FIG. 3.
Increased burdens of amastigotes in IFN-γ-treated MΦs. (A) C57BL/6 BM-MΦs (3 × 105 cells/well) were not treated or were treated with 20 ng of IFN-γ per ml for 4 h prior to infection with 4.5 × 105 amastigotes. The number of parasites in each well was determined at different times. The data are data from one of three experiments in which similar results were obtained. (B) Different concentrations of IFN-γ were tested by a procedure similar to that described above for panel A. The number of parasites in each well of a MΦ culture was determined at 48 h postinfection. The data represent the data from three independent experiments. (C) MΦs from different strains of mice and sources were treated with 20 ng of IFN-γ per ml for 4 h and then infected with amastigotes. The number of parasites was determined at 48 h postinfection. The data are data from one of two experiments in which similar results were obtained.