Avian Interferon-Inducible Transmembrane Protein Family Effectively Restricts Avian Tembusu Virus Infection

Chen, Shilong; Wang, Long; Chen, Jieying; Zhang, Lanlan; Wang, Song; Goraya, Mohsan U.; Chi, Xiaojuan; Na, Yang; Shao, Wenhan; Yang, Zhou; Zeng, Xiancheng; Chen, Shaoying; Chen, Ji-Long

These data were consistent with the in vivo studies presented above. Strikingly, duck IFITM1 was greatly induced and reached their maximum value (52-fold) at 12 hpi and then declined gradually ( Figure 3F) . Expression of duck IFITM2 and IFITM3 were enhanced modestly and reached their maximal levels by 6.8and 6.3-fold at 36 hpi, respectively (Figures 3G,H) . These results were further confirmed by RT-PCR analysis (Supplementary Figure 4) . Taken together, these data reveal that innate immune response is triggered in DEFs infected with ATMUV, as indicated by significant upregulation of IFNs and IFITMs. Because DEF cells are hard to survive after several passages, we employed chicken DF-1 cell line as a model system to further investigate the interaction between host innate immune system and ATMUV, and the role of IFITMs in defense against viral infection. As expected, mRNA levels of IFN-α, IFN-β, and IFNλ were greatly elevated by ATMUV infection and reached the maximal levels at 24 hpi and then declined gradually as compared to mock treatment (Figures 4A-C) . Similarly, expression of chicken IFITM1 (chIFITM1) was highly upregulated by 28fold at 24 hpi. Expression of chicken IFITM2 (chIFITM2) and IFITM3 (chIFITM3) was also significantly increased in response to ATMUV infection (Figures 4D-F) . These observations were further confirmed by RT-PCR analysis (Supplementary Figure 5) .