Cellular distribution of monoclonal antibody in human tumours after i.v. administration

Immune-suppressed mice carrying xenografts of several different types of human germ-cell tumours were injected with a radiolabelled monoclonal antibody (LICR LON/HT13) raised against membrane components of a human germ-cell tumour (HX39). Subsequent assessment of radioactivity in excised organs and tumours showed a selective accretion of antibody in the tumour. Quantitative autoradiography supported the results of radiolocalization observed in vivo in different tumours, and also showed that the antibody localized to viable tumour cells and in close association with their cell membrane. The vascular architecture of tumours was found to be an important factor governing antibody distribution. No localization occurred with radiolabelled normal mouse IgG.