Gp130 is the common receptor of the IL-6 family of cytokines and is involved in many biological processes, including acute phase response, inflammation and immune reactions. To investigate the role of gp130 under inflammatory conditions, T-cell-specific conditional gp130 mice were first bred to the IL-10-deficient background and were then infected with the gastrointestinal nematode Trichuris muris. While IL-10 À/À mice were highly susceptible to T. muris, developed a mixed Th1/Th17 response and displayed severe inflammation of the caecum, infection of mice with an additional T-cell-specific deletion of gp130 signalling completely reversed the phenotype. These mice showed an accelerated worm expulsion that was associated with the rapid generation of a strong Th2 immune response and a significant increase in Foxp3-expressing Treg. Therefore, gp130 signalling in T cells regulates a switch between proinflammatory and pathogenic Th1/Th17 cells and regulatory Th2/Treg in vivo. Taken together, the data demonstrate that gp130 signalling in T cells is a positive regulator of inflammatory processes, favouring the Th1/Th17 axis.Key words: Cytokine receptor . Helminthic infection . Inflammation Th1/Th2/Th17 cells Transgenic mice
IntroductionThe common receptor gp130 is constitutively expressed on immune and non-immune cells and is used by all members of the IL-6 family, which comprises IL-6, IL-11, leukaemia inhibitory factor, oncostatin M and the recently characterized cytokine IL-27, among others [1,2]. While gp130 acts as the obligate signalling subunit, each cytokine first binds to its specific receptor, which accounts for the difference in activities [3,4]. The lethality of mice with classical disruptions of two gp130 alleles demonstrated that gp130 signalling is important for the development of the nervous and hematopoietic systems [5,6]. Moreover, signals mediated by gp130 regulate multiple other biological functions, including acute phase response, immune reactions and inflammation [7,8]. The receptor is also involved in sustaining the disease state in inflammatory bowel disease, rheumatoid arthritis (RA) or MS [9][10][11]. The Th pathway is composed of, at least, three distinct subsets: Th1 cells produce IFN-g and are involved in the fight against intracellular pathogens. The Th2 immune response with T cells producing IL-4, IL-5 and IL-13 provides immunity to helminths [2]. Th17 cells produce cytokines like IL-17, IL-22 and mediate immunity to extracellular bacteria and fungi, but are also responsible for autoimmunity and inflammation [12,13]. Development of naïve T cells to Th17 cells requires the presence of IL-6, TGF-b1 and the transcription factor RORgt [14][15][16][17]. [20,21]. Since TGF-b1 is a common factor for Treg and Th17 cells, it is possible that a switch from Th17 to Treg exists in vivo in the absence of IL-6 signalling in T cells. The gastrointestinal helminth Trichuris muris is a good model to investigate Th-cell pathways. In common inbred mouse strains (BALB/c, C57BL/6), infection with T. muris is...