The Korean Journal of Nuclear Medicine (대한핵의학회지)

The Korean Society of Nuclear Medicine (대한핵의학회)
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$^{99m}Tc-Labeling$ of Monoclonal Antibody to Carcinoembryonic Antigen and Biodistribution

항 암태아성항원에 대한 단세포군항체의 $^{99m}Tc$ 표지법개발 및 생체분포

  • Moon, Dae-Hyuk (Department of Nuclear Medicine, Asan Medical Center, University of Ulsan, College of Medicine) ;
  • Chung, June-Key (Department of Internal Medicine, Cancer Research Institute Seoul National University, College of Medicine) ;
  • Lee, Myung-Chul (Department of Internal Medicine, Cancer Research Institute Seoul National University, College of Medicine) ;
  • Koh, Chang-Soon (Department of Internal Medicine, Cancer Research Institute Seoul National University, College of Medicine) ;
  • Chung, Hong-Keun (Department of Biochemistry, Cancer Research Institute Seoul National University, College of Medicine) ;
  • Park, Jae-Gahb (Department of General Surgery, Cancer Research Institute Seoul National University, College of Medicine)
  • 문대혁 (울산대학교 의과대학 아산재단 서울중앙병원 핵의학과) ;
  • 정준기 (서울대학교 의과대학 내과학교실 및 암연구소) ;
  • 이명철 (서울대학교 의과대학 내과학교실 및 암연구소) ;
  • 고창순 (서울대학교 의과대학 내과학교실 및 암연구소) ;
  • 정홍근 (서울대학교 의과대학 생화학교실 및 암연구소) ;
  • 박재갑 (서울대학교 의과대학 일반외과학교 및 암연구소)
  • Published : 1992.12.31
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Abstract

This study was designed to evaluate a direct method of $^{99m}Tc$ labeling using $\beta-mercaptoethanol$ as a reducing agent, and to investigate whether $^{99m}Tc$ labeled specific monoclonal antibody against carcinoembryonic antigen (CEA-92) can be used for the scintigraphic localization of human colon cancer xenograft. Purified CEA-92 IgG was fragmented into F $(ab')_2$ and then labeled with $^{99m}Tc$ by transchelation method using glucarate as a chelator. Labeling efficiency, immunological reactivity and in vitro stability of $^{99m}Tc$ CEA-92 F $(ab')_2$ were measured and then injected intravenously into nude mice bearing human colon cancer (SNU-C4). Scintigrams were obtained at 24 hour after injection. Then nude mice were sacrificed and the radioactivity was measured Labeling efficiency of injected $^{99m}Tc$ CEA-92 F $(ab')_2$, immunoreative fraction and in vitro stability at 24 hour of injected $^{99m}Tc$ CEA-92 F $(ab')_2$ was 45.2%, 32.8% and 57.4%, respectively. At 24 hour after injection, % ID/g in kidney (46.77) showed high uptake, but %ID/g in tumor (1.65) was significantly higher than spleen (0.69), muscle (0.16), intestine (0.45), stomach (0.75), heart (0.48) and blood (0.45). There was no significant difference between tumor and liver (1.81). Tumor contrast as quantitated by tumor to blood ratio of $^{99m}Tc$ CEA-92 F $(ab')_2$ was increased significantly (p<0.005) until 24 hours (3.70), and there was no statistical differece from tumor to blood ratio of I-131 CEA-92 F $(ab')_2$. The scintigram demonstrated localization of radioactivity over transplanted tumor, but significant background radioactivity was also noted over kidney and abdomen. It is concluded that CEA-92 F $(ab')_2$ can be labeled with $^{99m}Tc$ by a direct transchelation method using $\beta-mercaptoethanol$ as a reducing agent and $^{99m}Tc$ labeled CEA-92 F $(ab')_2$ can be used for the scintigraphic localization of human colon cancer xenograft in nude mice model.

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