FIG. 2.

Virus replication and type I interferon induction by rNDV in normal and human tumor cells. (A) Interferon sensitivity of rNDV. Normal human (SVHUC1) and tumor (HuTu80) cells in duplicate were treated with 10 pg/ml of human IFN-α for 24 h, and virus yield was examined by plaque assay on Vero cells at 24, 48, and 72 h postinfection with an rNDV multiplicity of infection of 0.01. (B) DF1 chicken embryo fibroblast cells and normal and human tumor cells were either mock infected or infected with rNDV at an MOI of 10 without IFN pretreatment. Culture supernatants were tested for IFN-β and IFN-α by ELISA. IFN-β production in rNDV-infected cells at 48 h postinfection. (C) IFN-α production at 48 h postinfection. (D) Time course analysis of IFN-β production in HuTu80 cells with an MOI of 0.01. (E) Time course analysis of IFN-α production in HuTu80 cells with an MOI of 0.01. (F) Multicycle virus replication of rNDV in normal and HuTu80 cells without IFN pretreatment. Cells were infected with an rNDV MOI of 0.01. Kinetics of the virus yield of rNDV in HuTu80 tumor cells was assessed in Vero cells. Results represent mean values plus standard errors of the means from two independent experiments.