Abstract: Interleukin 2(IL-2) and its receptor(IL-2R) constitute one of the most extensively studied cytokine receptor systems. Thus ,we used MT-2 cells that could specifically express IL-2R α on the surface to screen a random hexa-peptide library and obtained the phage clones which had good combinative activities studied by Elisa. After DNA sequencing , three groups of relative peptide sequences were founded. The two groups were respectively similar to the sequence of IL-2(N-terminal) at amino acids 17-24 (LLLDLQMI) and the sequence of IL-2(C-terminal) at amino acids 114-124 (IVEFLNRW). In addition , the other group was similar to the motif (WSXWS) of IL-2R β,γ. Therefore ,it is inferred that these sequences might have mimicked the interaction site of IL-2 ／IL-2R and the binding site of IL-2R αand β,γ. Further the synthesized peptide(AIVEFLNRW) could inhibit the T lymphocyte proliferation. These results provided the basis for the research and the development of the small peptide immunosuppressant drugs.

Key words: phage peptide library, immunosuppressant, interleukin 2 receptor α, organ transplantion