Production of monoclonal antibodies with pre-selected submolecular binding specificities to protein determinants: demonstration with sperm whale myoglobin.

Two monoclonal antibodies with pre-selected submolecular binding specificities to sperm whale myoglobin (Mb) were obtained by hybridizing Fa/0 mouse myeloma cells with spleen cells derived from mice which had been immunized with free (not coupled to any carrier) Mb synthetic peptides 132-153 or 145-151 (antigenic site 5). Both monoclonal antibodies were IgG1 (k). Their homogeneity was confirmed by analytical isoelectric focusing electrophoresis. According to competitive inhibition studies in which Mb, the five synthetic antigenic sites of Mb, Mb peptide 132-153, bovine serum albumin (BSA), and lysozyme were used as inhibitors, the binding specificities of both monoclonal antibodies were restricted to determinants present in the peptides used for immunizations. The results of direct binding studies confirmed this conclusion and suggested that monoclonal antibodies with pre-selected submolecular binding specificities can be readily obtained by the techniques of somatic cell hybridization when the corresponding free synthetic determinants are used as immunogens.