The interaction of human peripheral blood eosinophils with bacterial lipopolysaccharide is CD14 dependent

Sabine G. Plötz, Arnd Lentschat, Heidrun Behrendt, Werner Plötz, Lutz Hamann, Johannes Ring, Ernst Th Rietschel, Hans Dieter Flad, Artur J. Ulmer

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Bacterial lipopolysaccharide (LPS, endotoxin) is a ubiquitous component of dust and air pollution and is suspected to contribute after inhalation to an activation of eosinophils in bronchial tissues of asthmatic patents, provoking inflammatory and allergic processes. We were therefore interested in the interacton of eosinophil granulocytes with LPS and have examined the activaton of and uptake to human peripheral blood eosinophils by LPS. Eosinophils were stimulated by LPS and the endotoxic component lipid A and the release of tumor necrosis factor alpha (TNF-α) and of the eosinophil-specific granule protein eosinophil cationic protein (ECP) was estimated. The results show inducton of TNF-α and ECP-release by LPS and lipid A in a dose-dependent manner. Ant-CD14 monoclonal antibody (moAb) (clone MEM-18) and the synthetic lipid A partial structure 406 blocked the release of TNF-α and ECP by LPS-stimulated eosinophils. Studes with radioactively labeled LPS showed dose-dependent uptake of 3H-LPS to eosinophils. The 3H-LPS uptake was found to be specific because preincubaton with unlabeled LPS, compound 406 and also anti-CD14 antibodies inhibited uptake of 3H-LPS to eosinophil granulocytes. By flow cytometry usng anti-CD14 moAb and by reverse transcriptase-polymerase chain reaction (RT-PCR) technique, CD14 expression was detectable. Furthermore, messenger RNA (mRNA) expression of Toll-like receptors (TLR) 2 and TLR 4 was detected, indicating the presence of these CD14 coreceptors. The results indicate that eosinophils can take up LPS and can be stimulated by LPS in a CD14-dependent manner. Hence, in addition to allergens, eosinophils interact with endotoxin, a process that possibly exacerbates ongoing inflammatory and allergic processes.

Original languageEnglish
Pages (from-to)235-241
Number of pages7
JournalBlood
Volume97
Issue number1
DOIs
StatePublished - 1 Jan 2001

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