Studies on mediators of cellular immunity in experimental coccidioidomycosis.

The time course of delayed hypersensitivity (DH) to spherulin was regularly detected 3 days before and up to 140 days after sensitization of guniea pigs by repeated testing with the in vitro macrophage migration inhibition method. The properties of mycelial and spherule-derived coccidioidins in dermal sensitivity reactions were studied with regard to infected or vaccinated with Coccidioides immitis guinea pigs. The mediators for cellular immunity such as promotion of phagocytosis, skin reactive and fungicidal factors can be found in the supernatant of lymphocyte cultures from vaccinated or infected animals with mild disease in much greater quantity than those in control or infected with severe disease. Cell-mediated immunity to Coccidioides immitis involves both macrophages and lymphocytes, but the latter was the most likely mediator of the intracellular killing observedl