title: Competitive repopulation assay of two gene-marked cord blood units in NOD/SCID/gammac(null) mice.
abstract: In multiunit cord blood transplantation, hematopoietic stem cells from each unrelated cord blood (UCB) unit competitively reconstitute the hematopoietic system in a recipient. To evaluate the fate of the progeny of each UCB unit and to determine the effects of graft-versus-graft reaction, we established a novel competitive repopulation assay using NOD/SCID/gammac(null) mice in which human T lymphocytes develop from CD34+ cells. CD34+ cells from each UCB unit were labeled with recombinant lentivirus vectors carrying genes encoding either enhanced green fluorescent protein (EGFP) or enhanced yellow fluorescent protein (EYFP). Hematopoietic chimerism composed of both EGFP+ and EYFP+ cells was stably maintained up to 6 months after transplantation with purified CD34+ cells; the ratio of EGFP+ to EYFP+ cells in peripheral blood and bone marrow posttransplantation was equivalent to the ratio of these cells at transplantation. However, when mononuclear cells from two UCB units were cotransplanted with CD34+ cells, engraftment was highly competitive, with cells from only one or the other of the two UCB units surviving. Further subfractionations of mononuclear cells indicate that the skewed chimerism that is often observed in clinical multiunit cord blood transplantation may be mediated by the cooperation of both CD4+ and CD8+ T cells. The assay established here will be a useful tool for analyzing hematopoietic reconstitution in clinical multiunit cord blood transplantation.
authors.affiliation: Division of Hematopoiesis, Research Center for Regenerative Medicine, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yahata
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ando
authors.forename: Hiroko
authors.initials: H
authors.lastname: Miyatake
authors.forename: Tomoko
authors.initials: T
authors.lastname: Uno
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Sato
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ito
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kato
authors.forename: Tomomitsu
authors.initials: T
authors.lastname: Hotta
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics; D002454:Cell Differentiation; D003114:Colony-Forming Units Assay; D005312:Fetal Blood / Q000166:cytology*; D005819:Genetic Markers; D005822:Genetic Vectors / Q000235:genetics; D006086:Graft vs Host Disease / Q000517:prevention & control; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000821:virology; D053631:Interleukin Receptor Common gamma Subunit; D016086:Lentivirus / Q000235:genetics*; D007963:Leukocytes, Mononuclear / Q000502:physiology / Q000637:transplantation; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D020395:Receptors, Interleukin-7 / Q000235:genetics; D018183:Transplantation Chimera
chemical_list: D018952:Antigens, CD34; D001426:Bacterial Proteins; D005819:Genetic Markers; C507941:IL2RG protein, human; C507942:Il2rg protein, mouse; D053631:Interleukin Receptor Common gamma Subunit; D008164:Luminescent Proteins; D020395:Receptors, Interleukin-7; C485184:enhanced green fluorescent protein; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins