Effect of mycosuppressin on the respiration and growth of Mycobacterium tuberculosis.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.) and Guy P. Youmans. Effect of mycosuppressin on the respiration and growth of Mycobacterium tuberculosis. J. Bacteriol. 84:708-715. 1962.-A substance, called mycosuppressin, was found in the lungs of guinea pigs and rabbits vaccinated with BCG or with a particulate immunizing fraction isolated from mycobacterial cells, and was not found in lungs of unvaccinated animals. Mycosuppressin inhibited the endogenous respiration and the growth of the virulent H37Rv strain of Mycobacterium tuberculosis. It also inhibited the endogenous respiration of the avirulent H37Ra strain and the saprophyte, M. smegmatis, but it increased the respiration of M. phlei. The oxidation by the H37Rv strain of lactate, pyruvate, glycerol, and glucose was also inhibited. Cytochrome oxidase activity was suppressed. Mycosuppressin was most stable at pH 6 to 7. It was nondialyzable, stable at 98 C, and not affected by lyophilization or freezing. It was soluble, in alcohol and acetone, insoluble in ether and water. Under appropriate conditions, mycosuppressin combined with, or was adsorbed to, mycobacterial cells, and was inactivated by serum and bovine serum albumin. It did not inhibit but, instead increased markedly, the respiration of Staphylococcus aureus and Escherichia coli.