The Experimental Research Of MR Target Imaging On Nude Mouse Bearing Human Colon Carcinoma By Pretargeting Strategy

Objective1, Antihuman colon carcinoma monoclonal antibody CL3 was labeled with biotin using biotinl-N-hydroxysuccinimide ester(BNHS). The antigen binding activity and numbers of coupled biotin molecule were determined.2, Streptavidin(SA) was labeled with Gd³⁺ using DTP A cyclic anhydride(cDTPA).The SA activity units , biotin binding character, numbers of labeled Gd3+ and the effect of SA-DTPA-Gd on r1 relaxation rate were determined.3, CL3 , avidin and SA-DTPA-Gd were administered in sequence and the enhancement effect on nude mouce bearing human colon carcinoma was investigated in order to manifest the result of BAS mediated MR pretargeting imaging on small tumor;CL3-B was administered intraveniously and intraperitonealy by which different distribution pattern of binding site for SA-DTPA-Gd was made in order to investigated the effect of distribution patern of the binding site in tumors on the penetration of target material.Materials and MethodsThe preparation of biotinylated monoclonal antibodyCL3 was dissolved in 0.1M bicarbonate buffered saline .NHS-B was dissolvedin DMSO,whose concentration was 20mg/ml. While stiring, NHS-biotin was addedslowly to monoclonal antibody solution at molar ratio of 20:1.The mixture was gently...