利用噬菌体肽库筛选小肽免疫抑制剂

利用MT-2细胞系特异性表达白细胞介素2受体α(IL-2R α)在细胞表面,作为靶蛋白在噬菌体六肽库中筛选,经过4轮筛选得到能特异性结合IL-2R α的配体,挑选出与IL-2R α亲和性高的21个噬菌体克隆,经过DNA测序,得到3组肽序列,其中2组序列分别与白细胞介素2(IL-2)的N端17-24(LLLDLQMI)序列和C端114-121(IVEFLNRW)序列相似,另外一组与IL-2R β和γ有共同的保守序列(WSXWS)相似.因此推测这些筛选到的序列可能模拟IL-2与受体α相互作用的位点和IL-2R β,γ与α结合的位点.根据筛选结果,进一步合成了一个九肽AIVEFLNRW,以ConA诱导的淋巴细胞转化实验为模型,观察到这个肽在终浓度≥31.3μg/mL时抑制效果明显.

Searching for the Small Peptide Immunosuppressant in Phage Peptide Library

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.