ABSTRACT
A monoclonal antibody, C215, was first internally labelled with 75Se-methionine and then labelled with 125I. The biodistribution of the dual-labelled [125I][75Se]C215 was studied in tumour-bearing nude mice killed 3 days after injection. The biodistribution of the dual-labelled [125I][75Se]C215 was compared with the biodistribution of single-labelled [131I]C215 and [75Se]C215. Iodine-labelled antibodies seem to be damaged during iodination, affecting the disappearance rate and tumour uptake. There were no signs of dehalogenation of circulating antibodies or antibodies taken up in the tumour.
Subject(s)
Antibodies, Monoclonal/pharmacokinetics , Iodine Radioisotopes/chemistry , Isotope Labeling , Selenium Radioisotopes/chemistry , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Animals , Antibodies, Monoclonal/chemistry , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Female , Humans , Kidney/metabolism , Liver/metabolism , Mice , Mice, Inbred BALB C , Mice, Nude , Neoplasm Transplantation , Tissue DistributionABSTRACT
A monoclonal antibody, C-215, against colon cancer, was internally labelled with [75Se]methionine. The biodistribution was studied in tumour-bearing nude mice and compared with the biodistribution of [131I]C-215. The tissue uptake was divided into three parts: antibody bound to the antigen, antibody in the extracellular space and uptake of the released radionuclide. [75Se]C-215 showed a greater amount of antigen-bound antibody in the tumour, but also a greater unspecific uptake both in tumour and normal tissue.
