目的  从肿瘤患者外周血中构建全人源单链可变区抗体基因库，并采用真核核糖体展示技术高效筛选全人源抗表皮生长因子受体（epidermal growth factor receptor，EGFR）单链抗体。方法  采用PCR技术从52例晚期肿瘤患者外周血中构建大容量的全人源抗体基因库。针对EGFR抗原靶标，应用真核核糖体展示技术对该基因库进行高效富集筛选。通过大肠埃希菌表达体系对回收的基因库进行克隆、表达，并鉴定抗体活性。结果  构建的全人源抗体基因库库容估算为4.3×10¹³分子。对该基因库进行3轮富集筛选后，获得EGFR富集的单链抗体基因库。对回收基因库进行克隆、表达，并随机鉴定了49个克隆，获得结合力为10^-8~10^-7 mol/L的2株全人源抗EGFR单链抗体。结论  利用肿瘤患者外周血，结合核糖体展示技术可以较快获得具有医用价值的全人源单链抗体。

Objective  To construct a fully human single-chain variable fragment (scFv) DNA library and select anti-epidermal growth factor receptor (EGFR) scFvs using ribosome display technology. Methods  A fully human scFv library was constructed with peripheral blood samples collected from 52 advanced cancer patients. Eukaryotic ribosome display was used to screen anti-EGFR scFvs from the library. The selected scFvs were then expressed in E. coli and purified. Their binding affinities were validated by ELISA. Results  The size of constructed human scFv DNA library was 4.3×10¹³. After 3 rounds of selection, 49 unique clones were recovered. The top two binders were further purified and their binding affinities were determined by ELISA to be 10^-8-10^-7 mol/L. Conclusion  Ribosome display is an efficient screening method to obtain high affinity scFvs that may serve as potential therapeutic candidates.