Radioimmunotherapy of human glioma xenografts in nude mice by indium-111 labelled internalising monoclonal antibody

The potential of (111)Indium (In-111)-labelled internalising anti-integrin alpha 3 antibody GA17 in the radioimmunotherapy of human glioblastoma xenografts in nude mice was investigated. A radioisotope retention assay showed a rapid release of radioiodine from the glioblastoma cells after the binding of I-125-GA17, Whilst In-111-GA17 was retained in the cells for a longer time period. The glioblastoma xenografts showed a high and prolonged uptake of In-111-GA17, and tumour uptake of I-125-GA17 was lower and decreased with time. In the mice which received two injections of 18.5 MBq of In-111-GA17, the growth of the subcutaneous tumour was significantly suppressed compared with the untreated group and mice injected with an In-111-labelled control antibody. These results indicate that GA17 was internalised into the glioblastoma cells and that In-111 was retained within the cancer cells. The injection of a high-dose of In-111-GA17 can suppress the growth of tumour xenografts in nude mice. (C) 1999 Elsevier Science Ltd. All rights reserved.