Viral factors required for interferon induction by Newcastle disease virus in mouse macrophages and chicken embryo cells

Interferon synthesis in human diploid cells pretreated with insulin

Interferon production by Newcastle disease virus in human diploid (WI-38) cells was greatly reduced in the absence of serum. Pretreatment of the serum-free cells with insulin in excess of 1.2 IU/ml for 2 h before induction considerably increased the amount of interferon produced. No enhancement of interferon production was seen when the cells were exposed to insulin 2 h after induction or later. The insulin's effect persisted for at least 6 h after its removal, but not for 24 h. A possible mechanism of insulin action is discussed.