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Immune Responses
Published in Ronald Fayer, Lihua Xiao, Cryptosporidium and Cryptosporidiosis, 2007
Depending on the nature of the antigens that the immune system encounters, CD4+ T helper (Th) cells may induce a cell-mediated immune response (Th1) or antibody-mediated response (Th2). These diverse Th responses are determined by the spectrum of cytokines produced by the T-cells themselves and by the antigen-presenting cells. In a Th1 response, IL-12 produced by dendritic cells and macrophages drives the T-cells to produce IFN-?. This type of response is usually required to control and eliminate intracellular infections. In a Th1 response, CD8+ cytotoxic T-cells may also be induced with or without help from CD4+ T cells. These cells kill infected cells in an MHC class I-restricted fashion. A Th2 response is associated with production of IL-4, IL-5, IL-9, and IL-13, and polarized Th2 responses are observed in allergies and asthma; they may also be required to eliminate helminth infections (Wynn, 2003). The Th1 and Th2 pathways can oppose each other as Th1 responses are inhibited by Th2 cytokines such as IL-4 and IL-13 and, similarly, Th2 development is inhibited by Th1cytokines. Recently, another Th response associated with inflammation has been characterized. Th17 cells are induced by the IL-12-related cytokine IL-23, and they produce IL-17, IL-6, and TNF-a (Weaver et al., 2006). This response occurs in autoimmune diseases, but its involvement in immunity to infection is less clear.
Flavonoids from Quercus Genus: Applications in Melasma and Psoriasis
Published in Tatjana Stevanovic, Chemistry of Lignocellulosics: Current Trends, 2018
Esquivel-García Roberto, Velázquez-Hernández María-Elena, Valentín-Escalera Josué, Valencia-Avilés Eréndira, Rodríguez-Orozco Alain-Raimundo, Martha-Estrella García-Pérez
IL-12 and IL-23, which share a common p40 subunit, constitute an axis of regulation and activation of lymphocytes Th1 and Th17, which are characterized by the production of pro-inflammatory cytokines such as IL-17A, IL-17F, IFN-α and tumor necrosis factor alpha (TNF-α) (Croxford et al. 2014). These cytokines stimulate the production and release of chemokines and adhesion molecules by KCs (CCL20, CXCL1, CXCL2, CXCL8, CXCL9, CXCL10, and CXCL11), facilitating lymphocyte recruitment and infiltration into the psoriatic plaque (Kim and Krueger 2015). Psoriasis is now recognized as a disease mediated by polarized Th17 cells that produce IL-17 which originates a continuous circle responsible for the perpetuation of the disease (Fig. 3) (Harden et al. 2015).
Clinical Effects of Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
For over 35 years, immunologists have divided Th cells into functional subsets. Th1 cells—long thought to mediate tissue damage—might be involved in the initiation of damage, but they do not sustain or play a decisive role in many commonly studied models of autoimmunity, allergy, and microbial immunity. A major role for the cytokine IL-17 has now been described in various models of immune-mediated tissue injury, including organ-specific autoimmunity in the brain, heart, synovium and intestines, allergic disorders of the lung and skin, and microbial infections of the intestines and the nervous system.
Genetic variants affecting chemical mediated skin immunotoxicity
Published in Journal of Toxicology and Environmental Health, Part B, 2022
Isisdoris Rodrigues de Souza, Patrícia Savio de Araujo-Souza, Daniela Morais Leme
γδ T lymphocytes are lymphoid cells responsible for secreting keratinocyte growth factor (KGF) and insulin-like growth factor-1 (IGF-1) to maintain keratinocyte populations and migrate to draining lymph nodes after sensing stressed keratinocytes (Nguyen and Soulika 2019). γδ T lymphocytes are not MHC-restricted and recognize soluble antigens, derived from damaged or stressed cells, or those complexed with non-classical MHC molecules (Nguyen and Soulika 2019). After skin exposure to contact allergens, γδ T cells produce high amounts of IL-17 and IL-22 – pro – inflammatory cytokines that promote IL-1β secretion by keratinocytes and enhance the inflammatory process. IL-17 producing cells might participate in inflammatory processes of several skin diseases, such as psoriasis, contact hypersensitivity (CHS), atopic contact dermatitis and AD (Lee et al. 2020).
Understanding the complex microenvironment in oral cancer: the contribution of the Faculty of Dentistry, University of Otago over the last 100 years
Published in Journal of the Royal Society of New Zealand, 2020
Alison Mary Rich, Haizal Mohd Hussaini, Benedict Seo, Rosnah Bt Zain
Interleukin 17 is a pro-inflammatory cytokine with both pro- and anti-tumour effects which has been shown to have increased expression in some cancers. Its pro-tumour effects are mediated by mechanisms including inducing the expression of matrix metalloproteinases (MMPs) in tumour cells and/or stimulating increased tumour angiogenesis. The anti-tumour effects of IL17 are exerted through increased Tc cells and IFNγ activity. Our studies showed significantly more IL17+ cells were present in the TME of OSCC than inflammatory controls (Avadhani 2015). Double-labelling immunofluorescence studies revealed that Th cells, Tc cells, macrophages and mast cells co-expressed IL17 (Avadhani et al. 2017). Using an extracellular matrix (ECM) cell invasion assay kit with invasion assay chambers we found that IL17 significantly promoted the in vitro invasion of OSCC cell lines (Avadhani 2015). These results are consistent with the observations in other cancers where IL17 was found to facilitate tumour progression e.g. breast cancer cell lines, cervical cancer cell lines (Cochaud et al. 2013; Punt et al. 2015).
Effect of lyophilization and spray-drying on cytokine levels and antioxidant capacity in human milk
Published in Drying Technology, 2022
Vanessa Javera Castanheira Neia, Joana Maira Valentini Zacarias, Josiane Bazzo de Alencar, Patrícia Daniele Silva dos Santos, Christyna Beatriz Genovez Tavares, Meliana G. Paula, Silvio Claudio da Costa, Mariana Maciel de Oliveira, Celso Vataru Nakamura, Oscar Oliveira Santos, Jeane E. L. Visentainer, Jesuí V. Visentainer
The cytokines IL˗17A, IL-17F, IL-21, and IL-22 are produced by Th17 cells and are involved in the activation of neutrophils and increased barrier immunity against extracellular bacteria and fungi.[26] Among Th17 cytokines, IL-21 concentration was higher than IL-17A/F and IL-22, in our study. IL-21 acts on naive B cells and induces antibody isotype switching to IgA.[27] The presence of IgA in HM compensates for the small amount of IgA in the infant,[28] and seems to play a role in regulating the immune response to dietary antigens.[29]