Specific biodetection of a murine spontaneous mammary carcinoma with labelled anti-human blood group-A monoclonal antibody

Abstract The expression of cell surface antigens of the spontaneous transplantable M3-murine tumour was studied by means of the monoclonal antibody (MAb) B2C114 which recognizes the human blood group-A carbohydrate antigen. Following radioiodination the MAb retained their immunoreactivity and demonstrated a significantly higher in vitro binding with isolated M3-tumour cells as compared with a control antibody. B2C114 revealed 10 6 antigenic sites per cell, with a constant affinity of 5.1 × 10 9 /M. Biodistribution studies showed that B2C114 discriminated between malignant tumour and mouse normal tissues. Radioimmunodetection of Balb/c mice bearing s.c. M3-tumour showed that tumour was specifically defined without substraction 1 day after injection of the radiolabelled antibody.