Fever in rabbits induced by intravenous or intracerebroventricular injection of human recombinant interferon-β and -γ

Interavenous (I.V.) and intracerebroventricular (I.C.V.) injection of human recombinant interferon-β and interferon-γ produced dose-dependent vers in rabbits. The fever induced by I.V. injection was monophasic and the maximum elevation occurred 90-120 min after injection. The fever induced by I.C.V. injection was observed from about 20 min after injection and was remarkably prolonged over 4 hours. The pyrogenicity of interferon-γ was greater than that of interferon-β. The development of pyrogenic tolerance to interferon-β and -γ was observed when rabbits were given. I.V. injections on 3 successive days. The present results suggest that interferon is one of endogenous mediator proteins responsible for produsing fever.