Recent advances in the IL-17 cytokine family

Abstract

The IL-17/IL-17 receptor family is the newest and least understood of the cytokine subclasses. Composed of ligands IL-17A-IL-17F and receptors IL-17RA-IL-17RE, these cytokines have many unique structural and functional features. Since the discovery of the 'Th17' subset in 2005, particular attention has been paid to IL-17A and IL-17F and their cognate receptors. To date, far less is known about the rest of the family. This review discusses recent advances in the field, with an emphasis on IL-17A biology.

Copyright © 2011 Elsevier Ltd. All rights reserved.

Figures

Figure 1. Th17 differentiation and IL-17A gene regulation

A. Th17 cells arise from differentiative signals from IL-1, IL-6 and TGFβ, while stability and maintenance of Th17 cells is mediated by IL-23. In addition to IL-17A, Th17 cells produce IL-17F, IL-17A/F, IL-22, IL-26 (humans only) and GM-CSF. B. Summary of studies from the human and mouse il17a promoters indicates involvement of various positively (+) and negatively (−) acting transcription factors.

Figure 2. IL-17R Signaling

The IL-17R complex is composed of IL-17RA and IL-17RC. Major downstream signaling pathways mediated by this receptor are indicated.