中文摘要：

目的 探讨^99Tc^m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^99Tc^m标记及放射性HPLC分析,通过冷冻干燥法制备药盒,并观察^99Tc^m-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× 10^5.^99Tc^m-IgG的标记率大于95％,比活度为1.7×10^5 GBq/mmol.^99Tc^m-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,^99Tc^m-IgG注射后4h表现出持续的血液保留;24h时,^99Tc^m-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^99Tc^m-IgG并行生物学评价,对^99Tc^m标记蛋白工作具有一定借鉴意义.

英文摘要：

Objective To establish a novel direct radio-labeling method for ^99Tc^m-IgG and evaluate the biologic distribution of ^99Tc^m-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 ^99Tc^mO4-was analyzed with radio-HPLC.The product was prepared as frozen kits.The distribution and metabolic process of ^99Tc^m-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 1.47×10^5.The radiolabeling yield was over 95%,the specific activity was 1.7×10^5 GBq/mmol.All the radioactive conjugates of ^99Tc^m-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 ^99Tc^m-IgG was excreted mainly through the renal route.^99Tc^m-IgG kept its original biological activity after the modification.Conclusions Direct radio-labeling of ^99Tc^m-IgG was successfully established.The methods may be useful for radio-modification of monoclonal antibody.