To see if the highly resistant phenotype of young adult BALB/c mice was altered by augmenting IFN-γ availability early during infection, we followed the reverse approach and treated BALB/c mice (1.5 months) with rIFN-γ twice daily (2.5 μg/dose) until day 4 post infection (Fig. 3a). This evidence concerns the gene IFNG and infection.