GRK1 and infection: Figure 5A,B show that intranasally administrated G-rk1 protected mice from PR8 infection, significantly reflected by decreased weight loss and increased survivals, 66.7% (4/6) and 83.3% (5/6) in G-rk1-treated mice at 12.5 and 25 mg/kg/d, respectively, as no mouse survived in the PR8-infected untreated group.