STAT1 and infection: After 9 and 20 h infection of T1012G, p-STAT3 in the propranolol pretreatment group was significantly up-regulated 2.9 and 2.0-fold compared with T1012G only group (Fig. 4D and F, P < 0.05, P < 0.01) and total STAT3 was increased 2.3 and 1.9-fold (Fig. 4D and F, P < 0.05, P < 0.05), while the expression and activation of other IFN-I responsive genes-STAT1, STAT2 were not affected significantly (Additional file 1: Figure S1, P > 0.05).