抗IgE中和抗体表位的筛选和鉴定

Screening and identification of epitopes on human immunoglobulin E from 7^(TM) phage display peptide library

目的:对噬菌体线性7肽库进行筛选,得到诱发机体产生抗IgE中和抗体的IgE表位肽.方法:以抗IgE抗体为靶,筛选噬菌体线性7肽库,双夹心ELISA鉴定阳性克隆结果:ELISA鉴定随机挑选的经3轮筛选后所得48个噬菌体克隆,其中15个克隆显示与抗IgE抗体有较强的结合能力,序列测定得到氨基酸序列为:DHIDMGL;DHMWLGL;DHQD AGF;DHMDQNL.竞争性ELISA结果显示4个序列均能与IgE竞争性结合抗IgEmAb,MAP点杂交结果显示筛选得到的多肽能与抗IgE抗体特异性结合.结论:经筛选得到的7肽序列具有相似的骨架区,并与IgE的CH3区高度同源.初步验证这些噬菌体展示肽能与抗IgE中和抗体特异性结合,为IgE相关多肽疫苗的研究提供了依据.

AIM: To identify and characterize epitopes of human immunoglobulin E screened from 7 TMphage display peptide library. METHODS: The epitopes of human immunoglobulin E were screened from 7 TMphage display peptide library by using anti-IgE antibody as target protein and were identified by sandwich ELISA. RESULTS: After 3 rounds of screening, 15 of the 48 phage clones were identified as positive clones, which could bind to anti-human IgE antibody. The amino acid sequences of the positive clones were DHIDMGL, DHMWLGL, DHQDAGF and DHMDQNL. Competitive ELISA results demonstrated the competitive binding of the 4 sequences and IgG to anti-IgE mAb. Multiple antigenic peptides dot blot displayed that the screened multipeptides could specifically bind to anti-IgE antibody. CONCLUSION: The screened epitopes are similar in their framwork, and of extensive amino acid homology with IgE-CH3 region. These phage display peptides can bind specifically to anti-IgE antibody, providing a basis for further research on IgG related multipeptide vaccine.