The role of IL-27 in the development of T-cell responses during parasitic infections.
The recognition that CD4+ T-cell responses could be divided into at least two functional subsets either dominated by production of interferon (IFN)-gamma and associated with cell-mediated immunity (Th1) or characterized by production of interleukin (IL)-4 and IL-5 and associated with humoral immunity (Th2) provided a basis to understand the role of T cells in resistance or susceptibility to different types of pathogens. As a consequence, many studies have focused on the identification of cytokines that influence these events. For example, the development of Th1-type responses is largely dependent on IL-12. However, other cytokines also affect this process, and initial studies revealed that IL-27, a cytokine with close structural and functional similarity to IL-12, can promote Th1 responses required for immunity to Leishmania major. Subsequent work with IL-27R (WSX-1)-deficient mice infected with Toxoplasma gondii or Trypanosoma cruzi revealed that the IL-27/IL-27R system can act as a negative regulator of inflammatory T-cell responses. The aim of this review is to discuss recent studies from these laboratories on the role of IL-27 in immunity to parasitic infections in the context of previous work and to highlight the pleiotropic effects of the IL-27/IL-27R system in the development and regulation of Th1 and Th2 responses.
Hunter
Christopher A
CA
Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA. chunter@phl.vet.upenn.edu
Villarino
Alejandro
A
Artis
David
D
Scott
Phillip
P
D000818:Animals; D006801:Humans; D007107:Immune System / Q000276:immunology / Q000378:metabolism; D007378:Interleukins / Q000276:immunology / Q000378:metabolism*; D007896:Leishmaniasis / Q000276:immunology / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism*; D014123:Toxoplasmosis / Q000276:immunology / Q000378:metabolism*
C486767:Il27 protein, mouse; D007378:Interleukins