能与SLE患者血清总IgG抗体识别的噬菌体抗原表位模拟肽的研究

目的：从噬菌体随机肽库中，筛选能与SLE患者血清总IgG抗体特异结合的SLE相关抗原表位的噬菌体模拟肽，并寻找对SLE敏感性和特异性均高的模拟肽。方法：制备SLE患者血清总IgG抗体，以此作为筛选配基，按“吸附一洗脱一扩增”的淘洗过程，对噬菌体随机12肽库进行3轮免疫筛选，随机挑取噬菌体克隆并进行初步鉴定，最后取混合阳性克隆检测SLE患者和正常人血清，分析其与SLE反应的敏感性和特异性。结果：经3轮免疫淘洗后，特异结合的噬菌体富集增加近100倍。随机挑取的11个噬菌体克隆，经鉴定均能与总IgG抗体产生特异性反应，阳性率100%。混合的阳性克隆与SLE反应的敏感性和特异性分别为80%、和67％。结论：利用SLE患者血清总IgG抗体筛选噬菌体随机肽库，能获得多种SLE相关抗原表位的噬菌体模拟肽，因其对SLE的敏感性和特异性均高，故有潜在的诊断价值，有望利用该技术开发SLE特异性IgG抗体检测试剂盒.

The Study of phage mimetic peptides that could be recognized by serum IgG of SLE patients

Objective: To screen mimetic peptides of SLE related antigens that could be recognized by serum IgG of SLE patients from phage random polypeptide library displayed by phage, and to provide useful information for further study of the interaction between antigen and antibody in SLE patients. Methods: IgG was purified from sera of patients with SLE and was used as the ligand for biopanning of a phage-displayed random peptide library of 12 amino acid residuces. The positive phage clones were obstained through three rounds of biopanning. Double-antibody sandwich ELISA and Dot-ELISA were used to evaluate the characteristics of binding between phage-borne peptides and IgG of SLE patients. Mixed positive phage clones were used to detect SLE patients' sera and healthy persons' sera by Dot-ELISA. Results: The eluted phages were enriched nearly to 100 fold through three rounds of biopanning. In 11 phage clones selected randomly from the third round biopanning, all clones of them had an A_595 value 2.1 times higher than that of negative controls by sandwich ELISA. And Dot-ELISA tests proved that 11 phage clones could bind to IgG. The binding rate of mixed positive phage clones with IgG of SLE patients was significantly higher than that of healthy persons. Conclusion: By the use of serum IgG antibodies to screen the phage random polypeptide library, one can obtain multiple phage mimetic peptides of SLE related antigen epitope. Because of their high sensitivity and specificity for SLE, they possess potential diagnostic value, and this technique could be used to develop the kit for detecting SLE specific antibodies.