Immunization of mice against coccidioidomycosis.

Converse, J. L. (U. S. Army Chemical Corps, Frederick, Md.), M. W. Castleberry, A. R. Besemer, and E. M. Snyder. Immunization of mice against coccidioidomycosis. J. Bacteriol. 84:46-52. 1962-The observed lower virulence of Coccidioides immitis arthrospores of the M-11 strain compared with the Cash strain was ascribed to the lower ability of the M-11 spores to invade the lungs and brain. Endospores of strain M-11, grown in synthetic medium, were equally as virulent by the intraperitoneal route as arthrospores of strain Cash. Immunization of mice with viable strain M-11 arthrospores protected approximately 50% of the animals against challenge with strain Cash arthrospores. This was evidenced by lower mortality over a 5-month period and lack of gross pathological lesions in killed animals. Although fewer lesions resulted after the use of a viable vaccine, higher survival was obtained with formaldehyde-killed arthrospores. Either preparation tended to confine the infection to the peritoneal cavity.