Production and partial purification of a gonococcal growth inhibitor produced by a strain of Neisseria meningitidis isolated from a homosexual man.

A Neisseria meningitidis strain isolated from the oropharynx of a homosexual man was shown to produce antigonococcal activity in vitro. A production method, on solid medium, was developed which yielded a soluble activity. The activity was detected at the end of logarithmic growth phase and the maximum activity was reached after 24 h of incubation. The antigonococcal substance was purified more than 300 times by ammonium sulphate precipitation, gel filtration on Ultrogel AcA 54, and chromatography on DEAE-Sephacel. The molecular weight of the inhibitory substance, estimated by molecular filtration, was 29 X 10(3) daltons. The partially purified inhibitor showed two major bands, 32 and less than 12.5 X 10(3) daltons by sodium dodecyl-sulphate polyacrylamide electrophoresis. The chemical nature of the inhibitor is probably proteic on the basis of trypsin sensitivity and the absorbance spectrum.