Production, purification and characterization of rat interferon.

Priming with heterologous mouse interferon, increased production of an antiviral substance induced in rat diploid fibroblasts by Newcastle disease virus. This substance was characterized as an acid stable interferon. This rat interferon exhibited marked cross-species antiviral activity when tested in mouse L929B cells, guinea pig embryo fibroblasts, human fibroblasts and bovine cells but was not active on chick embryo cells.