| 1. |
- Forman, Ruth, et al.
(author)
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Eosinophils may play regionally disparate roles in influencing IgA+ plasma cell numbers during large and small intestinal inflammation
- 2016
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In: BMC Immunology. - : Springer Science and Business Media LLC. - 1471-2172. ; 17:1
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Journal article (peer-reviewed)abstract
- Background: Eosinophils are innate immune cells present in the intestine during steady state conditions. An intestinal eosinophilia is a hallmark of many infections and an accumulation of eosinophils is also observed in the intestine during inflammatory disorders. Classically the function of eosinophils has been associated with tissue destruction, due to the release of cytotoxic granule contents. However, recent evidence has demonstrated that the eosinophil plays a more diverse role in the immune system than previously acknowledged, including shaping adaptive immune responses and providing plasma cell survival factors during the steady state. Importantly, it is known that there are regional differences in the underlying immunology of the small and large intestine, but whether there are differences in context of the intestinal eosinophil in the steady state or inflammation is not known. Results: Our data demonstrates that there are fewer IgA+ plasma cells in the small intestine of eosinophil-deficient ΔdblGATA-1 mice compared to eosinophil-sufficient wild-type mice, with the difference becoming significant post-infection with Toxoplasma gondii. Remarkably, and in complete contrast, the absence of eosinophils in the inflamed large intestine does not impact on IgA+ cell numbers during steady state, and is associated with a significant increase in IgA+ cells post-infection with Trichuris muris compared to wild-type mice. Thus, the intestinal eosinophil appears to be less important in sustaining the IgA+ cell pool in the large intestine compared to the small intestine, and in fact, our data suggests eosinophils play an inhibitory role. The dichotomy in the influence of the eosinophil over small and large intestinal IgA+ cells did not depend on differences in plasma cell growth factors, recruitment potential or proliferation within the different regions of the gastrointestinal tract (GIT). Conclusions: We demonstrate for the first time that there are regional differences in the requirement of eosinophils for maintaining IgA+ cells between the large and small intestine, which are more pronounced during inflammation. This is an important step towards further delineation of the enigmatic functions of gut-resident eosinophils.
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| 2. |
- Svensson Frej, Marcus, et al.
(author)
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CD4+T-cell localization to the large intestinal mucosa during Trichuris muris infection is mediated by G alpha(i)-coupled receptors but is CCR6-and CXCR3-independent
- 2010
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In: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 129:2, s. 257-267
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Journal article (peer-reviewed)abstract
- P>Infection of mice with the gastrointestinal nematode Trichuris muris represents a valuable tool to investigate and dissect intestinal immune responses. Resistant mouse strains respond to T. muris infection by mounting a T helper type 2 response. Previous results have shown that CD4+ T cells play a critical role in protective immunity, and that CD4+ T cells localize to the infected large intestinal mucosa to confer protection. Further, transfer of CD4+ T cells from immune mice to immunodeficient SCID mice can prevent the development of a chronic infection. In the current study, we characterize the protective CD4+ T cells, describe their chemokine receptor expression and explore the functional significance of these receptors in recruitment to the large intestinal mucosa post-T. muris infection. We show that the ability to mediate expulsion resides within a subpopulation of CD4+ T cells marked by down-regulation of CD62L. These cells can be isolated from intestine-draining mesenteric lymph nodes (MLN) from day 14 post-infection, but are rare or absent in MLN before this and in spleen at all times post-infection. Among CD4+ CD62Llow MLN cells, the two most abundantly expressed chemokine receptors were CCR6 and CXCR3. We demonstrate for the first time that CD4+ CD62Llow T-cell migration to the large intestinal mucosa is dependent on the family of G alpha(i)-coupled receptors, to which chemokine receptors belong. CCR6 and CXCR3 were however dispensable for this process because neutralization of CCR6 and CXCR3 did not prevent CD4+ CD62Llow cell migration to the large intestinal mucosa during T. muris infection.
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| 3. |
- Withers, Sarah B., et al.
(author)
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Eosinophils are key regulators of perivascular adipose tissue and vascular functionality
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Journal article (peer-reviewed)abstract
- Obesity impairs the relaxant capacity of adipose tissue surrounding the vasculature (PVAT) and has been implicated in resultant obesity-related hypertension and impaired glucose intolerance. Resident immune cells are thought to regulate adipocyte activity. We investigated the role of eosinophils in mediating normal PVAT function. Healthy PVAT elicits an anti-contractile effect, which was lost in mice deficient in eosinophils, mimicking the obese phenotype, and was restored upon eosinophil reconstitution. Ex vivo studies demonstrated that the loss of PVAT function was due to reduced bioavailability of adiponectin and adipocyte-derived nitric oxide, which was restored after eosinophil reconstitution. Mechanistic studies demonstrated that adiponectin and nitric oxide are released after activation of adipocyte-expressed β3 adrenoceptors by catecholamines, and identified eosinophils as a novel source of these mediators. We conclude that adipose tissue eosinophils play a key role in the regulation of normal PVAT anti-contractile function.
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