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

IFITMs Are Significantly Induced in DEF and DF-1 Cells after ATMUV Infection or Treatment with IFN To confirm duck innate immune response induced by ATMUV, we further determined the expression of type I and type III IFNs and IFITMs following ATMUV infection in vitro. For this, DEFs were prepared and infected with ATMUV, and the mRNA expression of particular IFNs and IFITMs were then analyzed using qRT-PCR. ATMUV replicated well in DEFs with an obvious cytopathic effect (CPE) characterized by cell shrinking, rounding and detachment at 48 hpi ( Figure 3A) . Analysis of IFA showed that viral antigens were detected in DEF cells at 24-48 hpi, indicating that DEF cells could be infected by the virus (Figure 3B) . The mRNA levels of IFN-α, IFN-β, and IFN-λ were significantly elevated in ATMUV infected DEFs during ATMUV infection as compared to mock-treated control. Expression of IFN-α and IFN-β was increased by about 700-and 340-fold at 48 hpi, respectively (Figures 3C-E) . IFN-λ expression was also significantly induced with a highest 4.5-fold at 48 hpi. qRT-PCR analysis was performed to examine the mRNA expression of duck type I and type III IFNs (C-E) and IFITM1, 2, 3 (F-H). The mRNA levels were normalized to the endogenous β-actin level and the expression at 0 hpi was set to 1.0. Expression at 12-48 hpi was compared to its expression at 0 hpi. Plotted are the average levels from three independent experiments with three replicates per experiment (means ± SD). Statistical significance was determined by one tail Student's t-test analysis. *P < 0.05, **P < 0.01.