Induction of acid-stable canine interferon in vivo and in vitro.

Dogs were able to produce only small quantities of circulating interferon after intraperitonal injection of Newcastle disease virus or polyinosinic-polycytidylic acid. Similarly, canine cell cultures produced very low concentrations of interferon in response to Newcastle disease virus or polyinosinic-polycytidylic acid and no detectable concentrations of interferon in response to pyran copolymer or tilorone hydrochloride. The antiviral substance met the physiochemical characteristics classically associated with interferon.