Interleukin-21 is a type I cytokine with actions on both lymphoid and myeloid cells. Soon after its discovery, IL-21 was shown to induce cytotoxic activity in both CD8+ T cells and NK cells, leading to the elucidation of its antitumor activity in animal models. This preclinical work led to the inclusion of IL-21 in human clinical trials in patients with advanced solid tumors, including melanoma and renal cell carcinoma. Encouraging results were seen with the use of IL-21 as a single agent, and it is possible that IL-21 might yield enhanced results as a component of combination therapy or in adoptive immunotherapy approaches for the generation of CD8+ T cells with potent antitumor activity.
KeywordsIL-21 Anti-tumor CD8+ T cells NK cells
R.S. and W.J.L. are supported by the Division of Intramural Research, National Heart, Lung, and Blood Institute, and National Institutes of Health.
Conflict of interest statement: R.S. and W.J.L. are inventors on patents and patent applications related to IL-21.
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