Effects of CD34+ selection and T cell immunodepletion on cord blood hematopoietic progenitors: relevance to stem cell transplantation.
Cord blood (CB) has been used recently for stem cell transplantation. We have investigated two different approaches to deplete CB samples of T cells capable of mounting graft-vs.-host disease (GVHD). The methods used were selection of CD34+ cells using avidin-biotin columns (CellPro) and T cell immunodepletion with T10B9 monoclonal antibody (mAb) plus complement. Using the avidin-biotin columns, 10.3% of the original CD34+ cells were recovered. Although this technique yielded a population containing 60 +/- 5.5% CD34+ cells, about 1 log of CFU-GM progenitors were lost. In contrast, after the T10B9 mAb and complement immunodepletion, 75 +/- 19% and 62 +/- 7% of the CD34+ cells and CFU-GM were recovered, respectively. T cell depletion was 3.6 logs using the CellPro columns and 2.2 logs after immunodepletion. To investigate whether cell losses following T cell depletion could be overcome by ex vivo expansion, cells were cultured in the presence of recombinant human interleukin-3 (rhIL-3) and recombinant human c-kit ligand (stem cell factor [rhSCF]) for 7 days. There were 14- and six-fold expansions in the number of progenitors recovered after CellPro and immunodepletion, respectively. To asses the engraftment potential of expanded cells, we used a murine transplantation model in which the presence of human cells was identified by the anti-CD45 mAb. Cells expanded in vitro engrafted in irradiated BNXid mice as efficiently as nonexpanded cells, suggesting that expansion did not affect their transplantability. This study shows that both techniques resulted in significant T cell depletion of CB. Furthermore, in vitro expansion could overcome cell losses sustained during the separation techniques without impairing the engraftment potential of the expanded cells.
Department of Pediatrics, Medical University of South Carolina, Charleston 29425-3311, USA.
J
J
Laver
C M
CM
Traycoff
A
A
Abdel-Mageed
A
A
Gee
C
C
Lee
C
C
Turner
E F
EF
Srour
M
M
Abboud
D000818:Animals; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34 / Q000032:analysis*; D002469:Cell Separation; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006086:Graft vs Host Disease / Q000517:prevention & control; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007124:Immunoenzyme Techniques; D007377:Interleukin-3 / Q000494:pharmacology; D051379:Mice; D008819:Mice, Nude; D016513:Mice, SCID; D011994:Recombinant Proteins / Q000494:pharmacology; D019089:Stem Cell Factor / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology
D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D007377:Interleukin-3; D011994:Recombinant Proteins; D019089:Stem Cell Factor