Kinetics of human light chain synthesis by human-mouse myeloma hybrids

Human myeloma cells from a patient suffering from a lambda Bence-Jones myeloma were hybridized with a continuous mouse myeloma cell line. Several hybrids were obtained, two of which produced the same lambda chain produced by the patient. They have proved to be stable over long periods of time in continuous cell culture. Kinetics of growth of this line proved to be linear over 72 h. This growth rate is independent of any possible nutrient depletion effect from the media. Rate of production of lambda chain was highest (45 micrograms/10(6) cells/24 h) when cell density was between 3-5 X 10(5)/ml and decreased as cell density increased. Efficiency of human light chain synthesis in these hybrids is similar to murine Ig synthesis by the producer parental mouse cells. Human-mouse myeloma hybrids that produce large quantities of human Igs can be established routinely, are stable over long periods of time, and can be used as a model system for the study of the control of synthesis of human Igs.