Experimental paracoccidioidomycosis in immunosuppressed mice.

Mice were immunosuppressed by means of wholebody irradiation or cyclophosphamide, in order to investigate the influence on the initial phase of infection induced by a strain of the fungus, Paracoccidioides brasiliensis, in the yeast phase and inoculated intraperitoneally. A group of mice was irradiated with 600 rad (cobalt gamma-irradiation) 24 h before infection. Two groups were treated with cyclophosphamide (200 mg/kg intravenously), one two days before, and the other, one day after infection. A control group received the fungus, but no radiation or cyclophosphamide. All animals developed lesions at the site of inoculation. Metastatic lesions were observed in 100% of the animals in the irradiated group, 67% in each of the cyclophosphamide-treated groups and 33% in the control group. These lesions were found both in the liver and lungs, being more numerous in the irradiated group, followed by the cyclophosphamide-treated group in which the drug was given after the infection; they were slight in both viscera in the other cyclophosphamide-treated group and also slight in the liver and absent in the lungs of the controls.