta(-t) antigen elicited delayed hypersensitivity and vigorous primary and secondary humoral responses in rabbits, and it conferred immune protection against intraocular gonococcal infections.