Title: Labelling of anti-human bladder tumor chimeric antibody with 99 Tc m and radioimmunoimaging of bladder carcinoma xenograft in nude mice
Abstract: Objective To study the in vitro immunoreactivity and in vivo tissue distribution, tumor targeting property of anti-human bladder tumor human-murine chimeric antibody (ch-BDI) labeled with 99Tcm and to investigate its possibility for being used in guiding diagnosis and guiding therapy of bladder cancer. Methods The ch-BDI was labeled with 99Tcm by improved Schwarz method and the labeled antibody was purified by Sephadex G-50. Labeling yield and radiochemical purity were measured by paper chromatography. The immunoreactive fraction and association constant (K a) were measured by Lindmo method and Scatchard analysis, respectively. 11.1 MBq(30 μg) 99Tcm-ch-BDI was intravenously injected into nude mice bearing human bladder cancer xenografts in the right thigh and radioimmunoimaging (RII) was performed 2, 6, 20 and 24 h postinjection. The images were processed by region of interest (ROI) method to acquire the counts of whole body and the tumor and the counts ratios of tumor to contralateral normal tissue or to tissues of other non-tumor bearing organs. The mice were killed after 24 h postinjection imaging and tissue distribution was measured. %ID/g and target to nontarget (T/NT) ratios were calculated. Results The labeling yield and radiochemical purity of 99Tcm-ch-BDI were (66.5±7.3)% and 90%,respectively. The immunoreactive fraction was 76% and K a was 3.56×109 L/mol. RII showed that the tumor was clearly visualized 6 h postinjection and becoming clearer along with time prolonging. The radioactivity of whole body decreased rapidly with time, whereas the radioactivity of the tumor decreased slowly. The T/NT ratios was increased with time. Biodistribution results showed that tumor uptake was 17.4 %ID/g 24 h postinjection. T/NT ratios were very high except for the kidney. T/NT ratios for brain, muscle, intestinal wall, bone and heart wall were 136.0, 55.1, 39.3, 29.7 and 27.9, respectively. Conclusion 99Tcm-ch-BDI exhibits excellent immunoreactivity and tumor targeting property and has potential applications in guiding diagnosis and guiding therapy of bladder cancer.
Publication Year: 2003
Publication Date: 2003-01-01
Language: en
Type: article
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