[Expression and function of CD95/fas antigen and Bcl-2 on cord blood hematopoietic progenitor cells].
The cell-surface expression and functional status of the CD95/Fas antigen on primitive hematopoietic progenitors isolated from human cord blood were studied. The CD34(+) cells freshly isolated from cord blood displayed low CD95 expression, combinations of cytokines such as SCF+FL upregulated the expression of CD95 in CD34(+) cells. Tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) further increased the CD95 expression induced by positive cytokines. The functional status of CD95-mediated apoptosis was analysed by incubation of CD34(+) cells in the presence of anti-CD95 monocloned antibody (McAb). The effect of anti-CD95 McAb was measured by viable cells counting, flow cytometry, LTC-IC and CFU-C assays. Viable cells and CFU-C numbers were 31.9 +/- 11.2 and 43 +/- 2.0 respectively, the rate of apoptosis was 42.9 +/- 12.4 in the presence of anti-CD95 McAb and TNF-alpha or IFN-gamma. However, growth factor deprivation or the early-acting cytokine such as SCF and FL cross-linking of CD95 lead to low apoptosis of CD34(+) cells. The correlation of increased intracytoplasmic levels of Bcl-2 and the presence of CD95 on surface of CD34(+) cells suggests that Bcl-2 may be involved in protecting against CD95-mediated apoptosis of cord blood CD34(+) cell.
Ma
Yan-Ping
YP
Department of Hematology, Xiehe Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
Zhou
Ping
P
Xiao
Juan
J
D000906:Antibodies / Q000276:immunology; D018952:Antigens, CD34 / Q000032:analysis; D017209:Apoptosis; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis* / Q000502:physiology; D019014:fas Receptor / Q000096:biosynthesis* / Q000276:immunology / Q000502:physiology
D000906:Antibodies; D018952:Antigens, CD34; D019253:Proto-Oncogene Proteins c-bcl-2; D019014:fas Receptor