Hematopoietic repopulating ability of hematopoietic stem/progenitor cells expanded by mononuclear cells or CD34+ cells

Objective To compare the hematopoietic repopulating ability of cord blood hematopoietic stem/progenitor ceils(HS/PC)ex vivo expanded with different initiated cells by Nonobese diabetic/severe combined immunodeficiency(NOD/SCID)mouse model.Methods HS/PC were ex vivo expanded with enriched CD34+ cells and mononuclear cells(MNC)derived from umbilical cord blood.The 7-day expanded cells were transplanted into NOD/SCID mice which received sublethal irradiation from a 137Cs source.Six weeks after transplantation,peripheral blood,spleen and bone marrow ceils of the alive mice were harvested for flow cytometric,colony forming cells(CFC)and PCR analyses.Results Enriched CD34+ cells presented a higher proliferation potential than MNC in the expansion process.Six weeks after transplantation,all of the mice injected with cord blood cells survived.Human cells(C1945+ cells)could be detected in BM and spleen cells of the alive mice,and human CD34,CD3,CD19,CD33 and CD71 antigen all could be detected on these human cells.The human specific Alu sequence could be detected in the DNA obtained from NOD/SCID mice by PCR.Conclusion In vitro expanded cells has a decline of engraftment level in NOD/SCID mice compared with fresh cord blood cells,but there was no significant difference in the multi-lineage engraftment level of them.The ex vivo expanded cells initiated with MNC were superior to the cells expanded with enriched CD34+ cells in the engraftment level,but different initiated cells had no significant impact on the hematopoietic repopulating ability of expanded HS/PC in vivo. Key words: Cord blood stem cell transplantation; Cell culture techniques; Cell proliferation; Mice; Recovery of function