Preclinical Study for the Use of Abatacept to Prevent Rejection of Allogeneic CD34+ Cells in a Xenograft Model

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4271-4271
Author(s):  
Annie L. Oh ◽  
Dolores Mahmud ◽  
Vitalyi Senyuk ◽  
Elisa Bonetti ◽  
Nadim Mahmud ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
B Cells ◽  
Xenograft Model ◽  
Costimulatory Blockade ◽  
Nsg Mice ◽  
Human Cd34 ◽  
Cd34 Cells

Abstract The aims of this study were to analyze the role of T cells on the engraftment of allogeneic CD34+ cells after transplantation in immunodeficient nonobese diabetic/ltsz-scid/scid (NOD/SCID) IL2 receptor gamma chain knockout (NSG) mice and to test the in-vivo ability of abatacept (CTLA4-Ig) in preventing graft failure. Human CD34+ cells (0.2x106 cells/animal) were co- transplanted with allogeneic CD3+ T cells into sublethally irradiated NSG mice at ratios ranging from 1:50 to 1:0.5, or without T cells as a control. The engraftment of huCD45+ cell subsets in the bone marrow and spleen was measured by flow cytometry after 4-8 weeks. An expansion of T cells without engraftment of CD34+ cells was detected in each group of mice transplanted with CD34:T cells at ratios ≥ 1:0.5. To test whether T cells prevented any engraftment of CD34+ cells, or caused rejection after initial CD34+ cell homing in the bone marrow, kinetics experiments were performed by analyzing the marrow and spleen of mice at 1,2 or 4 weeks after transplant of CD34+ and T cells at 1:1 ratio. These experiments showed that at two weeks after transplant, CD34+ cells had repopulated the bone marrow but not the spleen, while T cells were found primarily in the spleen. Instead, in mice sacrificed at 4 weeks after transplant the marrow and the spleen contained only T cells and the CD34+ cells had been rejected. Based on our previous in-vitro studies showing that CD34+ cell immunogenicity is mainly dependent on B7:CD28 costimulatory signaling, we then tested whether costimulatory blockade with abatacept (CTLA4-Ig, Bristol Myers Squibb) would block stem cell rejection. Three groups of mice were transplanted with CD34+ and allo-T cells at 1:1 ratio and injected with Abatacept at 250 ug i.p. every other day from: a) day -1 to +28, b) day -1 to day +14 or c) day +14 to +28, then the animals were sacrificed at day +56 (8 weeks) after transplant to assess the engraftment. In Group a) the overall engraftment of huCD45+ cells was only <10%, but Abatacept completely prevented T cell-mediated stem cell rejection with >98% huCD45+ cells of myeloid or B cell lineage and <1% T cells in the marrow and spleen. In Group b) 70% of huCD45+ cells both in the marrow and spleen were T cells, and the remaining fraction of myeloid or B cells were derived from CD34+ cells. In Group c), instead, 100% of huCD45+ cells were T cells, with complete rejection of CD34+ cells. T cells recovered from the spleen of mice in groups b) and c) were also tested as responders in MLC stimulated with the original CD34+ cells and showed a brisk proliferation, consistent with lack of tolerance. Finally, another group of mice that received Abatacept from day -1 to + 28 was rechallenged with a boost of CD34+ cells on day +28 to test whether the low CD34+ cell engraftment was secondary to a latent rejection or partial stem cell exhaustion. The CD34+ cell boost resulted in a full hematopoietic recovery with 37% huCD45+CD3- cells, including myeloid and B cells, as well as CD34+ cells in the bone marrow and spleen. In this preclinical xenograft model we demonstrated that costimulatory blockade with Abatacept at the time of allogeneic transplant of human CD34+ cells can prevent T cell mediated rejection provide the basis for the future non-myeloablative protocols for incompatible stem cell transplantation. Disclosures No relevant conflicts of interest to declare.

Co-Stimulatory Blockade With CTLA4-Ig Permits Transplantation Of Human Hematopoietic Stem Cells and HLA Incompatible T Cells In NOD/SCID γ Null (NSG) Mouse Model

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1999-1999
Author(s):  
Annie L. Oh ◽  
Dolores Mahmud ◽  
Benedetta Nicolini ◽  
Nadim Mahmud ◽  
Elisa Bonetti ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Nsg Mice ◽  
Human Cd34 ◽  
Cd34 Cells

Abstract Our previous studies have shown the ability of human CD34+ cells to stimulate T cell alloproliferative responses in-vitro. Here, we investigated anti-CD34 T cell alloreactivity in-vivo by co-transplanting human CD34+ cells and allogeneic T cells of an incompatible individual into NSG mice. Human CD34+ cells (2x105/animal) were transplanted with allogeneic T cells at different ratios ranging from 1:50 to 1:0.5, or without T cells as a control. No xenogeneic GVHD was detected at 1:1 CD34:T cell ratio. Engraftment of human CD45+ (huCD45+) cells in mice marrow and spleen was analyzed by flow cytometry. Marrow engraftment of huCD45+ cells at 4 or 8 weeks was significantly decreased in mice transplanted with T cells compared to control mice that did not receive T cells. More importantly, transplantation of T cells at CD34:T cell ratios from 1:50 to 1:0.5 resulted in stem cell rejection since >98% huCD45+ cells detected were CD3+. In mice with stem cell rejection, human T cells had a normal CD4:CD8 ratio and CD4+ cells were mostly CD45RA+. The kinetics of human cell engraftment in the bone marrow and spleen was then analyzed in mice transplanted with CD34+ and allogeneic T cells at 1:1 ratio and sacrificed at 1, 2, or 4 weeks. At 2 weeks post transplant, the bone marrow showed CD34-derived myeloid cells, whereas the spleen showed only allo-T cells. At 4 weeks, all myeloid cells had been rejected and only T cells were detected both in the bone marrow and spleen. Based on our previous in-vitro studies showing that T cell alloreactivity against CD34+ cells is mainly due to B7:CD28 costimulatory activation, we injected the mice with CTLA4-Ig (Abatacept, Bristol Myers Squibb, New York, NY) from d-1 to d+28 post transplantation of CD34+ and allogeneic T cells. Treatment of mice with CTLA4-Ig prevented rejection and allowed CD34+ cells to fully engraft the marrow of NSG mice at 4 weeks with an overall 13± 7% engraftment of huCD45+ marrow cells (n=5) which included: 53±9% CD33+ cells, 22±3% CD14+ monocytes, 7±2% CD1c myeloid dendritic cells, and 4±1% CD34+ cells, while CD19+ B cells were only 3±1% and CD3+ T cells were 0.5±1%. We hypothesize that CTLA4-Ig may induce the apoptotic deletion of alloreactive T cells early in the post transplant period although we could not detect T cells in the spleen as early as 7 or 10 days after transplant. Here we demonstrate that costimulatory blockade with CTLA4-Ig at the time of transplant of human CD34+ cells and incompatible allogeneic T cells can prevent T cell mediated rejection. We also show that the NSG model can be utilized to test immunotherapy strategies aimed at engrafting human stem cells across HLA barriers in-vivo. These results will prompt the design of future clinical trials of CD34+ cell transplantation for patients with severe non-malignant disorders, such as sickle cell anemia, thalassemia, immunodeficiencies or aplastic anemia. Disclosures: No relevant conflicts of interest to declare.

C75 Fatty Acid Synthesis (FAS) Inhibitor Has Potent Immunosuppressive Activity

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2156-2156 ◽  
Author(s):  
Vitalyi Senyuk ◽  
Dolores Mahmud ◽  
Annie L. Oh ◽  
Pritesh R. Patel ◽  
Damiano Rondelli
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Fatty Acid ◽  
T Cell ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Nsg Mice ◽  
Human Cd34 ◽  
Cd34 Cells

Abstract Fatty acid synthesis (FAS) or oxidation (FAO) are important regulatory pathways in immune response. In fact, FAS plays a pivotal role in antigen presentation and T cells activation and FAO leads to fatty acid degradation which has been previously shown to regulate hematopoietic stem cell maintenance. Here we hypothesized that FAS can be a new target to suppress T cell alloimmune responses in solid organ or stem cell transplantations. Therefore, we tested if the FAS inhibitor C75 could suppress T cell alloreactivity without impairing normal hematopoiesis. The immuno-suppressive (IS) effect of moderate FAS inhibition was demonstrated in mixed leukocyte cultures (MLC) where C75 at 10 mkg/ml significantly reduced T cell proliferation and prevented the expansion of CD3+CD25+ and CD3+CD69+ T cells. In T cells stimulated by alloantigen, C75 also induced the downregulation of NF-kB gene expression and the upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) gene involved in ubiquitination and degradation of NF-kB protein. When compared to other standard IS agents, such as anti-thymocyte globulin (ATG), Cyclosporine A, Rapamycin or inhibitor of FAO Etomoxir, C75 showed similar anti-T cell activity. The same dose of C75 (10 mkg/ml) did not cause apoptotic death of human CD34+ cells in vitro, nor affected CD34+ cell clonogenicity in vitro. In fact, C75 increased the number of BFU-E and CFU-GM colonies (P < 0.05). We observed that the expression of de novo DNA methyltrasferases DNMT3A and DNMT3B, which are important regulators of stem cell renewal, was strongly reduced in CD34+ cells co-cultured for 3 days with allogeneic T cells. On the contrary, in the presence of C75 the expression of DNMT3A and DNMT3B was not different from baseline control. To test the in-vivo effect of C75 we utilized a xenograft model of stem cell rejection where 2 x 105 human CD34+ cells and HLA incompatible T lymphocytes were injected in immunodeficient nonobese diabetic/ltsz-scid/scid - IL2 receptor gamma chain knockout (NSG) mice at 1:1 ratio. Four weeks after transplantation, control NSG mice showed complete rejection of huCD45+CD34+ cells and the expansion of T cells in the marrow and spleen. NSG mice treated with intra-peritoneum injections of C75 every 3 days for 2 weeks, instead, showed 10-15% human CD45+ myeloid cells in the marrow and spleen at week 4 after transplant, suggesting at least a partial effect on preventing rejection of incompatible stem cells. We showed here that moderate FAS inhibition may represent a novel immunosuppressive strategy and our findings will prompt preclinical investigations exploiting the effect of FAS inhibitors alone or in combination with standard IS agents in models of allogeneic transplantation or bone marrow failure. Disclosures No relevant conflicts of interest to declare.

An in-Vivo Model of T Cell-Mediated Rejection of Human Hematopoietic CD34+ Stem Cells Using NOD/SCID γnull (NOG) Mice.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4474-4474
Author(s):  
Benedetta Nicolini ◽  
Dolores Mahmud ◽  
Nadim Mahmud ◽  
Giuseppina Nucifora ◽  
Damiano Rondelli
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Mouse Model ◽  
Hematopoietic Stem ◽  
Human Cd34 ◽  
Cell Engraftment ◽  
Cd34 Cells ◽  
Nog Mice

Abstract Abstract 4474 We have previously demonstrated that human CD34+ cells include subsets of antigen presenting cells capable of stimulating anti-stem cell T cell alloreactivity in-vitro. In this study we transplanted human CD34+ cells and allogeneic T cells in a NOD/SCID γnull (NOG) mouse model and evaluated the occurrence of stem cell rejection as well as xenogeneic graft-versus-host disease (GVHD) following the infusion of different doses of T cells. After sublethal irradiation NOG mice were cotransplanted with 2×105 CD34+ cells and HLA mismatched CD4+CD25- T cells at 1:0 (control), 1:2 or 1:10 CD34+ cell: T cell ratio (n=5-10 mice per group). Hematopoietic stem cell and T cell engraftment was assessed in the bone marrow and in the spleen 6 weeks following transplantation or earlier in case the animals died. Control mice transplanted with CD34+ cells alone showed a high level of stem cell engraftment (huCD45+ cells: 60±10%) in the bone marrow, encompassing CD19+ B cells (64±4%), CD34+ cells (18±1%), CD33+ myeloid cells (7±1%), CD14+ monocytes (3±1%), and no T cells within huCD45+ cells. In contrast, mice that were transplanted with CD34+ cells and 4×105 (1:2 ratio) or 2×106 (1:10 ratio) T cells had only 9±2% and 3±1% huCD45+ cells, respectively, in the bone marrow (p=0.01). Moreover, marrow samples of mice cotransplanted with CD34+ cells and T cells at 1:2 or 1:10 ratio included >98% huCD3+ T cells and no CD34+ cells. Spleen engraftment of huCD45+ cells was lower (25±8%) in control mice (1:0 ratio) as compared to 66±10% and 36±11% in 1:2 and 1:10 groups, respectively (p=0.05). As observed in the marrow, also the spleen of animals receiving CD34+ and T cells included >98% CD3+ T cells. Among the T cells, both in the marrow and in the spleen of mice in the 1:2 and 1:10 ratio groups, 60-70% were CD4+CD8- cells, 22-25% CD8+CD4- cells, 1-3% CD56+ cells, and 2-5% CD4+CD25+ cells. In mice receiving 4 ×105 T cells (1:2 ratio), on average 12±6% of the T cells in the bone marrow and spleen were CD4+CD8+. Only mice receiving 2×106 T cells (1:10 ratio) showed GVHD. This was demonstrated by fur changes, reduced survival (p=0.02) and weight loss (p=0.0001) compared to control mice or mice receiving a lower dose of T cells (1:2 ratio). The marrow engraftment of CD3+ cells with disappearance of CD34+ cells in mice receiving low doses of allogeneic T cells, in the absence of evident xenogeneic GVHD, suggests that NOG mouse model represents a useful tool to study human stem cell rejection. This model will be also utilized to investigate new strategies of immunosuppressive cell therapy applied to stem cell transplantation in an HLA mismatched setting. Disclosures: No relevant conflicts of interest to declare.

Generation of Human T/NK Cell Precursors for Adoptive Transfer To Enhance Immune Reconstitution in Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3209-3209
Author(s):  
Sonali Chaudhury ◽  
Johannes Zakarzewski ◽  
Jae-Hung Shieh ◽  
Marcel van der Brink ◽  
Malcolm A.S. Moore
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Hematopoietic Stem ◽  
Serum Free ◽  
Cd34 Cells

Abstract Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with significant post-transplant immunoincompetence which affects in particular the T cell lineage and results in an increased susceptibility to infections. Novel strategies to enhance immune recovery after HSCT could prevent malignant relapse and immune deficiency and improve the overall outcome of this therapy. We have established a serum free culture system using murine bone marrow stroma expressing the Notch ligand Delta-like 1 (DL1) to obtain high numbers of human pre-T cells from CD34+ cells. Human cord blood CD34+ cells were plated on OP9 DL1 stroma transduced with adenovirus expressing thrombopoietin (ad-TPO) at an MOI of 30. Media used was QBSF-60 (Serum free media prepared by Quantity Biologicals) supplemented with Flt-3 ligand and IL-7 (10ng/ml). At 4–5 weeks we obtained a 10 5–10 7 fold expansions of cultured cells of which about 70–80% were CD5, CD7 positive pre T cells (Fig 1). We then developed an optimal system to study human lymphohematopoiesis using mouse models (NOD/SCID/IL2rϒnull and NOD/SCIDβ2null) and established an adequate pre T cell number (4 × 10 6) and radiation dose (300 Rads). We injected CD34 and pre-T cells (CD45 +, CD4−, CD5+, CD7+) derived from OP9 DL1 cultures into these mice and achieved ~50%engraftment of NK in the bone marrow and spleen of the mice at 2 weeks following transplant. The thymus from the same mice showed evidence of about 12–15% CD7+ pre T cells. We are currently studying the function of the generated NK and T cells both in vivo and in vitro studies. Figure Figure

Clinical stem-cell sources contain CD8+CD3+ T-cell receptor–negative cells that facilitate bone marrow repopulation with hematopoietic stem cells

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1735-1738 ◽  
Author(s):  
Stephanie Bridenbaugh ◽  
Linda Kenins ◽  
Emilie Bouliong-Pillai ◽  
Christian P. Kalberer ◽  
Elena Shklovskaya ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Hematopoietic Stem ◽  
Cd8 Cells ◽  
Human Cd34 ◽  
Cd34 Cells

Abstract Clinical observations in patients undergoing bone marrow transplantation implicate the involvement of CD8+ cells in promoting the stem-cell engraftment process. These findings are supported by mouse transplant studies, which attributed the engraftment-facilitating function to subpopulations of murine CD8+ cells, but the analogous cells in humans have not been identified. Here, we report that clinical stem-cell grafts contain a population of CD8α+CD3ϵ+ T-cell receptor– negative cells with an engraftment facilitating function, named candidate facilitating cells (cFCs). Purified cFC augmented human hematopoiesis in NOD/SCID mice receiving suboptimal doses of human CD34+ cells. In vitro, cFCs cocultured with CD34+ cells increased hematopoietic colony formation, suggesting a direct effect on clonogenic precursors. These results provide evidence for the existence of rare human CD8+CD3+TCR− cells with engraftment facilitating properties, the adoptive transfer of which could improve the therapeutic outcome of stem-cell transplantation.

MDS-Derived Stromal Cells Exhibit Altered Gene Expression and Support The Engraftment Of lin-CD34+CD38- Disease-Initiating Stem Cells In a Xenograft Model Of Lower Risk MDS

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 100-100
Author(s):  
Hind Medyoup ◽  
Maximilian Mossner ◽  
Johann-Christoph Jann ◽  
Florian Nolte ◽  
Christian Eisen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Stromal Cells ◽  
Lower Risk ◽  
Xenograft Model ◽  
Cellular Adhesion ◽  
Ecm Remodeling ◽  
Nsg Mice ◽  
Cd34 Cells

Abstract Introduction Myelodysplastic syndromes (MDS) are clonal hematologic disorders characterized by ineffective hematopoiesis, dysplasia and increased risk of progression to acute myeloid leukemia. The development of targeted therapies for MDS has been lagging behind and remains a key clinical challenge that has been hampered, at least in part, by difficulties to establish in vivo model systems that recapitulate disease heterogeneity and complexity. Attempts to generate a xenograft model of lower risk MDS have only achieved low and often transient levels of engraftment. Recent evidence from mouse studies suggests that MDS is a disease in which both the hematopoietic system and the bone marrow microenvironment might be involved. Thus, we hypothesized that a specific MDS microenvironment might be required for the successful modeling of low risk MDS in mice, proposing a dependency of the “disease propagating cells“ on their corresponding niche cells in human MDS. Methods Our study is based on xenotransplantation of material from 19 MDS patients classified as follows: IPSS low risk (n=6), intermediate-1 risk (n=13), WHO 2008 classification: MDS 5q- (n=7), MDS RCMD (n=7), MDS RAEB I (n=3), MDS-U (n=1), MDS RARS (n=1). MDS CD34+ cells were co-injected with patient-derived mesenchymal stromal cells (MSCs) directly in the bone marrow cavity (i.f) of NOD.Cg-Prkdscid Il2rgtm1Wjl/Szj (NSG) or NSGS (NSG mice expressing human SCF, IL3 and GM-CSF) mice. Molecular tracking of MDS cells was carried out by copy number analysis (Affymetrix SNP 6.0 Arrays), metaphase cytogenetics, interphase FISH, Roche 454 deep sequencing and pyrosequencing of known mutations. Mice were analyzed after a minimum of 16 weeks post transplantation. Results We show that co-injection of MDS CD34+ cells with their corresponding MSCs leads to significant and long-term engraftment of over 77% of the MDS patients analyzed, both in NSG (10/13 patients, range hCD45+= 1-18%) and NSGS mice (7/8 patients, range hCD45+=2.2-74%). In contrast, absence of MSCs or co-injection of healthy age-matched MSCs only gave rise to limited engraftment in NSG mice (2/7 patients (hCD45+=1-3.8%) and 1/2 patients (hCD45+=2%), respectively). Transplanted samples exhibited a clear myeloid bias and significant engraftment of cells with progenitor (CD34+CD38+) and stem cell phenotype (CD34+CD38-) that could be serially transplanted. In addition, presence of morphologically dysplastic cells was readily detectable in NSGS mice. Importantly, molecular analysis of the engrafted cells confirmed their “diseased” origin as they carried identical lesions to the ones present in the original MDS patient. Furthermore, we could demonstrate that disease-propagating stem cells in lower risk MDS exclusively reside within the lin-CD34+CD38- stem cell fraction. Finally, RNA sequencing analysis comparing MDS and age-matched healthy control MSCs revealed altered expression of key genes involved in cellular adhesion, extra-cellular matrix (ECM) remodeling and cellular cross-talk in diseased MSCs, strongly supporting the notion of a complex interplay between MDS hematopoietic cells and their corresponding stroma. In addition, patient MSCs exhibited clear molecular features of fibrosis, a clinical feature often associated with MDS. Conclusion In this study we have identified patient-derived MSCs as a critical functional component of lower risk MDS. Together with MDS stem cells, these patient MSCs form a functional stem cell-niche unit, which allows the propagation of the disease in a xenograft recipient. The striking changed expression in diseased MSCs of genes involved in processes like cytokine-cytokine receptor interaction, cellular adhesion, ECM remodeling as well as hypoxia further suggests that diseased MDS cells might alter the function of the normal HSC niche into one that can support the requirement of MDS cells. Studying the interaction of MDS stem cells and MSCs at the cellular and molecular level will provide a platform for unraveling the molecular basis of clonal dominance in MDS as well as allow the design of targeted strategies aimed to disrupt the MDS stem cell-MSC niche interactions. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Extrathymic T Cell Deletion and Allogeneic Stem Cell Engraftment Induced with Costimulatory Blockade Is Followed by Central T Cell Tolerance

1998 ◽  
Vol 187 (12) ◽  
pp. 2037-2044 ◽  
Author(s):  
Thomas Wekerle ◽  
Mohamed H. Sayegh ◽  
Joshua Hill ◽  
Yong Zhao ◽  
Anil Chandraker ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
Bone Marrow Transplantation ◽  
T Cell ◽  
Marrow Transplantation ◽  
T Cell Tolerance ◽  
Cell Tolerance ◽  
Costimulatory Blockade ◽  
Cell Engraftment

A reliable, nontoxic method of inducing transplantation tolerance is needed to overcome the problems of chronic organ graft rejection and immunosuppression-related toxicity. Treatment of mice with single injections of an anti-CD40 ligand antibody and CTLA4Ig, a low dose (3 Gy) of whole body irradiation, plus fully major histocompatibility complex–mismatched allogeneic bone marrow transplantation (BMT) reliably induced high levels (&gt;40%) of stable (&gt;8 mo) multilineage donor hematopoiesis. Chimeric mice permanently accepted donor skin grafts (&gt;100 d), and rapidly rejected third party grafts. Progressive deletion of donor-reactive host T cells occurred among peripheral CD4+ lymphocytes, beginning as early as 1 wk after bone marrow transplantation. Early deletion of peripheral donor-reactive host CD4 cells also occurred in thymectomized, similarly treated marrow recipients, demonstrating a role for peripheral clonal deletion of donor-reactive T cells after allogeneic BMT in the presence of costimulatory blockade. Central intrathymic deletion of newly developing T cells ensued after donor stem cell engraftment had occurred. Thus, we have shown that high levels of chimerism and systemic T cell tolerance can be reliably achieved without myeloablation or T cell depletion of the host. Chronic immunosuppression and rejection are avoided with this powerful, nontoxic approach to inducing tolerance.

Enhanced Myeloid and T Cell Development and Improved Functionality of Cord Blood Xenografts In the NSGS Mouse.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3729-3729
Author(s):  
Mark Wunderlich ◽  
Pietro Presicce ◽  
Fu-Sheng Chou ◽  
Claire Chougnet ◽  
Julio Aliberti ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cord Blood ◽  
B Cell ◽  
Human Cells ◽  
Nsg Mice ◽  
Human Cd34 ◽  
Human T Cells ◽  
Cd34 Cells ◽  
Nog Mice

Abstract Abstract 3729 The advent of NOD/SCID mouse strains lacking interleukin-2 receptor gamma (IL2RG) function (NSG and NOG mice) has greatly improved efforts to develop xenograft models of human hematopoiesis. Notably, these mice exhibit markedly reduced adaptive and innate immunity and are well suited for stable engraftment of human CD34+ cells. Importantly, these mice also allow for the development of human T cells, setting them apart from other immunodeficient strains. As a result, NSG and NOG mice are increasingly used for the building of model systems to study HIV infection, graft versus host disease, and immunity. While significant improvements have been realized, IL2RG knockouts lack robust myeloid components, and lymphoid function is likely to be suboptimal due to problems with B cell differentiation defects and delayed appearance of T cells. Recently, we have generated an NSG mouse strain with transgenic expression of several human myelo-supportive cytokines (SCF, GM-CSF, and IL-3), the NSGS mouse. In our initial characterization and study of this novel strain, we found a significant improvement in engraftment of AML cell lines and patient samples relative to NSG mice. In the current study we have extended these findings to include xenografts obtained using umbilical cord blood CD34+ cells (UCB). We have found the NSGS mouse to be equal to the NSG as a host for long-term stable engraftment of these cells when saturating cells doses are used, and superior when limiting numbers of CD34+ cells are injected. While CD34+ levels are much lower in established grafts in primary NSGS recipients compared to NSG mice, possibly as a result of continual mobilization of these cells by the cytokines, human cells were readily detected in secondary NSGS recipients, indicating maintenance of a primitive stem/progenitor cell compartment in vivo. Bone marrow of NSGS mice was predominantly composed of human myeloid cells, while the NSG mice show primarily CD19+ B cells. In contrast, the lineage of the human cells in the peripheral blood were very similar in these two strains, with both showing a gradual switch from myeloid to B cell dominance between weeks 3 and 7 post engraftment. Surprisingly, human T cells were found in the PB of transplanted adult NSGS mice as early as 8 weeks post engraftment, a full 8 weeks before T cells were detectable in NSG mice engrafted with the same UCB sample in parallel. These CD3+ cells presumably develop from the CD34+ stem cells and not from contaminating CD3+ T cells, since FACS-sorted CD3−CD34+ UCB samples produced the same result. Furthermore, normal donor human T cells did not exhibit any advantage in engraftment, cycling, or expansion in NSGS mice when compared to NSG mice in models of GVHD. Characterization of the T cells generated from human CD34+ xenografts revealed CD4+ and CD8+ subpopulations with phenotypes resembling activated, naïve, and memory T cell subsets. CD3+ spleen cells cultured ex vivo were responsive to activation by PHA/IL-2 stimulation and were susceptible to HIV-1 infection. Finally, humanized NSGS mice immunized with a toxoplasmosis extract were able to mount a response to virulent toxoplasmosis infection sufficient to significantly prolong survival while humanized NSG mice or non-humanized NSGS did not. This difference could not be attributed simply to T cell levels, because several of the NSG mice had comparable CD3+ populations at the time of exposure to antigen and subsequent challenge. While T cells are likely to be required for a response to toxoplasmosis challenge, the increased myeloid and dendritic cell populations generated in the NSGS mouse may prove to be equally critical for the functionality of UCB CD34+ xenografts. Disclosures: No relevant conflicts of interest to declare.

scholarly journals T Cell-Depleted Related Haploidentical Peripheral Blood Stem Cell Transplantation in a Patient with Fanconi Anemia. Cagliari Experience.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 5175-5175
Author(s):  
Maria Adele Sanna ◽  
Maria Grazia Orofino ◽  
Fausto Cossu ◽  
Maria Carmen Addari ◽  
Antonio Piroddi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Peripheral Blood ◽  
Bone Marrow Failure ◽  
Unrelated Donor ◽  
Cd34 Cells

Abstract Stem cell transplantation is presently the best treatment for Fanconi Anaemia (FA) patients developing bone marrow failure. 70% of success is reported in patients with a HLA identical sibling whereas the outcome for HSCT in those transplanted from unrelated donors is in the range of 29–43%, graft rejection, GVHD and regimen related toxicity beeing the main causes of failure. This results limited the ability to perform marrow transplantation other than HLA identical siblings for this disease. Recently a fludarabine based cytoreductive regimen has been successfully used in T cell depleted haploidentical/mismatched transplant of FA patients. We report a case of a 7 year old boy with bone marrow failure since 1999. Androgens treatment was uneffective, no HLA identical family donor was available and the search for a suitable marrow or cord blood unrelated donor was unsuccessful. After 4 years he underwent T-cell depleted haploidentical PBSCT from his father. Conditioning regimen was: fludarabine 30 mg/mq from day −6 to day −3, cytoxan 300 mg/mq from day −6 to day −3, rabbit ATG (3.75 mg/kg) from day −5 to day −3. GvHD prophylaxis consisted of cyclosporine 1 mg/kg from day −1. The donor received G-CSF 8 ug/kg/dose twice daily for 6 days and underwent leukapheresis on day 5 and 6. Donor stem cells were depleted of T cells by positive selection of CD34+ cells using the Clinimacs device according to the suggested procedures (Milteny Biotec). On day 0, 15.3x106 x kg CD34+ cells were infused with 1.5 x 105 CD3 + cells. The clinical postransplant course was uneventful. Neutrophil engraftment ( >0.5 x 109 ) occurred on day 14, platelet count >100x109 on day 15. He was discharged on day 39 without signs of GVHD. Molecular analysis of DNA-VNTRs at 1, 3, 6, 9, 12 months showed >95% donor chimerism on peripheral blood. At 14 months after transplantation the patient is well, normal blood cell count (WBC 5.4 x 109/l, Hb 13.6 gr /dl, platelets 293x 109 /l). Count of T-cells are reported in the normal reference range ( CD3+ :1865 ug/l, CD8+ :1026ug/l, CD19+ :732ug/l, CD56+: 452). Karnofsky score is 100%. Conclusion: the case reported shows that the fludarabine based regimen and the infusion of a high number of T-cell depleted CD34+ was successful in absence of peri-transplant complications and can be proposed for the cure of FA patients at high risk of clonal disease and without HLA-matched sibling donor.

scholarly journals Low Dose Umbilical Cord Blood Transplant Results in Skewed Immune Cell Composition Which May Impact Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5672-5672
Author(s):  
Chi Hua Sarah Lin ◽  
Beth Shaz ◽  
Rona Singer Weinberg
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
T Cell ◽  
Cell Population ◽  
Peripheral Blood ◽  
Low Dose ◽  
High Dose ◽  
Hematopoietic Stem ◽  
Nsg Mice ◽  
Cd34 Cells

Abstract Introduction Reconstitution of donor-derived immune system after allogeneic hematopoietic stem cell transplantation (HSCT) is essential for recovery and long-term survival. Despite routine use of human umbilical cord blood (hUCB) as a stem cell source for allogeneic HSCT, much remains unknown regarding the kinetics of immune recovery and correlation with different transplant cell dosages. To study the hUCB repopulating potential, different hUCB CD34+ cell dosages were transplanted into immune deficient NSG mice; hematopoietic cells were then collected and engraftment was analyzed. Methods NOD/SCID/IL-2Rγnull recipient (NSG) mice (Jackson Laboratories, Bar Harbor, ME) were kept in pathogen-free facilities. CD34+ cells were isolated from a pool of six hUCB donors using a CD34+ microbead kit (Miltenyi Biotec). Each sublethal irradiated (220 or 300 cGy) 8 week old female NSG mice received either low dose (15x103, N=15) or high dose (75x103, N=15) CD34+ cells transplanted intravenously via retro-orbital route. Animal experiments were performed in accordance with Institutional Animal Care and Use Committee guidelines. Statistical analysis was performed with Prism software (GraphPad Software, Inc) and Excel. Data are presented as mean ± standard error of the mean (SEM). Results To determine the effects of hUCB CD34+ cell dosages on the rate of engraftment, NSG mice were transplanted with low doseor high dose CD34+ cells. The transplanted CD34+ cell dosages were comparable to clinical dosages based on body weight (Mavroudis et al. 1996). The engrafted cells were analyzed for expression of surface markers that define human hematopoietic cells. During the follow up period of up to 18 weeks, the high dose infused group had increased hUCB engraftment compared with the low dose infused group in peripheral blood (Fig 1A), bone marrow (Fig 1B & 1C) and spleen (Fig 1D), which is consistent with reported clinical observations that infused cell dosage is inversely correlated with time to engraftment (Migliaccio et al. 2000 Blood). Interestingly, we observed different lymphoid subset frequencies between low and high dose infused groups at the post-engraftment stage (18 weeks post transplantation) (data not shown). To investigate different lymphoid subset engraftment frequencies in low and high dose hUCB transplanted recipient mice at early engraftment stage, peripheral blood and hematopoietic organs were collected and analyzed up to 10 weeks post transplantation. The low dose infused group had significantly lower CD3+ (T cells) and CD56+ (NK cells) frequency in peripheral blood at 4 and 8 weeks (Fig 2A & 3A). More importantly, CD3+ (T cells) frequency was close to non-detectable in the bone marrow and spleen in the low dose infused group (Fig 2B & 2C), and CD56 (NK cells) frequency was decreased in the low dose infused group compared with the high dose infused group (Fig 3B & 3C). The absolute CD3+ and CD56+ number, displayed as fold difference, were even more dramatically decreased in the femur (Fig 2D & 3D) and the spleen (Fig 2E & 3E) of low dose infused group. Because of the substantial difference in T cell subset frequencies between the two dosage groups in bone marrow and spleen, thymuses were collected and analyzed to study T cell development and maturation. Engraftment of hCD45+ cells in the thymuses were observed in 10 out of 15 animals (66.7%) in the low dose infused group and 12 out of 14 animals (85.7%) in the high dose infused group. Interestingly, in animals with high hCD45+ frequency, the total thymocyte CD3+ frequency was lower in the low dose infused group (Fig 4A). Additionally, the low dose infused group had lower CD3+CD4+ T cell frequency (Fig 4B) and higher CD3+CD4+CD8+ T cell frequency (Fig 4C), suggesting low dose infused group had a decreased mature T cell population and increased immature T cell population in the thymus. In contrast, the low dose hUCB CD34+ cells infused group had increased hCD19 (B cells) frequency in the peripheral blood, bone marrow and spleen (Fig 5A-5C), while the absolute hCD19 (B cells), displayed as fold difference, did not show a statistically significant difference between the two groups (Fig 5D & 5E). Conclusions In summary, our findings suggest that (1) transplanted hUCB cell dosage is inversely correlated with time to engraftment (2) low transplanted hUCB cell dosage resulted in skewed immune cell population which may contribute to delayed immune recovery after allogeneic HSCT. Disclosures No relevant conflicts of interest to declare.

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