Therapy with 125I-labelled internalized and non-internalized monoclonal antibodies in nude mice with human colon carcinoma xenografts.

The therapeutic effects of 125I-labelled (18-97 MBq) monoclonal antibodies (MAb) C-242, C-215 and S-S.1 were studied in nude mice with human colorectal adenocarcinoma tumours. The antibodies were administered 2 or 10-16 days after implantation of the tumour cells. The monoclonal antibody C-242 was internalized into the tumour cells, C-215 was internalized to a lower degree while S-S.1 (unspecific MAb) was not internalized at all. No enhanced therapeutic effect of 125I-C-242 was observed, as a result of Auger electrons, compared with 125I-C-215 and 125I-S-S.1.