Ionomycin stimulates a synergistic effect of IL-8 and induced sputum on PMN chemotaxis during COPD
Author | Affiliation | |
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Stakauskas, Rimantas | Institute of Immunology, University of Veterinary Medicine, Hannover, Germany | |
Lietuvos sveikatos mokslų universitetas. Medicinos akademija | ||
Date |
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2010-09-18 |
Migration of polymorphonuclear neutrophils (PMN) from blood to the airway is increased during COPD. This process is regulated by chemotactic factors and intracellular Ca2+ concentration, as well. The role of chemokines and airway mucous in PMN activated by increased intracellular Ca2+ is unknown. The aim was to evaluate a role of both IL-8 in combination with induced sputum (IS) and increased Ca2+ on PMN chemotaxis. Methods. PMN were isolated by high density gradient from peripheral blood of 21 patients with moderate COPD and 10 healthy non-smoking individuals (HI). PMN chemotaxis was evaluated in 10-well chemotaxis chamber. The lower and upper wells were separated with polycarbonate membrane. Ionomycin (750 ng/ml) was added to increase intracellular Ca2+ concentration. IL-8 (10, 30, 100 ng/ml) and a pool of IS from 20 COPD (50%/RPMI) were used to stimulate PMN chemotaxis. The lower wells were filled with: (1) IL-8 or IL-8/ionomycin, (2) IS or IS/ionomycin (3) IL-8/IS or IL-8/IS/ionomycin. The upper wells were filled with 2.5x106/ml PMN and incubated for 2h. PMN chemotaxis was evaluated by FACS using reference cell beads. Results. Ionomycin enhanced IL-8 (max. 100 ng/ml: COPD: 79±5% vs 63±4%, HI: 42±5% vs 36±3% p<0.05) and IS (COPD: 60±7% vs 45±5%, HI: 32±6% vs 17±4% p<0.05) stimulated PMN chemotaxis. IL-8 (30-100 ng/ml)/IS induced a higher PMN migration than IL-8 or IS alone (p<0.05). The highest PMN chemotaxis was induced by combination of IL-8 (30 ng/ml)/IS/ionomycin both in COPD group (91±3%) and HI (78±3%). Conclusions. IL-8 and IS acted synergistically on PMN chemotaxis. Ionomycin enhanced a synergistic effect of IL-8 and IS and it was higher in COPD group.