Creation of Interferon-α8 Mutants with Amino Acid Substitutions Against Interferon-α Receptor-2 Binding Sites Using Phage Display System and Evaluation of Their Biologic Properties

In this study, we describe the creation of three interferon-α (IFN-α)8 mutants with markedly higher antiviral and antiproliferative activities in comparison with those of the wild-type (wt)IFN-α8, wtIFN-α2, and IFN-con1 using a phage display system. Sequence analysis showed that three out of the six hot-spot amino acid residues of wtIFN-α8 known to be important for the interaction with the IFN-α receptor-2 (IFNAR-2)-binding sites were substituted to other amino acids and the others remained. Although affinity analysis revealed that the dissociation constant (KD) of IFN-α8 mutants was almost the same with that of wtIFN-α8, furthermore, the rates of association (ka) and dissociation (kd) were relatively lower. These results suggest that changes in the surface electronic charge of amino acid residues lead to changes in binding affinity and kinetics (prolonged dissociation time) toward the IFNAR-2, resulting in the modification of the biological activity. Moreover, our results demonstrate that the molecular e...