title: IL-22, not simply a Th17 cytokine.
abstract: Interleukin-22 (IL-22) has important functions in host defense at mucosal surfaces as well as in tissue repair. It is unique as a cytokine that is produced by immune cells, including T-helper (Th) cell subsets and innate lymphocytes, but acts only on non-hematopoietic stromal cells, in particular epithelial cells, keratinocytes, and hepatocytes. Although IL-22 is beneficial to the host in many infectious and inflammatory disorders, depending on the target tissue it can be pathogenic due to its inherent pro-inflammatory properties, which are further enhanced when IL-22 is released together with other pro-inflammatory cytokines, in particular IL-17. To avoid pathology, IL-22 and IL-17 production have to be controlled tightly and independently. While common factors such as signal transducer and activator of transcription 3 (STAT3) and retinoid orphan receptor γt (RORγt) drive the expression of both cytokines, other factors, such as c-Maf act specifically on IL-22 and enable the separate expression of either cytokine. Here, we discuss the production of IL-22 from various T-cell populations as well as protective versus pathogenic roles of IL-22. Finally, we focus on recent advances in our understanding of the molecular regulation of IL-22 in T cells.
authors: Department of Immunology, Genentech, South San Francisco, CA 94080, USA. saschar@gene.com
authors: Sascha
authors: S
authors: Rutz
authors: Céline
authors: C
authors: Eidenschenk
authors: Wenjun
authors: W
authors: Ouyang
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D007113:Immunity, Innate; D018928:Immunity, Mucosal; D020381:Interleukin-17 / Q000235:genetics / Q000276:immunology*; D007378:Interleukins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000235:genetics / Q000276:immunology*; D051257:Proto-Oncogene Proteins c-maf / Q000235:genetics / Q000276:immunology*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000276:immunology*; D015398:Signal Transduction; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology*; D000097043:Interleukin-22
chemical_list: D020381:Interleukin-17; D007378:Interleukins; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; D051257:Proto-Oncogene Proteins c-maf; D050796:STAT3 Transcription Factor; D000097043:Interleukin-22; C495607:MAF protein, human; C539900:RORC protein, human; C494086:STAT3 protein, human