title: Ex vivo expansion of stem cells from umbilical cord blood: expression of cell adhesion molecules.
abstract: Expansion of stem cells from cord blood has been demonstrated to increase the numbers of CD34+ cells, CD34+ subsets, long-term culture-initiating cells, and severe combined immunodeficient mouse, repopulating cells. However, reports suggest that the ex vivo expanded population behaves differently than freshly isolated cells and shows a delayed or diminished engraftment. In this study, we investigated the effects of the cytokines flt3 ligand, stem cell factor, and thrombopoietin on expansion of CD34+ and CD34+/CD38- cells. In addition, we studied the expression of adhesion molecules, very late activation antigen-4 (VLA-4) and leukocyte function antigen-1 (LFA-1), on CD34+ cells from cord blood by flow cytometry. We also looked at the expression of an adhesion receptor, namely, vascular cell adhesion molecule-1 (VCAM-1) on bone marrow stromal cells by Western blot analysis after exposure to low dose gamma irradiation. After culturing for 7 days, increases in the absolute numbers of CD34+, CD34+/CD38-, CD34+/VLA-4+, and CD34+/LFA-1+ cells were 5.67 +/- 2.91 (mean +/- standard deviation) fold, 7.21 +/- 4.38 fold, 99.56 +/- 101.5 fold, and 101.39 +/- 83.25 fold, respectively. There was a transient upregulation in the expression levels of VCAM-1 on stromal cells, which peaked at 4 hours. Though there was an increase in the absolute numbers of CD34+ cells expressing the adhesion molecules, the expression levels (antigen density) of the adhesion molecules on the CD34+ cells remained unaffected.
authors.affiliation: Chemotherapy and Stem Cell Biology Division, Cancer Research Institute, Tata Memorial Centre, Parel, Mumbai, India.
authors.forename: G
authors.initials: G
authors.lastname: Dravid
authors.forename: S G A
authors.initials: SG
authors.lastname: Rao
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD; D018952:Antigens, CD34 / Q000378:metabolism*; D000943:Antigens, Differentiation / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology; D005312:Fetal Blood / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D006085:Graft Survival / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D039041:Integrin alpha4beta1; D016023:Integrins / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D008562:Membrane Glycoproteins; D009244:NAD+ Nucleosidase / Q000378:metabolism; D010952:Plasma Substitutes / Q000378:metabolism*; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000528:radiation effects; D016378:Tissue Transplantation / Q000379:methods; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D014965:X-Rays
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules; D039041:Integrin alpha4beta1; D016023:Integrins; D016169:Lymphocyte Function-Associated Antigen-1; D008562:Membrane Glycoproteins; D010952:Plasma Substitutes; D016201:Receptors, Lymphocyte Homing; D019010:Vascular Cell Adhesion Molecule-1; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1