Role of endogenous interferon in the high sensitivity of C3H/10T1/2 cells to the antiviral activity of interferon.

Addition of anti-mouse interferon (IFN) serum to untransformed 10T1/2 cells at the time of virus challenge led to a reduction of the IFN titers as determined by inhibition of CPE. The titers were reduced to values comparable to those usually observed for transformed 10T1/2 cells. In contrast, no change in IFN titers was observed when anti-IFN serum was added to transformed 10T1/2 cells. There was no significant difference between the two types of cells in the level of IFN induced by the challenge virus, VSV. The IFN level was low and did not increase after pretreatment of the cells with IFN. The distinct effect exerted by anti-IFN serum on untransformed and x-ray transformed 10T1/2 cells was not unique and comparable results were obtained in several other normal and transformed cells.