Radioimmunoscintigraphy of colorectal cancer with technetium-99m-labeled murine anti-carcinoembryonic antigen monoclonal antibody in athymic nude mice

Abstract

Technetium-99m(Tc-99m) is an ideal radionuclide for clinical use. A murine monoclonal antibody (Mab) designated F33-104 binds to specific parts of carcinoembyronic antigen (CEA). In the present study, intact Mab F33-104 was labeled with Tc-99m, and the immunoreactivity and biodistribution of Tc-99m-labeled F33-104 were studied in athymic nude mice bearing human colorectal cancer xenografts. Mab F33-104, reduced under optimal conditions, was quickly and stably tagged with Tc-99m without loss of immunoreactivity. Higher tumor uptake of Tc-99m-labeled F33-104 was noted in the biodistribution, resulting in a higher localization index and specific-to-non-specific tumor ratio than those of radioiodinated F33-104. These results suggest the potential of Tc-99m-labeled Mab F33-104 for the radioimmunoimaging of colorectal cancer.

Different biodistribution of 99mTc-labelled chimeric mouse-human monoclonal antibody between athymic mice model and human

“…Antibody-HMDP mixture was then incubated with 740 MBq of 99"Tc pertechnetate eluted from a 9Mo/9Tc generator (Dainabot, Tokyo, Japan) for 10 min. The labelling efficiency was determined by the cellulose acetate electrophoresis and quantitative measurement as reported previously (Watanabe et al, 1994).…”

In Vitro and in Vivo Comparison of Binding of 99m-Tc-Iabeled Anti-CEA MAb F33-104 with 99m-Tc-labeled Anti-CEA MAb BW431/26

“…A murine MAb F33-104 (intact IgG,) reacting with B3-domain of CEA epitopes was generated by the hybridoma method (2). The MAb F33-104 was tagged with 99m-Tc by a reduction-mediated labeling method (4,8) with good immunoreactivity and tumor-localizing properties (10). In this study, the in vitro and in vivo binding of 99m-Tclabeled anti-CEA MAb F33-104 in tumor-model expressing CEA was compared with that of 99m-Tc-labeled anti-CEA MAb BW431/26, and the potential clinical use of 99m-Tc-labeled anti-CEA MAb F33-104 is discussed.…”

“…99m-Tc-labeled anti-CEA MAb F33-104 and 99m-Tc-labeled anti-CEA MAb BW431/26 were incubated with human normal serum and PBS (4 mM N a 2 H P 0 4 -7 H 2 0 , 1.4 mM K H 2 P 0 4 , 137 mM NaCl, 2.7 mM KCl, pH 7.2) as a control at 37° C for 0,3 and 18 h in an atmosphere of 5% carbon dioxide in air (11.8 jxg of MAb/ml of serum and PBS). The radiochemical purity was estimated by a cellulose diacetate electrophoresis method (4,10). Cellulose diacetate membrane (Separax-S®, Fuji Photo Film Co. Ltd., Tokyo, Japan) was cut into 110 mm X 10 mm strips, and these were soaked in 60 mM barbital buffer solution, pH 8.6.…”