Fig. 5. Microbat and pig IFITM3 inhibit influenza virus replication. A549 cells stably expressing human, pig or microbat IFITM3 were infected with influenza A virus. (a) At 7 h after infection with influenza A/WSN/33, NP expression was analysed by flow cytometry. (b) At 16 h after infection with influenza A/WSN/33 or A/swine/453/06 or mock infection (−V) cells were lysed and Western blotting was performed to detect influenza NP, actin and HA-tagged IFITM3 or green fluorescent protein (GFP). The molecular mass (kDa) of protein size markers is indicated. (c, d) Virus yields following infection with influenza A/WSN/33 at an m.o.i. of 3 (c) or an m.o.i. of 0.01 (d) were measured using plaque assays. Results are shown as means±sd (n = 3). In (b)–(d) pig IFITM3 clone 1 and microbat IFITM3 clone 2 were used. *P<0.05; **P<0.01; ****P<0.0001 relative to GFP-expressing cells (Student’s t-test).