Bioassay development of cytokines produced by Th17 cells (42.16)

The description of a new subpopulation of IL-17 producing T helper cells opened a new avenue in the understanding of immune mechanisms and immune pathologies. This recently described subpopulation has been called Th17 cells, and has a different cytokine profile from the previously described subpopulations Th1 and Th2. Th1 produce IFNγ and Th2 produce IL-4, IL-5, IL-6, and IL-13. Murine Th17 cells produce a large series of cytokines: IL-17A, IL-17F, IL-21, IL-22, IL-26, IL-6 and tumor necrosis factor (TNF)α. In humans, IL-17A, IL-17F, IL-21, IL-22 have been identified as effector cytokines that are preferentially produced by Th17 cells. In this study, we describe bioassays for cytokines produced by Th17 cells. IL-17A activity was measured by its ability to induce IL-6 in human dermal fibroblast (HDF). HDF were incubated with serial dilutions of IL-17A for 48 h, and the IL-6 was measure by ELISA. hIL-17A has ED 50 of 2-4 ng/ml. IL-22 bioactivity was measure using human Colo-205 cells. IL-22 is known to induce IL-10 production in endothelial cells. Colo-205 cells were treated with IL-22 for 48 h, and IL-10 was measured by ELISA. hIL-22 shows an ED 50 of 0.062-0.177 ng/ml. Mouse IL-21 was measured in a proliferation assay using CTLL-2. The ED 50 for mouse IL-21 is 40 ng/ml. We have successfully expressed these cytokines and shown that they have potent biological activity. BioLegend.