SUMMARY

The species specificity of chick and L cell interferons were studied with respect to uptake and activity in mouse and chick embryo cell cultures. Heterologous inter-ferons conditioned cells for the rapid uptake and accelerated development of the antiviral state for homologous interferons. Heterologous interferons were neither taken up nor antiviral, regardless of whether the cells were conditioned with homologous or heterologous interferons