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Non-allergenic antigen in allergic sensitization: responses to the mite ferritin heavy chain antigen by allergic and non-allergic subjects

Authors

  • M. J. Epton,

    1. Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, Perth, and Departments of
    2. Paediatrics and
    3. Asthma and Allergy Research Institute, University of Western Australia, Nedlands, Western Australia
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  • W. Smith,

    1. Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, Perth, and Departments of
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  • B. J. Hales,

    1. Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, Perth, and Departments of
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  • L. Hazell,

    1. Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, Perth, and Departments of
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  • P. J. Thompson,

    1. Medicine, and
    2. Asthma and Allergy Research Institute, University of Western Australia, Nedlands, Western Australia
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  • W. R. Thomas

    1. Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, Perth, and Departments of
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Wayne R. Thomas, Centre for Child Health Research, University of Western Australia, TVW Telethon Institute for Child Health Research, PO Box 855, West Perth 6872, Western Australia. E-mail: wayne @ichr.uwa.edu.au

Summary

Background The majority of house dust mite proteins are non-allergenic. There is, however, no information on the type of immune responses produced to these proteins and if the responses are affected by allergic sensitization.

Objective To identify and produce a non-allergenic antigen of the house dust mite and compare antibody and T cell responses with the responses to allergens in sensitized and non-sensitized individuals.

Results Ferritin heavy chain was cloned from a cDNA library as a candidate non-allergen of the house dust mite. It bound IgG but not IgE in the sera of allergic and non-allergic subjects and induced high T cell proliferative responses that correlated highly with the responses to the major allergen Der p 2. The cytokine response to the non-allergen was characterized by the release of high levels of both Th1 and Th2 cytokines from the PBMC of both allergic and non-allergic subjects. In contrast, the response to Der p 2 showed the expected high level of Th2 cytokine release from the PBMC of allergic subjects, while the Th2 cytokine production from PBMC of non-allergic subjects was low and even lower than that induced by ferritin heavy chain. The levels of IFN-γ release were similar for all groups. Der p 2 induced significantly more IL-10 than ferritin in the non-allergic group.

Conclusion The T cell responses to a non-allergenic protein of the house dust mite were high and strongly correlated with the response to the major allergen. The non-allergenic protein induced high levels of Th1 and Th2 cytokine in both allergic and non-allergic subjects, while the allergen induced high levels of Th2 cytokine in allergic subjects and low levels in non-allergic subjects. The responses to the allergen were thus independently up- and down-regulated with no evidence of bystander regulation.

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