title: Engraftment of cultured human hematopoietic cells in sheep.
abstract: In an effort to expand human hematopoietic progenitors and stem cells in vitro, we cultured human CD34(+)c-kitlow bone marrow cells in suspension in the presence of KIT ligand, FLK2/FLT3 ligand, interleukin-6 (IL-6), and erythropoietin with or without IL-3 and tested their engrafting capabilities by injecting them into sheep fetuses. As markers for engraftment, we analyzed CD45(+) cells and karyotypes of the colonies grown in methylcellulose culture. In three separate experiments, day-60 engraftment in the bone marrow was seen with both fresh cells and cells cultured in the presence or absence of IL-3. When fetuses were allowed to be born and analyzed for CD45(+) cells, no long-term engraftment was seen with cultured cells. We then pooled the CD45(+) cells of the fetal samples and transplanted them into secondary recipient fetuses. Day-60 engraftment in the secondary recipients was again noted when transplantation in the primary recipients was initiated with fresh cells. There were 3 cases in which cultured cells showed signs of engraftment in the secondary recipients, but the remaining 24 cases showed no signs of engraftment. These data documented that suspension culture for 2 weeks of enriched adult human bone marrow cells can maintain short-term (2 months) engrafting cells, but may not maintain longer term engrafting cells. This sheep/human xenograft model may serve as an excellent method for the evaluation of the engraftment potential of in vitro-expanded cells.
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.forename: M
authors.initials: M
authors.lastname: Ogawa
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: G
authors.initials: G
authors.lastname: Almeida-Porada
authors.forename: E D
authors.initials: ED
authors.lastname: Zanjani
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers; D001805:Blood Transfusion, Intrauterine; D002478:Cells, Cultured / Q000187:drug effects / Q000637:transplantation; D002678:Chimera; D003114:Colony-Forming Units Assay; D004921:Erythropoietin / Q000494:pharmacology; D006085:Graft Survival; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D007621:Karyotyping; D017493:Leukocyte Common Antigens / Q000032:analysis; D008565:Membrane Proteins / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D012756:Sheep / Q000196:embryology / Q000276:immunology*; D013045:Species Specificity; D019089:Stem Cell Factor / Q000494:pharmacology; D014183:Transplantation, Heterologous
chemical_list: D015415:Biomarkers; D007377:Interleukin-3; D015850:Interleukin-6; D008565:Membrane Proteins; D011994:Recombinant Proteins; D019089:Stem Cell Factor; C084881:flt3 ligand protein; D004921:Erythropoietin; D017493:Leukocyte Common Antigens