There is no currently identified exotoxin produced by Neisseria meningitidis, however in 1931 a report was made of the production of a soluble substance with hemolytic and """"""""protective"""""""" properties when meningococci were grown under conditions which produced heavy pellicle formation. In earlier studies, we attempted to reproduce the culture conditions described and assay the filtrates of these cultures for evidence of hemolysis of human red blood cells. Weak hemolysis, after overnight incubation, was found in culture filtrates of some strains showing heavy pellicle formation. We are expanding our investigation to search for evidence of inducible products in either cells or filtrates under a variety of culture conditions and in the presence or absence of nicotine. We also plan to screen a number of human cell lines with culture filtrates for possible cytotoxic effects.
