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胃泌素释放肽前体(progastrin-releasingpeptide(31-98), ProGRP(31-98))是一种灵敏、可靠的小细胞肺癌标志物, 在小细胞肺癌的早期诊断中优于其他指标, 有关ProGRP的研究近年来较活跃[1-5]。抗Pro-GRP(31-98)单链抗体(anti-ProGRP(31-98) single-chain anti-body fragment, anti-ProGR(31-98) scFv)是中国辐射防护研究院通过基因工程改造的一种单链抗体, 本研究对anti-ProGRP(31-98) scFv的131I标记方法及其稳定性和免疫活性进行了研究, 现报道如下。
131I标记抗胃泌素释放前体单链抗体的制备及其稳定性和免疫活性研究
Preparation and evaluation of 131I-anti-ProGRP(31-98) single-chain antibody fragment
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摘要:
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和免疫活性进行分析。 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、放化纯和稳定性,通过细胞结合试验测定131I-anti-ProGRP(31-98) scFv的免疫活性。 结果 131I-anti-ProGRP(31-98)标记率为93.35%。标记产物纯化后即刻放化纯为98.49%,在37℃水浴箱中放置24 h后放化纯为94.59%,48 h后测定仍大于90%,与正常人血清充分混合24 h后放化纯为85.16%,48 h测定大于80%。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%和21.02%。 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,有望成为高表达ProGRP的恶性肿瘤放射免疫显像及治疗药物,值得进一步深入研究。 Abstract:Objective Tostudythe 131I labeling methods, stability and immunological activity of antiprogastrin-releasing peptide(31-98) single-chain antibody(anti-ProGRP(31-98) scFv). Methods The anti-Pro-GRP(31-98) scFv was labeled by Chloramine-T method using 131I, and purified by gel column separation method. The labeling efficiency, radiochemical purity and stability were estimated by using paper chromatography. Immunological activity was detected with cell conjugation assay. Results The labeling efficiency and radiochemical purity of 131I-anti-ProGRP(31-98) scFv were 93.35%and 98.49%, respectively.The radiochemical purity was 94.59%after incubation in water bath at 37℃ for 24h, and still maintained above 90%for 48 h. After incubation with healthy human serum for 48 h, the radiochemical purity was still above 80%.The immunobinding ratios of 131I-anti-ProGRP(31-98) scFv for NCI-H446 cells and A549 cells were 85.36%and 21.02%, respectively. Conclusions 131I-anti-ProGRP(31-98) scFv not only has high labeling efficiency and radiochemical purity, but also has good stability and keeps good immunological activity.Therefore, it could be a promising agent for radioimmunoimaging and radioimmunotherapy for the malignant tumors which highly express ProGRP. -
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