目的:鉴定CD133+-HepG2肝癌细胞的干细胞特性,然后通过131I标记CD133单克隆抗体(131I-CD133抗体),研究其在人肝癌HepG2细胞裸鼠模型体内的生物学分布及对移植肿瘤的放射免疫靶向性。方法:采用免疫磁珠法分选出人肝癌CD133+-HepG2细胞,应用FCM法检测其CD133表达率,然后应用体外成球、克隆形成及体内成瘤实验鉴定其干细胞特性;采用氯胺T法制备131I-CD133抗体,并鉴定其标记率、放化纯度、稳定性及细胞结合活性;建立HepG2肝癌裸鼠模型,向模型鼠尾静脉注射131I-CD133抗体,2、12、24和48 h时测量并计算模型鼠体内各组织器官的每克组织百分注射剂量率;同时采用同型131I-IgG作为对照,比较24 h时2种标记物在HepG2肝癌裸鼠模型体内的各组织生物分布及肿瘤/非肿瘤组织比值。结果:成功分选出人肝癌CD133+-HepG2细胞,其CD133表达率为(93.58±3.74)%,并具有很强的体外成球、克隆形成及体内成瘤能力。131I-CD133抗体的标记率为(86.95±1.16)%,放化纯度为98.07%;与血清孵育48 h后,131I-CD133抗体的放化纯度仍为(89.63±0.64)%;131I-CD133抗体与CD133+-HepG2细胞的结合率最高可达(69.30±0.69)%。131I-CD133抗体注入HepG2肝癌裸鼠模型后,随着时间延长,包括肿瘤在内各组织器官的每克组织百分注射剂量率均降低;与131I-IgG对照组相比,131I-CD133抗体组在24 h时的肿瘤放射性摄取量以及肿瘤/非肿瘤组织(除血液和胃)比值明显增加(P<0.05)。结论:131I-CD133抗体在裸鼠体内能有效结合CD133+肝癌细胞,从而聚集在肿瘤组织中。推测CD133有可能成为肝癌治疗的新靶点。 OBJECTIVE: To identify the characteristics of stem cells of CD133 + -HepG2 hepatocarcinoma cells, and to study the biological distribution of 131I-CD133 monoclonal antibody (131I-CD133 antibody) in nude mouse model of HepG2 human hepatocellular carcinoma in vivo and the radioimmunoassay Sexuality. Methods: Human hepatocellular carcinoma CD133 + -HepG2 cells were sorted by immunomagnetic beads method. The expression of CD133 was detected by FCM. Then the stem cells were identified by in vitro immunospotting, cloning and in vivo tumorigenicity assay. 131I-CD133 antibody, and its labeling rate, radiochemical purity, stability and cell-binding activity were identified. The HepG2 hepatocellular carcinoma model was established in nude mice and the 131I-CD133 antibody was injected into the caudal vein of the model mice and measured at 2, 12, 24 and 48 h At the same time, the same type of 131I-IgG was used as a control to compare the biodistribution of each of the two markers in HepG2 hepatocarcinoma nude mice model and the tumor / Non-tumor tissue ratio. Results: The CD133 positive expression rate of CD133 + -HepG2 cells was (93.58 ± 3.74)%, and it had strong ability of spheroid formation, colony formation and in vivo tumorigenesis. The 131I-CD133 antibody was labeled with (86.95 ± 1.16)% and the radiochemical purity was 98.07%. After incubation with serum for 48 h, the radiochemical purity of 131I-CD133 was still (89.63 ± 0.64)%. The binding rate to CD133 + -HepG2 cells was up to (69.30 ± 0.69)%. After the 131I-CD133 antibody was injected into HepG2 hepatocarcinoma nude mice model, with the extension of time, the percent of injected dose per gram of tissue in all tissues and organs, including tumor, was decreased. Compared with 131I-IgG control group, 131I-CD133 antibody group The tumor radioactivity uptake and tumor / non-tumor tissue (except blood and stomach) ratio increased significantly at 24 h (P <0.05). Conclusion: The 131I-CD133 antibody can effectively bind CD133 + hepatoma cells in nude mice and thus accumulate in the tumor tissue. Speculated that CD133 may become a new target for the treatment of liver cancer.