利用噬菌体随机肽库筛选Rh(D)血型抗原的模拟表位

Mimic epitope of Rh ( D) blood group antigen selected from a phage display random peptide library

目的从纯化的人抗Rh(D)抗体阳性血清中筛选Rh(D)血型抗原模拟表位。方法用纯化的多克隆抗Rh(D)抗体血清对噬菌体随机十二肽库进行3轮"吸附-洗脱-扩增"过程筛选,随机挑取噬菌体克隆;用ELISA法检测其特异性及其与抗体的结合能力。提取阳性克隆DNA并进行测序,推导外源多肽的氨基酸序列。凝集抑制试验检测噬菌体展示的多肽对Rh(D)血型抗原结合的模拟作用。结果经过3轮筛选和相应鉴定后得到6个抗Rh(D)抗体的特异性噬菌体克隆,其中4个克隆展示相同的氨基酸序列为PSQGYVILLDEK,命名为C2,另外2个克隆展示相同的氨基酸序列为TMLNRAHDFSEC,命名为C21。凝集抑制试验结果表明这两个多肽的噬菌体可以抑制Rh(D)抗原阳性红细胞的凝集作用。结论多肽PSQGYVILLDEK和TMLNRAH-DFSEC可以模拟Rh(D)血型抗原表位。

Objective To screen the mimic epitope of Rh （D） blood group antigen from purified positive anti-Rh （D） antibody serum. Methods A twelve mer phage peptide library was biopanned with purified anti-Rh （D） polyclonal antibody serum. Clones were randomly selected and were identified by ELISA for specificity and the abil- ity of the bond between clones and antibodies. DNA sequencing of positive clones were performed to- deduce the a- mino acid sequence of exogenous polypeptide. The hemagglutination inhibition （HI） test detected the simulation effect of the combination between phage-displayed peptide and Rh （D） blood group antigen. Results After pan- ning three times and corresponding identification, 6 specific clones of anti-Rh （D） antibody were obtained. Four of them displayed the same amino acid sequence as PSQGYVILLDEK, and were named C2. Other two clones were named C21 which displayed the same amino acid sequence as TMLNRAHDFSEC. The results of HI test showed that phages that displayed these two polypeptides could inhibit the agglutination of Rh （D） antigen positive red blood cells. Conclusion The polypeptides PSQGYVILLDEK and polypeptides TMLNRAHDFSEC could mimic the antigen epitope of Rh（D） blood type.