Jubinsky P T, Laurie A S, Nathan D G, Yetz-Aldepe J, Sieff C A
Division of Pediatric Hematology and Oncology, Children's Hospital, Boston, MA.
Blood. 1994 Dec 15;84(12):4174-85.
To determine the expression and function of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor alpha chain (GMR alpha) during hematopoiesis and on leukemic cells, monoclonal antibodies were raised by immunizing mice with cells expressing high levels of human GMR alpha. A pool of five antibodies isolated from three different mice was used to characterize GMR alpha. This antibody pool (anti-GMR alpha) immunoprecipitated a protein with the expected molecular weight of GMR alpha from COS cells transiently transfected with the GMR alpha gene. In factor-dependent cells, GMR alpha existed as a phosphoprotein. However, its phosphorylation was not stimulated by the presence of GM-CSF. Anti-GMR alpha inhibited the GM-CSF-dependent growth of cell lines and normal bone marrow cells and inhibited the binding of iodinated GM-CSF to its receptor. Cell surface expression of GMR alpha was examined using anti-GMR alpha and flow cytometry. GMR alpha was readily detectable on both blood monocytes and neutrophils. In adherence-depleted normal bone marrow, two separate populations expressed GMR alpha. The most positive cells were predominantly macrophages, whereas the cells that expressed less GMR alpha were largely myelocytes and metamyelocytes. A small population of lin-CD34+ or CD34+CD38- cells also expressed GMR alpha, but they were not capable of significant growth in colony-forming assays. In contrast, the majority of lin-CD34+ and CD34+CD38- cells were GMR alpha-, yet they produced large numbers of myeloid and erythroid colonies in the same assay. Malignant cells from patients with leukemia were also tested for GMR alpha expression. All of the myeloid leukemias and only rare lymphoid leukemias surveyed tested positive for GMR alpha. These results show that anti-GMR alpha is useful for the functional characterization of the GMR alpha and for the detection of myeloid leukemia and that GMR alpha is expressed on certain lineages throughout hematopoietic development; however, progenitors that express the receptor may have a reduced capacity to proliferate in response to hematopoietic growth factors.
为了确定粒细胞-巨噬细胞集落刺激因子（GM-CSF）受体α链（GMRα）在造血过程及白血病细胞中的表达和功能，通过用表达高水平人GMRα的细胞免疫小鼠制备了单克隆抗体。从三只不同小鼠中分离得到的一组五种抗体用于鉴定GMRα。该抗体组（抗GMRα）从瞬时转染了GMRα基因的COS细胞中免疫沉淀出一种分子量与GMRα预期相符的蛋白质。在因子依赖性细胞中，GMRα以磷酸化蛋白形式存在。然而，GM-CSF的存在并未刺激其磷酸化。抗GMRα抑制细胞系和正常骨髓细胞的GM-CSF依赖性生长，并抑制碘化GM-CSF与其受体的结合。使用抗GMRα和流式细胞术检测GMRα的细胞表面表达。在血液单核细胞和中性粒细胞上均可轻易检测到GMRα。在去除贴壁细胞的正常骨髓中，有两个不同的群体表达GMRα。阳性最强的细胞主要是巨噬细胞，而表达较少GMRα的细胞主要是髓细胞和晚幼粒细胞。一小部分lin-CD34+或CD34+CD38-细胞也表达GMRα，但它们在集落形成试验中不能显著生长。相反，大多数lin-CD34+和CD34+CD38-细胞不表达GMRα，但它们在相同试验中能产生大量髓系和红系集落。还检测了白血病患者恶性细胞的GMRα表达。所检测的所有髓系白血病以及仅少数淋巴系白血病检测出GMRα呈阳性。这些结果表明，抗GMRα可用于GMRα的功能鉴定以及髓系白血病的检测，并且GMRα在造血发育的某些谱系中表达；然而，表达该受体的祖细胞对造血生长因子的增殖反应能力可能降低。
