FIG 9.

Phosphorylation of eIF2α in response to TGEV is linked to induction of IFN-I production and suppression of viral replication. (A) The expression levels of supernatant IFN-α/β in HA-eIF2αwt-transfected ST cells were analyzed by ELISA after TGEV infection. (B) The expression levels of supernatant IFN-α/β in eIF2α knockdown cells were analyzed by ELISA after TGEV infection. (C) The expression levels of IFN-α/β in salubrinal-treated ST cells were analyzed after TGEV infection. (D) The expression levels of IFN-α/β in PERK inhibitor-treated ST cells were analyzed after TGEV infection. (E) IFN-α suppressed TGEV replication in a dose-dependent manner. Viral replication was measured after treatment with porcine IFN-α. The relative quantification of TGEV infection is presented. (F and G) ST cells were transfected with 2.5 μg/ml HA-eIF2αwt (F) and eIF2α siRNA number 2 or control siRNA (G) for 24 h, stimulated or not with poly(I·C) for 12 h, and then infected with TGEV H87 (MOI = 1). The virus titers were measured. Means and SD of the results from three independent experiments are shown. *, P < 0.05; **, P < 0.01; ***, P < 0.001.