Production of Interferon by Ultraviolet Radiation Inactivated Newcastle Disease Virus

MYXOVIRUSES, irradiated with ultraviolet light, are good inducers of interferon formation in both chick and L cells1–4. Unirradiated virus does not induce interferon formation in chick cells1–3, but does so in mouse L cells4, and, in both systems, inducing capacity is lost on prolonged irradiation. Three questions therefore may be asked: (1) why do infective Newcastle disease virus (NDV) and influenza virus fail to provoke interferon formation in chick cells; (2) by what mechanism does irradiated, non-infective, virus produce interferon; and (3) why is this capacity lost on prolonged irradiation?