earticle

영어

Phage display is a technology which can display the foreign peptides or proteins on the surface of the phages to interact with exterior
molecules/materials. Using this technology, we have constructed the antibody and peptide libraries to select the specific ligands binding
to the target molecules. We presented here two types of the studies, one is the isolation of human antibody fragments specific to tumor
cells from human single chain Fv (scFv) antibody fragment phage library and the other is the design of peptide ligands specific to human IgG using a random peptide phage library. ATL (adult T cell leukemia) is a disease caused by the infection of a retrovirus HTLV-1 to CD4 T cells. Its carrier is estimated to be 10–20 million people worldwide and especially in Japan the carrier is distributed in south area of Kyushu Island. To find a new tumor marker for ATL and a candidate of antibody therapeutics of ATL, we tried to isolate specific antibody toward the S1T cells (ATL patient-derived cell line) from our scFv library using biopanning on a flow cytometer. The successfully isolated clone maintained the binding specificities to S1T cells and indicated the strong cell death-inducing activity, suggesting this small fragment can be a candidate of antibody therapeutics for ATL. On the other hand, we also isolated the specific peptides toward human immunoglobulin G (IgG) from the random peptide library constructed on T7 phage display system. The isolated IgG-specific peptides were classified to two types of the peptides, Type I and II. Type I peptides recognized the normal conformation of IgG and was applied for the purification of IgG from human serum using the peptide-conjugated column. Type II peptide did not bind to the normal conformation of IgG but specifically recognized the alternative conformation of IgG induced by acidic condition. We would like to discuss about the potentials in the applications of these ligand molecules for the clinical and industrial uses.