Differentiation of human B lymphocytes by B cell stimulating cytokines = B세포 자극 cytokine들에 의한 human B 림프구의 분화효과

Abstract

To investigate the effects of IL-2, IL-4 and IL-6 on the proliferation and differentiation of human B lymphocytes, the production of Ig classes & IgG subclasses, IL-2 & IL~6 receptors expression and Ig isotype switch were examined using highly purified tonsilar B lymphocytes divided into four developmental stages : small resting B lymphocytes, large B lymphocytes, SAC-blast B lym-phocytes and mature B lymphocytes. IL-2 was found as major cytokine inducing Ig production from SAC-blast B lymphocytes, on which IL-2 receptors were highly expressed. IL-4 showed some effects on ig production, which might be from the IL-4 induced B lymphocytes proliferation, but did not show any evidence of Ig class switch as seen in murine system‘ IL-6 induced remarkable Ig production from mature B lymphocytes at the final stage of differentiation^ on which IL-6 receptors were highly expressed. The synergistic effects on Ig production by combining treatment of IL~2 and IL-4, or IL-2 and IL-6 were observed from SAC-blast B lymphocytes, but not from the combination of IL-4 and IL-6. Ig class switch from IgM to IgG and IgA and IgG subclass switch from IgG3 to IgGl，IgG2 and IgG4 were observed with the progression of B lymphocytes differentiation.

These results suggest that IL-2 and IL-6 appear to be major factors of B lymphocytes different tiation and Ig isotype are switched in the downstream order of Ig heavy chain constant region genes with the progression of B lymphocytes differentiation