Effect of vaccines prepared from Histoplasma capsulatum and other yeasts on experimental tuberculosis.

Hedgecock, Loyd W. (Veterans Administration Hospital, Kansas City, Mo.). Effect of vaccines prepared from Histoplasma capsulatum and other yeasts on experimental tuberculosis. J. Bacteriol. 82:115-123. 1961.-Resistance to experimental tuberculosis was enhanced by the injection of a nonviable vaccine prepared from Histoplasma capsulatum in the mycelial phase but not by the organism in the yeast phase. Acquired resistance was established within 7 days or less and usually maintained for at least 29 days. When both mycelium vaccine of H. capsulatum and a vaccine prepared from tubercle bacilli were utilized in vaccination, the results were additive (in terms of acquired resistance) provided that an interval of 3 weeks was maintained between injection of each of the vaccines. Resistance to tuberculosis was also demonstrable 14 days after the injection of nonviable preparations of Brucella abortus and Cryptococcus neoformans, as well as by yeast and mycelial vaccines of Blastomyces dermatitidis and Sporotrichum schenckii. Resistance decreased significantly when the animals were challenged 29 days after vaccination, with the exception of those injected with the yeast phase of B. dermatitidis.