Abstract:
Objective: The mechanisms involved in bone marrow eosinophil emigration and recruitment to inflammatory sites are not fully understood. The involvement of CD11b/CD18 in marrow eosinophil release induced by lipopolysaccharide (LPS) or allergen was investigated in mice. Methods: Eosinophil and neutrophil counts in the pleural cavity, blood and bone marrow were performed at different time intervals after the intrathoracic injection of LPS (250 ng/ cavity) or ovalbumin (OVA, 12 μg/cavity; into actively sensitized mice) and compared to anti-CD11b/CD18 (5C6, 1mg/ mouse) or anti-IL-5 (TRFK-5, 500 μg/kg) treated mice.¶Results: LPS induced local eosinophil influx, that peaked within 24 h and that was preceded by a decrease in marrow eosinophils at 4 h. Antigenic challenge induced a decrease in marrow eosinophils within 4 h, followed by a long lasting pleural eosinophil accumulation and a persistent increase in marrow eosinophil numbers. Pretreatment with anti-CD11b/CD18 abolished LPS-induced neutrophil and eosinophil accumulation in the pleural cavity at 4 and 24 h, respectively. This pretreatment failed to modify neutrophil emigration from bone marrow, but significantly inhibited marrow eosinophil release at 4 h post-LPS or OVA challenge. Anti-IL-5 pretreatment failed to inhibit LPS-induced pleural eosinophil accumulation and mobilization from bone marrow, but it abolished allergen-induced effects, indicating a role for IL-5 in marrow eosinophil mobilization induced by antigen, but not by LPS challenge.¶Conclusions: Our results suggest that eosinophil migration induced by antigen or LPS into the pleural cavity is preceded by bone marrow eosinophil release through a mechanism that depends on CD11b/CD18.
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Received 21 July 2000; returned for revision 13 September 2000; accepted by G. Letts 10 January 2001
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Larangeira, A., Silva, A., Gomes, R. et al. Mechanisms of allergen- and LPS-induced bone marrow eosinophil mobilization and eosinophil accumulation into the pleural cavity: a role for CD11b/CD18 complex. Inflamm. res. 50, 309–316 (2001). https://doi.org/10.1007/PL00000249
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DOI: https://doi.org/10.1007/PL00000249