Interleukin-17 and Type 17 Helper T Cells

Type 17 helper T cells (Th17) — a third class of T cells — and their major cytokine, interleukin-17, are essential for the defense against certain fungi, extracellular bacteria, and Mycobacterium tuberculosis. Defective control of Th17 cells and production of interleukin-17 are prominent in chronic inflammation and several immunoinflammatory disorders. Monoclonal antibodies against cytokines produced by Th17 cells are being investigated in clinical trials.