Studies on the B Cell Proliferation and Differentiation Factors in Human B Cell System

ABSTRACT

We have studied the function of lymphokines on human tonsillar B cell prolifertion and differentiation. B cells were stimulated with Staphylococcus aureus Cowanl (SAC) or anti- bead. The followings showed the results of this study. 1) In B cell activation, SAC induced B cell DNA synthesis but anti-mubead did not. SAC could activate and proliferate B cells. Minimal number of B cells were required to proliferate effectively. 2) In B cell proliferation, SAC could proliferate B cell in the abscence of lymphokines. Exogenous IL-2 or IL-4 enhanced B cell proliferation. The roles of IL-2 were very important in B cell proliferation. The effect of IL-4 on the IL-2 induced B cell proliferation was inhibitory in SAC-B cells. IL-4 could enhance the proliferation of anti-mu bead activated B cells. 3) In B cell differentiation, IL-2 was a major factor to differentiate SAC activated B cells, but IL-4 did not. IL-6 had a synergistic effect on the differentiation. The results of this study showed that the different signal transduction mechanisms were involved in B cell proliferation and differentiation. The B cell resposes to lymphokine were different, and it is depend upon antigens or mitogens.