Arabinogalactan isolated from cowshed dust extract protects mice from allergic airway inflammation and sensitization

doi:10.1016/j.jaci.2010.05.011

Journal of Allergy and Clinical Immunology

Volume 126, Issue 3, September 2010, Pages 648-656.e4

https://doi.org/10.1016/j.jaci.2010.05.011 Get rights and content

Background

Extract from cowshed dust (CDE) is a source of immunomodulating substances. We have previously shown that such substances protect from experimental allergic disorders in a mouse model of asthma.

Objective

The objective of this study was to identify immunomodulatory molecules in extracts of dust from an allergy protective farming environment.

Methods

Polysaccharides were isolated from CDE and plants by chromatography and precipitation with specific reagents. Polysaccharides were then characterized by nuclear magnetic resonance spectroscopy. Subsequently, the allergy-protective potential of isolated polysaccharides was tested in a mouse model of asthma.

Results

The authors demonstrate that plant arabinogalactans are contained in CDE in high concentrations. The source of this arabinogalactan is fodder, in particular a prevalent grass species known as Alopecurus pratensis. Treatment of murine dendritic cells with grass arabinogalactan resulted in autocrine IL-10 production. Interestingly, these dendritic cells were not able to induce an allergic immune response. Furthermore, intranasal application of grass arabinogalactan protected mice from developing atopic sensitization, allergic airway inflammation and airway hyperreactivity in a mouse model of allergic asthma. This allergy-protective effect is specific for grass arabinogalactan because control experiments with arabinogalactan from gum arabic and larch revealed that these molecules do not show allergy-protective properties. This is likely because of structural differences because we were able to show by nuclear magnetic resonance spectroscopy that although they are predominantly composed of arabinose and galactose, the molecules differ in structure.

Conclusions

The authors conclude that grass arabinogalactans are important immunomodulatory substances that contribute to the protection from allergic airway inflammation, airway hyperresponsiveness, and atopic sensitization in a mouse model of asthma.

Section snippets

Extraction of cowshed dust, hay, and fresh grass

Cowshed dust was collected and extracted with isotonic sodium chloride solution as previously described.¹³ Hay was collected from barns, and sorted grass species (Alopecurus pratensis, Holcus lanatus) were freshly harvested from meadows that were used to generate hay for feeding cattle. Hay and grass were frozen in liquid nitrogen and ground in a mortar under sterile conditions. Pulverized material was extracted with isotonic sodium chloride solution and subsequently dialyzed against water. All

Arabinogalactan isolated from CDE showed immune modulating activity in vivo

In search for arabinogalactans in CDE, we identified most of them in a high-molecular-mass fraction (P1) after size exclusion chromatography of CDE. Concentration of arabinogalactan in CDE as measured by sandwich ELISA was found to be 131 μg arabinogalactan mg⁻¹ CDE. This equals about 13 weight percent in CDE, indicating that the arabinogalactan concentration is significantly higher than the LPS concentration in CDE.¹³ To test the potential immune modulatory activity of arabinogalactan in the

Discussion

Cowshed dust represents an important component of the farm environment that protects children from development of allergies and asthma. We present evidence that cowshed dust contains relevant amounts of plant arabinogalactan contributing to the immunomodulatory activity of these extracts shown in vitro and in vivo. This is the first report describing arabinogalactan as an antiallergic substance protecting from sensitization, allergic lung inflammation, and airway hyperreactivity in a mouse

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: Supported by Deutsche Forschungsgemeinschaft (DFG: BU-762/5-1, HO-1259/4-1), intramural research funding of Ruhr-University Bochum (FoRUM 476-2005), the European Commission as part of GABRIEL (a multidisciplinary study to identify the genetic and environmental causes of asthma in the European Community), and Protectimmun GmbH.

: Disclosure of potential conflict of interest: E. von Mutius has consulted for Glaxo SmithKline, UCB, and Protectimmun and has received research support from Airsonett AB. O. Holst has received research support from Deutsche Forschungsgemeinschaft and the European Union. The rest of the authors have declared that they have no conflict of interest.

View full text

Mechanisms of allergy and clinical immunologyArabinogalactan isolated from cowshed dust extract protects mice from allergic airway inflammation and sensitization

Background

Objective

Methods

Results

Conclusions

Section snippets

Extraction of cowshed dust, hay, and fresh grass

Arabinogalactan isolated from CDE showed immune modulating activity in vivo

Discussion

J Allergy Clin Immunol

Lancet

J Allergy Clin Immunol

J Allergy Clin Immunol

J Allergy Clin Immunol

J Biol Chem

J Allergy Clin Immunol

Phytomedicine

Int Immunopharmacol

Carbohydr Res

Immunity

Immunobiology

J Allergy Clin Immunol

Carbohydr Res

Carbohydr Res

Environmental exposure to endotoxin and its relation to asthma in school-age children

N Engl J Med

Immunostimulatory DNA sequences inhibit IL-5, eosinophilic inflammation, and airway hyperresponsiveness in mice

J Immunol

Mechanisms of allergy and clinical immunology
Arabinogalactan isolated from cowshed dust extract protects mice from allergic airway inflammation and sensitization