FIG 1.

Protective effect of IL-7–mFc against lethal influenza virus infection. (A) Mice (BALB/c, n = 8 mice per group) were treated with 1 μg of IL-7–mFc via the indicated routes. At 14 days after the treatment, the mice were infected with 3 LD₅₀ of H5N2. (B) Mice (BALB/c, n = 6 mice per group) received the indicated dose of IL-7–mFc, IL-7, or PBS intranasally and then were infected with 3 LD₅₀ of H5N2 14 days later. (C) C57BL/6 and FcRn^−/− mice (n = 8 mice per group) were administered PBS or 1 μg of IL-7–mFc intranasally. At 14 days after treatment, the mice were infected with 3 LD₅₀ of H5N2 virus. (D) The mice (BALB/c, n = 11 mice per group) received 1 μg of IL-7–mFc intranasally at the indicated time points prior to the infection. All groups of mice were then simultaneously infected with 3 LD₅₀ of H5N2 at day 0. The survival rate was analyzed by the Kaplan-Meier method. The results are representative of more than two independent experiments with similar results. ††, P < 0.01 by log-rank test.