CXC chemokine receptor 3 expression on CD34(+) hematopoietic progenitors from human cord blood induced by granulocyte-macrophage colony-stimulating factor:chemotaxis and adhesion induced by its ligands, interferon gamma-inducible protein 10 and monokine induced by interferon gamma

CXC chemokine receptor 3 (CXCR3), which is known to be expressed predominately on memory and activated T lymphocytes, is a receptor for both interferon gamma (IFN-gamma)-inducible protein 10 (gamma IP-10) and monokine induced by IFN-gamma (Mig). We report the novel finding that CXCR3 is also expressed on CD34(+) hematopoietic progenitors from human cord blood stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) but not on freshly isolated CD34(+) progenitors. Freshly isolated CD34(+) progenitors expressed low levels of CXCR3 messenger RNA, but this expression was highly up-regulated by GM-CSF, as indicated by a real-time quantitative reverse transcriptase-polymerase chain reaction technique. gamma IP-10 and Mig induced chemotaxis of GM-CSF-stimulated CD34(+) progenitors by means of CXCR3, since an anti-CXCR3 monoclonal antibody (mAb) was found to block gamma IP-10-induced and Mig-induced CD34(+) progenitor chemotaxis. These chemotactic attracted CD34(+) progenitors are colony-forming units-granulocyte-macrophage. gamma IP-10 and Mig also induced GM-CSF-stimulated CD34(+) progenitor adhesion and aggregation by means of CXCR3, a finding confirmed by the observation that anti-CXCR3 mAb blocked these functions of gammaIP-10 and Mig but not of chemokine stromal cell-derived factor 1 alpha. gamma IP-10-induced and Mig-induced up-regulation of integrins (CD49a and CD49b) was found to play a crucial role in adhesion of GM-CSF-stimulated CD34(+) progenitors. Moreover, gamma IP-10 and Mig stimulated CXCR3 redistribution and cellular polarization in GM-CSF-stimulated CD34(+) progenitors. These results indicate that CXCR3-gamma IP-10 and CXCR3-Mig receptor-ligand pairs, as well as the effects of GM-CSF on them, may be especially important in the cytokine/chemokine environment for the physiologic and pathophysiologic events of differentiation of CD34(+) hematopoietic progenitors into lymphoid and myeloid stem cells, subsequently immune and inflammatory cells