Fig. 1.

IFN-γ inhibits TGEV in a dose-dependent manner. (a, e) ST cells or IEC cells were treated with different concentrations of IFN-γ (1000 ng/mL, 100 ng/mL, 10 ng/mL, 1 ng/mL) for 24 h, followed by infection with TGEV. Cells were harvested at 24 hpi for quantification of the TGEV genome. (c) ST cells were treated with IFN-γ and infected TGEV, and cell lysates were analyzed by Western blotting for detection of the TGEV N protein. (b, f) Cell culture supernatants were collected for virus titration. (d) IFN-γ treatment inhibits infection of ST cells by TGEV-GFP. ST cells were treated with IFN-γ 24 h prior to TGEV-GFP infection. GFP-positive cells at 24 hpi are shown. The data represent the mean ± SEM from three independent experiments. Asterisks indicate statistical significance relative to the no-IFN-γ control. *, p < 0.05; **, p < 0.01; ***, p < 0.001