Stimulation of eosinophil adherence to human vascular endothelial cells in vitro by platelet-activating factor

• Published in: The Journal of immunology (1950) Vol. 140; no. 9; pp. 3161 - 3166
• Main Authors: Kimani, G, Tonnesen, MG, Henson, PM
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Assoc Immnol 01.05.1988; American Association of Immunologists
• Subjects: Antibodies, Monoclonal - immunology; Antigens, Differentiation - physiology; Antigens, Surface - physiology; Biological and medical sciences; Cell Adhesion - drug effects; Cell Adhesion Molecules; Endothelium, Vascular - cytology; Eosinophils - classification; Eosinophils - cytology; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immediate hypersensitivity. Allergy. Anaphylaxis, etc; Immunobiology; In Vitro Techniques; N-Formylmethionine Leucyl-Phenylalanine - pharmacology; Platelet Activating Factor - pharmacology; Reaction mechanisms, antibodies, chemical mediators; Human; Cell culture; Endothelial cell; Leukocyte; Granulocyte; Chemical mediator; Adhesion; In vitro; Biological activity; Eosinophil; Platelet activating factor; Peptide FLMP; Anaphylaxis; Leucocyte function; Umbilical vein
• ISSN: 0022-1767; 1550-6606; 1550-6606
• DOI: 10.4049/jimmunol.140.9.3161

111In-Labeled eosinophils from mildly eosinophilic subjects have been examined for their capacity to adhere to cultured human umbilical vein endothelial cells. In assay buffer alone, 32.0% +/- 2.6 eosinophils adhered spontaneously to endothelial cells. Platelet-activating factor (PAF) (1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) at concentrations as low as 10(-9) M increased this adherence to a level of 46.7% +/- 2.0. The effects of PAF were confirmed to be on eosinophils by parallel adherence assays done on serum-coated plastic plates where comparably enhanced adhesion of the eosinophils was seen. Lyso-PAF, the biologically inactive precursor/metabolite of PAF, had no stimulatory properties. FMLP caused an increase in eosinophil adherence, comparable to that of PAF, but only at high concentrations (10(-6) to 10(-7) M). Further examination of eosinophil subpopulations separated on metrizamide gradients indicated that "hypodense" eosinophils had a significantly higher ability to adhere spontaneously to endothelial cells than "normal" dense eosinophils, (35.5% +/- 4.2 vs 23.8% +/- 2.5, respectively) and could be stimulated with PAF to higher levels, although the magnitude of stimulation was similar for both populations. A mouse mAb TS1/18 to the common beta-subunit of the Mac-1 cell surface glycoprotein complex (CDw18) reduced by up to 94.6% the PAF-induced increase in adherence, but had no effect on the spontaneous adhesion. Eosinophils were also shown by cytofluorography to be capable of binding the TS1/18 antibody on their cell surface, and in some experiments to exhibit an increased expression of the Mac-1 complex on stimulation with PAF. These studies indicate that eosinophils are capable of binding to endothelial cells in culture, that PAF is a potent stimulator of eosinophil adherence, and that the Mac-1 complex has a critical role in this adhesion process.