T helper 17 cell
T helper 17 cells (Th17) are a subset of interleukin 17-producing T helper cells. They are considered developmentally distinct from Th1 and Th2 cells and are thought to play a key role in autoimmune disease.
Activation of precursor T helper cells in the presence of TGF-beta and IL-6 is thought to drive differentiation of Th17 cells. Aside from cytokine environment, it is unclear whether any other elements of the initial activation of Th17 cells differ from those of other T helper cells. It has been suggested that IL-23 is involved in the expansion of established Th17 populations, but that cytokine alone does not induce differentiation of naive T-cell precursors into that cell type. IL-21, a cytokine produced by Th17 cells themselves, has also been shown to initiate an alternative route for the activation of Th17 populations. Both Interferon gamma and IL-4, the main stimulators of Th1 and Th2 differentiation respectively, have been shown to negatively regulate Th17 differentiation.
On initial characterisation, Th17 cells were broadly implicated in autoimmune disease and auto-specific Th17 were shown to be highly pathogenic. A more natural role for Th17 cells is suggested by studies which have demonstrated preferential induction of IL-17 in cases of host infection with various bacterial and fungal species. Th17 primarily produce two main members of the IL-17 family; IL-17A and IL-17F which are involved in the recruitment, activation and migration of neutrophils.
- Harrington, LE; RD Hatton & PR Mangan et al. (2005), "Interleukin 17-producing CD4+ effector T cells develop via a lineage distinct from the T helper type 1 and 2 lineages", Nature Immunology 6(11): 1023-32, PMID 16200070
- Stockinger B, Veldhoen M (2007). "Differentiation and function of Th17 T cells". Curr. Opin. Immunol. 19 (3): 281–6. PMID 17433650.
- Bettelli E, Carrier Y, Gao W; et al. (2006). "Reciprocal developmental pathways for the generation of pathogenic effector TH17 and regulatory T cells". Nature. 441 (7090): 235–8. PMID 16648838. doi:10.1038/nature04753.
- Korn, T; E Bettelli & W Gao et al. (2007), "IL-21 initiates an alternative pathway to induce proinflammatory Th17 cells", Nature 448: 484-488, PMID 17766098
There are some open access Network Protocols for studying TH17 cells at Nature Protocols:
- TH17 cells contribute to uveitis and scleritis and are inhibited by IL-27/STAT1 in the retina - Western Blot Analysis
- TH17 cells contribute to uveitis and scleritis and are inhibited by IL-27/STAT1 in the retina - Confocal microscopy
- TH17 cells contribute to uveitis and scleritis and are inhibited by IL-27/STAT1 in the retina - Chromatin immunoprecipitation