From 6 h before the inoculation to day 14 post-infection, the mice in the PR8 + IGF1 group were intraperitoneally injected with IGF1 protein (20 μg/kg/24 h); PR8 + PPP mice were injected intraperitoneally with an IGF1 receptor inhibitor, picropodophyllin (PPP, 20 mg/kg/12 h); and the PR8 + PBS group was injected with PBS (30 μl/24 h). The gene discussed is IGF1; the disease is infection.