Differential expression of granulocyte-macrophage colony-stimulating factor and IL-3 receptor subunits on human CD34(+) cells and leukemic cell lines

[摘要] Cytokines transduce their signals through specific receptors. Receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-3, and IL-5 share the common signal transducing subunit (beta c), whereas the a subunits function as specific ligand binding components. In this study we prepared specific mouse monoclonal antibodies against human GM-CSF receptor-alpha subunit (hGMR alpha) by immunizing mice with Ba/F3 cells transfected with hGMR alpha complementary DNA. Using these anti-hGMR alpha antibodies in combination with antibodies against IL-3 receptor-alpha (IL-3R alpha), beta c subunits, and c-kit, we examined expression patterns and modulation of these receptor subunits on sever-al human hematopoietic cells, including CD34(+) cells and leukemic cell lines. GMR alpha and IL-3R alpha were expressed on GM-CSF- and IL-3-responsive cell lines, such as TF-1 and UT-7, whereas the expression levels were much lower on UT-7E, a GM-CSF- and IL-3-unresponsive subline of UT-7. The GMR alpha subunit was expressed only on mature granulocytes and monocytes, and IL-3R alpha was expressed on monocytes but not on mature granulocytes, and none of these subunits were expressed on lymphocytes. For CD34(+) cells, GMR alpha was expressed more abundantly on CD34(+)CD33(high) cells than on CD34(+)CD33(low) cells, whereas IL-3R alpha was expressed more abundantly on CD34(+)CD33(low) cells than on CD34(+)CD33(high) and CD34(+)CD33(neg) cells. Slight but significant expression of the beta c subunit was detected on CD34(+) cells. Expression of not only GMR alpha and IL-3R alpha subunits but also c-kit was specifically downregulated by 48-hour incubation with their respective ligands. Receptor transmodulation between GM-CSF, IL-3, and stem cell factor (or kit ligand) was not detected on CD34(+) cells in 48-hour cultures. We also detected upregulation of these or subunits by IL-1 alpha and interferon-gamma on leukemic cell lines. Our. study showed expression levels for each receptor subunit-including GMR, IL-3R, and c-kit on human bone marrow and peripheral blood cells and leukemic cell lines-and revealed differential regulation of the expression of the receptor subunits.

[发布日期] 1995-12-01

[效力级别]  Proceedings Paper

[关键词] GM-CSF receptor;IL-3 receptor;c-kit;CD34;anti-receptor antibody;hematopoietic stem cell