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The α4bβ7‐integrin is dynamically expressed on murine eosinophils and involved in eosinophil trafficking to the intestine
Author(s) -
Brandt E. B.,
Zimmermann N.,
Muntel E. E.,
Yamada Y.,
Pope S. M.,
Mishra A.,
Hogan S. P.,
Rothenberg M. E.
Publication year - 2006
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/j.1365-2222.2006.02456.x
Subject(s) - eosinophil , integrin , cd18 , bronchoalveolar lavage , immunology , eosinophil peroxidase , eosinophil cationic protein , integrin alpha m , eosinophilia , biology , lung , medicine , receptor , asthma , flow cytometry , biochemistry
Summary Background Of the numerous adhesion molecules expressed by eosinophils, the α4‐integrin has been identified as critically involved in eosinophil trafficking in the lung. Most studies have focused on the role of the α4β1‐adhesion complex, but eosinophils also express the α4β7‐integrin complex. Objective To investigate the role of α4β7, by assessing its membrane expression on eosinophils from different compartments using allergen‐challenged mice and IL‐4/IL‐5 bi‐transgenic mice. In addition, we aim to determine the impact of β7‐integrin deficiency on eosinophil recruitment to the lungs and intestine in specific experimental allergic models. Results Evaluation of α4β7 expression on bronchoalveolar lavage fluid (BALF) and lung tissue eosinophils revealed a down‐regulation of this integrin as eosinophils migrate through the lungs. Indeed eosinophils isolated from the BALF and lung of allergic mice had low expression of the α4β7‐complex. While expression of the α4‐chain remained unchanged, a significant decrease in β7‐surface expression was observed. Intestinal eosinophils, isolated from Peyer's patches, also displayed a down‐regulation of the α4β7‐integrin, albeit only modest. In contrast, circulating eosinophils, isolated from the blood and spleen, expressed high levels of the α4β7‐integrin. However, eosinophil trafficking into the lungs of β7‐integrin‐deficient mice was not significantly impaired in response to respiratory allergen challenges. In contrast, β7‐deficient mice had impaired eosinophil recruitment to the intestine. Conclusion Taken together, these results identify differential expression of the α4β7‐integrin on eosinophils and its critical role in regulating eosinophil responses in the intestine.