Nomenclature of avian interferon proteins.

Abstract

547 THE FIRST AVIAN INTERFERON (IFN) cloned was a type I molecule from a cDNA library generated from chicken embryonic cells that had been aged in vitro to produce large amounts of IFN when induced.(1) This chicken interferon (ChIFN) was indistinguishable from native material in that it possessed high antiviral activity, was acid and heat stable, induced the Mx gene, was active in a glycosylated or nonglycosylated form, and lacked macrophage-activating factor activity.(1–3) The first type II ChIFN was cloned from a cDNA expression library generated from a chicken T cell line and was shown to be acid and heat labile and capable of inducing nitric oxide (NO) and MHC class II antigen expression in chicken macrophages,(4,5) as well as guanylate-binding proteins (GBP) and IFN regulatory factor-1 (IRF-1) in a chicken fibroblast line.(5) ChIFN types I and II are antigenically distinct.(4–6) Thus, as in mammalian systems, avian IFN can be assigned to two types based on biologic, biochemical, and antigenic properties. Several IFN genes now have been cloned from the chicken(1–6) as well as from other avian species,(7–10) and the activity of their encoded proteins has been characterized. There follows a brief description of these characteristics and a standardized nomenclature for avian IFN based on their genetic, structural, and functional features. Although avian IFN reveal low overall levels of amino acid identity to mammalian IFN of comparable function, conservation of several features, including a highly conserved region, along with the analogous biologic and biochemical attributes they share, prompted us to adopt a similar nomenclature for practical use, recognizing that it may not reflect gene phylogeny.(11)