Interleukin-17 and its expanding biological functions

Abstract

Interleukin-17 (IL-17) and IL-17-producing cells have been shown to play important roles in inflammation and the immune response. IL-17 is believed to be mainly produced by T helper 17 (Th17) cells, a unique helper T-cell subset different from Th1 and Th2 cells. Other subsets of T cells such as cdT and natural killer T (NKT) cells have also been found to produce IL-17 in response to innate stimuli. IL-17 acts as a proinflammatory cytokine that can induce the release of certain chemokines, cytokines, matrix metalloproteinases (MMPs) and antimicrobial peptides from mesenchymal and myeloid cells. This leads to the expansion and accumulation of neutrophils in the innate immune system and links innate and adaptive immunity in vivo. Furthermore, increasing evidence indicates that IL-17 and IL-17-producing cells are involved in the pathogenesis of various diseases such as allergies, autoimmune diseases, allograft transplantation and even malignancy. They may also play protective roles in host defense against infectious diseases and promote induction of cytotoxic T lymphocyte (CTL) responses against cancer. Targeting of the IL-17 axis is under investigation for the treatment of inflammatory disorders.

IL-17 response mediates acute lung injury induced by the 2009 Pandemic Influenza A (H1N1) Virus

“…IL-17 has been shown to play critical roles in the immune response and be associated with various models of immune-mediated tissue injury [24,33]. IL-17 acts as a pro-inflammatory cytokine that induces the expansion and accumulation of neutrophils of the innate immune system and links innate and adaptive immunity [33]. Our mouse model of the BJ501 strain of S-OIV H1N1 showed a cytokine profile similar to that observed in patient serum samples ( Figure 3B).…”

“…Although further studies are necessary to elucidate the complex role of IL-17 in PR8 influenza infection, our S-OIV infection studies support the hypothesis that IL-17 mediates acute lung injury in mice. IL-17 has been shown to play critical roles in the immune response and be associated with various models of immune-mediated tissue injury [24,33]. IL-17 acts as a pro-inflammatory cytokine that induces the expansion and accumulation of neutrophils of the innate immune system and links innate and adaptive immunity [33].…”

“…IL-17 could be secreted by many cells, such as Th-17 cells, gamma delta T cells and natural killer cells [32,33]. Cytokine kinetics of mice BALFs infected with BJ501 virus were assessed.…”

Small-Molecule Inhibitors of IL-2/IL-2R: Lessons Learned and Applied

“…This usage is due to two factors. First, IL-2 signaling and CD25+ (IL-2Ra expressing) T cells are probably secondary to other cytokines and co-receptors in coordinating long-term graft survival (Nashan 1999;Kishimoto et al 2000;Waldmann 2002;Larsen et al 2006;Racape et al 2009;Benghiat et al 2009;Xu and Cao 2010). Second, it reflects an important cost-benefit relationship in transplant management.…”

Regulatory T Cell Deficiency in Systemic Autoimmune Disorders – Causal Relationship and Underlying Immunological Mechanisms

“…IL-17 mediates various inflammatory responses such as recruitment of monocytes and neutrophils [102], T cell infiltration and activation [103], induction of further proinflammatory cytokine expression [104] and, Th17 as a new pathogenic cell type, has been implicated in many autoimmune inflammatory diseases (reviewed in [105]). IL-17 producing Th17 cells also contribute to the pathogenesis and development of SLE.…”