title: Binding and activity of all human alpha interferon subtypes.
abstract: Vertebrates have multiple genes encoding Type I interferons (IFN), for reasons that are not fully understood. The Type I IFN appear to bind to the same heterodimeric receptor and the subtypes have been shown to have different potencies in various experimental systems. To put this concept on a quantitative basis, we have determined the binding affinities and rate constants of 12 human Alpha-IFN subtypes to isolated interferon receptor chains 1 and 2. Alpha-IFNs bind IFNAR1 and IFNAR2 at affinities of 0.5-5 μM and 0.4-5 nM respectively (except for IFN-alpha1 - 220 nM). Additionally we have examined the biological activity of these molecules in several antiviral and antiproliferative models. Particularly for antiproliferative potency, the binding affinity and activity correlate. However, the EC50 values differ significantly (1.5 nM versus 0.1 nM for IFN-alpha2 in WISH versus OVCAR cells). For antiviral potency, there are several instances where the relationship appears to be more complicated than simple binding. These results will serve as a point of reference for further understanding of this multiple ligand/receptor system.
authors.affiliation: PBL InterferonSource, 131 Ethel Road West, Piscataway, NJ 08554, United States. tlavoie@pblbio.com
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Lavoie
authors.forename: Eyal
authors.initials: E
authors.lastname: Kalie
authors.forename: Sara
authors.initials: S
authors.lastname: Crisafulli-Cabatu
authors.forename: Renne
authors.initials: R
authors.lastname: Abramovich
authors.forename: Gina
authors.initials: G
authors.lastname: DiGioia
authors.forename: Karlene
authors.initials: K
authors.lastname: Moolchan
authors.forename: Sidney
authors.initials: S
authors.lastname: Pestka
authors.forename: Gideon
authors.initials: G
authors.lastname: Schreiber
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D016898:Interferon-alpha / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D017471:Receptors, Interferon / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D016898:Interferon-alpha; D017471:Receptors, Interferon