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Query: UMLS:C0751781 (NOD)
 6,696 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purification of primitive human hematopoietic stem cells has been impaired by the absence of repopulation assays. By using a stringent two-step strategy involving depletion of lineage-positive cells followed by fluorescence-activated cell sorting, we have purified a cell population that is highly enriched for cells capable of multilineage repopulation in nonobese diabetic/severe combined immunodeficient (NOD/SCID) recipients. These SCID-repopulating cells (SRCs) were exclusively found in a cell fraction that expressed high levels of CD34 and no CD38. Through limiting dilution analysis using Poisson statistics, we calculated a frequency of 1 SRC in 617 CD34(+) CD38(-) cells. The highly purified SRC were capable of extensive proliferation in NOD/SCID mice. Mice transplanted with 1 SRC (at limiting cell doses) were able to produce approximately 400, 000 progeny 6 weeks after the transplant. Detailed flow cytometric analysis of the marrow of highly engrafted mice demonstrated both lymphoid and myeloid differentiation, as well as the retention of a significant fraction of CD34(+) CD38(-) cells. These highly purified fractions should be useful for identification of the cellular and molecular mechanisms that regulate primitive human hematopoietic cells. Moreover, the ability to detect and purify primitive cells provides a means to develop conditions for maintaining and/or expanding these cells during in vitro culture.
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PMID:Purification of primitive human hematopoietic cells capable of repopulating immune-deficient mice. 914 35

Understanding the repopulating characteristics of human hematopoietic stem/progenitor cell fractions is crucial for predicting their performance after transplant into high-risk patients following high-dose therapy. We report that human umbilical cord blood cells, 78% to 100% of which express the hematopoietic progenitor cell surface marker CD34, can consistently engraft, develop, and proliferate in the hematopoietic tissues of sublethally irradiated NOD/LtSz-scid/scid mice. Engraftment and development of CD34+ cells is not dependent on human growth factor support. CD34+ cells home to the mouse bone marrow (BM) that becomes the primary site of human hematopoietic development containing myeloid, lymphoid, erythroid, and CD34+ progenitor populations. Myeloid, and in particular lymphoid cells possessing more mature cell surface markers, comprise the human component of mouse spleen and peripheral blood, indicating that development proceeds from primary hematopoietic sites to the periphery. Repopulation of secondary recipients with human cells by BM from primary recipients demonstrates the maintenance of substantial proliferation capacity of the input precursor population. These data suggest that the cells capable of initiating human cell engraftment (SCID-repopulating cells) are contained in the CD34+ cell fraction, and that this mouse model will be useful for assaying the developmental potential of other rare human hematopoietic cell fractions in vivo.
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PMID:Engraftment and development of human CD34(+)-enriched cells from umbilical cord blood in NOD/LtSz-scid/scid mice. 920 42

On the subject of acute myeloid leukemia (AML), there is little consensus about the target cell within the hematopoietic stem cell hierarchy that is susceptible to leukemic transformation, or about the mechanism that underlies the phenotypic, genotypic and clinical heterogeneity. Here we demonstrate that the cell capable of initiating human AML in non-obese diabetic mice with severe combined immunodeficiency disease (NOD/SCID mice) - termed the SCID leukemia-initiating cell, or SL-IC - possesses the differentiative and proliferative capacities and the potential for self-renewal expected of a leukemic stem cell. The SL-ICs from all subtypes of AML analyzed, regardless of the heterogeneity in maturation characteristics of the leukemic blasts, were exclusively CD34++ CD38-, similar to the cell-surface phenotype of normal SCID-repopulating cells, suggesting that normal primitive cells, rather than committed progenitor cells, are the target for leukemic transformation. The SL-ICs were able to differentiate in vivo into leukemic blasts, indicating that the leukemic clone is organized as a hierarchy.
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PMID:Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell. 921 98

Human hematopoiesis originates in a population of stem cells with transplantable lympho-myeloid reconstituting potential, but a method for quantitating such cells has not been available. We now describe a simple assay that meets this need. It is based on the ability of sublethally irradiated immunodeficient nonobese diabetic-scid/scid (NOD/SCID) mice to be engrafted by intravenously injected human hematopoietic cells and uses limiting dilution analysis to measure the frequency of human cells that produce both CD34(-)CD19(+) (B-lymphoid) and CD34(+) (myeloid) colony-forming cell progeny in the marrow of such recipients 6 to 8 weeks post-transplant. Human cord blood (CB) contains approximately 5 of these competitive repopulating units (CRU) per ml that have a similar distribution between the CD38(-) and CD38(+) subsets of CD34(+) CB cells as long-term culture-initiating cells (LTC-IC) (4:1 vs. 2:1). Incubation of purified CD34(+)CD38(-) human CB cells in serum-free medium containing flt-3 ligand, Steel factor, interleukin 3, interleukin 6, and granulocyte colony-stimulating factor for 5-8 days resulted in a 100-fold expansion of colony-forming cells, a 4-fold expansion of LTC-IC, and a 2-fold (but significant, P < 0.02) increase in CRU. The culture-derived CRU, like the original CB CRU, generated pluripotent, erythroid, granulopoietic, megakaryopoietic, and pre-B cell progeny upon transplantation into NOD/SCID mice. These findings demonstrate an equivalent phenotypic heterogeneity amongst human CB cells detectable as CRU and LTC-IC. In addition, their similarly modest response to stimulation by a combination of cytokines that extensively amplify LTC-IC from normal adult marrow underscores the importance of ontogeny-dependent changes in human hematopoietic stem cell proliferation and self-renewal.
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PMID:Expansion in vitro of transplantable human cord blood stem cells demonstrated using a quantitative assay of their lympho-myeloid repopulating activity in nonobese diabetic-scid/scid mice. 927 12

Time course studies of sublethally irradiated non-obese mice with severe combined immunodeficiency (NOD/ SCID mice) transplanted intravenously with 10(7) human cord blood cells showed a rapid and parallel regeneration of human erythroid, granulopoietic, megakaryopoietic and B-lymphoid progenitors, as well as more primitive subpopulations of CD34+ cells (defined by their multi-lineage in vitro colony-forming ability, coexpression of Thy-1, or functional activity in long-term culture-initiating cell [LTC-IC] assays), in the marrow, spleen and blood. Maximum numbers of human cells were reached within 6 weeks and were then sustained for another 18-20 weeks. 3H-thymidine suicide studies showed all types of in vitro clonogenic human progenitors tested and the human LTC-IC to be proliferating in vitro throughout this period. A 2-week course of injections of human Steel factor, interleukin-3, granulocyte-macrophage colony-stimulating factor and erythropoietin given just prior to assessment of the mice had no effect on any of these human engraftment parameters. 4-6 weeks post-transplant, the marrow of primary NOD/SCID recipients contained human cells that were able to regenerate lymphopoiesis and/or myelopoiesis in secondary irradiated NOD/SCID mice. These findings establish a baseline for the kinetics of engraftment, multi-lineage differentiation and self-renewal of human cord blood stem cells in this xenogeneic transplant model and thus set the stage for future studies of their regulation in vivo.
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PMID:Sustained proliferation, multi-lineage differentiation and maintenance of primitive human haemopoietic cells in NOD/SCID mice transplanted with human cord blood. 932 7

To understand the role of key molecules in determining the strength and nature of allogeneic T-cell response to leukemia, we transfected HLA-DR1 into the major histocompatibility complex (MHC)-deficient, natural killer (NK)-cell sensitive K562 leukemia cell line. Untransfected K562 cells stimulated NK proliferation in vitro and formed subcutaneous tumors in severe combined immunodeficiency/non-obese diabetic (SCID/NOD) mice. Tumor growth was inhibited by adoptive intravenous transfer of fresh unprimed peripheral blood mononuclear cells (PBMC). In contrast, HLA-DR1 transfected cells stimulated CD4(+) T cells, but not NK-cell proliferation in vitro and formed tumors resistant to fresh PBMC in SCID/NOD mice. Tumors not expressing MHC were infiltrated with CD16(+)CD56(+) lymphocytes whereas nonregressing HLA-DR1 expressing tumors showed only a scanty infiltration with both T-cell and NK-cell subsets. The results indicate that MHC class II expression by leukemia cells can determine the effector cell type that it engages. In vivo MHC class II expression rendered K562 cell tumors resistant to NK-cell mediated antitumor reactivity.
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PMID:Regulation of a graft-versus-leukemia effect by major histocompatibility complex class II molecules on leukemia cells: HLA-DR1 expression renders K562 cell tumors resistant to adoptively transferred lymphocytes in severe combined immunodeficiency mice/nonobese diabetic mice. 937 66

This paper introduces a model which incorporates fetal thymus organ culture (FTOC) from NOD mice to replicate thymic development of diabetogenic T cells. NOD fetal pancreas organ culture (FPOC) co-cultured with 13-16 day NOD FTOC for an additional 14-21 days produced less insulin than FPOC cultured alone. Insulin production from the FTOC of non-diabetic strains C57BL/6 and BALB/c was not inhibited by co-culture with FTOC from their syngeneic counterparts. Sections of the NOD co-cultures showed peri-islet infiltration with lymphocytes. Insulin reduction by FTOC/FP co-culture was prevented by co-culture of the NOD FT with FT from immunologically incompetent C.B-17 SCID/SCID mice. Co-culture of NOD FP with NOD FT prior to the development of T cells prevented generation of diabetogenic FTOC. Thus, early exposure of NOD T cell precursors to the thymic stromal elements of C.B-17 SCID/SCID FT or to islet antigens can negatively select for diabetogenic T cells or activate immuno-regulatory cells that can suppress diabetogenic T cell activity. The addition of blocking F(ab')2 fragments of anti-CD3epsilon monoclonal antibody to NOD FTOC/FP co-cultures prevented insulin reduction, implicating a role for TcR-mediated recognition in this "in vitro IDDM" model. The addition of activating whole anti-CD3epsilon caused the complete ablation of insulin production in FTOC/FP co-cultures from all strains tested. Transfer of unprimed syngeneic FTOC cells to prediabetic NOD mice prevented the onset of IDDM while transfer of islet-cell primed FTOC/FP cells slightly increased disease incidence. These data suggest that while diabetogenic T cells are present in the FT, they are normally suppressed, even after organ culture. However, these cells can induce the destruction of islet cells, in vitro and in vivo, if they are appropriately activated with pancreatic tissue.
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PMID:NOD fetal thymus organ culture: an in vitro model for the development of T cells involved in IDDM. 937 74

Substantial barriers exist to the engraftment of hematopoietic cells in mice after in utero transplantation. Although high levels of donor-derived hematopoiesis have been reported in SCID mice, the majority of chimeric recipients exhibit decreasing levels of donor cells over time. To directly test whether the natural killer cell and macrophage activity of the recipients represents a barrier to sustained engraftment, fetal NOD/SCID mice were injected on day 13.5 of gestation with an enriched congenic hematopoietic progenitor cell population. Forty-four percent of pups showed the presence of Ly5.1+ donor cells 4 weeks after transplantation. The mean number of donor-derived nucleated cells in the peripheral blood (PB) was 30%. Although the majority of circulating donor cells were lymphocytes, up to 15% expressed myelomonocytic markers. Serial PB samples from individual mice indicated that the percentage of circulating donor cells increased from 17% to 55% between 4 and 24 weeks. At 6 months posttransplantation, an increased frequency of multilineage, donor-derived cells was also observed in the bone marrow (BM) and the spleen of chimeric recipients. The engraftment of pluripotent hematopoietic stem cells was evaluated by transplanting BM from chimeric mice into irradiated congenic recipients. Irradiated secondary recipients also exhibited multilineage donor-derived hematopoiesis in the PB, BM, and spleen for up to 6 months. These results show that the in utero transplantation of lineage-depleted BM cells into NOD/SCID recipients produces a high frequency of sustained engraftment of allogeneic hematopoietic stem cells.
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PMID:Sustained multilineage engraftment of allogeneic hematopoietic stem cells in NOD/SCID mice after in utero transplantation. 937 6

Granulocyte-macrophage colony-stimulating factor (GM-CSF ) and tumor necrosis factor alpha (TNFalpha) have been implicated in the pathogenesis of the fatal childhood disease termed juvenile myelomonocytic leukemia (JMML). We used a severe combined immunodeficient/nonobese diabetic (SCID/NOD) mouse model of JMML and examined the effect of inhibiting these cytokines in vivo with the human GM-CSF antagonist and apoptotic agent E21R and the anti-TNFalpha monoclonal antibody (MoAb) cA2 on JMML cell growth and dissemination in vivo. We show here that JMML cells repopulated to high levels in the absence of exogeneous growth factors. Administration of E21R at the time of transplantation or 4 weeks after profoundly reduced JMML cell load in the mouse bone marrow. In contrast, MoAb cA2 had no effect on its own, but synergized with E21R in virtually eliminating JMML cells from the mouse bone marrow. In the spleen and peripheral blood, E21R eliminated JMML cells, while MoAb cA2 had no effect. Importantly, studies of mice engrafted simultaneously with cells from both normal donors and from JMML patients showed that E21R preferentially eliminated leukemic cells. This is the first time a specific GM-CSF inhibitor has been used in vivo, and the results suggest that GM-CSF plays a major role in the pathogenesis of JMML. E21R might offer a novel and specific approach for the treatment of this aggressive leukemia in man.
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PMID:Inhibition of granulocyte-macrophage colony-stimulating factor prevents dissemination and induces remission of juvenile myelomonocytic leukemia in engrafted immunodeficient mice. 938 8

Although glutamic acid decarboxylase (GAD) has been implicated in IDDM, there is no direct evidence showing GAD-reactive T cells are diabetogenic in vivo. To address this issue, 3-wk-old NOD mice received two injections of purified rat brain GAD; one mouse rapidly developed diabetes 3 wk later. Splenocytes from this mouse showed a proliferative response to purified GAD, and were used to generate a CD4+ T cell line, designated 5A, that expresses TCRs encoding Vbeta2 and Vbeta12. 5A T cells exhibit a MHC restricted proliferative response to purified GAD, as well as GAD65 peptide 524-543. After antigen-specific stimulation, 5A T cells secrete IFNgamma and TNFalpha/beta, but not IL-4. They are also cytotoxic against NOD-derived hybridoma cells (expressing I-Ag7) that were transfected with rat GAD65, but not nontransfected hybridoma cells. Adoptive transfer of 5A cells into NOD/SCID mice produced insulitis in all mice. Diabetes occurred in 83% of the mice. We conclude that GAD injection in young NOD mice may, in some cases, provoke diabetes due to the activation of diabetogenic T cells reactive to GAD65 peptides. Our data provide direct evidence that GAD65 autoimmunity may be a critical event in the pathogenesis of IDDM.
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PMID:GAD-reactive CD4+ Th1 cells induce diabetes in NOD/SCID mice. 942 67


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