[Monoclonal antibodies produced by human-human hybridomas].

Generation of human monoclonal antibodies by human-human hybridomas was briefly reviewed. Monoclonal antibodies derived from human lymphocytes, once produced, would be better than those that are animal-derived with regard to in vivo use, such as immunotherapy by immunotoxin and diagnosis by antibody-targeted radioisotope imaging in the cancer patient. To date, very few human monoclonal antibodies, even against conventional antigens, have been reported. Their development by hybridoma techniques has been hampered for a variety of reasons of which the most important is probably the lack of reliable methods for antigen specific stimulation of human lymphocytes. A second problem would be the human myeloma lines for the fusion partner. Thus, we selected GM 1500 6TG-A1 2 line as the fusion partner and tested their ability to form hybrids with human spleen cells, secrete monoclonal immunoglobulin (Ig), clone, and maintain Ig secretion with the same Ig composition. The results were somewhat disappointing in regard to hybrid formation (5 X 10(-6), antibody secretion(0.1 approximately 100 micrograms/ml, majority approximately 1 microgram/ml), and stability in comparison with their murine counterparts. It is encouraging, however, that some cloned hybridomas produced large quantities (approximately 100 micrograms/ml) of IgM, which were nearly equivalent to those of murine hybridomas, for at least 6 month after fusion. The other available human myeloma lines have been reported to have similar or inferior characteristics to GM 1500 6TG line. The successful development of human-derived monoclonal antibodies would depend upon improvements in in vitro primary immunization of peripheral blood mononuclear cells as well as in establishing novel human myeloma or B cell lines, if possible Ig non secretors.