血清肝癌特异性结合多肽的筛选

The screening of liver cancer specific binding peptide from serum

目的从噬菌体展示肽库中筛选出能够用于血清学筛查的多肽。方法利用M13噬菌体随机展示肽库，对15例临床确诊肝癌患者的血清和15例正常体检者的血清进行4轮吸附-洗脱筛选。挑取筛选后的噬菌体单克隆，用血清试验筛选特异性及阳性率较高的单克隆。目标单克隆通过DNA测序确定其表达的多肽序列，进而人工合成带FITC标记的多肽，再对血清进行鉴定。结果随机挑取的50个经过4轮筛选的噬菌体单克隆。通过血清试验，从中筛选出9个特异性和确诊率较高的单克隆，其中单克隆ZH-3对肝癌血清确诊率达到46．7％。ZH-3经DNA测序分析，确定其表达的多肽序列为：SAHGTSTGVPWP。结论ZH-3多肽在肝癌患者血清中有一定的检出率，提示ZH-3多肽能够为研发肝癌诊断试剂奠定基础。

Objective To find the liver cancer specific peptide for serological screen of liver cancer patients via screening phage-display peptide library. Methods Fifteen sera from liver cancer patients and physical examinates were collected for the four-round screening with Ph. D.-12^TM phage display peptide kit. Highly specific phage monoclones were selected based on the ELISA results of the serological assay. The peptide labeled with FITC was synthesized according to the DNA sequencing of the optimal monoclone and tested with serum via fluorescent imagery. Results Nine highly specific monoclones were found among 50 selected ones after 4 rounds of screenings. The positive rate of the optimal monoclone, ZH-3, reached 46.7% . The peptide sequence of ZH-3 was concluded by DNA sequencing as SAHGTSTGVPWP. Desirable specificity and affinity were also shown in the serum of liver cancer patients. Conclusion The peptide ZH-3 can be used as a diagnostic reagent for liver cancer.