目的 研究抗胃泌素释放前体（ProGRP(31-98)）单链抗体（scFv）的131I标记方法，并对其标记后的稳定性、免疫活性及生物分布进行分析。方法 采用氯胺T法碘化标记制备131I-anti-ProGRP(31-98)scFv，凝胶柱层析法分离纯化标记产物，利用纸层析法测定标记物的标记率、放化纯度和稳定性，采用细胞结合分析法比较131I-anti-ProGRP(31-98)scFv对小细胞肺癌细胞株NCI-H446和肺腺癌细胞株A549的免疫结合率。将131I-ProGRP(31-98)scFv注射入动物体内，研究其在实验动物体内的分布情况。结果 131I-anti-ProGRP(31-98)标记率为（93.35±0.67）%，标记产物纯化后即刻放化纯度为（98.49±1.21）%。131I-anti-ProGRP(31-98)scFv对人小细胞肺癌NCI-H446和肺腺癌A549细胞株的免疫结合率分别为（85.36±1.45）%和（21.02±2.16）%，且差异有统计学意义（P<0.05）。131I-anti-ProGRP(31-98) scFv在实验动物体内主要通过肾脏和肝脏代谢，血液清除快。结论 131I-anti-ProGRP(31-98)scFv的标记率高，且有良好的稳定性和免疫活性，在实验动物体内主要通过肝脏和肾脏代谢，血液清除快。

Objective To study the radiolabeling of anti-progastrin-releasing peptide single-chain antibody (anti- ProGRP(31-98)scFv) with 131I and evaluate its stability, immunological activity and biodistribution. Methods The anti-ProGRP(31-98)scFv was labeled with 131I by Chloramine-T method, and purified by gel column separation method. The labeling efficiency, radiochemical purity and stability were estimated by using paper chromatography. The immunological activity of radiolabeled antibody was detected with cell conjugation assay. The biodistribution of 131I-anti-ProGRP(31-98) scFv antibody was carried out in Kunming mice. Results The labeling efficiency and radiochemical purity of 131I-anti-ProGRP(31-98)scFv were 93.35±0.67% and 98.49±1.21%, respectively. The immunobinding ratios of 131I-anti-ProGRP(31-98)scFv for NCI-H446 cells and A549 cells were 85.36±1.45% and 21.02±2.16%, respectively（P<0.05）. The 131I-anti-ProGRP(31-98)scFv antibody was mainly digested through liver and kidney and with rapid elimination in blood. Conclusion 131I-anti-ProGRP(31-98) scFv has high labeling efficiency and good stability, and also keeps good immunological activity. It mainly metabolize thought liver and kidney and with rapid elimination in blood.