Quantification of progenitors capable of generating T cells in human cord blood.
OBJECTIVE
For transplantation of cord blood (CB) cells, it is important to select a CB sample that can reconstitute not only myelo-erythropoiesis but also lymphopoiesis in recipients. However, until now the reconstitution ability of CB samples has been assessed by colony forming unit-culture (CFU-C) assay or by simply counting CD34+ cells. The present study aims at establishing a method capable of assessing the potential of T lymphopoieses of CB samples.


METHODS
CD34+ CD38- cells sorted from CB were cultured on a monolayer of murine stromal cell line TSt-4, transduced with the human Delta-like 1 gene.


RESULTS
Immature T cells expressing CD5 and/or CD7 were generated in the culture. As these immature T cells can easily be discriminated from mature T cells that are included in the mononuclear cell population (MNCs), we can use the MNCs as starting material for quantification of progenitors capable of generating T cells (TGP). By applying a limiting dilution analysis, we succeeded in determining the frequency of TGP in MNCs. It was found that the ratios for the number of TGP vs. that of CFU-C differ among CB samples maximally by 3.5 times.


CONCLUSIONS
The present assay system provides a novel tool for the evaluation of CB samples, especially for their T-cell-generating potential.
Kato
Maiko
M
Division of Cell Regeneration and Transplantation, Advanced Medical Research Center, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.
Masuda
Kyoko
K
Kakugawa
Kiyokazu
K
Kawamoto
Hiroshi
H
Mugishima
Hideo
H
Katsura
Yoshimoto
Y
D051997:ADP-ribosyl Cyclase 1 / Q000096:biosynthesis; D000818:Animals; D018952:Antigens, CD34 / Q000096:biosynthesis; D019011:Antigens, CD7 / Q000096:biosynthesis; D018956:CD5 Antigens / Q000096:biosynthesis; D002135:Calcium-Binding Proteins; D036101:Cord Blood Stem Cell Transplantation / Q000379:methods*; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D015321:Gene Rearrangement; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000166:cytology; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D013234:Stem Cells / Q000166:cytology*; D017154:Stromal Cells / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology*
D018952:Antigens, CD34; D019011:Antigens, CD7; D018956:CD5 Antigens; D002135:Calcium-Binding Proteins; C512941:DLK1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051997:ADP-ribosyl Cyclase 1