scholarly journals Human cord blood cells as targets for gene transfer: potential use in genetic therapies of severe combined immunodeficiency disease.

1993 ◽  
Vol 178 (2) ◽  
pp. 529-536 ◽  
Author(s):  
T Moritz ◽  
D C Keller ◽  
D A Williams
Keyword(s):  
Bone Marrow ◽  
Gene Transfer ◽  
Cord Blood ◽  
Progenitor Cells ◽  
Severe Combined Immunodeficiency ◽  
Genetic Material ◽  
Retroviral Vectors ◽  
Transduction Efficiency ◽  
Human Cord Blood

Human cord blood (CB) contains large numbers of both committed and primitive hematopoietic progenitor cells and has been shown to have the capacity to reconstitute the lympho-hematopoietic system in transplant protocols. To investigate the potential usefulness of CB stem and progenitor cell populations to deliver new genetic material into the blood and immune systems, we have transduced these cells using retroviral technology and compared the efficiency of gene transfer into CB cells with normal adult human bone marrow cells using a variety of infection protocols. Using two retroviral vectors which differ significantly in both recombinant viral titers and vector design, low density CB or adult bone marrow (ABM) cells were infected, and committed progenitor and more primitive hematopoietic cells were analyzed for gene expression by G418 drug resistance (G418r) of neophosphotransferase and protein analysis for murine adenosine deaminase (mADA). Standard methylcellulose progenitor assays were used to quantitate transduction efficiency of committed progenitor cells, and the long term culture-initiating cell (LTC-IC) assay was used to quantitate transduction efficiency of more primitive cells. Our results indicate that CB cells were more efficiently transduced via retroviral-mediated gene transfer as compared with ABM-derived cells. In addition, stable expression of the introduced gene sequences, including the ADA cDNA, was demonstrated in the progeny of infected LTC-ICs after 5 wk in long-term marrow cultures. Expression of the introduced ADA cDNA was higher than the endogenous human ADA gene in the LTC-IC-derived colonies examined. These studies demonstrate that CB progenitor and stem cells can be efficiently infected using retroviral vectors and suggest that CB cells may provide a suitable target population in gene transfer protocols for some genetic diseases.

A Modified Foamy Viral Envelope Enhances Gene Transfer Efficiency and Reduces Toxicity of Lentiviral FANCA Vectors in Fanca-/- HSCs.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 696-696
Author(s):  
Zejin Sun ◽  
Yan Li ◽  
Jingling Li ◽  
Shanbao Cai ◽  
Yi Zeng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Gene Transfer ◽  
Cord Blood ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Transduction Efficiency ◽  
Gene Transfer Efficiency

Abstract Abstract 696 Fanconi anemia (FA) is a recessive DNA repair disorder characterized by bone marrow failure, genomic instability, and a predisposition to malignancies. Stem cell gene transfer technology is a potentially promising therapy, however, we have previously shown that prolonged ex vivo culture of cells using gamma retroviruses, results in a high incidence of apoptosis and predisposes the surviving reinfused cells to hematological malignancy in a murine model of FA. Here, we developed a lentiviral vector encoding the human FANCA cDNA and tested the ability of this construct pseudotyped with either VSV-G or a modified foamy virus (FV) envelope to correct murine Fanca-/- stem and progenitor cells. An overnight transduction protocol was utilized to minimize genotoxic stress due to extended ex vivo manipulations. Transduction and expression of hFANCA was confirmed by three classical functional and biochemical measures in vitro: improved survival of clonogenic progenitors in the presence of mitomycin C (MMC), correction of MMC-induced G2/M arrest, and by the restoration of Fancd2 mono-ubiquitination. Furthermore, in vivo competitive repopulation experiments demonstrated that the repopulating ability of Fanca-/- stem cells transduced with the lentivirus encoding hFANCA was equivalent to that of wild-type stem cells, and the genetically-corrected reconstituting Fanca-/- cells were resistant to MMC and TNF-αa. Importantly, while a significant toxicity was observed using the VSV-G envelope, the toxicity of the FV envelope to murine c-kit+ cells was limited. In parallel experiments, human umbilical cord blood CD34+ cord blood cells were transduced with either a VSV-G- or FV envelope-pseudotyped lentivirus encoding the EGFP reporter gene. Transplantation of 4×105 cells into NOD/SCID/gamma-chainnull yielded a peripheral blood human chimerism comparable to the untransduced control cells (∼30%) regardless of the envelope. However, a much higher gene transfer efficiency of CD34+ cells was observed prior to transplantation when the FV envelope was employed (∼60%), as compared to the VSV-G envelope (∼15%). Furthermore, a similar 4 fold increase in transduction efficiency was observed in peripheral blood and in progenitors isolated from the bone marrow of both primary and secondary long term reconstituted mice. Collectively, these data indicate that the lentiviral construct pseudotyped with FV envelope can efficiently correct murine FA HSC/progenitor cells in a short transduction protocol and that the modified foamy envelope offers significantly greater transduction efficiency at comparable titers in long term reconstituting human cells in a xenograft model. This envelope may offer significant advantages compared to VSV-G in moving forward to phase 1 clinical trials. Disclosures: No relevant conflicts of interest to declare.

Expression of CD10 and CD7 Defines Distinct In Vivo Lymphoid Reconstituting Capacity within Human Cord Blood CD34+CD38-Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3184-3184
Author(s):  
Shuro Yoshida ◽  
Fumihiko Ishikawa ◽  
Leonard D. Shultz ◽  
Noriyuki Saito ◽  
Mitsuhiro Fukata ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
Cord Blood ◽  
Nk Cells ◽  
Progenitor Cells ◽  
Human Cord Blood ◽  
Cd34 Cells

Abstract Human cord blood (CB) CD34+ cells are known to contain both long-term hematopoietic stem cells (LT-HSCs) and lineage-restricted progenitor cells. In the past, in vitro studies suggested that CD10, CD7 or CD127 (IL7Ra) could be candidate surface markers that could enrich lymphoid-restricted progenitor cells in human CB CD34+ cells (Galy A, 1995, Immunity; Hao QL, 2001, Blood; Haddad R, 2004, Blood). However, in vivo repopulating capacity of these lymphoid progenitors has not been identified due to the lack of optimal xenogeneic transplantation system supporting development of human T cells in mice. We aim to identify progenitor activity of human CB CD34+ cells expressing CD10/CD7 by using newborn NOD-scid/IL2rgKO transplant assay that can fully support the development of human B, T, and NK cells in vivo (Ishikawa F, 2005, Blood). Although LT-HSCs exist exclusively in Lin-CD34+CD38- cells, not in Lin-CD34+CD38+ cells, CD10 and CD7 expressing cells are present in Lin-CD34+CD38- cells as well as in Lin-CD34+CD38+ cells (CD10+CD7+ cells, CD10+CD7- cells, CD10-CD7+ cells, CD10-CD7- cells accounted for 4.7+/−2.7%, 10.5+/−1.9%, 7.6+/−4.4%, and 77.1+/−5.2% in Lin-CD34+CD38- CB cells, respectively). We transplanted 500–6000 purified cells from each fraction into newborn NOD-scid/IL2rgKO mice, and analyzed the differentiative capacity. CD34+CD38-CD10-CD7- cells engrafted long-term (4–6 months) in recipient mice efficiently (%hCD45+ cells in PB: 30–70%, n=5), and gave rise to all types of human lymphoid and myeloid progeny that included granulocytes, platelets, erythroid cells, B cells, T cells, and NK cells. Successful secondary reconstitution by human CD34+ cells recovered from primary recipient bone marrow suggested that self-renewing HSCs are highly enriched in CD34+CD38–CD10–CD7- cells. CD10–CD7+ cells were present more frequently in CD34+CD38+ cells rather than in CD34+CD38- cells. Transplantation of more than 5000 CD34+CD38+CD10–CD7+ cells, however, resulted in less than 0.5% human cell engraftment in the recipients. Within CD34+CD38–CD10+ cells, the expression of CD7 clearly distinguished the distinct progenitor capacity. At 8 weeks post-transplantation, more than 70% of total human CD45+ cells were T cells in the CD10+CD7+ recipients, whereas less than 30% of engrafted human CD45+ cells were T cells in the CD10+CD7– recipients. In the CD10+CD7- recipients, instead, more CD19+ B cells and HLA–DR+CD33+ cells were present in the peripheral blood, the bone marrow and the spleen. Both CD34+CD38–CD10+CD7+ and CD34+CD38–CD10+CD7- cells highly repopulate recipient thymus, suggesting that these progenitors are possible thymic immigrants. Taken together, human stem and progenitor activity can be distinguished by the expressions of CD7 and CD10 within Lin-CD34+CD38- human CB cells. Xenotransplant model using NOD-scid/IL2rgKO newborns enable us to clarify the heterogeneity of Lin-CD34+CD38- cells in CB by analyzing the in vivo lymphoid reconstitution capacity.

scholarly journals Stromal support enhances cell-free retroviral vector transduction of human bone marrow long-term culture-initiating cells

Blood ◽  
1992 ◽  
Vol 79 (6) ◽  
pp. 1393-1399 ◽  
Author(s):  
KA Moore ◽  
AB Deisseroth ◽  
CL Reading ◽  
DE Williams ◽  
JW Belmont
Keyword(s):  
Gene Therapy ◽  
Bone Marrow ◽  
Gene Transfer ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
Transduction Efficiency ◽  
Hematopoietic Stem ◽  
Long Term Culture ◽  
Stromal Support

Gene transfer into hematopoietic stem cells by cell-free virions is a goal for gene therapy of hematolymphoid disorders. Because the hematopoietic microenvironment provided by the stroma is required for stem cell maintenance both in vivo and in vitro, we reasoned that cell- free transduction of bone marrow cells (BMC) may be aided by stromal support. We used two high-titer replication-defective retroviral vectors to differentially mark progenitor cells. The transducing vector was shown to be a specific DNA fragment by polymerase chain reaction of colony-forming cells derived from progenitors maintained in long-term culture (LTC). BMC were infected separately by cell-free virions with or without pre-established, irradiated, allogeneic stromal layers, and in the presence or absence of exogenous growth factors (GF). The GF assessed were interleukin-3 (IL-3) and IL-6 in combination, leukemia inhibitory factor (LIF), mast cell growth factor (MGF), and LIF and MGF in combination. In addition, we developed a competitive LTC system to directly assess the effect of infection conditions on the transduction of clonogenic progenitors as reflected by the presence of a predominate provirus after maintenance in the same microenvironment. The results show gene transfer into human LTC-initiating cells by cell-free retroviral vector and a beneficial effect of stromal support allowing a transduction efficiency of 64.6% in contrast to 15.8% without a supporting stromal layer. A high transduction rate was achieved independent of stimulation with exogenous GF. We propose that autologous marrow stromal support during the transduction period may have application in clinical gene therapy protocols.

scholarly journals Stromal support enhances cell-free retroviral vector transduction of human bone marrow long-term culture-initiating cells

Blood ◽  
1992 ◽  
Vol 79 (6) ◽  
pp. 1393-1399 ◽  
Author(s):  
KA Moore ◽  
AB Deisseroth ◽  
CL Reading ◽  
DE Williams ◽  
JW Belmont
Keyword(s):  
Gene Therapy ◽  
Bone Marrow ◽  
Gene Transfer ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
Transduction Efficiency ◽  
Hematopoietic Stem ◽  
Long Term Culture ◽  
Stromal Support

Abstract Gene transfer into hematopoietic stem cells by cell-free virions is a goal for gene therapy of hematolymphoid disorders. Because the hematopoietic microenvironment provided by the stroma is required for stem cell maintenance both in vivo and in vitro, we reasoned that cell- free transduction of bone marrow cells (BMC) may be aided by stromal support. We used two high-titer replication-defective retroviral vectors to differentially mark progenitor cells. The transducing vector was shown to be a specific DNA fragment by polymerase chain reaction of colony-forming cells derived from progenitors maintained in long-term culture (LTC). BMC were infected separately by cell-free virions with or without pre-established, irradiated, allogeneic stromal layers, and in the presence or absence of exogenous growth factors (GF). The GF assessed were interleukin-3 (IL-3) and IL-6 in combination, leukemia inhibitory factor (LIF), mast cell growth factor (MGF), and LIF and MGF in combination. In addition, we developed a competitive LTC system to directly assess the effect of infection conditions on the transduction of clonogenic progenitors as reflected by the presence of a predominate provirus after maintenance in the same microenvironment. The results show gene transfer into human LTC-initiating cells by cell-free retroviral vector and a beneficial effect of stromal support allowing a transduction efficiency of 64.6% in contrast to 15.8% without a supporting stromal layer. A high transduction rate was achieved independent of stimulation with exogenous GF. We propose that autologous marrow stromal support during the transduction period may have application in clinical gene therapy protocols.

scholarly journals Delayed Targeting of Cytokine-Nonresponsive Human Bone Marrow CD34+ Cells With Retrovirus-Mediated Gene Transfer Enhances Transduction Efficiency and Long-Term Expression of Transduced Genes

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3693-3701 ◽  
Author(s):  
Ponnazhagan Veena ◽  
Christie M. Traycoff ◽  
David A. Williams ◽  
Jon McMahel ◽  
Susan Rice ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Gene Transfer ◽  
Progenitor Cells ◽  
Cultured Cells ◽  
Retroviral Vector ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Transduction Efficiency ◽  
Cd34 Cells

Abstract Primitive hematopoietic progenitor cells (HPCs) are potential targets for treatment of numerous hematopoietic diseases using retroviral-mediated gene transfer (RMGT). To achieve high efficiency of gene transfer into primitive HPCs, a delicate balance between cellular activation and proliferation and maintenance of hematopoietic potential must be established. We have demonstrated that a subpopulation of human bone marrow (BM) CD34+ cells, highly enriched for primitive HPCs, persists in culture in a mitotically quiescent state due to their cytokine-nonresponsive (CNR) nature, a characteristic that may prevent efficient RMGT of these cells. To evaluate and possibly circumvent this, we designed a two-step transduction protocol usingneoR-containing vectors coupled with flow cytometric cell sorting to isolate and examine transduction efficiency in different fractions of cultured CD34+ cells. BM CD34+ cells stained on day 0 (d0) with the membrane dye PKH2 were prestimulated for 24 hours with stem cell factor (SCF), interleukin-3 (IL-3), and IL-6, and then transduced on fibronectin with the retroviral vector LNL6 on d1. On d5, half of the cultured cells were transduced with the retroviral vector G1Na and sorted on d6 into cytokine-responsive (d6 CR) cells (detected via their loss of PKH2 fluorescence relative to d0 sample) and d6 CNR cells that had not divided since d0. The other half of the cultured cells were first sorted on d5 into d5 CR and d5 CNR cells and then infected separately with G1Na. Both sets of d5 and d6 CR and CNR cells were cultured in secondary long-term cultures (LTCs) and assayed weekly for transduced progenitor cells. Significantly higher numbers of G418-resistant colonies were produced in cultures initiated with d5 and d6 CNR cells compared with respective CR fractions (P < .05). At week 2, transduction efficiency was comparable between d5 and d6 transduced CR and CNR cells (P > .05). However, at weeks 3 and 4, d5 and d6 CNR fractions generated significantly higher numbers ofneoR progenitor cells relative to the respective CR fractions (P < .05), while no difference in transduction efficiency between d5 and d6 CNR cells could be demonstrated. Polymerase chain reaction (PCR) analysis of the origin of transducedneoR gene in clonogenic cells demonstrated that mature progenitors (CR fractions) contained predominantly LNL6 sequences, while more primitive progenitor cells (CNR fractions) were transduced with G1Na. These results demonstrate that prolonged stimulation of primitive HPCs is essential for achieving efficient RMGT into cells capable of sustaining long-term in vitro hematopoiesis. These findings may have significant implications for the development of clinical gene therapy protocols.

Retrovirally Transduced Human Dendritic Cells Express a Normal Phenotype and Potent T-Cell Stimulatory Capacity

Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2160-2167 ◽  
Author(s):  
Paul Szabolcs ◽  
H.F. Gallardo ◽  
David H. Ciocon ◽  
Michel Sadelain ◽  
James W. Young
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Cord Blood ◽  
Genetic Material ◽  
Retroviral Vectors ◽  
Transduction Efficiency ◽  
Stimulatory Capacity ◽  
Cell Stimulatory Capacity

Abstract Dendritic cells are attractive candidates for vaccine-based immunotherapy because of their potential to function as natural adjuvants for poorly immunogenic proteins derived from tumors or microbes. In this study, we evaluated the feasibility and consequences of introducing foreign genetic material by retroviral vectors into dendritic cell progenitors. Proliferating human bone marrow and cord blood CD34+ cells were infected by retroviral vectors encoding the murine CD2 surface antigen. Mean transduction efficiency in dendritic cells was 11.5% from bone marrow and 21.2% from cord blood progenitors. Transduced or untransduced dendritic cell progeny expressed comparable levels of HLA-DR, CD83, CD1a, CD80, CD86, S100, and p55 antigens. Granulocytes, macrophages, and dendritic cells were equally represented among the transduced and mock-transduced cells, thus showing no apparent alteration in the differentiation of transduced CD34+ precursors. The T-cell stimulatory capacity of retrovirally modified and purified mCD2-positive allogeneic or nominal antigen-pulsed autologous dendritic cells was comparable with that of untransduced dendritic cells. Human CD34+ dendritic cell progenitors can therefore be efficiently transduced using retroviral vectors and can differentiate into potent immunostimulatory dendritic cells without compromising their T-cell stimulatory capacity or the expression of critical costimulatory molecules and phenotypic markers. These results support ongoing efforts to develop genetically modified dendritic cells for immunotherapy.

scholarly journals Delayed Targeting of Cytokine-Nonresponsive Human Bone Marrow CD34+ Cells With Retrovirus-Mediated Gene Transfer Enhances Transduction Efficiency and Long-Term Expression of Transduced Genes

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3693-3701
Author(s):  
Ponnazhagan Veena ◽  
Christie M. Traycoff ◽  
David A. Williams ◽  
Jon McMahel ◽  
Susan Rice ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Gene Transfer ◽  
Progenitor Cells ◽  
Cultured Cells ◽  
Retroviral Vector ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Transduction Efficiency ◽  
Cd34 Cells

Primitive hematopoietic progenitor cells (HPCs) are potential targets for treatment of numerous hematopoietic diseases using retroviral-mediated gene transfer (RMGT). To achieve high efficiency of gene transfer into primitive HPCs, a delicate balance between cellular activation and proliferation and maintenance of hematopoietic potential must be established. We have demonstrated that a subpopulation of human bone marrow (BM) CD34+ cells, highly enriched for primitive HPCs, persists in culture in a mitotically quiescent state due to their cytokine-nonresponsive (CNR) nature, a characteristic that may prevent efficient RMGT of these cells. To evaluate and possibly circumvent this, we designed a two-step transduction protocol usingneoR-containing vectors coupled with flow cytometric cell sorting to isolate and examine transduction efficiency in different fractions of cultured CD34+ cells. BM CD34+ cells stained on day 0 (d0) with the membrane dye PKH2 were prestimulated for 24 hours with stem cell factor (SCF), interleukin-3 (IL-3), and IL-6, and then transduced on fibronectin with the retroviral vector LNL6 on d1. On d5, half of the cultured cells were transduced with the retroviral vector G1Na and sorted on d6 into cytokine-responsive (d6 CR) cells (detected via their loss of PKH2 fluorescence relative to d0 sample) and d6 CNR cells that had not divided since d0. The other half of the cultured cells were first sorted on d5 into d5 CR and d5 CNR cells and then infected separately with G1Na. Both sets of d5 and d6 CR and CNR cells were cultured in secondary long-term cultures (LTCs) and assayed weekly for transduced progenitor cells. Significantly higher numbers of G418-resistant colonies were produced in cultures initiated with d5 and d6 CNR cells compared with respective CR fractions (P < .05). At week 2, transduction efficiency was comparable between d5 and d6 transduced CR and CNR cells (P > .05). However, at weeks 3 and 4, d5 and d6 CNR fractions generated significantly higher numbers ofneoR progenitor cells relative to the respective CR fractions (P < .05), while no difference in transduction efficiency between d5 and d6 CNR cells could be demonstrated. Polymerase chain reaction (PCR) analysis of the origin of transducedneoR gene in clonogenic cells demonstrated that mature progenitors (CR fractions) contained predominantly LNL6 sequences, while more primitive progenitor cells (CNR fractions) were transduced with G1Na. These results demonstrate that prolonged stimulation of primitive HPCs is essential for achieving efficient RMGT into cells capable of sustaining long-term in vitro hematopoiesis. These findings may have significant implications for the development of clinical gene therapy protocols.

Identification and Long-Term Repopulating Potential of Human Cord Blood-Derived CD34−Flt3− Cells with Very Immature Phenotype Using Intra-Bone Marrow Injection.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 797-797
Author(s):  
Yoshiaki Sonoda ◽  
Takafumi Kimura ◽  
Rumiko Asada ◽  
Jianfeng Wang ◽  
Takashi Kimura ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tyrosine Kinase ◽  
Cord Blood ◽  
Severe Combined Immunodeficiency ◽  
Tyrosine Kinase Receptor ◽  
Human Cord Blood ◽  
Hematopoietic Stem ◽  
And Function

Abstract Recently, we have successfully identified human cord blood (CB)-derived CD34-negative (CD34−) severe combined immunodeficiency (SCID)-repopulating cells (SRCs) with extensive lymphoid and myeloid repopulating ability using the intra-bone marrow injection (IBMI) method (Blood101:2924,2003). These CD34− SRCs could home into the BM niche only by IBMI, because they expressed lower levels of homing receptors including CXCR4. These CD34− SRCs did not express CD38 as well as c-kit. It is well documented that the tyrosine kinase receptors c-kit and flt3 are expressed and function in early mouse and human hematopoiesis. In murine model, it was reported that Lin−CD34−Sca−1+c-kit+flt3− cells supported long-term multilineage hematopoietic reconstitution. In contrast, Lin−CD34−Sca-1+c-kit+flt3+ cells are progenitors for the common lymphoid progenitor. More recently, these Lin−CD34−Sca-1+c-kit+flt3+ hematopoietic stem cells (HSCs) have been revealed to lack erythro-megakaryocytic potential. In this study, we have investigated the function of flt3 in our identified human CB-derived CD34− SRCs. First, we studied the SRC activity of CB-derived Lin-CD34+Flt3+/− or CD34−Flt3+/− cells using IBMI. Both CD34+FLT3+/− cells repopulated all 13 recipient mice. The level of human CD45+ cells in murine BMs received transplants of CD34+Flt3+ cells (29.3~90.8%, median 62.8%) was higher than those received transplants of CD34+Flt3− cells (9.8~45.1%, median 17.7%). On the other hand, only CD34−Flt3− cells repopulated all 7 recipient mice and the level of human CD45+ cells in murine BMs was 11.7~63.3% (median 37.9%). To further evaluate the long-term repopulating potential of these three populations, including CD34+Flt3+/− and CD34−Flt3− cells, BM cells obtained from each primary recipient mice were accessed for their SRC activities by secondary transplantation by IBMI. While CD34+Flt3+ cells did not show secondary repopulating activity, CD34+Flt3− cells could repopulate 83% (5/6) of secondary recipients. Moreover, CD34−Flt3− cells did repopulate all 5 secondary recipient mice with higher repopulating rate. Next, we cocultured CD34−Flt3−cells with the murine stromal cell line, HESS-5 in the presence of SCF, TPO, IL-3, IL-6, and G-CSF. After one week, significant numbers of CD34+Flt3− and CD34+Flt3+ cells were generated. Then we sorted these two populations, CD34+Flt3+/− cells, and tested their SRC activities by IBMI. Seven out of 10 and 5 out of 10 mice received CD34+Flt3+/− cells were repopulated with human cells, respectively. These results indicated that human CB-derived Lin−CD34−Flt3− cells produced CD34+Flt3− as well as CD34+Flt3+ SRCs in vitro. Our present study has demonstrated that human CB-drived CD34− SRCs do not express Flt3 tyrosine kinase receptor as did murine CD34− KSL cells. Based on these data, we propose that the immunophenotype of very primitive long-term repopulating human HSC is Lin−CD34−CD38−c-kit-Flt3−.

scholarly journals High-efficiency gene transfer and expression in normal human hematopoietic cells with retrovirus vectors

Blood ◽  
1988 ◽  
Vol 71 (3) ◽  
pp. 811-814 ◽  
Author(s):  
P Laneuville ◽  
W Chang ◽  
S Kamel-Reid ◽  
AA Fauser ◽  
JE Dick
Keyword(s):  
Bone Marrow ◽  
Gene Transfer ◽  
Progenitor Cells ◽  
High Efficiency ◽  
Bone Marrow Cells ◽  
Fibroblast Cell ◽  
Retroviral Vectors ◽  
Semisolid Medium ◽  
Bacterial Gene

Abstract Retroviral vectors containing the selectable bacterial gene for G418 resistance (neo) were used to demonstrate gene transfer into primary human bone-marrow progenitor cells. To obtain populations of cells in which a high proportion of cells were expressing the neo gene, several important modifications were made to earlier procedures. Cells from normal donors were infected in vitro, were exposed to high concentrations of G418 for two days in liquid culture to enrich for cells expressing the neo gene, and were plated in semisolid medium. Gene transfer and expression were detected in colonies arising from progenitors of granulocyte-macrophage and erythroid lineages. Survival curves indicated that a high proportion of progenitor cells, approaching 100%, were G418 resistant. Furthermore, addition of growth factors contained in 5637-conditioned medium to the bone marrow improved the recovery of G418-resistant progenitors twofold to threefold. In addition to these biological measurements of gene expression in progenitor cells, significant levels of neo-specific RNA, similar to the levels of RNA expression in the virus-producing fibroblast cell line, were detected in the bone marrow cells after preselection. These results demonstrate that retrovirus vectors can be used successfully to transfer genes at high efficiency into progenitor cells in the human blood-forming system.

Sign in / Sign up

Export Citation Format

Share Document