Long-term production of human monoclonal antibodies by human-mouse heterohybridomas.

Production of monoclonal antibodies (mAbs) by fused somatic cells was first developed by Köhler and Milstein two decades ago, but its utilization for the production of human mAbs, particularly those bearing kappa chains, has been difficult because heterohybridomas formed with mouse myeloma cells are unstable and tend to lose certain of their human chromosomes. We have stabilized two such heterohybridomas over one year period and induced the production of kappa-bearing and lambda-bearing human mAb, respectively. Increased productivity was achieved by adding the Na+K(+)-ATPase inhibitor, ouabain and a cell mitosis inhibitor, cytochalasin B, to the cell culture media.