Characteristics of five monoclonal anti-alpha-fetoprotein antibodies.

Five monoclonal anti-alpha-fetoprotein (AFP) antibodies (IgG1) were isolated from six fusions. They were characterized by examining titration values, affinity constants, isotypes, and epitope binding. Employing an epitope-blocking procedure which was based on the exclusion of like antibodies, four of the five monoclonal antibodies were found to be different. Antibody individuality was further demonstrated by comparison of isoelectric focusing patterns. The existence of four distinct anti-AFP antibodies strongly suggests the presence of at least that many epitopes on the AFP molecule.