Use of radiolabelled monoclonal anti-CEA antibodies for the detection of human carcinomas by external photoscanning and tomoscintigraphy.

Paul Ehrlich's inspired concept of 'magic bullets' for the cure of diseases has been revitalized by recent advances in immunology(1). In particular, the development of cell fusion technology allowing the production of monoclonal antibodies (Mabs) with exquisite specificities(2) triggered new hopes that we may now have the perfect carrier molecules with which to deliver cytotoxic drugs(3) or toxins(4) to the hidden cancer cells. This article reviews data on one aspect of the magic bullet concept, the use of radiolabelled antibodies as tracers for tumour localization. It will also discuss the very recent clinical use of (131)I-labelled Mabs against carcinoembryonic antigen (CEA)(5) to detect carcinoma either by conventional external photoscanning or by single photon emission computerized tomography (SPELT). This alliance of the most modern tools from immunology (Mabs) and nuclear medicine (SPELT) appears promising as a way to improve the sensitivity of 'immunoscintigraphy'. However, this approach is not yet ready, for widespread clinical use.