HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ikehara, S. Search for Related Content PubMed PubMed Citation Articles by Ikehara, S.

---

Review Article

Pluripotent Hemopoietic Stem Cells in Mice and Humans

First Department of Pathology, Transplantation Center, Kansai Medical University, Moriguchi, Osaka 570–8506, Japan

	Abstract

Top Abstract Introduction Mouse P-HSCs Human P-HSCs MHC Restriction Exists Between... References

 
Although it has been reported previously that pluripotent hemopoietic stem cells (P-HSCs) express c-kit, the receptor for stem cell factor (steel factor), we and other groups have recently shown that P-HSCs do not express c-kit. In this review, we provide evidence that c-kit^<low P-HSCs in mice have long-term-reconstituting activity (LTRA > 2 years) and the capacity to form colony-forming units in spleen (CFU-S) on Day 16, although c-kit^low HSCs or c-kit⁺ HSCs have LTRA less than 1.5 years and the capacity to form CFU-S on Day 14 or on Day 10, respectively. In addition, we have found that there is a major histocompatibility complex (MHC) restriction between P-HSCs and stromal cells; normal P-HSCs can proliferate and differentiate efficiently in collaboration with MHC class I-compatible (but not MHC class I-incompatible) stromal cells. In humans, we also show that c-kit^<low P-HSCs can differentiate into c-kit^low cells, then c-kit⁺ cells in vitro.

	Introduction

Top Abstract Introduction Mouse P-HSCs Human P-HSCs MHC Restriction Exists Between... References

 
Pluripotent hemopoietic stem cells (P-HSCs) are defined as cells with the capacity to self-renew and differentiate eternally into all hemopoietic lineage cells. Purification of P-HSCs has been carried out on the basis of the retention of rhodamine 123 (1, 2) and/or the expression of Sca-1 (3-6), Thy-1 (3-6), CD4 (7), Mac-1 (7), and CD34 (8).The expression of c-kit molecules (the receptor for stem cell factor) has also been a marker to purify P-HSCs. In earlier studies, P-HSCs in the mouse bone marrow (9-12) and in the adult liver (13) have been reported to be c-kit⁺. However, recent mouse and human studies have provided evidence that P-HSCs are c-kit^low; mouse hemopoietic progenitors (in the dormant stage) and human CD34⁺ primitive progenitors are enriched in c-kit^low cells when assayed by colony formation and long-term culture-initiating cells (14, 15). We have very recently shown that P-HSCs are c-kit^<low (phenotypically c-kit^-, but the c-kit message is only detectable by reverse-transcriptase-polymerase chain reaction [RT-PCR]) by assessing LTRA activity after serial bone marrow transplantation (BMT). This was very recently confirmed by Oritz et al. (16). This minireview provides evidence that P-HSCs are c-kit^<low in mice and also humans.

	Mouse P-HSCs

Top Abstract Introduction Mouse P-HSCs Human P-HSCs MHC Restriction Exists Between... References

 
LTRA.
The first step was to examine which cells (c-kit^low or c-kit^<low cells) have LTRA. HSCs (Lin^-/CD71^-/class I^high cells) were fractionated on the basis of the expression of c-kit. Figure 1a shows the flow cytometric profile of Lin^-/CD71^- cells stained with anti-H-2K^b and anti-c-kit mAbs. H-2K^{b high} cells were gated, and two cell populations—c-kit^low and c-kit^<low (which are comparable to the negative control level)—were fractionated by sorting on the basis of c-kit expression. Sorting gates and histogram are shown in Figures 1a and 1b; the sorting gate of c-kit^<low cells was set not to overlap that of c-kit^low cells. The FACS profile is very similar to that reported by Katayama et al. (15); the c-kit^low and c-kit^<low populations were identified as shown in Figures 1a and 1b. Purified Lin^-/CD71^-/class I^high/c-kit^low cells or Lin^-/CD71^-/class I^high/c-kit^<low cells were 0.006% or 0.008% of the 5-FU-treated whole BMCs, respectively.

View larger version (16K): [in this window] [in a new window]   Figure 1.   (a, b) Staining profiles and (c) RT-PCR analyses of Lin-/CD71-/class Ihigh/c-kit<low cells. Lin-/CD71- cells were stained with anti-H-2Kb and antic-kit mAbs, and cells with a high expression of MHC class I were collected (represented in a). These cells were further divided into two populations based on the expression of c-kit [a and b (histogram)], and (A) c-kit<low and (B) c-kitlow cells were sorted by a FACStar. The dotted line in b represents a negative control stained by isotype-matched rat mAb. (c) RT-PCR-amplified products from (upper) a c-kit gene and (lower) a glyceraldehyde 3-phosphate dehydrogenase (G3PDH) gene as an internal standard were electrophoresed, transferred to a nylon membrane, and probed with internal oligonucleotides. Lanes: 1, Lin-/CD71-/class Ihigh/c-kit<low cells; 2, Lin-/CD71-/class Ihigh/c-kitlow cells; and 3, Lin-/CD71- unsorted BMCs.

Five hundred cells of each fraction from 5-FU-treated B6 Ly5.1 mice were intravenously (iv) injected into irradiated B6 Ly5.2 recipients along with B6 Ly5.2 compromized cells. Six months after the transplantation, cells from several organs were double-stained with a panel of mAbs against mature myeloid/lymphoid cells and anti-Ly5.1 mAb to check for donor-derived cells. Ly5.1⁺ donor-derived mature cells (B cells, T cells, granulocytes, and macrophages) were detected in both recipients that received either Lin^-/CD71^-/class I^high/c-kit^low cells or Lin^-/CD71^-/class I^high/c-kit^<low cells, in all organs tested such as the bone marrow, thymus, spleen, lymph nodes, peripheral blood, and peritoneal cavity (data not shown).

To examine the LTRA of these two cell populations, 1 x 10⁶ BMCs either from recipients of Lin^-/CD71^-/class I^high/c-kit^low cells or Lin^-/CD71^-/class I^high/c-kit^<low cells were re-transplanted into irradiated B6 Ly5.2 mice. Six months later, several organs were again examined to check for original donor-derived Ly5.1⁺ cells. In contrast to the results observed in the primary recipients, original donor-derived Ly5.1⁺ cells could be detected only in secondary recipients originally reconstituted with Lin^-/CD71^-/class I^high/c-kit^<low cells; Ly5.1⁺ cells were observed in the myeloid and lymphoid cells in all organs tested (Fig. 2a). However, in the secondary recipients of BMCs from the mice that originally received Lin^-/CD71^-/class I^high/c-kit^low cells, no Ly5.1⁺ donor-derived cells were detected at all (Fig. 2b). These findings clearly show that P-HSCs with LTRA are Lin^-/CD71^-/class I^high/c-kit^<low cells, but not Lin^-/CD71^-/class I^high/c-kit^low cells.

View larger version (19K): [in this window] [in a new window]   Figure 2.   Detection of donor-derived cells in the secondary recipients. Six months after the primary transplantation, BMCs from the primary recipients were transferred to the irradiated secondary B6 Ly5.2 recipients. Six months later, cells from various organs were stained with a panel of mAbs and donor-specific anti-Ly5.1 mAb to determine whether the original donor-derived cells could be detected among the multilineage cells.

View larger version (11K): [in this window] [in a new window]   Figure 3.   Survival rates in serial BMT using c-kit<low or c-kitlow cells.

View larger version (64K): [in this window] [in a new window]   Figure 4.   CFU-S assays using c-kit<low, c-kitlow, or c-kit+ cells. The female C57BL/6 Ly 5.2 mice that received 103 c-kit<low, c-kitlow, or c-kit+ cells were killed on Days 8–20; c-kit<low and c-kitlow cells were obtained from the BMCs of 5-FU-treated male Ly 5.1 mice, and c-kit+ cells were obtained from the BMCs of male Ly 5.1 mice without 5-FU treatment. The spleens were removed and fixed with Bouin's fixing fluid before the spleen colonies were counted.

Peripheral Blood Stem Cells in Mice.
The next step was to examine whether peripheral blood stem cells (PBSCs) are true P-HSCs or not. PBSCs were mobilized in mice by treatment with cytosine-arabinoside on Day 0, followed by the administration of granulocyte colony-stimulating factor for 4 days. There were remarkable increases in the numbers of cells with Lin^-/c-kit⁺ markers, cells with colony-forming unit-cell (CFU-C) and CFU-S activities, and cells with marrow-repopulating ability (MRA) in the extramedullary sites (the spleen, peripheral blood, and liver) on Day 5, whereas the number of these immature hemopoietic cells decreased in the bone marrow (BM) on Day 5. This finding suggests the mobilization of immature hematopoietic cells from the BM to the extramedullary sites. Three-color flow cytometric analyses showed that CD4 antigen was not expressed on the Lin^-/Sca-1⁺ cells in the mobilized PB cells (PBCs), although CD71^- CD4^low cells were found in those of normal BM cells. Lin^-/c-kit⁺ cells in the mobilized PBCs contained more cells with immature phenotypes (Sca-1⁺/Thy1.2^low/CD71^-/Rh123^dull) than in normal BMCs, indicating an alteration of the hierarchical composition of the Lin^-/c-kit⁺ cells. We could find neither Lin^-/Sca-1⁺/c-kit^low cells nor Lin^-/Sca⁺/c-kit^<low cells in the PBCs. Electron microscopic studies of these cells in the mobilized PBCs showed that only 10% to 20% of these cells had a thin rim of cytoplasm with poorly developed organelles (Fig. 5a). In contrast, P-HSCs present in the bone marrow had a large nucleus with narrow cytoplasm. Their chromatin pattern was dispersed, but small aggregates appeared at nuclear margins. There were few cytoplasmic organelles but abundant free ribosomes (Fig. 5b). It should be noted that P-HSCs possess microvilli; they show active movement like neutrophils when observed on video tape. Thus, PBSCs seem to be more mature than P-HSCs in the bone marrow (19).

View larger version (115K): [in this window] [in a new window]   Figure 5.   Electron microscopic (EM) findings in (a) PBSCs (Lin-/Sca-1+/c-kit+ cells) and (b) P-HSCs in the bone marrow. P-HSCs show large nuclei with narrow cytoplasm and microvilli, whereas PBSCs show a more spacious cytoplasm with more abundant mitochondrias than P-HSCs.

View larger version (14K): [in this window] [in a new window]   Figure 6.   Survival rate in [B6C3H] chimeric mice reconstituted with normal BMCs (1.5 x 107 cells) or PBSCs (7 x 106 cells).

	Human P-HSCs

Top Abstract Introduction Mouse P-HSCs Human P-HSCs MHC Restriction Exists Between... References

Another functionally and phenotypically important molecule is c-kit, which plays an important role in the early stage of hemopoiesis (28-31). In previous studies, it was found that the CD34⁺/c-kit^low population contained the majority of cycle-dormant progenitors, multilineage colony-forming cells, colony-forming unit granulocyte-erythroid-macrophage-megakaryocyte (CFU-GEMM) and LTC-ICs (14, 32, 33). In addition, LTRA was found to be enriched in the CD34⁺/c-kit^low population using an in utero transplantation system (34). In contrast, CD34⁺/c-kit^- cells were rejected because of their low proliferative responses or the absence of such responses to several stimuli (30, 32-35), in spite of the existence of these cells in the human BM and CB. However, it has also been shown that the expression of c-kit molecules on HSCs is dependent on the differentiation steps (30, 35, 36). Therefore, there is a possibility that the induction of c-kit molecules is a first step in the differentiation of P-HSCs, being accompanied by the acquirement of reactivity to SCF. Furthermore, taking the dormancy of HSCs into consideration, it would be logical for HSCs not to express c-kit on their surface and so protect them from stimuli that would induce them to enter the cell cycle. In this sense, CD34⁺/c-kit^low cells could be more primitive HSCs.

These findings prompted us to examine whether human P-HSCs are c-kit^<low, c-kit^low, or c-kit⁺. We purified CD34⁺/c-kit^<low cells (phenotypically c-kit-negative but only detectable at the message level) from the human cord blood and examined their maturational steps in relation to the expression of c-kit molecules. When the CD34⁺/c-kit^<low cells were cultured with cytokines (flt3-ligand, IL-6, and IL-7) plus immobilized anti-CD34 monoclonal antibody (mAb) (to cross-link CD34 molecules), c-kit molecules were clearly induced within 24 hr (Fig. 7). The c-kit expression gradually increased until Day 8. Although the colony-forming ability of sorted CD34⁺/c-kit^<low cells is less than that of the other two populations (CD34⁺/c-kit⁺ and CD34⁺/c-kit^low), when CD34⁺/c-kit^low or CD34⁺/c-kit⁺ cells that had been induced from CD34⁺/c-kit^<low cells were re-sorted and re-cultured using a methylcellulose culture system, they showed the same colony-forming ability as the freshly isolated CD34⁺/c-kit^low or CD34⁺/c-kit⁺ cells, respectively. These data indicate that the changes in the expression of c-kit molecules reflect the changes not only in their immunophenotypes but also in the functional maturation of the CD34⁺/c-kit^<low cells. This is in accordance with the report by Gunji et al. (14) where: (i) CD34⁺/c-kit^high cells were induced from CD34⁺/c-kit^low cells after four-week culture with stromal cells and (ii) LTC-ICs were enriched in the CD34⁺/c-kit^low population, but not in differentiated CD34⁺/c-kit^high cells with the ability to form CFU-GM. However, they only reported the induction of differentiation from c-kit^low to c-kit^high. Our purified CD34⁺/c-kit^<low or ^low and CD34⁺/c-kit⁺ cells may correspond to CD34⁺/c-kit^- and CD34⁺/c-kit^low cells, respectively, in the previous reports, based on FCM pattern and colony-forming ability (32, 34). Therefore, our results clearly show that the changes in the intensity of c-kit molecules are closely related to the earliest maturational phase of hematopoiesis. Furthermore, CD34⁺/c-kit^<low cells have a similar hemopoietic potential to CD34⁺/c-kit^low cells in assays for LTC-IC and CFU-C generated from long-term cultures. These findings suggest that CD34⁺/c-kit^<low cells differentiate into CD34⁺/c-kit^low and CD34⁺/c-kit⁺ cells and acquire the reactivity to various humoral hemopoietic stimuli. Moreover, CD34⁺/c-kit^<low cells showed a low level of rhodamine 123 (Rh123) retention, suggesting that these cells have multidrug resistance. Electron microscopic studies revealed the presence of P-HSCs, similar to those seen in the mouse bone marrow (Fig. 5b) (37) in the cord blood (Fig. 8). Therefore, we conclude that human cord blood contains CD34⁺/c-kit^<low cells that correspond to mouse P-HSCs (38).

View larger version (23K): [in this window] [in a new window]   Figure 7.   Induction of human c-kit+ cells from c-kit<low cells in vitro.

View larger version (167K): [in this window] [in a new window]   Figure 8.   Electron microscopic findings in human P-HSCs (CD34+/c-kit<low). A human P-HSC shows a large nucleus with narrow cytoplasm and microvilli, as seen in mouse P-HSCs (see Fig. 5).

	MHC Restriction Exists Between Normal P-HSCS and Stromal Cells

Top Abstract Introduction Mouse P-HSCs Human P-HSCs MHC Restriction Exists Between... References

View larger version (15K): [in this window] [in a new window]   Figure 9.   Necessity of stromal cells for P-HSCs to proliferate. When P-HSCs were cocultured with stromal cells, the P-HSCs proliferated without the addition of cytokines, whereas they did not without stromal cells.

View larger version (18K): [in this window] [in a new window]   Figure 10.   In vitro MHC restriction between P-HSCs and stromal cells. When B10 (H-2b) P-HSCs (300 or 100 cells) are cocultured with B10 stromal cells, the P-HSCs proliferate. In contrast, when B10 P-HSCs are cocultured with B10D2 (H-2d) stromal cells, the P-HSCs (10–300 cells) show poor proliferative responses.

	Acknowledgments

 
These experiments were carried out in collaboration with researchers who appear in the references of this paper. I would like to express my deep appreciation to them. I would also like thank Mr. Hilary Eastwick-Field and Ms. Keiko Ando for preparing this manuscript.

	Footnotes

 
This work was supported by a grant from the Japanese Ministry of Health and Welfare; a grant from "Haiteku Research Center" of the Ministry of Education, Science and Culture, Japan, and the Science Research Promotion Fund of the Japan Private School Promotion Foundation.

¹ To whom requests for reprints should be addressed at First Department of Pathology, Kansai Medical University, 10–15 Fumizono-cho, Moriguchi City, Osaka 570–8506, Japan. E-mail: ikehara{at}takii.kmu.ac.jp

	References

Top Abstract Introduction Mouse P-HSCs Human P-HSCs MHC Restriction Exists Between... References

 

1. Wolf NS, Kone A, Priestley GV, Bartelmez SH. In vivo and in vitro characterization of long-term repopulating primitive hematopoietic stem cells isolated by sequential hoechst 33342-rhodamine 123 FACS selection. Exp Hematol 21:614–622, 1993.[Medline]
2. Spangrude GJ, Brooks DM, Tumas DB. Long-term repopulation of irradiated mice with limited numbers of purified hematopoietic stem cells: In vivo expansion of stem cell phenotype but not function. Blood 85:1006–1016, 1995.[Abstract/Free Full Text]
3. Spangrude GJ, Brooks DM. Mouse strain variability in the expression of the hematopoietic stem cell antigen Ly-6A/E by bone marrow cells. Blood 82:3327–3332, 1993.[Abstract/Free Full Text]
4. Uchida N, Weissman IL. Searching for hematopoietic stem cells: Evidence that Thy-1.1^lowLin^-Sca-1⁺ cells are the only stem cells in C57BL/Ka-Thy-1.1 bone marrow. J Exp Med 175:175–184, 1992.[Abstract/Free Full Text]
5. Spangrude GJ, Brooks DM. Phenotype analysis of mouse hematopoietic stem cells shows a Thy-1-negative subset. Blood 80:1957–1964, 1992.[Abstract/Free Full Text]
6. Chung LL, Johnson GR. Long-term hemopoietic repopulation by Thy-1^low, Lin^-, Ly6A/E⁺ cells. Exp Hematol 20:1309–1315, 1992.[Medline]
7. Morrison SJ, Weissman IL. The long-term hemopoietic repopulating subset of hematopoietic stem cells is deterministic and isolatable by phenotype. Immunity 1:661–673, 1994.[Medline]
8. Krause DS, Ito T, Fackler MJ, Smith OM, Collector MI, Sharkis SJ, May WS. Characterization of murine CD34, a marker for hematopoietic progenitors and stem cells. Blood 84:691–701, 1994.[Abstract/Free Full Text]
9. Orlic D, Fischer R, Nishikawa S-I, Nienhuis AW, Bodine DM. Purification and characterization of heterogeneous pluripoent hematopoietic stem cell populations expressing high levels of c-kit receptor. Blood 2:762–770, 1993.
10. Ikuta K, Weissman IL. Evidence that hematopoietic stem cells express c-kit, but do not depend on steel factor for their generation. Proc Natl Acad Sci U S A 89:1502–1506, 1992.[Abstract/Free Full Text]
11. Ogawa M, Matsuzaki Y, Nishikawa S, Hayashi S-I, Kunisada T, Sudo T, Kina T, Nakauchi H, Nishikawa S-I. Expression and function of c-kit in hemopoietic progenitor cells. J Exp Med 174:63–71, 1991.[Abstract/Free Full Text]
12. Li CL, Johnson GR. Murine hematopoietic stem and progenitor cells: I. Enrichment and biologic characterization. Blood 85:1472–1479, 1995.[Abstract/Free Full Text]
13. Taniguchi H, Toyoshima T, Fukao K, Nakauchi H. Presence of hematopoietic stem cells in the adult liver. Nat Med 2:198–203, 1996.[Medline]
14. Gunji Y, Nakamura M, Osawa H, Nagayoshi K, Nakauchi H, Miura Y, Yanagisawa M, Suda T. Human primitive hematopoietic progenitor cells are more enriched in KIT^low cells than in KIT^high cells. Blood 82:3283–3289, 1993.[Abstract/Free Full Text]
15. Katayama N, Shih J-P, Nishikawa S-I, Kina T, Clark SC, Ogawa M. Stage-specific expression of c-kit protein by murine hematopoietic progenitors. Blood 82:2353–2360, 1993.[Abstract/Free Full Text]
16. Oriz M, Wine JW, Lohrey N, Ruscetti FW, Spence SE, Keller JR. Functional characterization of a novel hematopoietic stem cell and its place in the c-kit maturation pathway in bone marrow cell development. Immunity 10:173–182, 1999.[Medline]
17. Doi H, Inaba M, Yamamoto Y, Taketani S, Mori S-I, Sugihara A, Ogata H, Toki J, Hisha H, Inaba K, Sogo S, Adachi M, Matsuda T, Good RA, Ikehara S. Pluripotent hemopoietic stem cells are c-kit^low. Proc Natl Acad Sci U S A 94:2513–2517, 1997.[Abstract/Free Full Text]
18. Lian Z, Feng B, Sugiura K, Inaba M, Yu C, Jin T, Fan T, Cui Y, Yasumizu R, Toki J, Adachi Y, Hisha H, Ikehara S. c-kit^low pluripotent hemopoietic stem cells form CFU-S on Day 16. Stem Cells 17:39–44, 1999.[Abstract/Free Full Text]
19. Yamamoto Y, Yasumizu R, Amou Y, Watanabe N, Nishio N, Toki J, Fukuhara S, Ikehara S. Characterization of peripheral blood cells in mice. Blood 88:445–454, 1996.[Abstract/Free Full Text]
20. Bernstein ID, Andrewa RG, Zsebo KM. Recombinant human stem cell factor enhances the formation of colonies by CD34⁺ and CD34⁺lin^– cells, and the generation of colony-forming cell progeny from CD34⁺lin^– cells cultured with interleukin-3, granulocyte colony-stimulating factor, or granulocyte-macrophage colony-stimulating factor. Blood 77:2316–2321, 1991.[Abstract/Free Full Text]
21. Xiao M, Leemhuis T, Broxmeyer HE, Lu L. Influence of combinations of cytokines on proliferation of isolated single cell–sorted human bone marrow hematopoietic progenitor cells in the absence and presence of serum. Exp Hematol 20:276–279, 1992.[Medline]
22. Lu L, Xiao M, Shen R-N, Grigsby S, Broxmeyer HE. Enrichment, characterization, and responsiveness of single primitive CD34 human umbilical cord blood hematopoietic progenitors with high proliferative and replating potential. Blood 81:41–48, 1993.[Abstract/Free Full Text]
23. Siena S, Bregni M, Brando B, Ravagnani F, Bonadonna G, Gianni AM. Circulation of CD34⁺ hematopoietic stem cells in the peripheral blood of high-dose cyclophosphamide-treated patients: Enhancement by intravenous recombinant human granulocyte-macrophage colony-stimulating factor. Blood 74:1905–1914, 1989.[Abstract/Free Full Text]
24. Hao Q-L, Shah AJ, Thiemann FT, Smogorzewaska EM, Crooks GM. A functional comparison of CD34⁺CD38^– cells in cord blood and bone marrow. Blood 86:3745–3753, 1995.[Abstract/Free Full Text]
25. Murray L, Chen B, Galy A, Chen S, Tushinski R, Uchida N, Negrin R, Tricot G, Jagannath S, Vesole D. Enrichment of human hematopoietic stem cell activity in the CD34⁺Thy-1⁺Lin^- subpopulation from human mobilized peripheral blood. Blood 85:368–378, 1995.[Abstract/Free Full Text]
26. Craig W, Kay R, Cutler RL, Lansdorp PM. Expression of Thy-1 on human hematopoietic progenitor cells. J Exp Med 177:1331–1342, 1993.[Abstract/Free Full Text]
27. Mayani H, Lansdorp PM. Thy-1 expression is linked to functional properties of primitive hematopoietic progenitor cells from human umbilical cord blood. Blood 83:2410–2417, 1994.[Abstract/Free Full Text]
28. Katayama N, Clark SC, Ogawa M. Growth factor requirement for survival in cell-cycle dormancy of primitive murine lymphohematopoietic progenitors. Blood 8:610–616, 1993.
29. Tsuji K, Lyman SD, Sudo T, Clark SC, Ogawa M. Enhancement of murine hematopoiesis by synergistic interactions between steel factor (ligand for c-kit), interleukin-11, and other early acting factors in culture. Blood 79:2855–2860, 1992.[Abstract/Free Full Text]
30. Simmons PJ, Aylett GW, Niutta S, To LB, Juttner CA, Asman LK. c-Kit is expressed by primitive human hematopoietic cells that give rise to colony-forming cells in stroma-dependent or cytokine-supplemented culture. Exp Hematol 22:157–165, 1994.[Medline]
31. Gore SD, Amin S, Weng L-J, Civin CI. Steel factor supports the cycling of isolated human CD34+ cells in the absence of other growth factors. Exp Hematol 23:413–421, 1995.[Medline]
32. Laver JH, Abboud MR, Kawashima I, Leary AG, Ashman LK, Ogawa M. Characterization of c-kit expression by primitive hematopoietic progenitors in umbilical cord blood. Exp Hematol 23:1515–1519, 1995.[Medline]
33. Briddell RA, Broudy VC, Bruno E, Brabdt JE, Srour EF, Hoffman R. Further phenotypic characterization and isolation of human hematopoietic progenitor cells using a monoclonal antibody to the c-kit receptor. Blood 79:3159–3167, 1992.[Abstract/Free Full Text]
34. Kawashima I, Zanjani ED, Almaida-Porada G, Flake AW, Zeng H, Ogawa M. CD34+ human marrow cells that express low levels of kit protein are enriched for long-term marrow-engrafting cells. Blood 87:4136–4142, 1996.[Abstract/Free Full Text]
35. De Jong MO, Wagemaker G, Wognum AW. Separation of myeloid and erythroid progenitors based on expression of CD34 and c-kit. Blood 86:4076–4085, 1995.[Abstract/Free Full Text]
36. Uoshima N, Ozawa M, Kimura S, Tanaka K, Wada K, Kobayashi Y, Kondo M. Changes in c-kit expression and effects of SCF during differentiation of human erythroid progenitor cells. Br J Haematol 91:30–36, 1995.[Medline]
37. Miyama-Inaba M, Ogata H, Toki J, Kuma S, Sugiura K, Yasumizu R, Ikehara S. Isolation of murine pluripotent hemopoietic stem cells in the Go phase. Biochem Biophys Res Commun 147:687–694, 1987.[Medline]
38. Sogo S, Inaba M, Ogata H, Hisha H, Adachi Y, Mori S-I, Toki J, Yamanishi K, Kanzaki H, Adachi M, Ikehara S. Induction of c-kit molecules on human CD34⁺/c-kit^low cells: Evidence for CD34⁺/c-kit^low cells as primitive hematopoietic stem cells. Stem Cells 15:420–429, 1997.[Abstract/Free Full Text]
39. Ishida T, Inaba M, Hisha H, Sugiura K, Adachi Y, Nagata N, Ogawa R, Good RA, Ikehara S. Requirement of donor-derived stromal cells in the bone marrow for successful allogeneic bone marrow transplantation: Complete prevention of recurrence of autoimmune diseases in MRL/MP-lpr-lpr mice by transplantation of bone marrow plus bone (stromal cells) from the same donor. J Immunol 152:3119–3127, 1994.[Abstract]
40. Hisha H, Nishino T, Kawamura M, Adachi S, Ikehara S. Successful bone marrow transplantation by bone grafts in chimeric-resistant combination. Exp Hematol 23:347–352, 1995.[Medline]
41. Hashimoto F, Sugiura K, Inoue K, Ikehara S. Major histocompatibility complex restriction between hematopoietic stem cells and stromal cells in vivo. Blood 89:49–54, 1997.[Abstract/Free Full Text]
42. Sugiura K, Inaba M, Hisha H, Borisov K, Sardi–a EE, Good RA, Ikehara S. Requirement of major histocompatibility complex-compatible microenvironment for spleen colony formation (CFU-S on Day 12 but not on Day 8). Stem Cells 15:461–468, 1997.[Abstract/Free Full Text]

This article has been cited by other articles:

				O. E. Sigurjonsson, M.-C. Perreault, T. Egeland, and J. C. Glover Adult human hematopoietic stem cells produce neurons efficiently in the regenerating chicken embryo spinal cord PNAS, April 5, 2005; 102(14): 5227 - 5232. [Abstract] [Full Text] [PDF]

				M. Sosnova, M. Bradl, and J. V. Forrester CD34+ Corneal Stromal Cells Are Bone Marrow-Derived and Express Hemopoietic Stem Cell Markers Stem Cells, April 1, 2005; 23(4): 507 - 515. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ikehara, S. Search for Related Content PubMed PubMed Citation Articles by Ikehara, S.