Effect of interferon on deoxyribonuclease induction in chick fibroblast cultures infected with cowpox virus

An exonuclease which degrades native deoxyribonucleic acid at pH 9.2 was induced in chick embryo fibroblast cultures and in human amnion cells by infection with cowpox virus. Highly purified chick embryo interferon suppressed the induction of the enzyme in the homologous cell system but not in the human amnion cell cultures. "Mock" interferon prepared from uninfected chicken eggs and purified in the same manner as biologically active interferon preparations had no effect on the induction of the enzyme.