Rat leukocyte interferons: production of an acid-labile interferon after induction with Newcastle disease virus.

Rat leukocytes produce three interferon species after infection with Newcastle disease virus. Two of the three interferon species (22-24,000 and 30,000 daltons) were acid and heat stable, protected rat and mouse cells from virus-mediated cytopathic effect (CPE), and were neutralized by antisera to mouse L-cell (alpha/beta) interferon. The third, 30,000-dalton interferon species was heat and acid labile; protected rat, mouse, human, and bovine cells from virus-mediated CPE; and was neutralized by antisera to mouse L-cell interferon and human leukocyte interferon. Thus, the rat leukocyte interferon system is similar to the human system in the kinetics of interferon production, the production of multiple interferons, heterologous antiviral activity, molecular weight, and in the production of an acid-labile species. The rat leukocyte interferon system therefore represents an important model for examining the normal production and action of acid-labile interferons and their possible role in the regulation of leukocyte function and cellular differentiation.