Engineering human interferon alpha 1c/86D with phage display technology

Human interferon-alpha 1c/86D (IFN alpha 1c/86D) was functionally displayed on the surface of the filamentous bacteriophage using a phagemid vector sy stem (pCANTABSE). The key amino acid residues involved in the receptor bind ing were further defined with phage displayed 6-mer peptide library and two neutralizing antibodies against linear epitopes on the IFN-alpha lb, indic ating that residues 30, 33, 34, (AB-loop) and residues 124, 126, 127 (D hel ix, DE-loop) were more critical than the adjacent residues for recognition of receptor. In addition, a cassette mutagenesis library was generated by f ully randomizing the sequence of the four positions 29, 31, 32 and 35 in AB -loop, and used to select phage-IFN variants with WISH-based panning method . Three phage-IFN variants were isolated to possess more antiviral activity in the range of 4-16-fold than parental phage-IFN after IPTG-induced solub le expression. The results suggest that phage displayed phage-IFN alpha 1c/ 86D Variants with increased specific activity might be obtained after purif ication procedures.