Radioimmunolocalization of human pancreatic carcinoma xenograft by 99mTc-labeled YPC3 monoclonal antibody.
Monoclonal antibodies specific to tumor cells may be a useful tool for the diagnosis and treatment of carcinomas. In this study, YPC3 mAb, a specific monoclonal antibody against the human pancreatic carcinoma cell line Capan-2, was labeled directly with 99mTc after being pretreated with 2-mercaptoethanol. The radiolabeling efficiency was found to be high (88%-95%) and the immunoreactivity retained, as assessed by immunohistochemistry and enzyme-linked immunosorbent assay. The biodistribution of 99mTc-YPC3 mAb in nude mice bearing Capan-2 pancreatic carcinoma xenografts was studied and compared with that of labeled mouse immunoglobulin G(99mTc-nmIgG). The xenograft uptake values per gram of tissue 6 h and 24 h after injection of 99mTc-YPC3 mAb were found to be, respectively, 4.72%ID/g and 8.42%ID/g, and the tumor/blood ratios 1.16 and 2.24. At 6 h and 24 h after injection of 99mTc-nmIgG, the uptakes were 2.89%ID/g and 1.80%ID/g, and the tumor/blood ratios 0.84 and 1.02 respectively. External imaging by single-proton emission computed tomography, 24 h after injection of 99mTc-YPC3 mAb, revealed clear scintigraphic visualization of Capan-2 xenografts, whereas injection of 99mTc-nmIgG did not. This study suggests that 99mTc labeling of monoclonal antibody YPC3 might be of practical value in localization diagnosis of human pancreatic carcinoma.
Gastrointestinal Division of Internal Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University of Medical Sciences, P.R. China.
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Chen
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Yuan
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000918:Antibody Specificity; D004195:Disease Models, Animal; D006801:Humans; D000922:Immunotoxins / Q000493:pharmacokinetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism*; D016719:Radioimmunodetection / Q000379:methods*; D013667:Technetium / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
D000911:Antibodies, Monoclonal; D000922:Immunotoxins; D013667:Technetium