Conze Tim, Lammers Reiner, Kuci Selim, Scherl-Mostageer Marwa, Schweifer Norbert, Kanz Lothar, Buhring Hans-Jorg
Department of Internal Medicine II, Division of Hematology, Immunology, and Oncology, University of Tübingen, Tübingen, Germany.
Ann N Y Acad Sci. 2003 May;996:222-6. doi: 10.1111/j.1749-6632.2003.tb03249.x.
CDCP1 is a transmembrane protein that contains three CUB domains within the extracellular region and a hexalysine stretch within the cytoplasmic region. CDCP1 mRNA is highly expressed in lung and colon tumors and in the erythroleukemic cell line K562. To analyze CDCP1 protein expression, monoclonal antibodies against the extracellular domain of CDCP1 were raised. For this purpose, CDCP1 was overexpressed in NIH-3T3 cells. Balb/c mice were then immunized with the resultant cell line NIH-3T3/huCDCP1. After fusion of SP2/0 cells with immune spleen cells, hybridoma clones were selected that secreted antibodies reacting with NIH-3T3/huCDCP1 cells but not with parental cells. Four antibodies (CUB1-CUB4) were obtained that fulfilled these criteria. Screening of peripheral blood cells revealed that the antibodies did not recognize mature lymphocytes, monocytes, granulocytes, erythrocytes, or platelets. In contrast, multi-color analyses revealed that CDCP1 protein is almost exclusively expressed on a subset of CD34(+) stem/progenitor cells in bone marrow. Transplantation of purified CDCP1(+) cells into NOD/SCID mice resulted in engraftment of human cells with multi-lineage differentiation potential, suggesting that CDCP1 is a novel marker for hematopoietic stem cells.
CDCP1是一种跨膜蛋白，其细胞外区域包含三个CUB结构域，细胞质区域包含一个六赖氨酸延伸序列。CDCP1 mRNA在肺癌和结肠癌肿瘤以及红白血病细胞系K562中高度表达。为了分析CDCP1蛋白的表达情况，制备了针对CDCP1细胞外结构域的单克隆抗体。为此，CDCP1在NIH-3T3细胞中过表达。然后用所得的细胞系NIH-3T3/huCDCP1免疫Balb/c小鼠。将SP2/0细胞与免疫脾细胞融合后，筛选出分泌与NIH-3T3/huCDCP1细胞反应但不与亲本细胞反应的抗体的杂交瘤克隆。获得了四种符合这些标准的抗体（CUB1-CUB4）。对外周血细胞的筛选显示，这些抗体不识别成熟淋巴细胞、单核细胞、粒细胞、红细胞或血小板。相反，多色分析显示，CDCP1蛋白几乎仅在骨髓中CD34(+)干/祖细胞亚群上表达。将纯化的CDCP1(+)细胞移植到NOD/SCID小鼠中，导致具有多谱系分化潜能的人类细胞植入，这表明CDCP1是造血干细胞的一种新型标志物。
