Variant human neuroblastoma cell lines resistant to the differentiation-inducing effect of interferon-gamma

Human recombinant interferon, (rIFN)-gamma, induced a human neuroblastoma cell line GOTO to differentiate, but neither rIFN-alpha A nor -beta did. To elucidate the mechanism of this rIFN-gamma-specific differentiation-inducing effect, we established two rIFN-gamma-resistant variant GOTO clones. They were insensitive to the growth-inhibitory and differentiation-inducing effect of 1 X 10(3) IU/ml rIFN-gamma. They were slightly sensitive to the growth-inhibitory effect of rIFN-gamma (2 X 10(4) IU/ml). Parental GOTO cells were very insensitive to the antivesicular stomatitis virus (VSV) effect of all three types of rIFNs and even 2 X 10(4) IU/ml rIFN-gamma could not inhibit the cytopathic effect of 5 TCID50 VSV by 50%. The degree of this insensitivity was the same in the variant GOTO cells as in the parental GOTO cells.