The Role Th17 and Treg Cells Play in the Gut and Autoimmunity
Recent research indicates that T helper 17 (Th17) and regulatory T (Treg) cells are critical contributors to mucosal and systemic immune responses, especially within the gut. Imbalances in Th17 and Treg responses are thought to contribute to autoimmune processes and chronic inflammation, as discussed in a recent review article.1
Th17 cells normally function to promote inflammatory responses against extracellular bacteria and fungi. For example, in the normal, healthy gastrointestinal tract, Th17 cells not only help to protect against pathogens and opportunistic organisms, such as Candida, but also to help keep the normal resident (commensal) gut microbes in check.
Treg cells have a critical role in restraining inflammatory responses and promoting immune tolerance to antigens from normally harmless sources such as food and commensal gut microbes. Th17 and Treg responses function together in a yin-yang-type manner to maintain homeostasis in the mucosal immune system.
Cytokines play a big role in the development of Th17 and Treg cells, as well as in their pro-inflammatory and anti-inflammatory roles, respectively.The presence of the pro-inflammatory cytokine IL-6, for example, promotes the production of Th17 cells, but its absence contributes to the production of Treg cells.
Cytokines produced by Th17 cells, including interleukin-17 (IL-17) causes other cells, such as macrophages, to release pro-inflammatory cytokines such as TNF-alpha, IL-1beta, and IL-6. In this way, Th17 cells contribute to a cascade of responses that characterize an inflammatory response.
Among the cytokines produced by Treg cells is IL-10, which inhibits the production of pro-inflammatory cytokines from several types of immune cells. It is thought that insufficient Treg responses, including IL-10 production, may enhance or prolong Th17 responses, contributing to a wide range of chronic inflammatory and autoimmune conditions, including Rheumatoid Arthritis, Inflammatory Bowel Disease, Multiple Sclerosis, and Psoriasis.
Assess pro-inflammatory and anti-inflammatory systemic immune balance, including TH17 and Treg cells, using the CytoDx™ panel.
1 Lee, G.R. The Balance of Th17 versus Treg Cells in Autoimmunity. Int. J. Mol. Sci. 2018, 19, 730.
PubMed open access link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5877591/