Generation of the rNDV-hBD4 virus. (A) Construction of the full-length NDV-hBD4 plasmid (pNDV-hBD4). (B) After rescuing the virus via reverse genetics, the forward and reverse hBD4 primers were used for hBD4 detection (the PCR product was ~270 nucleotides in length). (C) The 3013P forward and 3430M reverse primers were used for detecting the region between the C-terminal P gene and the N-terminal M gene of the rNDV-hDB4. An hBD4 T-vector and wild-type pNDV/Lasota were used as controls.