Evaluation of hBD4 expression in rNDV-hBD4-infected cells. (A) A549, HEp-2, MDCK, MDBK, HDF, and CEF cells were infected with the rNDV-GFP virus and assessed for GFP expression (***, p < 0.001). (B) MDBK cells were infected with the rNDV-hBD4 and treated with GolgiStop, and hBD4 (green), NDV proteins (red), and the cell nuclei (blue) were detected in a confocal microscopy. (C) MDBK cells were infected with the rNDV-hBD4, and the expressed hBD4 in the cell supernatants was quantified at 24 hpi by ELISA (**, p < 0.01). (D) The expressed NDV proteins were also quantified and the mock-infected cell supernatants were used as a control.