~(125)|标记的免疫毒素(TCS-Hepama-1)在荷人肝癌裸鼠体内分布及肿瘤显像

~(125)I标记的免疫毒素TCS-Hepama-1及对照用TCS-NM IgG在荷瘤裸鼠体内分布及肿瘤显像结果表明:实验组裸鼠尾静脉注入~(125)I-TCS-Hepama-1后第2天,血的放射性最高,随着时间延长,血及各组织器官的放射量逐渐减少,而肿瘤组织的每克放射剂量逐渐增多,第6天起T/NT值均＞1,第8天达最高,瘤/血、瘤/肝比为1.45及2.05。与对照组的比值0.31和0.97相比,差异显著(P＜0.05)。实验组从第2天起肿瘤即显示阳性定位,随肿瘤内放射浓度增加,肿瘤显像逐渐清楚,以第8天最为清晰。而对照组的裸鼠放射性呈全身均匀分布,肿瘤内未见浓聚,随时间延长放射性均匀减弱。说明Hepama-1在免疫毒素中仍保持其识别功能,免疫毒素TCS-Hepama-1在荷瘤裸鼠体内对人肝癌组织有很高的专一亲和力。

Distribution and Imaging of I-125-Labelled TCS-Hepama-1 Immunotoxin in Human Hepatoma in Tumor-bearing Nude Mice

Trichosanthin (TCS) is extracted from Trichosanthes-kirilowii which is a Chinese herbal medicine. Hepama-1 is a monoclonal antibody with specific affinity to hepatoma. TCS-Hepama-1 acted as immunotoxin is prepared with TCS and Hepama-1 through bisulphuric bond. Distribution and radioimaging of I-125-la-belled TCS-Hepama-1 and its analogue TCS-NMIgG as control in human hepatoma bearing nude mice were observed. The results showed that (1) considerable radioactivity was detectable in blood 2 days after injection of I-125-TCS-Hepama-l and faded out soon. However, radioactivity in tumor was strengthened gradually reaching a peak on the 8th day; (2) the tumor/nontumor radioactivity ratio exceeded 1 from the 6th day after injection while the tumor/blood and tumor/liver ratios were 1. 45 and 2. 05 respectively on the 8th day, which were obviously higher than the ratios 0. 31 and 0. 97 in the control group (P<0. 05); (3) all tumors in the experimental group were positively visualized with gamma camera being best on the8th day.The radioactivity in the control group showed generalized distribution in the body, with no sign of tumor predisposition.The results suggested that TCS-Hepama-1 immunotoxin has good specificity and affinity to human hepatoma in tumor-bearing nude mice.