The transcription factor GATA-3 is necessary and sufficient for Th2 cytokine gene expression in CD4 T cells.

CD4 T cells potentiate the inflammatory or humoral immune response through the action of Th1 and Th2 cells, respectively. The molecular basis of the differentiation of these cells from naive T cell precursors is, however, unclear. We found that GATA-3 was selectively expressed in Th2 cells. GATA-3 is expressed at a high level in naive, freshly activated T cells and Th2 lineage cells, but subsides to a minimal level in Th1 lineage cells as naive cells commit to their Th subset. Antisense GATA-3 inhibited the expression of all Th2 cytokine genes in the Th2 clone D10. GATA-3 directly activated an IL-4 promoter-luciferase reporter gene in M12 cells. In transgenic mice, elevated GATA-3 in CD4 T cells caused Th2 cytokine gene expression in developing Th1 cells. Thus, GATA-3 is necessary and sufficient for Th2 cytokine gene expression.