Synthesis of spontaneous interferon by mouse peritoneal cells in vitro. I. Attempts to elucidate the origin of spontaneous interferon.

Interferon-like substance has been obtained in the media of mice 129/AoBoy peritoneal cell cultures after incubation at 26 degrees C. The substance showed characteristics that permitted it to be accepted as an interferon. Looking for the presence (in the media or in the sera) of infectious agents responsible for this event experiments were performed that excluded this possibility. Peritoneal cells cultures in media without calf sera (MEM, PBS) produced spontaneous interferon, too. In the same medium the peritoneal cells from various mouse strains differed in the capacity to spontaneous interferon formation. Finally it was found that the level of this interferon was raised with the age of mice.