Plating efficiencies of EBV transformed human B cells seeded in single cell cultures are far lower (less than 1%) than observed in T cell cloning experiments. This report describes the stimulatory effect of several crude as well as recombinant growth factors on proliferation of EBV transformed B cells measured by [3H]thymidine uptake. Supernatant of LPS activated monocytes (HSF) and recombinant interleukin 4 (rIL-4), but not recombinant IL-1 beta, IL-2, IL-6, TNF alpha, GM-CSF, and interferon gamma increased [3H]thymidine incorporation. The combination of HSF and rIL-4 was found to be synergistic on B cell proliferation. Plating efficiency of EBV transformed B cells at limiting dilution was improved by HSF, but not by the combination of HSF and rIL-4.
