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.

ABSTRACT 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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