The interaction of erythropoietin with fetal liver cells. II. Inhibition of the erythropoietin effect by interferon.

To investigate the effect of interferon on the proliferation of normal erythroid precursor cells, various interferon preparations were added to mouse fetal liver cells cultured in a liquid microculture system. The effect of interferon was studied using cellular tritiated thymidine incorporation both in the presence and in the absence of erythropoietin. Interferon was found to suppress cellular tritiated thymidine incorporation. The suppression was directly related to the antiviral activity and was not found when control preparations were used. The mechanism of suppression seemed to involve a direct effect on the cells which was dependent of erythropoietin. These studies suggest that the viral inhibitory effects of interferon may also be accompanied by effects on normal cellular proliferation.