Approaches to the production of monoclonal antibodies specific for concanavalin A binding and non-binding forms of alphafetoprotein.

Attempts have been made to make monoclonal antibodies which would react preferentially with either the concanavalin A (con A) binding or non-binding from of human alphafetoprotein (AFP). Mice were immunised with con A non-binding AFP in a variety of schedules, and their spleens used in four separate fusions. Despite identification of 467 hybridomas secreting anti-AFP antibodies, no monoclonals could be found with consistent or reproducible specificity for either con A binding or non-binding AFP. Ten of the hybridomas were grown as ascitic tumours. The resulting ascitic fluids defined 4 discrete epitopes on the AFP molecule. There was no apparent difference in the binding of a particular monoclonal antibody to its target epitope in the con A binding and non-binding forms of AFP. This finding is discussed in the light of current knowledge of the molecular structure of the carbohydrate chains of con A binding and non-binding forms of AFP.