Thrombopoietin is a major limiting factor for selective outgrowth of human umbilical cord blood cells in non-obese diabetic/severe combined immunodeficient recipient mice.
A single dose (0.3 microg) of recombinant human thrombopoietin (TPO) was injected into sublethal irradiated non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice immediately after transplantation of 1.5 x 10(5) purified CD34+ umbilical cord blood (UCB) cells. Bone marrow (BM) was analysed for human cells by immunophenotyping and colony culture at d 35. TPO treatment produced a two- to sixfold increase in the frequency and number of human CD45+ cells. The lineage distributions among the human cells were similar irrespective of TPO treatment; however, a prominent increase was observed in CD71+GpA- cells, reflecting the proliferative stimulus provided by TPO. The frequency of immature CD34+ cells and human granulocyte-macrophage colony-forming units and erythroid burst-forming units in TPO-treated mice was similar to that of untreated mice, but their absolute numbers had increased proportionally to the increase in human cells. The results demonstrate that human TPO is a major limiting factor for multilineage outgrowth of human UCB cells in NOD/SCID mice and can be conveniently supplemented by single-dose treatment immediately after transplantation. TPO did not affect the survival of mice after transplantation and did not significantly increase the number of immature CD34+CD38- cells; secondary transplantation revealed that TPO administration also had no significant effect on long-term repopulation. The findings demonstrate that human TPO is required for proper outgrowth of human haematopoietic stem cells after transplantation. In addition, a single administration of TPO may improve the efficiency and reproducibility of the NOD/SCID mouse assay for human immature transplantable progenitor cells.
Verstegen
Monique M A
MM
Institute of Hematology, Erasmus University Rotterdam, The Netherlands.
Wognum
Albertus W
AW
Wagemaker
Gerard
G
D000818:Animals; D015496:CD4-Positive T-Lymphocytes; D002455:Cell Division / Q000187:drug effects; D036101:Cord Blood Stem Cell Transplantation; D019650:Hematopoietic Stem Cell Mobilization; D006801:Humans; D016130:Immunophenotyping; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D011994:Recombinant Proteins / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013926:Thrombopoietin / Q000494:pharmacology*; D014183:Transplantation, Heterologous
D011994:Recombinant Proteins; D013926:Thrombopoietin