Mouse L-A9 cell
interferon was induced by
infection with Newcastle disease virus.
Interferon production was 1.5 X 10(5) IU/10(7) cells.
Interferon was partially purified by precipitation with
ammonium sulphate, chromatography on CM-
Sephadex and hydrophobic chromatography on octyl-
agarose. The specific activity of the final preparation was 1.7 X 10(7) IU/mg
protein. Treatment of L-A9 cells with 20 IU/ml
interferon prior to
viral infection inhibited the intracellular accumulation of reovirus-specific
double-stranded RNA. Dose-response studies of the cells to
interferon indicated that L-A9 cells require 10, 13 and 15 IU/ml to obtain 50% viral plaque reduction for Marituba virus,
vesicular stomatitis virus and reovirus, respectively. The present results demonstrate the potential of mouse L-A9 cells as an
interferon-producing system and also as a model for the study of the effect of cellular response to exogenous
interferon treatment on the replication of RNA viruses.