论文部分内容阅读
目的利用生物素亲和素系统(biotin avidinsystem,BAS)的靶向定位效应和生物放大作用,提高MR分子免疫成像的敏感性。方法制备生物素化抗人肝癌细胞单克隆抗体HAb18并测定其生物素化程度及抗原结合活性。20只荷人肝细胞癌裸鼠分为3组,二步法预定位组8只,先静脉注射生物素化单克隆抗体600μg,24h后再给予钆喷替酸葡甲胺链霉亲和素(Gd DTPA streptavidin,Gd DTPA SA);HAb18单克隆抗体Gd DTPA组6只,经尾静脉注射Gd DTPA HAb18;Gd DTPA对照组6只,静脉注射Gd DTPA。对实验动物行MR扫描,测量SET1WI平扫及增强后10、30、60min及3、6、12、24、48h图像内肿瘤的信号强度,绘制信号强度时间曲线,并计算肿瘤强化率及对比度噪声比(contrast to noiseratio,CNR)。结果HAb18单克隆抗体经生物素化后,每个抗体分子平均可结合20个分子生物素,其抗原结合活性约为91%。二步法预定位组内,肿瘤信号强度缓慢升高,增强后第6小时,肿瘤的强化率、CNR达到最大值,与其他两组相比较差异有统计学意义。48h后,肿瘤的强化仍肉眼可辨。单克隆抗体组内,肿瘤表现为缓慢轻度强化,增强后24h的强化率达13.5%,肿瘤信号强度、CNR与平扫比较差异均有统计学意义(P值均<0.05)。Gd DTPA对照组内,肿瘤表现为快进快出特点的强化特点。结论二步法预定位技?
OBJECTIVE: To improve the sensitivity of MR molecular immuno-imaging using the targeting effect and biomagnification of biotin avidinsystem (BAS). Methods Biotinylated anti-human hepatocellular carcinoma cell monoclonal antibody HAb18 was prepared and its biotinylation degree and antigen-binding activity were determined. Twenty human hepatocellular carcinoma nude mice were divided into three groups, two-step pre-targeted group of eight, the first intravenous injection of biotinylated monoclonal antibody 600μg, 24h and then given gadolinium pentosidine acid streptozotocin streptavidin Gd DTPA streptozotocin (Gd DTPA SA); Gb DTPA group; HAb18 monoclonal antibody Gd DTPA group; Gd DTPA HAb18 was injected through tail vein; Gd DTPA control group was injected with Gd DTPA. The MR scan of the experimental animals was performed to measure the signal intensities of the tumors within 10, 30, 60min and 3, 6, 12, 24 and 48h after the SET1WI scan and the enhancement, and the signal intensity time curve was plotted. The enhancement rate and contrast noise Contrast to noiseratio (CNR). Results After biotinylation of HAb18 monoclonal antibody, an average of 20 molecules of biotin could be bound to each antibody molecule with an antigen binding activity of about 91%. In the two-step pre-positioning group, the tumor signal intensity increased slowly. At the 6th hour after the enhancement, the enhancement rate of the tumor and CNR reached the maximum, which was statistically significant compared with the other two groups. Forty-eight hours later, the enhancement of the tumor was still visible to the naked eye. In the monoclonal antibody group, the tumors showed mild mild enhancement and 13.5% enhancement after 24 h enhancement. There was significant difference in tumor signal intensity, CNR and plain scan (all P <0.05). Gd DTPA control group, the tumor showed the characteristics of the fast forward fast features. Conclusion two-step pre-positioning technology?