Immune response to allergens in sheep sensitized to house dust miteReport as inadecuate

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Journal of Inflammation

, 5:16

First Online: 20 October 2008Received: 26 March 2008Accepted: 20 October 2008


BackgroundHouse dust mite HDM allergens are a major cause of allergic asthma. Most studies using animal models of allergic asthma have used rodents sensitized with the -un-natural- allergen ovalbumin. It has only recently been recognized that the use of animal models based on HDM provide a more relevant insight into the allergen-induced mechanisms that underpin human allergic disease. We have previously described a sheep model of human allergic asthma that uses Dermatophagoides pteronyssinus HDM. The present study extends our understanding of the immune effects of HDM and the allergens Der p 1 and Der p 2 in the sheep model of asthma.

MethodsPeripheral blood sera from non-sensitized control sheep and sheep sensitized to HDM was collected to determine immunoglobulin Ig reactivities to HDM, Der p 1 and Der p 2 by ELISA. Bronchoalveolar lavage BAL fluid collected following allergen challenge was also assessed for the presence of HDM-specific antibodies. To examine the cellular immune response to HDM allergens, T cell proliferation and cutaneous responses were assessed in sensitized and control sheep.

ResultsStrong HDM- and Der p 1-specific IgE, IgG1, IgG2 and IgA serum responses were observed in sensitized sheep, while detectable levels of HDM-specific IgG1 and IgA were seen in BAL fluid of allergen-challenged lungs. In contrast, minimal antibody reactivity was observed to Der p 2. Marked T cell proliferation and late phase cutaneous responses, accompanied by the recruitment of eosinophils, indicates the induction of a cellular and delayed-type hypersensitivity DTH type II response by HDM and Der p 1 allergen, but not Der p 2.

ConclusionThis work characterizes the humoral and cellular immune effects of HDM extract and its major constituent allergens in sheep sensitized to HDM. The effects of allergen in HDM-sensitized sheep were detectable both locally and systemically, and probably mediated via enzymatic and immune actions of the major HDM allergen Der p 1. This study extends our understanding of the actions of this important allergen relevant to human allergic asthma and its effects in sheep experimentally sensitized to HDM allergens.

Electronic supplementary materialThe online version of this article doi:10.1186-1476-9255-5-16 contains supplementary material, which is available to authorized users.

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Author: Robert J Bischof - Ken J Snibson - Joanne Van Der Velden - Els NT Meeusen


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