~(131)I标记抗CD80单克隆抗体在荷瘤裸鼠体内的放射免疫显像

目的探讨放射性核素131I标记抗CD80单克隆抗体及标记物在荷淋巴瘤裸鼠体内的放射免疫显像。方法采用Iodogen法进行抗CD80单克隆抗体4E5的131I标记,并对标记抗体的免疫活性及稳定性进行分析。经荷淋巴瘤裸鼠模型尾静脉注入剂量为7.4 MBq/0.2 ml的131I-4E5抗体,分别于注药后24 h、48 h和72 h进行SPECT平面显像,采用感兴趣区(ROI)技术进行半定量分析,计算肿瘤与非瘤组织的放射性计数比值(T/NT)。显像结束后处死荷瘤裸鼠,分别取肿瘤、血等14种脏器或组织称重并测量其放射性计数,计算各脏器或组织的每克组织百分注射剂量率(%ID/g)。结果131I标记单克隆抗体4E5的标记率为(78.3±2.4)%,放射化学纯度为(95.7±1.8)%;131I-4E5抗体与Raji细胞的最大结合率为(36.1±2.6)%,131I-4E5抗体加入到血清中放置3天后放化纯度仍90%;荷瘤裸鼠注入131I-4E5抗体后,随时间的延长,肿瘤部位放射性浓聚逐渐增加,在72 h时肿瘤显影最为清晰,T/NT值此时最大达到3.2。结论131I-4E5抗体在荷淋巴瘤裸鼠体内具有靶向定位能力,可获得良好的放射免疫显像图像,为进一步利用131I-4E5进行淋巴瘤CD80为靶点的放射免疫治疗奠定了基础。

Radioimmunoimaging of Anti-CD80 Monoclonal Antibody Labeled with 131I in Nude Mice Bearing Human B-cell lymphoma

Objective To explore the radioimmunoimaging of anti - CD80 monoclonal antibody labeled with 131I in nude mice bearing human lymphoma. Methods The monoelonal antibody 4E5 against human CD80 was radiolabeled with 131I using the Iodogen method at room temperature. The immune activity and stability of 131I -4E5 were analyzed. The plannar imaging of nude mice bearing human B -cell lymphoma was performed by SPECT at 24 h, 48h and 72 h after injection, and the radioactivity ratio of tumor to non -tumor tissue （T/NT） was assayed using the ROI technique. The injected dose/gramtissue percentages （% ID/g） of different organs, including tumor, blood, et al were measured by calibrator and calculated. Results The labeling rate of ,131I - 4E5 was （78.3±2.4） %, and the radiochemical purity was （95.7 ± 1.8 ） %. The madimun specif- ic binding efficiency of 131I - 4E5 with Raji cells was （ 36.1 ± 2.6 ） %. The radioehemieal purity of 131I - 4E5 mixing with serm was over 90% after three days. The radioimmunoimaging showed that 131I - 4E5 was selectively accumulated in tumor tis- sue. Tumors could be clearly visualized in SPECT planar images, and the T/NT reached their peak value of 3.2 in the tumor at 72 h after injection of 131I -4E5. Conclusion 131I -4E5 antibody can target the tumor tissue in nude mice bearing human lymphoma, and provide good radioimmunoimages, which lay a foundation for further study on the radioimmunotherapy of B - cell lymphoma.