title: A functional hierarchy among the CD34+ hematopoietic cells based on in vitro proliferative and differentiative potential of AC133+CD34(bright) and AC133(dim/)-CD34+ human cord blood cells.
abstract: The 5-transmembrane receptor AC133 is expressed on a subpopulation of human hematopoietic cells that includes the CD34(bright) cells. We evaluated the developmental potential of AC133+CD34(bright) and AC133(dim/-)CD34+ cells isolated from 5 cord blood (CB) samples by studying the in vitro proliferative and differentiative potential of each population in both progenitor and mature cell expansion cultures. Seven-day culture of AC133+CD34(bright) cells with a cytokine combination favoring primitive progenitor cells causes a significant increase in CD34+, CFU-C and noncycling stem/progenitor cells HPP-Q (High Proliferative Potential-Quiescent), whereas culture of AC133(dim/-)CD34+ cells shows a limited increase in committed progenitor cells only. HPP-Q cells were not found in freshly isolated AC133(dim/-)CD34+ nor in expanded CD34+ cells derived from AC133(dim/-)CD34+ cells. No statistically significant difference was observed between the 1-week expanded AC133+ and the initial AC133+CD34(bright) cells regarding their clonogenic efficiency (CE), while expanded CD34+ cells derived from AC133(dim/-)CD34+ cells exhibited a decreased CE. Subexpansion of the reselected AC133+ derived from AC133+CD34(bright) cells reveals a further increase of stem/progenitor cells and the 14-day expanded AC133+ cells reveal an unchanged CE. Subexpansion of reselected 7-day CD34+ cells derived from AC133(dim/-)CD34+ cells was not possible. Culture of AC133+CD34(bright) cells in cytokines that favor megakaryopoiesis or erythropoiesis resulted in a significant expansion of CD41+ and CD71+ cells, respectively; AC133(dim/-)CD34+, in comparison, showed a limited potential to megakaryocytic differentiation and a decreased production of erythroid cells. Our data indicate that early high proliferating stem/progenitor cells and early committed progenitors are present in AC133+CD34(bright) cells, but not in AC133(dim/-)CD34+ cells; the latter represent late committed progenitors with limited proliferative potential.
authors.affiliation: Bone Marrow Transplantation Unit, St. Sophia Children's Hospital, Thivon and Levadias, Athens 11527, Greece. paedbmt@hellasnet.gr
authors.forename: E
authors.initials: E
authors.lastname: Goussetis
authors.forename: M
authors.initials: M
authors.lastname: Theodosaki
authors.forename: G
authors.initials: G
authors.lastname: Paterakis
authors.forename: J
authors.initials: J
authors.lastname: Peristeri
authors.forename: D
authors.initials: D
authors.lastname: Petropoulos
authors.forename: V
authors.initials: V
authors.lastname: Kitra
authors.forename: C
authors.initials: C
authors.lastname: Papassarandis
authors.forename: S
authors.initials: S
authors.lastname: Graphakos
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34 / Q000097:blood*; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D005434:Flow Cytometry; D006023:Glycoproteins / Q000097:blood*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D018189:Immunomagnetic Separation; D016130:Immunophenotyping; D010455:Peptides / Q000097:blood*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34; D016207:Cytokines; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides