摘要目的 探讨99Tcm标记IgG分子及相关药盒的制备方法并进行生物学评价.方法 利用巯基乙醇还原法对IgG进行分子修饰,采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)、紫外分光光度法和基质辅助激光解析电离飞行时间质谱(MALDI-TOF)方法测定修饰后IgG-SH的浓度、完整性;对IgG-SH进行99Tcm标记及放射性HPLC分析,通过冷冻干燥法制备药盒,并观察99Tcm-IgG在新西兰大白兔体内的代谢情况.结果 SDS-PAGE检测显示修饰后的IgG-SH与修饰前的IgG相比相对分子质量无明显变化,MALDI-TOF测定其相对分子质量为1.47× 105.99Tcm-IgG的标记率大于95％,比活度为1.7×105 GBq/mmol.99Tcm-IgG在PBS中稳定性良好,在质量分数5％ BSA中放置6h放化纯＞95％.大白兔γ显像示,99Tcm-IgG注射后4h表现出持续的血液保留;24h时,99Tcm-IgG主要通过肝肾代谢;修饰后的IgG-SH保持了原有的抗体性质.结论 该研究成功制备了99Tcm-IgG并行生物学评价,对99Tcm标记蛋白工作具有一定借鉴意义.

abstractsObjective To establish a novel direct radio-labeling method for 99Tcm-IgG and evaluate the biologic distribution of 99Tcm-IgG.Methods IgG protein was modified with 2-mercaptoethanol.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE),UV-vis spectrophotometer,matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) were used to identify the concentration,integrity of the modified protein.Then radiolabeled IgG-SH with 99TcmO4-was analyzed with radio-HPLC.The product was prepared as frozen kits.The distribution and metabolic process of 99Tcm-IgG were observed in New Zealand white rabbits.Results The relative molecular mass of IgG-SH and IgG measured by SDA-PAGE were similar.The relative molecular mass measured by MALDI-TOF was 1.47× 105.The radiolabeling yield was over 95％,the specific activity was 1.7× 105 GBq/mmol.All the radioactive conjugates of 99Tcm-IgG showed excellent stability in vitro.And more than 95％ conjugates retained their original structures for 6 h in 5％ BAS.Gamma imaging in New Zealand white rabbits showed blood retention in first 4 h after injection,and prominent uptake of radiotracers in the liver,kidneys,and urinary bladder at 24 h after injection,which indicated that 99Tcm-IgG was excreted mainly through the renal route.99Tcm-IgG kept its original biological activity after the modification.Conclusions Direct radio-labeling of 99Tcm-IgG was successfully established.The methods may be useful for radio-modification of monoclonal antibody.