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Interleukin‐4 production by human alveolar macrophages
Author(s) -
Pouliot P.,
Turmel V.,
Gélinas É.,
Laviolette M.,
Bissonnette É. Y.
Publication year - 2005
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.1365-2222.2005.02246.x
Subject(s) - immunocytochemistry , bronchoalveolar lavage , immunology , immunoglobulin e , flow cytometry , microbiology and biotechnology , antibody , pulmonary alveolus , biology , immune system , interleukin 4 , lung , andrology , medicine , endocrinology , respiratory disease
Summary Background IL‐4 is a key factor for T helper type 2 (Th2) differentiation and Ig class switching to IgE and IgG 4 during the development of immune responses. IL‐4 is produced by T cells, mast cells, basophils, and eosinophils. However, there is also evidence suggesting that rat alveolar macrophages (AMs) produce IL‐4. Objective Given the importance of AMs and Th2‐related diseases in the lung, we investigated the production of IL‐4 by human AMs. Methods Human AMs were isolated from bronchoalveolar lavage, purified, and IL‐4 production was investigated at mRNA and protein levels using real‐time PCR, flow cytometry, immunocytochemistry, and ELISA. The presence of IL‐4 was investigated in subjects with asthma or asymptomatic airway hyper‐responsiveness, and in normal non‐smokers. Results IL‐4 and IL‐4δ2 (a splice variant found in other IL‐4 producing cells) mRNAs were found in all these subjects, but IL‐4 expression could not be correlated with a particular disease. Protein production was verified by immunocytochemistry and flow cytometry analysis demonstrating, respectively, up to 69% and 59% positive AMs, regardless of the subject condition. Furthermore, phorbol‐12‐myristate‐13‐acetate and calcium ionophore stimulated the release of IL‐4 after 48 h treatment in the presence of anti‐IL‐4 receptor antibody. Conclusion Our results show for the first time that IL‐4 and IL‐4δ2 mRNA are expressed and IL‐4 protein produced and released by human AMs, suggesting a contribution of these cells in the modulation of Th2 immune response.