Cyclophilin A Interacts with Viral VP4 and Inhibits the Replication of Infectious Bursal Disease Virus

Figure 4

Knock-down of CypA benefits IBDV growth. (a) Interference effect of siRNAs. pCAF-CypA was cotransfected with RNA#1, RNA#2, RNA#3, or negative control (NC) into DF-1 cells. The exogenous CypA expression was used to evaluate the interference effect of the siRNAs. At 24 h after transfection, CypA was detected by western blot with anti-Flag mAb, and β-tubulin was used as a loading control. (b) The IBDV VP2 (or pVP2) expression increased in the CypA-knock-down cells. DF-1 cells were treated with RNA#3 or NC for 48 h and then infected with the IBDV Gt strain at an MOI of 0.01 for another 48 h. The cells were harvested to detect IBDV VP2 (or pVP2) by western blot. GAPDH was used as a loading control. (c) The viral RNA copies were detected by real-time RT-PCR. (d) The virus titers in the culture supernatants of IBDV-infected DF-1 cells were detected by the Reed-Muench method. (e) The cell viability and proliferation of DF-1 cells were evaluated using CCK-8 kit. The error bars represent the standard errors of the mean from three independent experiments. The values are shown above the bars. and indicate significant differences.

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