FIG 4.

rVSV-NDV is sensitive to antiviral type I interferon, and its replication and cytoxicity are attenuated in healthy hepatocytes and neurons. (A) IFN-sensitive A549 cells were infected with rVSV or rNDV or rVSV-NDV at an MOI of 0.01. Cells were lysed at 48 h postinfection, and intracellular viral titers were measured by TCID₅₀ analysis. Experiments were performed in triplicate, and mean values ± standard errors of the means of the results are shown. (B and C) Primary human hepatocytes (B) or primary embryonic mouse neurons (C) were infected at an MOI of 0.01 with rVSV, rNDV, or rVSV-NDV. Cell lysates were subjected to TCID₅₀ analysis of intracellular virus titers at various time points. Additionally, aliquots of supernatant were collected at various time points to quantify cytotoxicity using either an LDH assay (for hepatocytes) or an MTS assay (for neurons). Experiments were performed in triplicate, and means ± standard errors of the means of the results are shown. *, P < 0.05.