Interleukin-13 Increases Prostaglandin E-2 (Pge(2)) Production by Normal Human Polymorphonuclear Neutrophils by Enhancing Cyclooxygenase 2 (Cox-2) Gene Expression

Objective. To investigate whether interleukin-13 (IL-13) can affect arachidonic acid metabolism and phagocytic activity of normal human polymorphonuclear neutrophils (PMN). Methods : Normal human PMN (1 x 10(6) cells/ml) were incubated with different concentrations of IL-13 (0.1-10ng /ml) for a variety of times (30-120 min). Phagocytosis and intracellular cyclooxygenase-2 (COX-2) were detected by flow cytometry. The expression of COX-1 and COX-2 mRNA was detected by RT-PCR, The concentration of PGE(2 ) in the PMN cultured supernatants was determined by EIA. Results: We found that IL-13 at an optimal concentration of 1 ng/ml significantly enhanced COX-2 gene expression and PGE(2) production (121.57 +/- 22.17 pg/ ml in IL-13 stimulation vs. 73.16 +/- 11.72 pg/ml in controls) by PMN. In addition, IL- 13 stimulated PMN phagocytosis via increased complement receptor type 1 (CR1) and type 3 (CR3), but not IgG Fc gamma receptor type 3 (Fc gamma RIII). The cytoplasmic neutral esterase activity of PMN was also enhanced by IL-13 stimulation for 24 h. Conclusions: These results suggest that IL-13 can stimulate PMN and modulates the inflammatory reactions via the cyclooxygenase pathway