At 5 days post-infection, IFN-γ and CCL5 mRNA levels in the brains of theinfected CCR5−/− mice were significantly higher thanthose of the infected wild-type animals (Figure 5A); however, there was no significant difference in the IFN-γand TNF-α expression levels in the liver (Figure 5B). The gene discussed is CCR5; the disease is infection.