Progenitor numbers in the spleen of infected mice. (A) Spleen CFC counts were performed at different times after infection from wild-type (□) or IFN-γ −/− mice (▪). Results are reported as total CFCs per spleen. The “0” time point is from naive mice. (B) Total bone marrow CFC in wild-type (□) or IFN-γ −/− mice (▪) from the same experiment shown in (A). Results are reported as the total CFCs recovered in the leg bones of each mouse. Each time point is an average of four to six mice per group. Results were similar in three independent experiments.