微量^(131)I标记抗CD20单克隆抗体的标记及储存方法探讨

Study of Suitable Techniques and Optimal Storage Condition for Labeling Rituximab with ^(131)I

目的探讨微量131I标记抗CD20单克隆抗体的标记方法和储存条件。方法采用IODO-GEN碘化标记方法,检测不同标记时间(2、4、6、8分钟)和不同标记比例(l∶10、1∶15、1∶20)时标记物的标记率、放化纯度及免疫活性;并检测不同存放时间和储存条件下放化纯度的变化。结果标记时间4分钟以上标记率即可达90%、放化纯度达98%,标记4分钟的标记物免疫活性高于6、8分钟(P<0.05)。当重量(mg)与放射性活度(mCi)比为1∶10时,标记率、免疫活性高于1∶15、1∶20(P<0.05)。标记物内加l%人血清白蛋白注射液、37℃CO2孵箱储存放化纯度高于原液4℃储存(P<0.05)。结论微量、高比活度131I-Rituximab标记时重量(mg)与放射性活度(mCi)比为1∶10、标记时间为4分钟,宜内加1%人血白蛋白37℃CO2孵箱储存、时间不超过24小时。

Objective To exploit the techniques suitable for labeling Rituximab with 131I and to determine the optimal storage condition. Methods 131I was labeled with Rituximab by IODO-GEN, detecting the labeling efficiency, radiochemical purity and immunoreactive fraction of 131I-Rituximab at different reaction time （2, 4, 6, 8 minutes） and different specific mass-radioactivity ratio （1 ∶ 10, 1 ∶ 15, 1 ∶ 20）, and measuring the changes of radiochemical purity in 0 ~ 5 days at different storage conditions. Results The labeling efficiency was over 90% and the radiochemical purity was over 98% when the reaction time was more than 4 minutes. The immunoreactive fraction of 4 minutes was higher than 6 and 8 minutes （P 0.05）. The labeling efficiency and immunoreactive fraction at 1 ∶ 10 were both higher than those at 1 ∶ 15 and 1 ∶ 20 （P 0.05）. The radiochemical purity was higher when 131I-Rituxmab stored with 1% human serum albumin （HSA） at 37 ℃ rather than pure 131I-Rituxmab at 4℃ （P 0.05）. Conclusion The optimal conditions for labeling Rituximab with 131I lie in two aspects： 4 minutes of reaction time and 1 ∶ 10 ratio of mass-radioactivity. 131I-Rituxmab should be stored with 1% human serum albumin （HSA） at 37 ℃ in 24 hours.