Expression of the interleukin-8 receptors CXCR1 and CXCR2 on cord-blood-derived cultured human mast cells

Background. An increase in mast cell number at sites of inflamed tissues has been observed. However, the expression of CXC chemokine receptors on human mast cells is poorly understood. Methods: Cultured human mast cells were raised from human umbilical cord blood cells in the presence of stem cell factor and interleukin-6 (IL-6). The expression of surface chemokine receptors on the mast cells was analyzed by flow cytometry and that of mRNA was examined by the method of reverse transcriptase-polymerase chain reaction (RT-PCR). As functional assays for the receptors, mast cell migration was examined by a microchemotaxis assay and changes in the cytosolic free intracellular calcium concentrations ([Ca2+](i)) was measured using fura-2-loaded mast cells, respectively. Results: Expression of IL-8 receptors CXCR1 and CXCR2 was demonstrated by flow cytometry and of both mRNA by RT-PCR; however, CC chemokine receptors including CCR3 were not expressed on cordblood-derived cultured human mast cells. IL-8 and its homologues showed chemotactic activity toward them in a dose-dependent manner, and IL-8 induced a close-dependent rapid and transient increase in [Ca2+](i) in the mast cells. Conclusions: Our results suggest the surface expression of functional CXCR1 and CXCR2 on cordblood-derived cultured human mast cells. Copyright (C) 2002 S. KargerAG, Basel.