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,d IL-2 & LI-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 lymphocytes and mature B lymphocytes.
LI-2 was found as major cytokine inducing Ig production form SAC-blast B lymphocytes, on which IL-2 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 form mature B lymphofcytes at the final stage of differentiation 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 with from
IgM
to
and IgG subclass swithch from IgG3 to IgG1, IgG2 and IgG4 were observed with the progression fo B lymphocytes differentiation.
Thses results suggest that IL-2 and IL-6 appear to be major to be major factors of B lymphocytes differentiation and Ig isotype are switched in the downstream order of Ig heavy chain constant region genes with the progression of B lymphocytes
differentiation.
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