Impaired Engraftment of Lineage-Depleted Marrow Cultured for Ex Vivo Gene Transfer in Submyeloablated Murine Hosts.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5545-5545
Author(s):  
Brandon K. Wyss ◽  
Justin L. Meyers ◽  
Anthony L. Sinn ◽  
Shanbao Cai ◽  
Karen E. Pollok ◽  
...  
Keyword(s):  
Stem Cell ◽  
Gene Transfer ◽  
Cell Function ◽  
Ex Vivo ◽  
Transduction Efficiency ◽  
Cell Recovery ◽  
Donor Chimerism ◽  
Ex Vivo Culture ◽  
Cells Cultured ◽  
Marrow Cells

Abstract We previously demonstrated that engraftment of murine whole bone marrow (WBM) transduced with an oncoretroviral vector using an optimized 5-fluorouracil (5-FU)-based transduction protocol is reduced ~3-fold compared to fresh WBM upon transplantation into sublethally irradiated hosts, although competitive repopulating ability in ablated hosts is not decreased (Goebel et al., Exp. Hematol. 30:1324, 2002). We therefore sought to determine whether marrow cells transduced using a clinically relevant, non-5-FU-containing protocol would engraft more efficiently. Li et al. (Exp. Hematol. 31:1206, 2003) showed that lineage-depleted (lin−) marrow cells from donor mice not treated with 5-FU were effectively transduced, and repopulated myeloablated hosts. We hypothesized that ex vivo culture for gene transfer in the absence of 5-FU would lead to improved donor marrow engraftment in submyeloablated hosts. Lin− cells, isolated from B6.SJL (Boy J; CD45.1+) WBM using a Miltenyi kit and VarioMACS apparatus, were prestimulated in StemSpan serum-free medium with SCF and IL-6 for 48 hours, followed by overnight transduction on RetroNectin-coated plates preloaded with ecotropic SF1-EGFP retroviral supernatant. Cell recovery from the MACS column (1.9 ± 1.4%), bulk transduction efficiency (77.3 ± 12%), and lin− cell purity (58 ± 17%; all from 7–13 experiments) was similar to that previously described. Transplantation of 106 lin− transduced cells into 300 cGy-conditioned congenic C57Bl6/J (B6; CD45.2+) hosts produced only 1.4 ± 0.5% donor chimerism 4–6 months post-transplant, significantly lower than that observed using 106 fresh lin− cells (29 + 18.8%; N = 8–9 hosts each from 2–3 experiments). The percentage of EGFP+ cells in the donor population, nevertheless, was 55.6 ± 18%, indicating that stem cells were marked but engrafted poorly. The repopulating ability of transduced lin− marrow was reduced ~10-fold compared to fresh lin− cells as determined in competitive repopulation assays in ablated hosts. Together, these data suggest that lin cells cultured ex vivo for gene transfer acquired an engraftment defect despite the absence of 5-FU. Increasing the conditioning radiation dose to 550 cGy, a dose used in prior canine and non-human primate gene transfer studies, markedly improved donor chimerism following transplantation of 106 fresh lin− cells (90 ± 1.3% at 4 months, N = 5) or 106 transduced lin− cells (38.5 ± 14% at 2 months, N = 10), suggesting that greater reduction in host stem cell function may be needed for engraftment of cells cultured ex vivo for gene transfer. Ongoing studies to investigate the mechanism responsible for this engraftment defect indicate that expression of adhesion molecules important for homing and engraftment (CD29, 44, 49d, 49e, 62L), CXCR4 expression, and the percentage of cells actively cycling are not significantly altered by the transduction process, although functional studies are underway. The percentage of Sca-1+lin−c-kit+ (SLK) cells in the transduced cell pool is similar to that of freshly isolated lin− cells; thus, transplantation of lin− cells cultured ex vivo for gene transfer results in significantly lower donor chimerism than fresh lin− cells despite the grafts containing similar numbers of SLK cells. Secondary transplants and limiting dilution studies to determine stem cell self-renewal and engraftment capacity before and after ex vivo culture for gene transfer are in progress.

Reducing Stem Cell Loss and Ex Vivo Differentiation during Lentivirus Gene Transfer to Murine Stem Cells - an Ultra-Short Transduction Protocol.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2113-2113
Author(s):  
Peter Kurre ◽  
Ponni Anandakumar ◽  
Vladimir A. Lesnikov ◽  
Hans-Peter Kiem
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Gene Transfer ◽  
Ex Vivo ◽  
Lentivirus Vectors ◽  
Ex Vivo Culture ◽  
Marrow Cells

Abstract Most gene transfer models using Moloney murine leukemia virus (MLV) - derived vectors to target hematopoietic repopulating cells require progenitor cell enrichment and extended ex vivo culture for efficient long-term marking. Both may result in qualitative, and/or quantitative, loss of stem cells thereby limiting gene transfer rates in vivo. This can be a critical obstacle in candidate applications with exhausted autologous stem cell pools, such as Fanconi Anemia. Among the advantages of HIV-derived lentivirus vectors is their ability to transduce non dividing cells, permitting shortened ex vivo culture durations while maintaining gene transfer to long-term repopulating cells. We have previously reported long-term gene transfer rates of 12–40% after VSV-G/ lentivirus vector transduction of murine stem cells by targeting unseparated marrow cells after reduced prestimulation and a single 12 hour vector exposure (Kurre et al., Mol. Ther. 2004 Jun;9(6):914–22). We herein report studies showing maintenance of gene transfer efficiency in this model at drastically reduced ex vivo vector exposure times. In initial in vitro experiments we studied cytokine support, vector particle density, and minimum exposure duration requirements for efficient gene transfer to unseparated marrow cells. We determined that fibronectin fragment support was critical in maintaining minimum gene transfer efficiencies, even during brief 1, or 3-hour exposures. In an effort to extend these in vitro findings targeting a mixed leukocyte population and explore the feasibility in vivo, we next performed repopulation experiments in myeloablated murine recipients. Unseparated marrow cells harvested from donor animals were depleted of red blood cells, washed and immediately transduced on fibronectin fragment in the presence of murine stem cell factor. Following a 1 hour exposure to lentivector (VSV-G/RRLsin-cPPThPGK-EGFPwpre), cells were washed repeatedly, resuspended and injected into myeloablated recipients (n=10). Animals showed ready hematopoietic reconstitution and demonstrated average GFP marking of 31% (range: 17–41.2%) in peripheral blood 20 weeks after transplantation. Gene marking in secondary recipients 9 weeks after reconstitution (n=15, 3 recipient animals per donor) persisted at 29% on average (range 14.9–66%). Results also demonstrate transduction of granulocytes, B- and T-lymphocytes, as well as stable long-term GFP expression in primary and secondary animals. Copy number determination by real-time PCR in marrow cells from primary recipients shows an average of 4 proviral copies (range 2.1–8.1) per GFP-expressing cell. Our studies confirm that HIV-derived lentivirus vectors are ideally suited for the transduction of murine long-term repopulating cells. We hypothesize that ultra-short transduction actively preserves stem cell content in the inoculum. Moreover, this protocol represents an ideal platform for subsequent in vivo selection to achieve complete phenotype correction and high-level therapeutic chimerism required for some applications. We anticipate that our strategy may prove particularly useful in situations where the target stem cell quantity is greatly limited and cells are of poor ex vivo viability.

Lentiviral FANCA Vectors Pseudotyped with a Modified Prototype Foamy Viral Envelope Corrects Murine Fanca−/− Hematopoietic Stem Cells with Reduced Toxicity.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1677-1677
Author(s):  
Zejin Sun ◽  
Yanzhu Yang ◽  
Yan Li ◽  
Daisy Zeng ◽  
Jingling Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Gene Transfer ◽  
Ex Vivo ◽  
Bone Marrow Failure ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Ex Vivo Culture

Abstract Fanconi anemia (FA) is a recessive DNA repair disorder characterized by congenital abnormalities, bone marrow failure, genomic instability, and a predisposition to malignancies. As the majority of FA patients ultimately acquires severe bone marrow failure, transplantation of stem cells from a normal donor is the only curative treatment to replace the malfunctioning hematopoietic system. Stem cell gene transfer technology aimed at re-introducing the missing gene is a potentially promising therapy, however, prolonged ex vivo culture of cells, that was utilized in clinical trials with gammaretroviruses, results in a high incidence of apoptosis and at least in mice predisposes the surviving reinfused cells to hematological malignancy. Consequently, gene delivery systems such as lentiviruses that allow a reduction in ex vivo culture time are highly desirable. Here, we constructed a lentiviral vector expressing the human FANCA cDNA and tested the ability of this construct pseudotyped with either VSVG or a modified prototype foamyvirus (FV) envelope to correct Fanca−/− stem and progenitor cells in vitro and in vivo. In order to minimize genotoxic stress due to extended in vitro manipulations, an overnight transduction protocol was utilized where in the absence of prestimulation, murine Fanca−/− bone marrow cKit+ cells were co-cultured for 16h with FANCA lentivirus on the recombinant fibronectin fragment CH296. Transduction efficiency and transfer of lentivirally expressed FANCA was confirmed functionally in vitro by improved survival of consistently approximately 60% of clonogenic progenitors in serial concentrations of mitomycin C (MMC), irregardless of the envelope that was utilized to package the vector. Transduction of fibroblasts was also associated with complete correction of MMC-induced G2/M arrest and biochemically with the restoration of FancD2 mono-ubiquitination. Finally, to functionally determine whether gene delivery by the recombinant lentivirus during such a short transduction period is sufficient to correct Fanca−/− stem cell repopulation to wild-type levels, competitive repopulation experiments were conducted as previously described. Follow-up of up to 8 months demonstrated that the functional correction were also achieved in the hematopoietic stem cell compartment as evidenced by observations that the repopulating ability of Fanca−/− stem cells transduced with the recombinant lentivirus encoding hFANCA was equivalent to that of wild-type stem cells. Importantly, despite the fact that the gene transfer efficiency into cells surviving the transduction protocol were similar for both pseudotypes, VSVG was associated with a 4-fold higher toxicity to the c-kit+ cells than the FV envelope. Thus, when target cell numbers are limited as stem cells are in FA patients, the foamyviral envelope may facilitate overall greater survival of corrected stem cells. Collectively, these data indicate that the lentiviral construct can efficiently correct FA HSCs and progenitor cells in a short transduction protocol overnight without prestimulation and that the modified foamy envelope may have less cytotoxicity than the commonly used VSVG envelope.

One-Day Ex Vivo Culture Allows Effective Gene Transfer Into Human Nonobese Diabetic/Severe Combined Immune-Deficient Repopulating Cells Using High-Titer Vesicular Stomatitis Virus G Protein Pseudotyped Retrovirus

Blood ◽  
1999 ◽  
Vol 93 (7) ◽  
pp. 2217-2224 ◽  
Author(s):  
Vivienne I. Rebel ◽  
Mayumi Tanaka ◽  
Jeng-Shin Lee ◽  
Sheila Hartnett ◽  
Michael Pulsipher ◽  
...  
Keyword(s):  
Stem Cell ◽  
Gene Transfer ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Ex Vivo ◽  
High Titer ◽  
Hematopoietic Stem ◽  
Nonobese Diabetic ◽  
Vesicular Stomatitis ◽  
Ex Vivo Culture

Retrovirus-mediated gene transfer into long-lived human pluripotent hematopoietic stem cells (HSCs) is a widely sought but elusive goal. A major problem is the quiescent nature of most HSCs, with the perceived requirement for ex vivo prestimulation in cytokines to induce stem cell cycling and allow stable gene integration. However, ex vivo culture may impair stem cell function, and could explain the disappointing clinical results in many current gene transfer trials. To address this possibility, we examined the ex vivo survival of nonobese diabetic/severe combined immune-deficient (NOD/SCID) repopulating cells (SRCs) over 3 days. After 1 day of culture, the SRC number and proliferation declined twofold, and was further reduced by day 3; self-renewal was only detectable in noncultured cells. To determine if the period of ex vivo culture could be shortened, we used a vesicular stomatitis virus G protein (VSV-G) pseudotyped retrovirus vector that was concentrated to high titer. The results showed that gene transfer rates were similar without or with 48 hours prestimulation. Thus, the use of high-titer VSV-G pseudotyped retrovirus may minimize the loss of HSCs during culture, because efficient gene transfer can be obtained without the need for extended ex vivo culture.

One-Day Ex Vivo Culture Allows Effective Gene Transfer Into Human Nonobese Diabetic/Severe Combined Immune-Deficient Repopulating Cells Using High-Titer Vesicular Stomatitis Virus G Protein Pseudotyped Retrovirus

Blood ◽  
1999 ◽  
Vol 93 (7) ◽  
pp. 2217-2224 ◽  
Author(s):  
Vivienne I. Rebel ◽  
Mayumi Tanaka ◽  
Jeng-Shin Lee ◽  
Sheila Hartnett ◽  
Michael Pulsipher ◽  
...  
Keyword(s):  
Stem Cell ◽  
Gene Transfer ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Ex Vivo ◽  
High Titer ◽  
Hematopoietic Stem ◽  
Nonobese Diabetic ◽  
Vesicular Stomatitis ◽  
Ex Vivo Culture

Abstract Retrovirus-mediated gene transfer into long-lived human pluripotent hematopoietic stem cells (HSCs) is a widely sought but elusive goal. A major problem is the quiescent nature of most HSCs, with the perceived requirement for ex vivo prestimulation in cytokines to induce stem cell cycling and allow stable gene integration. However, ex vivo culture may impair stem cell function, and could explain the disappointing clinical results in many current gene transfer trials. To address this possibility, we examined the ex vivo survival of nonobese diabetic/severe combined immune-deficient (NOD/SCID) repopulating cells (SRCs) over 3 days. After 1 day of culture, the SRC number and proliferation declined twofold, and was further reduced by day 3; self-renewal was only detectable in noncultured cells. To determine if the period of ex vivo culture could be shortened, we used a vesicular stomatitis virus G protein (VSV-G) pseudotyped retrovirus vector that was concentrated to high titer. The results showed that gene transfer rates were similar without or with 48 hours prestimulation. Thus, the use of high-titer VSV-G pseudotyped retrovirus may minimize the loss of HSCs during culture, because efficient gene transfer can be obtained without the need for extended ex vivo culture.

scholarly journals Stem cell integrins: Implications for ex-vivo culture and cellular therapies

2011 ◽  
Vol 6 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Andrew B.J. Prowse ◽  
Fenny Chong ◽  
Peter P. Gray ◽  
Trent P. Munro
Keyword(s):  
Stem Cell ◽  
Ex Vivo ◽  
Cellular Therapies ◽  
Ex Vivo Culture

scholarly journals Notch-Mediated Expansion of Human Hematopoietic Stem and Progenitor Cells By Culture Under Hypoxia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 28-29
Author(s):  
Daisuke Araki ◽  
Stefan Cordes ◽  
Fayaz Seifuddin ◽  
Luigi J. Alvarado ◽  
Mehdi Pirooznia ◽  
...  
Keyword(s):  
Er Stress ◽  
Progenitor Cells ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Human Adult ◽  
Hypoxic Conditions ◽  
Cd34 Cells ◽  
Human Hscs ◽  
Ex Vivo Culture ◽  
Cells Cultured

Notch activation in human CD34+ hematopoietic stem/progenitor cells (HSPCs) by treatment with Delta1 ligand has enabled clinically relevant ex vivo expansion of short-term HSPCs. However, sustained engraftment of the expanded cells was not observed after transplantation, suggesting ineffective expansion of hematopoietic stem cells with long-term repopulating activity (LTR-HSCs). Recent studies have highlighted how increased proliferative demand in culture can trigger endoplasmic reticulum (ER) stress and impair HSC function. Here, we investigated whether ex vivo culture of HSPCs under hypoxia might limit cellular ER stress and thus offer a simple approach to preserve functional HSCs under high proliferative conditions, such as those promoted in culture with Delta1. Human adult mobilized CD34+ cells were cultured for 21 days under normoxia (21% O2) or hypoxia (2% O2) in vessels coated with optimized concentrations of Delta1. We observed enhanced progenitor cell activity within the CD34+ cell population treated with Delta1 in hypoxia, but the benefits provided by low-oxygen cultures were most notable in the primitive HSC compartment. At optimal coating densities of Delta1, the frequency of LTR-HSCs measured by limiting dilution analysis 16 weeks after transplantation into NSG mice was 4.9- and 4.2-fold higher in hypoxic cultures (1 in 1,586 CD34+ cells) compared with uncultured cells (1 in 7,706) and the normoxia group (1 in 5,090), respectively. Conversely, we observed no difference in expression of the homing CXCR4 receptor between cells cultured under normoxic and hypoxic conditions, indicating that hypoxia increased the absolute numbers of LTR-HSCs but not their homing potential after transplantation. To corroborate these findings molecularly, we performed transcriptomic analyses and found significant upregulation of a distinct HSC gene expression signature in cells cultured with Delta1 in hypoxia (Fig. A). Collectively, these data show that hypoxia supports a superior ex vivo expansion of human HSCs with LTR activity compared with normoxia at optimized densities of Delta1. To clarify how hypoxia improved Notch-mediated expansion of LTR-HSCs, we performed scRNA-seq of CD34+ cells treated with Delta1 under normoxic or hypoxic conditions. We identified 6 distinct clusters (clusters 0 to 5) in dimension-reduction (UMAP) analysis, with a comparable distribution of cells per cluster between normoxic and hypoxic cultures. Most clusters could be computationally assigned to a defined hematopoietic subpopulation, including progenitor cells (clusters 0 to 4) and a single transcriptionally defined HSC population (cluster 5). To assess the relative impact of normoxia and hypoxia on the HSC compartment, we performed gene set enrichment analysis (GSEA) of cells within HSC cluster 5 from each culture condition. A total of 32 genes were differentially expressed, and pathways indicative of cellular ER stress (unfolded protein response [UPR], heat shock protein [HSP] and chaperone) were significantly downregulated in hypoxia-treated cells relative to normoxic cultures (Fig. B). When examining expression of cluster 5 top differentially expressed genes across all cell clusters, we observed a more prominent upregulation of these genes within transcriptionally defined HSCs exposed to normoxia relative to more mature progenitors (Fig. C, red plots). Hypoxia lessened the cellular stress response in both progenitors and HSCs, but the mitigation was more apparent in the HSC population (Fig. C, grey plots), and decreased apoptosis was observed only within the HSC-enriched cluster 5 (Fig. D). These findings are consistent with several reports indicating that HSCs are more vulnerable to strong ER stress than downstream progenitors due to their lower protein folding capacity. In conclusion, we provide evidence that ex vivo culture of human adult CD34+ cells under hypoxic conditions enables a superior Delta1-mediated expansion of hematopoietic cells with LTR activity compared with normoxic cultures. Our data suggest a two-pronged mechanism by which optimal ectopic activation of Notch signaling in human HSCs promotes their self-renewal, and culture under hypoxia mitigates ER stress triggered by the increased proliferative demand, resulting in enhanced survival of expanding HSCs. This clinically feasible approach may be useful to improve outcomes of cellular therapeutics. Disclosures No relevant conflicts of interest to declare.

Expansion of human cord blood CD34+CD38−cells in ex vivo culture during retroviral transduction without a corresponding increase in SCID repopulating cell (SRC) frequency: dissociation of SRC phenotype and function

Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Craig Dorrell ◽  
Olga I. Gan ◽  
Daniel S. Pereira ◽  
Robert G. Hawley ◽  
John E. Dick
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cord Blood ◽  
Cell Function ◽  
Cultured Cells ◽  
Genetic Manipulation ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Retroviral Transduction ◽  
Large Expansion

Abstract Current procedures for the genetic manipulation of hematopoietic stem cells are relatively inefficient due, in part, to a poor understanding of the conditions for ex vivo maintenance or expansion of stem cells. We report improvements in the retroviral transduction of human stem cells based on the SCID-repopulating cell (SRC) assay and analysis of Lin− CD34+CD38−cells as a surrogate measure of stem cell function. Based on our earlier study of the conditions required for ex vivo expansion of Lin−CD34+ CD38− cells and SRC, CD34+–enriched lineage–depleted umbilical cord blood cells were cultured for 2 to 6 days on fibronectin fragment in MGIN (MSCV-EGFP-Neo) retroviral supernatant (containing 1.5% fetal bovine serum) and IL-6, SCF, Flt-3 ligand, and G-CSF. Both CD34+CD38− cells (20.8%) and CFC (26.3%) were efficiently marked. When the bone marrow of engrafted NOD/SCID mice was examined, 75% (12/16) contained multilineage (myeloid and B lymphoid) EGFP+ human cells composing as much as 59% of the graft. Half of these mice received a limiting dose of SRC, suggesting that the marked cells were derived from a single transduced SRC. Surprisingly, these culture conditions produced a large expansion (166-fold) of cells with the CD34+CD38− phenotype (n = 20). However, there was no increase in SRC numbers, indicating dissociation between the CD34+CD38− phenotype and SRC function. The underlying mechanism involved apparent downregulation of CD38 expression within a population of cultured CD34+CD38+ cells that no longer contained any SRC function. These results suggest that the relationship between stem cell function and cell surface phenotype may not be reliable for cultured cells. (Blood. 2000;95:102-110)

The Use of Granulocyte Colony-Stimulating Factor During Retroviral Transduction on Fibronectin Fragment CH-296 Enhances Gene Transfer Into Hematopoietic Repopulating Cells in Dogs

Blood ◽  
1999 ◽  
Vol 94 (7) ◽  
pp. 2287-2292 ◽  
Author(s):  
Martin Goerner ◽  
Benedetto Bruno ◽  
Peter A. McSweeney ◽  
Greg Buron ◽  
Rainer Storb ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Stem Cell ◽  
Gene Transfer ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Cell Gene ◽  
Stimulating Factor ◽  
Stem Cell Gene ◽  
Stem Cell Gene Therapy ◽  
Marrow Cells

A competitive repopulation assay in the dog was used to develop improved gene transfer protocols for hematopoietic stem cell gene therapy. Using this assay, we previously showed improved gene transfer into canine hematopoietic repopulating cells when CD34-enriched marrow cells were cocultivated on gibbon ape leukemia virus (GALV)–based retrovirus vector-producing cells. In the present study, we have investigated the use of fibronectin fragment CH-296 and 2 growth factor combinations to further improve gene transfer efficiency. CD34-enriched marrow cells from each dog were prestimulated for 24 hours and then divided into 3 equal fractions. Two fractions were placed into flasks coated with either CH-296 or bovine serum albumin (BSA) and virus-containing medium supplemented with growth factors, and protamine sulfate was replaced 4 times over a 48-hour period. One fraction was cocultivated on irradiated PG13 (GALV-pseudotype) packaging cells for 48 hours. In 2 animals, cells of the different fractions were transduced in the presence of human FLT-3 ligand (FLT3L), canine stem cell factor (cSCF), and human megakaryocyte growth and development factor (MGDF), and in 2 other dogs, transduction was performed in the presence of FLT3L, cSCF, and canine granulocyte-colony stimulating factor (cG-CSF). The vectors used contained small sequence differences, allowing differentiation of cells genetically marked by the different vectors. After transduction, nonadherent and adherent cells from all 3 fractions were pooled and infused into lethally irradiated dogs. Polymerase chain reaction and Southern blot analysis were used to determine the persistence of the transferred vectors in the peripheral blood and marrow cells after transplantation. The highest levels of gene transfer were obtained when cells were transduced in the presence of FLT3L, cSCF, and cG-CSF (gene transfer levels of more than 10% for more than 8 months so far). Compared with the 2 animals that received cells transduced with FLT3L, cSCF, and MGDF, gene transfer levels were significantly higher when dogs received cells that were transduced in the presence of cG-CSF. Transduction on CH-296 resulted in gene transfer levels that were at least as high as transduction by cocultivation. In summary, the overall levels of gene transfer obtained with these conditions should be sufficiently high to allow stem cell gene therapy studies aimed at correcting genetic diseases in dogs as a model for human gene therapy.

scholarly journals Ex vivo expansion with stem cell factor and interleukin-11 augments both short-term recovery posttransplant and the ability to serially transplant marrow

Blood ◽  
1996 ◽  
Vol 87 (11) ◽  
pp. 4589-4595 ◽  
Author(s):  
TL Holyoake ◽  
MG Freshney ◽  
L McNair ◽  
AN Parker ◽  
PJ McKay ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Factor ◽  
Ex Vivo ◽  
Culture Conditions ◽  
Ex Vivo Expansion ◽  
Short Term ◽  
Ex Vivo Culture ◽  
Interleukin 11 ◽  
Transplantation Model

The characterization of many cytokines involved in the control of hematopoiesis has led to intense investigation into their potential use in ex vivo culture to expand progenitor numbers. We have established the optimum ex vivo culture conditions that allow substantial amplification of transient engrafting murine stem cells and which, simultaneously, augment the ability to sustain serial bone marrow transplantation (BMT). Short-term incubation of unfractionated BM cells in liquid culture with stem cell factor (SCF) and interleukin-11 (IL- 11) produced a 50-fold amplification of clonogenic multipotential progenitors (CFU-A). Following such ex vivo expansion, substantially fewer cells were required to rescue lethally irradiated mice. When transplanted in cell doses above threshold for engraftment, BM cells expanded ex vivo resulted in significantly more rapid hematopoietic recovery. In a serial transplantation model, unmanipulated BM was only able to consistently sustain secondary BMT recipients, but BM expanded ex vivo has sustained quaternary BMT recipients that remain alive and well more than 140 days after 4th degree BMT. These results show augmentation of both short-term recovery posttransplant and the ability to serially transplant marrow by preincubation in culture with SCF and IL-11.

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