Interferon production by individual cells in culture

A simple tecnique is descibed which permits detection of the interferon released by individual cultured cells. The method has been employed to measure the fraction of induced human or murine fibroblast populations which actually release interferon. The results indicate that approximately 30% of mouse L-cells and 50% of human skin fibroblasts produce interfern after induction using Newscastle disease virus, and that approximately 50% of human and mouse cells produce interferon after induction using polyriboinosinate-polyribpcytidylate duplex.