title: Differential modulation of adhesion markers with ex vivo expansion of human umbilical CD34+ progenitor cells.
abstract: The effect of different expansion protocols on the expression levels of CD49dw/CD29 (VLA-4), CD11a/CD18 (LFA-1), CD31 (PECAM-1), CD44, and CD34 was determined after cord blood CD34+ cells were cultured for defined periods with the following: 1) A growth factor mix (GFmix) containing interleukin (IL)-1, IL-3, IL-6, kit ligand (KL), G-CSF, GM-CSF, and erythropoietin (Epo); 2) IL-3 + KL; and 3) HS-5 (a human stromal cell line supernatant) + KL. Before culturing, cord blood CD34+ cells (> 95% purity) were 94 +/- 5% CD31+, 98 +/- 1% CD44+, 66 +/- 29% VLA-4+, and 68 +/- 18% LFA-1+ (mean +/- SEM). Immunophenotyping and morphological examination of pre- and post-cultured cells indicated that GFmix preferentially supported erythroid development, while IL-3+KL and HS-5+KL preferentially supported myeloid development. Similar to what other investigators have reported, there was an absolute increase in CD34+ cell numbers as well as clonogenic precursors with ex vivo expansion. However, the majority of clonogenic precursors post-expansion expressed CD34 antigen at reduced levels. Examination of adhesion molecules indicated that a majority of cells cultured with GFmix expressed PECAM-1 and LFA-1 at undetectable levels, but PECAM-1 and LFA-1 levels remained essentially unchanged when cells were cultured with IL-3+KL and HS-5+KL. Overall VLA-4 expression levels slightly increased and CD44 expression levels were more heterogeneous with ex vivo expansion. Nevertheless, LFA-1, VLA-4, PECAM-1, and CD44 expression levels remained essentially unchanged on cultured progeny retaining a CD34 phenotype, independent of the culture system used. Together these results indicate that differential modulation of adhesion markers occur with different culture conditions, yet adhesion receptor expression levels on progeny cells retaining a CD34 phenotype are essentially maintained independent of the culture conditions. And although there is an absolute increase in CD34+ cells after ex vivo expansion, a majority of clonogenic precursors have reduced levels of CD34 antigen.
authors.affiliation: Department of Transplantation Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. jreems@imap3.asu.ed
authors.forename: J A
authors.initials: JA
authors.lastname: Reems
authors.forename: M
authors.initials: M
authors.lastname: Mielcarek
authors.forename: B
authors.initials: B
authors.lastname: Torok-Storb
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis / Q000187:drug effects; D018952:Antigens, CD34 / Q000096:biosynthesis / Q000097:blood* / Q000187:drug effects; D015415:Biomarkers / Q000097:blood; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D019070:Cell Lineage; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D016207:Cytokines / Q000494:pharmacology; D015672:Erythroid Precursor Cells / Q000187:drug effects; D004921:Erythropoietin / Q000494:pharmacology; D005260:Female; D005312:Fetal Blood / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D018960:Hyaluronan Receptors / Q000097:blood / Q000187:drug effects; D039041:Integrin alpha4beta1; D016023:Integrins / Q000097:blood / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000097:blood / Q000187:drug effects; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000097:blood / Q000187:drug effects; D016201:Receptors, Lymphocyte Homing / Q000097:blood / Q000187:drug effects; D019089:Stem Cell Factor / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015415:Biomarkers; D015815:Cell Adhesion Molecules; D016207:Cytokines; D018960:Hyaluronan Receptors; D039041:Integrin alpha4beta1; D016023:Integrins; D007375:Interleukin-1; D007377:Interleukin-3; D015850:Interleukin-6; D016169:Lymphocyte Function-Associated Antigen-1; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D016201:Receptors, Lymphocyte Homing; D019089:Stem Cell Factor; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor