Bronchial lesions of mouse model of asthma are preceded by immune complex vasculitis and induced bronchial associated lymphoid tissue (iBALT).

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Bronchial lesions of mouse model of asthma are preceded by immune complex vasculitis and induced bronchial associated lymphoid tissue (iBALT).

Lab Invest. 2015 Jun 1;

Authors: Guest IC, Sell S

Abstract
We systematically examined by immune histology the lungs of some widely used mouse models of asthma. These models include sensitization by multiple intraperitoneal injections of soluble ovalbumin (OVA) or of OVA with alum, followed by three intranasal or aerosol challenges 3 days apart. Within 24?h after a single challenge there is fibrinoid necrosis of arterial walls with deposition of immunoglobulin (Ig) and OVA and infiltration of eosinophilic polymorphonuclear cells that lasts for about 3 days followed by peribronchial B-cell infiltration and slight reversible goblet cell hypertrophy (GCHT). After two challenges, severe eosinophilic vasculitis is present at 6?h, increases by 72?h, and then declines; B-cell proliferation and significant GCHT and hyperplasia (GCHTH) and bronchial smooth muscle hypertrophy recur more prominently. After three challenges, there is significantly increased induced bronchus-associated lymphoid tissue (iBALT) formation, GCHTH, and smooth muscle hypertrophy. Elevated levels of Th2 cytokines, IL-4, IL-5, and IL-13, are present in bronchial lavage fluids. Sensitized mice have precipitating antibody and positive Arthus skin reactions but also develop significant levels of IgE antibody to OVA but only 1 week after challenge. We conclude that the asthma like lung lesions induced in these models is preceded by immune complex-mediated eosinophilic vasculitis and iBALT formation. There are elevations of Th2 cytokines that most likely produce bronchial lesions that resemble human asthma. However, it is unlikely that mast cell-activated atopic mechanisms are responsible as we found only a few presumed mast cells by toluidine blue and metachromatic staining limited to the most proximal part of the main stem bronchus, and none in the remaining main stem bronchus or in the lung periphery.Laboratory Investigation advance online publication, 1 June 2015; doi:10.1038/labinvest.2015.72.

PMID: 26006019 [PubMed – as supplied by publisher]

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IL-25 Elicits Innate Lymphoid Cells and Multipotent Progenitor Type 2 Cells That Reduce Renal Ischemic/Reperfusion Injury.

IL-25 Elicits Innate Lymphoid Cells and Multipotent Progenitor Type 2 Cells That Reduce Renal Ischemic/Reperfusion Injury.

J Am Soc Nephrol. 2015 Jan 2;

Authors: Huang Q, Niu Z, Tan J, Yang J, Liu Y, Ma H, Lee VW, Sun S, Song X, Guo M, Wang Y, Cao Q

Abstract
IL-25 is an important immune regulator that can promote Th2 immune response-dependent immunity, inflammation, and tissue repair in asthma, intestinal infection, and autoimmune diseases. In this study, we examined the effects of IL-25 in renal ischemic/reperfusion injury (IRI). Treating IRI mice with IL-25 significantly improved renal function and reduced renal injury. Furthermore, IL-25 treatment increased the levels of IL-4, IL-5, and IL-13 in serum and kidney and promoted induction of alternatively activated (M2) macrophages in kidney. Notably, IL-25 treatment also increased the frequency of type 2 innate lymphoid cells (ILC2s) and multipotent progenitor type 2 (MPP(type2)) cells in kidney. IL-25-responsive ILC2 and MPP(type2) cells produced greater amounts of Th2 cytokines that associated with the induction of M2 macrophages and suppression of classically activated (M1) macrophages in vitro. Finally, adoptive transfer of ILC2s or MPP(type2) cells not only reduced renal functional and histologic injury in IRI mice but also induced M2 macrophages in kidney. In conclusion, our data identify a mechanism whereby IL-25-elicited ILC2 and MPP(type2) cells regulate macrophage phenotype in kidney and prevent renal IRI.

PMID: 25556172 [PubMed – as supplied by publisher]

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Group 2 innate lymphoid cells in lung inflammation.

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Group 2 innate lymphoid cells in lung inflammation.

Immunology. 2013 Jul 19;

Authors: Li BW, Hendriks RW

Abstract
Although allergic asthma is a heterogeneous disease, allergen-specific T helper 2 (Th2) cells producing the key cytokines involved in type 2 inflammation, IL-4, IL-5 and IL-13, are thought to play a major role in asthma pathogenesis. This model is challenged by the recent discovery of group 2 innate lymphoid cells (ILC2) that represent a critical innate source of type 2 cytokines. These ILC2 are activated by epithelial cell-derived cytokines, including IL-25 and IL-33, which have been implicated in the initiation of asthma. In this review, we will discuss recent studies supporting a significant role for ILC2 in lung inflammation, with special attention to allergen-induced asthma. This article is protected by copyright. All rights reserved.

PMID: 23866009 [PubMed – as supplied by publisher]

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