Systemic candidiasis in mice treated with prednisolone and amphotericin B. 2. Ultrastructure and evidence for fungal toxin.

The principal ultrastructural changes in cells of Candida albicans treated with amphotericin B (AmB), either in vitro or in vivo, and in the presence or absence of prednisolone included plasmolysis, vacuolation and destruction of organelles. Lamination of the cell wall, although discernible after 4 h antibiotic treatment in vitro, was conspicuous in vivo, especially in prednisolone-treated mice given AmB 72 h after inoculation and was seen in both phagocytosed cells and those free in inflammatory exudates. Somatic extracts from control cells and somatic extracts and leachates from AmB-treated cells showed the presence of low-grade toxic components when given i.p. to mice receiving antinomycin D(AMD) s.c. Culture filtrates were negative. Eighteen hour cultures were more toxic than those grown for 3 days and no toxicity was shown for cultures after 8 or 14 days. The behaviour of toxic materials during electrophoresis in polyacrylamide gels suggested that they were proteins of relatively high molecular weight.