CHICKEN-EMBRYO FIBROBLASTS PRODUCE 2 TYPES OF INTERFERON UPON STIMULATION WITH NEWCASTLE-DISEASE VIRUS

Controversy has long surrounded the question of whether chickens, Like mammals, can produce two types of interferon (IFN). Recently, type-I and type-II chicken IFNs have been cloned. Our study focuses on the fu rther characterization of native fibroblast and spleen IFNs and shows that chicken embryo fibroblasts (CEFs) produce a mixture of type-I and type-II IFNs. IFN was purified by three different methods, controlled pore-glass chromatography, ion-exchange chromatography and preparativ e SDS-PAGE. Three protein bands showing IFN-Like anti-viral activity, from CEFs which had been virus-stimulated for IFN production, were det ected at 25, 27 and 29 kDa. Polyclonal antibodies produced against the se bands showed partial cross-reaction with purified media from mitoge n-stimulated spleen cells in ELISA, western blot analysis and anti-vir al activity neutralization assay. Differences between purified conditi oned media from CEF and spleen were found with respect to the stimulat ion of macrophages for nitric oxide production, pH stability and signa l transduction pathways; only CEF IFN activated the IFN-stimulated gen e factor-3 complex, whereas both CEF and spleen IFNs activated the IFN regulatory factor-1 gene. These findings concur with the differences that are known to exist between mammalian type-I and type-II IFNs. Att empts at sequencing the 25 and 27 kDa proteins by Edman degradation yi elded evidence of N-terminal blockage. (C) 1997 Elsevier Science B.V.