RECOMBINANT CHICKEN INTERFERON - A POTENT ANTIVIRAL AGENT THAT LACKS INTRINSIC MACROPHAGE ACTIVATING FACTOR ACTIVITY

Crude preparations of chicken interferon (ChIFN) from various sources contain both antiviral and macrophage-activating factor (MAF) activity . Previous serological data indicated that unlike mammals, birds might express only a single type of IFN in response to viruses and mitogens that exhibits both activities. We have now expressed a complementary DNA for virus-induced ChIFN in transfected COS cells and in Escherichi a coli. Purified recombinant ChIFN is a powerful antiviral agent and h as high Mr promoter-inducing activity. However, as the sole agent, rec ombinant ChIFN lacks MAF activity: it does not induce the secretion of nitric oxide in primary monocyte-derived chicken macrophages. A neutr alizing antiserum prepared against cloned ChIFN blocks most of the ant iviral and Mr promoter-inducing activity present in preparations of na tural ChIFN, but does not inhibit the MAF activity These results demon strate that chicken cells can be induced to secrete a novel cytokine w hich probably represents the avian homolog of mammalian IFN-gamma.