Identification of a gamma c Receptor Antagonist That Prevents Reprogramming of Human Tissue-resident Cytotoxic T Cells by IL15 and IL21
GASTROENTEROLOGY
Authors: Ciszewski, Cezary; Discepolo, Valentina; Pacis, Alain; Doerr, Nick; Tastet, Olivier; Mayassi, Toufic; Maglio, Mariantonia; Basheer, Asjad; Al-Mawsawi, Laith Q.; Green, Peter H. R.; Auricchio, Renata; Troncone, Riccardo; Waldmann, Thomas A.; Azimi, Nazli; Tagaya, Yutaka; Barreiro, Luis B.; Jabri, Bana
Abstract
BACKGROUND & AIMS: Gamma chain (gamma c) cytokines (interleukin [IL]2, IL4, IL7, IL9, IL15, and IL21) signal via a common gamma c receptor. IL2 regulates the immune response, whereas IL21 and IL15 contribute to development of autoimmune disorders, including celiac disease. We investigated whether BNZ-2, a peptide designed to inhibit IL15 and IL21, blocks these cytokines selectively and its effects on intraepithelial cytotoxic T cells. METHODS: We obtained duodenal biopsies from 9 patients with potential celiac disease (positive results from tests for anti-TG2 but no villous atrophy), 30 patients with untreated celiac disease (with villous atrophy), and 5 patients with treated celiac disease (on a gluten-free diet), as well as 43 individuals without celiac disease (controls). We stimulated primary intestinal intraepithelial CD8(+) T-cell lines, or CD8(+) T cells directly isolated from intestinal biopsies, with gamma c cytokines in presence or absence of BNZ-2. Cells were analyzed by immunoblots, flow cytometry, or RNA-sequencing analysis for phosphorylation of signaling molecules, gene expression profiles, proliferation, and levels of granzyme B. RESULTS: Duodenal tissues from patients with untreated celiac disease had increased levels of messenger RNAs encoding IL15 receptor subunit alpha (IL15RA) and IL21 compared with tissues from patients with potential celiac disease and controls. Activation of intraepithelial cytotoxic T cells with IL15 or IL21 induced separate signaling pathways; incubation of the cells with IL15 and IL21 cooperatively increased their transcriptional activity, proliferation, and cytolytic properties. BNZ-2 specifically inhibited the effects of IL15 and IL21, but not of other gamma c cytokines. CONCLUSIONS: We found increased expression of IL15RA and IL21 in duodenal tissues from patients with untreated celiac disease compared with controls. IL15 and IL21 cooperatively activated intestinal intraepithelial cytotoxic T cells. In particular, they increased their transcriptional activity, proliferation, and cytolytic activity. The peptide BNZ-2 blocked these effects, but not those of other gamma c cytokines, including IL2. BNZ-2 might be used to prevent cytotoxic T-cell-mediated tissue damage in complex immune disorders exhibiting upregulation of IL15 and IL21.
T Helper 17 Cells and Related Cytokines after Allergen Inhalation Challenge in Allergic Asthmatics
INTERNATIONAL ARCHIVES OF ALLERGY AND IMMUNOLOGY
Authors: Naji, Nizar; Smith, Steven G.; Gauvreau, Gail M.; O'Byrne, Paul M.
Abstract
Background: T helper (Th) 17 cells may play a role in allergic asthma. This study assessed the effect of allergen inhalation challenge on circulating Th17 cells and related cytokines in allergic asthmatics. Methods: Peripheral blood mononuclear cells were collected from 16 atopic asthmatics before and 24 h after allergen challenge, as well as from 10 atopic nonasthmatics and 10 normal controls. Cells were stained for Th17 cytokines and their receptors (IL-17A, IL-17F, IL-21, IL22, IL-17R, and IL-23R) using flow cytometry. Cytokine concentrations from cell culture supernatants were quantified using a multiplex assay for IL-17A, IL-17F, IL-21, IL-22, and IL-23. Results: At baseline, asthmatics had a higher percentage of circulating Th17 cells (1.2 +/- 0.5%) compared to normal controls (0.9 +/- 0.66%, p < 0.001) but not compared to atopic nonasthmatics (1.13 +/- 0.5%). There was a significant increase in Th17 cells in asthmatics after allergen challenge to 1.55 +/- 0.4% (p < 0.05) and a trend toward significance in IL-17R expression from 3.4 +/- 4.3 to 6.86 +/- 6.84% after allergen challenge (p = 0.06). There was also a significant reduction in IL21- positive cells following allergen challenge from 3.46 +/- 1.85 to 2.33 +/- 1.37% (p < 0.001). There were no significant differences in IL-17F, IL-22 and IL-23R expression. The concentration of IL-17A in culture supernatant was significantly higher in asthmatics compared to normal controls and IL-7A significantly increased 24 h after allergen challenge. Conclusions: The increase of Th17 cells and IL-17A in atopic asthma after allergen inhalation challenge suggests a possible role for Th17 in allergen-induced airway responses. (C) 2014 S. Karger AG, Basel