Immunolocalisation of an anti-EMA monoclonal antibody to a renal carcinoma xenograft.

The monoclonal antibody 77-1 originally raised to a membrane extract of human bladder cancer reacted with a human renal carcinoma xenograft XK1 on immunoperoxidase staining. This suggested a potential role for its immunolocalisation to renal carcinoma, and prompted a localisation study of the I-125 and In-111 labelled 77-1 to the xenograft. The uptake of the radiolabelled antibody by the xenograft was measured as a tumour to blood ratio taken at 24 hour intervals for up to 72 hours. Four animals were used for each time point and the mean tumour to blood ratio obtained. A monoclonal antibody 48-1, non reactive with XK1, was similarly radiolabelled and administered to another group of animals bearing the xenografts to act as a control. Statistical analysis using the unpaired Student't' test showed that the uptake of the 1-125 and In-111 labelled 77-1 by the xenografts was significantly higher than the non-specific antibody 48-1 at all time points (p less than 0.002-0.018), demonstrating that a specific localisation to the xenograft XK1 by the radiolabelled 77-1 had occurred.