Efficient production of IgG human monoclonal antibodies by lymphocytes stimulated by lipopolysaccharide, pokeweed mitogen, and interleukin 4.

Extensive screening of the mitogens lipopolysaccharide (LPS), pokeweed mitogen (PWM), and Staphylococcus aureus Cowan I (SAC I), alone and in combination and with and without interleukin (IL) was performed for in vitro activation of regional lymph node lymphocytes from lung cancer patients for the production of human IgG, IgM, and IgA. As assessed by electrofusion of the lymphocytes following their exposure to these agents with mouse myeloma cells and incubation of the fused hybridoma, a remarkable stimulatory effect was shown by LPS and particularly by LPS plus IL-4, which was substantially greater than that of either SAC I or PWM with or without various IL. Optimization studies indicated that the addition of PWM to LPS and IL-4 in the culture medium further stimulated the human antibody (Ab) production, and that the optimal formulation for stimulation of human IgG production was a culture medium containing 20 micrograms/ml of LPS, 1/500 of PWM, and 100 u/ml of IL-4.