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Inflammation & Allergy-Drug Targets
(Formerly Current Drug Targets - Inflammation & Allergy)
ISSN (Print): 1871-5281
ISSN (Online): 2212-4055
VOLUME: 8
ISSUE: 1
DOI: 10.2174/187152809787582507









The IL-12 Family of Cytokines in Infection, Inflammation and Autoimmune Disorders

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Author(s): Katrina Gee, Christina Guzzo, Nor Fazila Che Mat, Wei Ma and Ashok Kumar
Pages 40-52 (13)
Abstract:
Cytokines are critical coordinators of the immune response necessary for resolving bacterial and viral assaults on the immune system. In particular, the IL-12 family of cytokines are key players in the regulation of T cell responses. These responses are orchestrated by monocytes, macrophages, and dendritic cells which produce the members of the IL- 12 family of cytokines in response to infection. IL-27 and IL-23 are two cytokines that are related to IL-12; these cytokines share homology at the subunit, receptor, and signalling levels. IL-12 is composed of p35 and p40 subunits, which, when combined together form the bioactive IL-12p70. IL-23 is composed of the IL-12p40 subunit as well as the IL-23p19 subunit, which shares homology with IL-12p35. IL-27 is composed of EBI3 and p28. These three cytokines activate similar members of the JAK/STAT signalling pathways as a result of homology in their receptor components. Production of these cytokines by activated monocytes, macrophages, and dendritic cells results in the activation and differentiation of T cells. In spite of their similarity, each of these cytokines has specific roles in the regulation of immune responses. IL-12 is required for the induction of IFN-γ production, critical for the induction of Th1 cells. IL-27 has been shown to play a role in the induction of Th1 cells from naive T cells, whereas IL-23 has been demonstrated to play a key role in the induction of the newly described Th17 cells. Recently, a novel heterodimeric and anti-inflammatory cytokine composed of the IL- 12p35 and EBI3 subunits has been identified as IL-35. The biological properties of the IL-12 family of cytokines, the signalling pathways mediated by these cytokines and their role in infection, inflammation, and autoimmune diseases will be the focus of this review.
Keywords:
Cytokines, Inflammation, Autoimmune Disorders, T cell, homology
Affiliation:
Departments of Pathology and Laboratory Medicine, Division of Virology and Molecular Immunology, Research Institute, Children's Hospital of Eastern Ontario, University of Ottawa, 401 Smyth Road, Ottawa, Ontario, Canada.