^(99m)Tc-labeled HAb18 McAb Fab fragment for radioimmunoimaging in nude mice bearing human hepatocellular carcinoma

AIM To establish a method of labeling anti hepatoma McAb (HAb18) Fab fragment modifier with 99m Tc. METHODS HAb18 Fab was modified with 2 iminotholane and labeled with 99m Tc by transchelation from 99m Tc GH. Labeling yield, radiochemical purity and immunoreactivity were determined by thin layer chromatography (TLC SG), paper chromatography (PC), gel chromatography (GC) and cell binding assay, respectively. The nude mice bearing human hepatoma were used for radioimmunoimaging (RII). RESULTS A radiolabeling yield of 50%-80% was obtained, and immunoreactivity (IR) was 30%-40%. Radioimaging results showed that 99m Tc HAb18 McAb Fab fragment was concentrated in the tumor 4-8 hours after injection, and the maximum concentration was seen in 12-24 hours, and the T/NT value was 5 18 and 7 48 at 6h and 8h after the injection. CONCLUSION 99m Tc HAb18 McAb Fab fragment could be specifically localized in the tumor of nude mice bearing human hepatocellular carcinoma within 24 hours and this method might be effectively used for labeling McAb Fab fragment with