Title: Three-step Pretargeted Radioimmunoimaging in Nude Mice Bearing Human B Cell Lymphoma by CD45 Monoclonal Antibody
Abstract: 【Objective】 To evaluate the value of three-step pretargeting radioimmuno imaging(RII) in nude mice bearing human B cell lymphoma by CD45 monoclonal antibody(mAb). 【Methods】 The radiolabeling of DTPA-biotin and CD45 mAb with99mTc was performed with direct method. 18 nude mice with implanted lymphoma by subcutaneous injection of Raji cells were randomly divided into two groups(9 per group). The first group was the three-step pretargeting RII in which first 100 μg of the biotinyled CD45 mAb was injected, followed by 200 μg avidin and finally received 7.4 MBq(20 μg) of the99mTc-biotin. Another group was the RII received 7.4 MBq(20 μg) of the99mTc-CD45 mAb. All nude mice were imaged at 3,6,and 12 h post-injection,and then immediately sacrificed for biodistribution study. The tissue and organ samples were collected, weighed and counted. Uptake of radioactivity in the tumor and normal tissues and organs was expressed as %ID / g and the ratio of tumor to normal tissue. 【Results】 The labeling ratio of99mTc-biotin was over 80% and for99mTc-CD45 mAb over 70%. In group of three-step pretargeting it was showed that there were the some radioactivity depositing in liver and spleen and less radioactivity retention in blood during the whole imaging. However for transplant tumor the tumor was clearly imaged at 3-6 h post-injection. It was also observed that the accumulation of radioactivity in tumor increased as time, and even at 12 h the tumor still be clearly imaged. The %ID / g of tumor at 3, 6, 12 h post-injection was 1.73 ±0.22, 1.24 ± 0.03, and 0.94 ± 0.07, respectively. And the ratios of tumor to blood reached 3.5, 4.9, and 7.8, respectively, while the ratios of tumor to muscle 8.2, 8.9 and 10.4, respectively. However, in group of99mTc-CD45 mAb the intensive radioactivity depositing in liver, spleen, kidney, blood and less radioactivity accumulation in tumor were observed. The %ID / g of tumor was 0.89± 0.13 at 12 h, and the ratios of tumor to blood and tumor to muscle reached 1.6 and 2.5, respectively. 【Conclusions】 Compared to99mTc-CD45 mAb, three-step pretargeting RII have improved the ratio of tumor to normal tissue. Tumor could be clearly revealed at 3hr post-injection.
Publication Year: 2014
Publication Date: 2014-01-01
Language: en
Type: article
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