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A cytokine derived from T4 lymphocytes that causes differentiation of B lymphocytes. Promotes Ig class switch. It stimulates DNA biosynthesis. SYN: B cell differentiating factor.
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(IL-4) a lymphokine produced by antigen- or mitogen-activated T cells; its principal role is regulation of IgE- and eosinophil-mediated immune reactions. It stimulates switching of B cells for production of IgE, is a growth and differentiation factor for T cells, particularly TH2 cells, is a growth factor for mast cells, and stimulates the expression of some adhesion molecules on endothelial cells. Formerly called B lymphocyte stimulatory factor 1.Medical dictionary. 2011.