Experimental study on the biodistribution and radioimmunotherapeutic use of 131I-labeled monoclonal antibody Nd2 in pancreatic cancer

We assessed the biodistribution and radioimmunotherapeutic use of anti-pancreatic cancer monoclonal antibody Nd2 in nude mice. In the biodistribution study, the percentage injected dose per gram of tumor was 16.4% at 12 hours, and 35.8%, 49.4%, and 43.1%, 1, 3, and 7 days, respectively, after intravenous injection. It was less than 6.0% in normal tissue. The tumor tissue concentration/blood concentration ratio was 0.55 at 12 hours and gradually rose to 3.66 on day 7, but the ratios for other organs were less than 0.5 throughout the entire period. Thus, there was high accumulation of 131I-labeled Nd2 in xenografts, but not in normal tissue, such as the reticuloendothelial system. In the radioimmunotherapy study injection of 200 μCi of 131I-labeled antibody showed that the xenografts gradually decreased in volume in nude mice injected 131I-Nd2, and were only 20% of their original size five weeks after injection. The xenografts in mice injected with 131I-non-specific IgG 1 increased in volume. These results indicate that 131I-Nd2 may be useful in the radioimmunotherapy of pancreatic cancer. (author)