The interleukin-17 cytokine family: critical players in host defence and inflammatory diseases

Abstract

The interleukin-17 (IL-17) cytokines, IL-17A to IL-17F, are emerging as critical players in host defence responses and inflammatory diseases. Substantial data support the role of these proteins in innate and adaptive immunity. Of these family members, IL-17A, IL-17F and IL-17E have been the best studied. Both IL-17A and IL-17F contribute to the host response to extracellular bacteria and fungi, and IL-17E has been shown to play a role in parasitic infections. In addition, numerous pre-clinical and clinical studies link these proteins to the pathogenesis of inflammatory diseases, and a number of therapeutic programmes targeting these family members are in clinical development. This review will highlight the cellular sources, receptors/target cells, and role in inflammation of these and the less-characterized family members, IL-17B, IL-17C and IL-17D.

© 2011 Genentech, Inc. Immunology © 2011 Blackwell Publishing Ltd.

Figures

Figure 1

Homology of interleukin-17 (IL-17) family members to IL-17A. The dendrogram indicates the percentage homology between each of the IL-17 family members and IL-17A. IL-17F shares greater homology with IL-17A, whereas other family members are more divergent. Percentages reflect both mouse and human IL-17 family members.