Purification of repopulating hemopoietic cells based on binding of biotinylated Kit ligand.
To characterize Kit expressing mouse bone marrow (BM) cells, and to determine their contribution to short- and long-term repopulation of the hemopoietic system of irradiated recipients, we have purified Kit+ BM cells by flow cytometry. A high level of Kit expression was detectable on 1-2% of BM cells after staining with biologically active biotinylated Kit ligand (KL) or with anti-Kit antibodies (ACK-2). Compared to unfractionated BM, the Kit+ fractions were enriched for immature hemopoietic cells, as shown by morphological differentiation, in vitro culture, and spleen colony formation. Enrichment of colony-forming cells was higher in biotin-KL+ than ACK-2+ fractions. Colony-forming cells were not found in the Kit- subsets. To study the hemopoietic repopulation capacity of the Kit+ and Kit- cells, serial dilutions of the sorted fractions were transplanted into irradiated mice, and peripheral blood of these recipients was monitored regularly for the presence of donor-derived cells during a 1 year period. Nucleated blood cell repopulation by male donor cells in female recipients was assessed using a Y-chromosome specific DNA probe; erythroid repopulation by normal donor cells in W/Wv recipients was examined flow cytometrically by measuring the forward light scatter of donor- and host-type erythrocytes. A 25- to 100-fold enrichment of long-term repopulating ability in the sorted Kit+ fractions showed that Kit+ cells are capable of reconstitution of circulating erythrocytes and nucleated blood cells after BM transplantation. Transient repopulation of the red blood cell lineage was observed after transplantation of Kit- cells. Detection of donor-derived nucleated cells 1 year after transplantation showed that Kit+ cells contributed to donor-type repopulation of bone marrow, spleen and thymus. Our data demonstrate that isolation of BM cells on the basis of Kit expression is a useful addition to the methods that are commonly applied in stem cell enrichment protocols.
Institute of Hematology, Erasmus University Rotterdam, The Netherlands.
M O
MO
de Jong
H
H
Rozemuller
D
D
Kieboom
J W
JW
Visser
A W
AW
Wognum
G
G
Wagemaker
D000818:Animals; D015415:Biomarkers; D001710:Biotin; D002454:Cell Differentiation; D002455:Cell Division; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D008297:Male; D051379:Mice; D012730:Sex Chromosomes; D019089:Stem Cell Factor / Q000494:pharmacology*
D015415:Biomarkers; D019089:Stem Cell Factor; D001710:Biotin