Murine T helper type 2 clones were stimulated with immobilized anti-CD3 antibody or with recombinant lymphokines to compare the expression of T-cell activation genes induced by these stimuli. Immobilized anti-CD3 antibody, recombinant interleukin 2 (IL-2), and recombinant interleukin 4 (IL-4) all induced proliferation of the T helper type 2 clones 10-5-17 and D10. Proliferation of these clones induced by anti-CD3 antibody was completely inhibited by cyclosporine A, whereas cyclosporine A had little effect on proliferation induced by recombinant IL-2 or recombinant IL-4. Both immobilized anti-CD3 antibody, and recombinant IL-2 induced the expression of the protooncogenes c-myc and c-myb. Immobilized anti-CD3 antibody also induced expression of the lymphokine genes IL-4, interleukin 5 (IL-5), and granulocyte-macrophage colony-stimulating factor. In contrast, recombinant IL-2 induced IL-5 mRNA expression but did not induce detectable expression of IL-4 or granulocyte-macrophage colony-stimulating factor mRNA. Likewise, recombinant IL-4 induced expression of IL-5 but not IL-4 mRNA. Thus, the IL-4 and IL-5 genes appear to be differentially regulated after stimulation with recombinant lymphokines. Effects of cyclosporine A and the protein synthesis inhibitors cycloheximide and anisomycin on IL-4 and IL-5 gene expression suggest that these genes are activated by different pathways after anti-CD3 stimulation. Cyclosporine A completely inhibited anti-CD3-induced expression of IL-4 mRNA but not of IL-5 mRNA, and protein-synthesis inhibitors completely inhibited induction of IL-5 mRNA but not of IL-4 mRNA. Together, our data show that T-cell receptor-mediated and lymphokine receptor-mediated signals induce different patterns of lymphokine gene expression and provide strong evidence that the IL-4 and IL-5 genes are differently regulated.