Immunological interactive effects between pollen grains and their cytoplasmic granules on Brown Norway rats.

World Allergy Organization Journal 09/2009; 2 - Issue 9 - pp 201-207:201 - 207.


Background: Grass pollen is one of the most important aeroallergens in Europe. Under some meteorological factors, pollen grains can release pollen cytoplasmic granules (PCG). PCG induce allergic responses. Several studies have shown that during thunderstorm periods the number of asthmatic patients increase because of higher PCG airborne concentrations.

Objective: The aims of the study were to assess the allergenicity of cross-reactions between pollen and PCG and to compare it with allergenicity of timothy grass pollen and PCG in Brown Norway rats.

Methods: Rats were sensitized (day 0) and challenged (day 21) with pollen grains and/or PCG. Four groups were studied: Pollen, PCG, Pollen-PCG and PCG-Pollen. Blood samples, Bronchoalveolar Lavage fluid (BALF) and bronchial lymph node were collected at day 25. IgE and IgG1 levels in sera were assessed by ELISA. Alveolar cells, total protein and cytokine concentrations were quantified in BALF. T-cell proliferation, in response to pollen or granules, was performed by lymph node assay.

Results: Cross-reactions between pollen and PCG increased IgE and IgG1 levels when compared to negative control. These increases were lower than those on pollen group but similar to the levels obtained by PCG group. Used whatever in the sensitization and/or challenge, PCG increased lymphocyte and Rantes levels compared to pollen group. Cross-reactions increased IL-1α and IL-1β than pollen and PCG groups.

Conclusion: An allergic cross-reactivity has been shown between pollen and PCG. For humoral and cellular allergic responses, cross-reactions between the 2 aeroallergens, used in this study, seem to be influenced mainly by PCG.

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Available from: Oussama R. Abou Chakra
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    • "PCGs elicit IgE-mediated responses in asthmatic patients and induce bronchial constriction in patients with rainfall-associated asthma [6]. In vivo studies show that PCGs, and pollen grains, induce humoral and cellular responses in animal models of allergy [7-10]. Furthermore, in vitro, PCGs increase inflammatory responses in bronchial epithelial human cells and rat macrophages [8,11]. "
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    ABSTRACT: : Grass pollen grain, an important aeroallergen, can disperse in the environment pollen cytoplasmic granules (PCGs) able to release water-soluble allergens when they are washed out by rainfall. The allergenicity of these washed PCGs is, however, preserved. : The purpose of the study was to assess the allergenic potential of washed and unwashed PCGs, from Phleum pratense pollen grains, in the Brown Norway rat, and to study the IgE reactivity of sera of sensitized rats to water-soluble and water-insoluble extracts of PCGs and pollen grains. : Rats were sensitized and challenged intratracheally with washed or unwashed PCGs or pollen grains. Using water-soluble and -insoluble extracts of pollen grains and/or PCGs, IgE ELISA and immunoblotting were performed with rat sera. Proliferation of bronchial lymph node cells was monitored by [H]-thymidine incorporation in a lymph node assay. Alveolar cells, proteins, and TH1 and TH2 cytokines were quantified in bronchoalveolar lavage fluid. : Rats sensitized with unwashed PCGs showed a predominant humoral response with high serum IgE and reactivity to water-soluble and -insoluble proteins together with low lymph node cell proliferation. Conversely, in rats sensitized to washed PCGs, cellular responses were higher with significant increases in eosinophils, lymphocytes, and TH2 cytokines observed in bronchoalveolar lavage fluid. : Allergic and inflammatory responses were induced by both grass pollen grains and their isolated washed and unwashed PCGs. However, on the basis of humoral and cellular responses, differential patterns were observed. Water-insoluble allergens seem to play a role in the centrally mediated inflammatory response, whereas water-soluble allergens may be involved in the peripheral humoral response.
    Full-text · Article · Jan 2011 · World Allergy Organization Journal