Expression of Fas/CD95 and Bcl-2 by primitive hematopoietic progenitors freshly isolated from human fetal liver
| Autor: | Eugene B. Mechetner, Alicia Bárcena, Marcus O. Muench, Babak Banapour, Suk W. Park |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
medicine.diagnostic_test
Growth factor medicine.medical_treatment Immunology chemical and pharmacologic phenomena hemic and immune systems Stem cell factor Cell Biology Hematology Biology CD38 Fas receptor Biochemistry Molecular biology Flow cytometry Haematopoiesis Apoptosis hemic and lymphatic diseases medicine Cancer research Tumor necrosis factor alpha biological phenomena cell phenomena and immunity |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1528-0020 0006-4971 |
| DOI: | 10.1182/blood.v88.6.2013.bloodjournal8862013 |
| Popis: | The cell-surface expression and the functional status of the CD95/Fas antigen on primitive hematopoietic progenitors (PHPs) freshly isolated from human fetal liver (FL) were studied. PHPs were phenotypically defined as CD34++ CD38 -/+ cells. The most immature subfractions of PHPs, CD34++CD38- and CD34+2CD38+ FL cells, expressed CD95, whereas the more mature CD34++CD38++ and CD34+CD38++2 FL cells displayed low CD95 expression. Combinations of cytokines, such as kit ligand (KL) + interleukin-3 or KL + granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulated the expression of CD95 on PHPs upon in vitro culture. Tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) further increased the CD95 expression induced by KL+GM-CSF. The hematopoietic potential of sorted CD34++lineage (lin)- CD95+ versus CD34++ lin-CD95-FL cells was compared by colony-forming unit-culture (CFU-C) assays performed in serum-deprived medium. Lin+ cells were composed of erythrocytes, monocytes, T cells, B cells, and natural killer cells. Our results indicated that both CD95- and CD95+ subsets contained pluripotent progenitors, generating myeloid and erythroid progenitors. The functional status of CD95 and the effects of TNF-alpha and IFN-gamma, cytokines known to induce CD95-mediated apoptosis, were analyzed by incubation of PHPs in the presence of anti-CD95 monoclonal antibodies (MoAbs). The effect of anti-CD95 MoAbs was measured by viable cell counting, flow cytometry, and CFU-C assays. A decrease of CFU-C numbers was observed in the presence of anti-CD95 MoAbs and TNF- alpha and/or IFN-gamma. However, whereas growth factor deprivation induced apoptosis of PHPs, cross-linking of CD95 did not lead to apoptosis of PHPs measured by flow cytometry and viable cell counting. The correlation of increased intracytoplasmic levels of bcl-2 with high levels of cell-surface CD34 and the presence of CD95 on fresh FL cells suggests that bcl-2 may be involved in protecting against CD95-mediated apoptosis of FL PHPs. |
| Databáze: | OpenAIRE |
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