WO2020061272A1 - Hybrid thymus. methods of making, and methods of using to induce xenograft tolerance, restore immunocompetence and thymic function - Google Patents
Hybrid thymus. methods of making, and methods of using to induce xenograft tolerance, restore immunocompetence and thymic function Download PDFInfo
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- A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
- A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
- A61L27/3604—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix characterised by the human or animal origin of the biological material, e.g. hair, fascia, fish scales, silk, shellac, pericardium, pleura, renal tissue, amniotic membrane, parenchymal tissue, fetal tissue, muscle tissue, fat tissue, enamel
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- A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
- A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
- A61L27/3683—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix subjected to a specific treatment prior to implantation, e.g. decellularising, demineralising, grinding, cellular disruption/non-collagenous protein removal, anti-calcification, crosslinking, supercritical fluid extraction, enzyme treatment
- A61L27/3695—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix subjected to a specific treatment prior to implantation, e.g. decellularising, demineralising, grinding, cellular disruption/non-collagenous protein removal, anti-calcification, crosslinking, supercritical fluid extraction, enzyme treatment characterised by the function or physical properties of the final product, where no specific conditions are defined to achieve this
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- A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
- A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
- A61L27/38—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells
- A61L27/3804—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
- A61L27/3813—Epithelial cells, e.g. keratinocytes, urothelial cells
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Definitions
- the present disclosure relates to making a pig-human hybrid thymus and using the hybrid thymus to induce tolerance in xenotransplantation.
- T-cell suppression is tolerance induction.
- the xenograft tolerance approaches include mixed chimerism induction and porcine thymic transplantation.
- Thymic xenotransplantation can also induce robust tolerance.
- Porcine thymic grafts can generate diverse and functional human T cell repertoires in mice that are specifically unresponsive to the donor pig in vitro.
- suboptimal recipient s immune function that fails to recognize efficiently foreign antigens
- suboptimal survival, homeostasis and inefficient removal of autoreactive T cells and lack of positive selection of regulatory T cells to prevent autoimmunity.
- the thymic function is essentially absent in the recipient mammal before performing step (a).
- the recipient mammal is a primate and in some embodiments, it is a human.
- the donor mammal is a swine and in some embodiments, it is a miniature swine.
- the thymic tissue from the donor mammal is a fetal thymic tissue. In some embodiments, the thymic tissue from donor mammal is a neonatal thymic tissue.
- the thymic epithelial cells from the recipient mammal are obtained from the recipient mammal’s thymus. In some embodiments, the thymic epithelial cells from the recipient mammal are generated from the recipient mammal’s induced pluripotent stem cells (iPSCs). In some embodiments, the thymic epithelial cells from the recipient mammal species are generated from embryonic stem cells that share HLA alleles with the recipient mammal. In some embodiments, the embryonic stem cells are genetically engineered to share HLA alleles with the recipient mammal. In some embodiments, the hybrid thymic tissue is implanted in the recipient mammal in step (a). In some embodiments, step (a) is conducted prior to, or simultaneous with, step (b).
- iPSCs induced pluripotent stem cells
- the hybrid thymic tissue is generated by a method comprising the following steps:
- the thymic epithelial cells from the first species are suspended in Matrigel before being injected into the 2DG-treated thymic tissue.
- the present disclosure also provides for a method of restoring or promoting thymus- dependent ability for T cell progenitors to develop into mature functional T cells in a recipient mammal of a first species, the method comprising introducing a hybrid thymic tissue into the recipient mammal of the first species, wherein the hybrid thymic tissue is a thymic tissue from a donor mammal of a second species and comprises thymic epithelial cells from the first species.
- thymic function is essentially absent in the recipient mammal before the introducing step.
- the recipient mammal is thymectomized before the introducing step.
- the recipient mammal has an immune disorder.
- the donor mammal is a swine and in some embodiments, the swine is a miniature swine.
- the recipient mammal is a primate. In some embodiments, the recipient mammal is a human.
- the thymic tissue from the donor mammal is a fetal thymic tissue. In some embodiments, the thymic tissue from the donor mammal is a neonatal thymic tissue.
- the thymic epithelial cells are obtained from the recipient mammal’s thymus. In some embodiments, the thymic epithelial cells are generated from the recipient mammal’s induced pluripotent stem cells (iPSCs). In some embodiments, the thymic epithelial cells are generated from embryonic stem cells that share HLA alleles with the recipient mammal. In some embodiments, the embryonic stem cells are genetically engineered to share HLA alleles with the recipient mammal.
- iPSCs induced pluripotent stem cells
- the hybrid thymic tissue is implanted in the recipient mammal.
- the hybrid thymic tissue is generated by introducing thymic epithelial cells from the first species into the thymic tissue from the donor mammal of the second species. In some embodiments, the hybrid thymic tissue is generated by injecting thymic epithelial cells from the first species into the thymic tissue from the donor mammal of the second species.
- the thymic epithelial cells from the first species are suspended in Matrigel before being injected into the 2DG-treated thymic tissue.
- the second mammalian species is a swine and in some embodiments, the swine is a miniature swine.
- the first mammalian species is a primate.
- the recipient mammal is a human.
- the thymic tissue from the second mammalian species is fetal thymic tissue. In some embodiments, the thymic tissue from the second mammalian species is a neonatal thymic tissue.
- the thymic epithelial cells are obtained from a thymus from a first mammalian species. In some embodiments, the thymic epithelial cells from the first mammalian species are obtained from fetal thymic tissue. In some embodiments, the thymic epithelial cells from the first mammalian species are obtained from neonatal thymic tissue. In some embodiments, the thymic epithelial cells are generated from induced pluripotent stem cells (iPSCs) from the first mammalian species. In some embodiments, the thymic epithelial cells are generated from embryonic stem cells that share HLA alleles with the first mammalian species. In some embodiments, the embryonic stem cells are genetically engineered to share HLA alleles with the first mammalian species.
- iPSCs induced pluripotent stem cells
- the present disclosure also provides for an isolated hybrid thymic tissue comprising thymic epithelial cells from a first mammalian species and a thymic tissue from a second mammalian species and a method for making a hybrid thymic tissue, comprising the steps of:
- the thymic epithelial cells from the first mammalian species are suspended in Matrigel before being injected into the 2DG-treated thymic tissue.
- Figure 1 Generation of human/pig hybrid thymus.
- humanized mice generated with hybrid pig/human thymus and human CD34+ cells were euthanized and the grafted thymi removed, sectioned and stained to detect human TECs using two- photon confocal microscopy.
- Figures 1A, 1B and 1C show images of the grafted pig thymus un- injected ( Figure 1A), injected with human fetal thymic stromal cells (gestational age of 20 weeks) ( Figure 1B), and injected with pediatric human thymic stromal cells (from a 4-month-old thymus) ( Figure 1C).
- FIG. 1D Quantitative analysis of entire sections shown in Figures 1A - 1C is shown in Figure 1D. Additional controls of human fetal and pediatric thymus and pig thymus were also included in quantitative analysis. The analysis was performed by lmarisColoc software, which allowed the calculation of colocalization of CK14+HLA-DR+ cells among all CK14+ cells in entire thymic sections. Numbers shown on top of the bars are percentages of CK14+HLA-DR+ cells among CK14+ cells.
- FIGS 1E and 1F show representative images of the expanded human thymic mesenchyme cells (TMCs) ( Figure 1E) and TECs (Figure 1F), which were cultured on a 3-D Matrigel culture system for 3 weeks from huCD45 -depleted human thymic cells following digestion of a l7-year-old pediatric thymus with liberase.
- Figures 1G and 1H show representative flow cytometric characterization of expanded TMCs and TECs, respectively.
- CD105-CD326+ are considered as TECs, while CD105+CD326- cells are considered to be TMCs.
- FIG. 2 CK14+HLA-DR+ cells were detected in hybrid thymi generated by injecting human thymic stromal cells (from a fetal thymus) (TEC) into the pig thymus.
- Figure 2A no human TEC injection.
- Figure 2B human TEC injected.
- Figure 2C 2-DG-treated pig thymus + human fetal TEC injected.
- Figure 3 Results showing the development of methods for use in generating a hybrid thymus.
- Figure 3A shows flow cytometry results showing the number of released cells after injection of cells into the swine fetal thymic fragments.
- PBMCs cells were resuspended in Matrigel to prevent them from leaking out of the pig thymus after injection.
- Three different methods were used for injection of the cells into the thawed swine fetal thymic fragments. Method A: Injection using Hamilton syringe while the pieces were placed inside the wells of a V-bottom 96-well plate.
- Method B Injection using PE50 tubing.
- Method C Injection using Hamilton syringe while the pieces were kept outside the well with forceps until the Matrigel is solidified. The number of released cells was determined by flow cytometry to track the CFSE-stained injected PBMCs.
- Figures 3B and 3C shows the results of various reagents to deplete the thymocytes in pig thymic fragments ex vivo.
- Figure 3B are graphs of the total live cell count for cells treated with each reagent (top panel) and the percent of live cells (bottom panel) for cells treated for each reagent.
- Figure 3C are graphs of the ratio of remaining live double positive CD4 and CD8 cells (DP) or single positive (SP) CD4 (SP-CD4) or SP-CD8 cells on double negative (DN) cells, which contain the stromal cells, used as the readout.
- Treatment with 2DG lOOnM for 12 hours resulted in the lowest ratios and therefore was the best strategy for removing thymocytes while preserving the stromal cells.
- Figure 5 shows graphs of the levels of human immune cell reconstitution after hybrid thymi transplantation either fetal pig thymus treated with 2DG and injected with human thymic stromal cells (represented by circles on the graphs), fetal pig thymus not treated with 2DG and injected with human thymic stromal cells (represented by squares on the graphs), and fetal pig thymus treated with 2DG and not injected with human thymic stromal cells (represented by triangles on the graph).
- Figure 5A shows percentage of hCD45+ within white blood cells.
- Figure 5B shows percentage of CD3+ cells in hCD45+.
- Figure 5C shows hCD45+ cell count per pl of blood.
- Figure 6 shows images of the detection of the injected human TECs admixed with pig TECs within the grafted thymus. Uninjected swine thymus grafted into a humanized mouse is shown on the left and a hybrid thymus grafted into a humanized mouse is shown on the right.
- Fetal pig thymus uninjected with human thymic stromal cells is represented by the circles, fetal pig thymus injected with human thymic stromal cells and not treated with 2DG are represented by squares, and fetal pig thymus injected with human thymic stromal cells treated with 2DG are represented by triangles.
- Figure 8 shows the increased responsiveness to human tissue restricted antigens (TRAs) (MART-l, NYESOl and islet antigen IA-2) among human T cells that develop in a pig thymus (SW/HU mice) compared to those developing in a human thymus (HU/HU mice).
- Figure 8 A is a schematic of the mice models.
- Figure 8B are graphs showing the proliferative responses of human peripheral T cells (18 weeks post-transplant) from the mice to human TRAs (IA-2, MART-l and NYESOl) presented by human HSC donor DCs.
- Figure 9C shows the percentage of Tregs within SP-CD4+ in the grafted thymi.
- Figure 9D shows the percental of Ki67+ cells in the grafted thymi.
- Figure 9E shows the percentage of CD45RO+ cells in the grafted thymi.
- Figure 9F shows the percentage of CTLA-4+ cells in the grafted thymi.
- Figure 9G shows the total cell count in the spleen and lymph nodes (LN) in each subset of mice.
- Figure 9H shows the percentage of hCD45+ cells in the spleen and lymph nodes (LN) in each subset of mice.
- Figure 10B are representative flow cytometric staining of gated CD45- negative cells in digested stroma from the various long-term thymic grafts showing the presence of EPCAM+, CDl05-negative hu-TECs only in the human thymus (top right) and SW grafts that had been injected with hPSC-TEC progenitors (bottom left panel) but not in the uninjected SW THY grafts (top left).
- Figure 10C is a graph of the quantification of the percentage of CD45- HLA- ABC+ EpCAM+ (injected human TECs) from multiple mice receiving human ES-TEC-injected SW thymus vs non-injected SW thymus.
- FIG. 11A is a graph of absolute number of human CD3 T cells in each group of mice.
- Figure 1 IB is a graph of the absolute numbers of human CD8 + T cells in each group of mice.
- Figure 11C is a graph of the absolute number of human CD4 + T cells in each group of mice.
- Figure 1 ID is a graph of the absolute number of recent thymic emmigrant CD31 + CD4 + naive cells defined as CD45RA CCR7 cells in mononuclear cells of the spleen in each group of mice.
- Figure 11E are graphs of number of indicated cells in thymocytes in each group of mice stained for expression of HuCD45, CD19, CD14, CD4, CD8, CD45RA and CD45RO. Thymocytes were gated as huCD45 + CD19 CD14 cells. Absolute count of thymocytes from half the thymus graft gated as total human CD45 cells, double positive CD4 + CD8 + , single positive CD4 + CD8 and CD4 CD8 are shown.
- SP- single positive cells either CD4+ or CD8+
- a hybrid thymic tissue refers to a thymic tissue from the donor mammal of a second species and comprises thymic epithelial cells from the recipient mammal of a first species.
- a hybrid thymus/thymic tissue is constructed where a pig thymus/thymic tissue (e.g., a fetal thymus/thymic tissue) containing human (e.g., patient-specific) TECs generated from human (e.g., patient- specific) induced pluripotent stem cells.
- a hybrid thymus/thymic tissue is constructed where a pig thymus/thymic tissue (e.g., a fetal thymus/thymic tissue) containing human TECs generated from embryonic stem cells that either naturally share HLA alleles with the patient or have been engineered to do so.
- the present disclosure also provides for a method to generate a primate-pig hybrid thymus/thymic tissue to achieve immune tolerance to pig antigens with optimal immune function of the primate T-cell repertoire generated.
- One embodiment of the present disclosure provides for a hybrid thymus/thymic tissue in the pig to baboon.
- the hybrid thymus/thymic tissue may be implanted as a primarily vascularized thymus lobe or composite thymo-kidney graft.
- the hybrid thymus/thymic tissue may be transplanted intramuscularly in the recipient.
- the hybrid thymus/thymic tissue may be transplanted either into the quadriceps muscle alone or with additional transplantation sites (e.g., kidney capsule and omentum) in the recipient.
- additional transplantation sites e.g., kidney capsule and omentum
- the recipient of the xenotransplantation is a mammal of a first mammalian species.
- the donor of the xenotransplantation refers to a mammal of a second mammalian species.
- the donor mammal is the donor of cells, tissues, and/or organs for the xenotransplantation.
- the present disclosure provides for a method of inducing tolerance in a recipient mammal of a first species to a graft obtained from a donor mammal of a second species, the method comprising the steps of: (a) introducing a hybrid thymic tissue into the recipient mammal, wherein the hybrid thymic tissue is a thymic tissue from the second species and comprises thymic epithelial cells from the first species; and (b) implanting the graft from the donor mammal in the recipient mammal. Step (a) may be conducted prior to, or simultaneous with, step (b).
- the present disclosure also provides for a method of restoring or inducing immunocompetence in a recipient mammal of a first species, the method comprising the step of introducing a hybrid thymic tissue into the recipient mammal, wherein the hybrid thymic tissue is a thymic tissue from a donor mammal of a second species and comprises thymic epithelial cells from the first species.
- Also encompassed by the present disclosure is a method of restoring or promoting thymus- dependent ability for T cell progenitors to develop into mature functional T cells in a recipient mammal of a first species, the method comprising introducing a hybrid thymic tissue into the recipient mammal, wherein the hybrid thymic tissue is a thymic tissue from a donor mammal of a second species and comprises thymic epithelial cells from the first species.
- thymic function is essentially absent in the recipient mammal before a hybrid thymic tissue is introduced.
- the recipient mammal is thymectomized before a hybrid thymic tissue is introduced.
- the recipient mammal has an immune disorder.
- the second species may be swine, such as a miniature swine.
- the first species is may be primate, such as non-human primate or human.
- the recipient mammal is a human and the donor mammal is a miniature swine.
- the thymic tissue from the second species may be a fetal thymic tissue, or a neonatal thymic tissue.
- the thymic epithelial cells from the first species may be obtained from the recipient mammal’s thymus.
- the thymic epithelial cells from the first species may be generated from the recipient mammal’s induced pluripotent stem cells (iPSCs).
- iPSCs induced pluripotent stem cells
- the thymic epithelial cells from the first species may be generated from embryonic stem cells that share HLA alleles with the recipient mammal.
- the embryonic stem cells may naturally share HLA alleles with the recipient mammal or are genetically engineered to share HLA alleles with the recipient mammal.
- the hybrid thymic tissue is implanted in the recipient mammal.
- the hybrid thymic tissue may be implanted as a primarily vascularized thymus lobe or composite thymo-kidney graft.
- the hybrid thymic tissue may be generated by introducing thymic epithelial cells from the first species into the thymic tissue from the second species.
- the hybrid thymic tissue may be generated by injecting thymic epithelial cells from the first species into the thymic tissue from the second species.
- the hybrid thymic tissue may be generated by a method comprising the following steps: (i) treating the thymic tissue from the second species with 2-deoxyglucose (2DG); and (ii) introducing thymic epithelial cells from the first species into the 2DG-treated thymic tissue.
- 2DG 2-deoxyglucose
- the thymic epithelial cells may be suspended in biomaterial, such as Matrigel, before being injected to the 2DG-treated thymic tissue.
- the thymic epithelial cells may be suspended in a biomaterial (e.g., Matrigel) before being injected to the thymic tissue from the second species.
- the thymic epithelial cells from the first species may be combined with (e.g., be suspended in) a biomaterial.
- the biomaterial may be a sol-gel, a hydrogel laden with proteins, a Matrigel, an artificially constructed scaffold with cells, and combinations thereof.
- Non-limiting examples of the biomaterials may also include, polyethylene-imine and dextran sulfate, poly(vinylsiloxane)ecopolymerepolyethyleneimine, phosphorylcholine, poly(ethylene glycol), poly(lactic-glycolic acid), poly(lactic acid), polyhydroxyvalerte and copolymers, polyhydroxybutyrate and copolymers, polydiaxanone, poly anhydrides, poly(amino acids), poly (orthoesters), polyesters, collagen, gelatin, cellulose polymers, chitosans, alginates, fibronectin, extracellular matrix proteins, vinculin, agar, agarose, hyaluronic acid, matrigel and combinations thereof.
- the present method may further comprise administering hematopoietic stem cells (HSCs) to the recipient mammal.
- HSCs hematopoietic stem cells
- the graft may comprise cells, a tissue or an organ.
- the graft comprises hematopoietic stem cells.
- the graft comprises bone marrow.
- the graft comprises a heart, a kidney, a liver, a pancreas, a lung, an intestine, skin, a small bowel, a trachea, a cornea, or combinations thereof.
- the present disclosure provides for an isolated hybrid thymic tissue comprising thymic epithelial cells from a first mammalian species and a thymic tissue from a second mammalian species.
- TCR T cell receptor
- the porcine thymic transplantation approach to tolerance has been extended to the humanized mouse model to provide proof-of-principle that human T cells can develop normally and are centrally tolerized to porcine xenoantigens in pig thymic grafts.
- Thymi were transplanted either as part of a composite“thymokidney” graft prepared in the donor pig several months earlier by placing autologous thymic fragments under the pig’s kidney capsule or by direct vascular anastomosis of a pig thymic lobe in a baboon.
- Limitations of generating a human T cell repertoire in a xenogeneic porcine thymus include the preferential recognition of microbial antigens on porcine MHC, which would be useful for protecting the graft but would not optimize protection against microbial pathogens infecting the host, as well as the failure to negatively select conventional T cells and positively select Tregs recognizing human tissue-restricted antigens (TRAs). Indeed, studies in humanized mice have shown reduced responses to peptides presented by human APCs following immunization when the human T cells developed in a pig rather than a human thymus graft.
- TRAs human tissue-restricted antigens
- the approach to overcome this limitation involves creation of a“hybrid thymus”, in which recipient thymic epithelial cells obtained either from thymectomy specimens or generated from stem cells are injected into the porcine thymic tissue. Hybrid thymi from post-natal thymus donors have been generated, where the hybrid thymus promotes tolerance to human TRAs among human T cells.
- Pig thymus grafts have been shown to support the development of normal, diverse murine or human T cell repertoires and that these T cells are specifically tolerant of the xenogeneic pig donor.
- recognition of foreign antigens presented by recipient HLA molecules in the periphery is suboptimal.
- immune function may be less than optimal.
- this can be overcome by providing recipient TECs in the pig-human hybrid thymus graft because these TECs will participate in positive selection, resulting in T cells that can more readily recognize foreign antigens presented by recipient HLA molecules in the periphery.
- the positive selecting ligand is the MHC/peptide complex on TECs that rescue thymocytes from programmed cell death when the thymocyte has a low affinity T cell receptor recognizing that complex.
- TECs produce antigens that are otherwise expressed only in very specific tissues in the periphery (i.e., tissue- specific antigens, TSAs).
- TSAs tissue- specific antigens
- Two important consequences of this expression of TSAs by TECs are: a) clonal deletion of thymocytes that strongly recognize them, removing these autoreactive T cells from the repertoire; b) positive selection of regulatory T cells recognizing them, adding a safety net to prevent autoimmunity in the periphery. Since many TSAs differ between human and pig, the addition of human TECs to make human TSAs in the pig-human hybrid thymus graft will help to assure protection from autoimmunity.
- the use of a hybrid thymus instead of a simple pig thymus can improve the function and self-tolerance of a human T cell repertoire generated in a pig thymus while allowing tolerance to the pig to develop.
- the recipient is thymectomized. In another embodiment, the recipient is not thymectomized. In yet another embodiment, the recipient has a low rate of thymopoiesis due to age. In still another embodiment, the recipient has a senescent thymus. Thymic xenotransplantation using the present hybrid thymus/thymic tissue may or may not be combined with mixed chimerism induction.
- both pig and human APCs would be present in the native human thymus and the porcine thymic xenograft, ensuring lifelong negative selection of thymocytes recognizing either pig or human antigens expressed on hematopoietic cells.
- conventional T cells recognizing pig or human TRAs would be deleted in the relevant species’ thymus and those escaping deletion due to development in the thymus of the opposite species would be adequately suppressed by TRA-specific Tregs developing in the other thymus.
- the mixed porcine chimerism would assure tolerance of natural antibodies recognizing unknown xenogeneic targets and NK cells would be tolerized as well.
- Xenotransplantation lends itself to tolerance induction more readily than allotransplantation from deceased human donors, as the ability to perform xenotransplantation electively permits the application of a tolerance protocol (e.g. mixed chimerism induction) in advance of the organ xenograft.
- a tolerance protocol e.g. mixed chimerism induction
- the present method involves tolerizing the immune system of the recipient first, confirming that tolerance has been achieved and subsequently performing the organ transplant without immunosuppression or with a shortened course of immunosuppression.
- the present disclosure provides a method of inducing tolerance in a recipient mammal of a first species (e.g., a primate such as a human) to a graft obtained from a mammal of a second species, e.g., a swine.
- the method includes: prior to or simultaneous with transplantation of the graft, introducing into the recipient mammal a hybrid thymus/thymic tissue; and (optionally) implanting the graft in the recipient.
- the hybrid thymus/thymic tissue prepares the recipient for the graft that follows, by inducing immunological tolerance at the T-cell level.
- the present disclosure provides methods for inducing xenograft tolerance in a recipient, the methods including the step of introducing a hybrid thymus/thymic tissue into the recipient.
- host T cells of an athymic, T cell-depleted recipient which has received a hybrid thymus/thymic tissue can mature in the hybrid thymus/thymic tissue.
- Host T cells which mature in the implanted hybrid thymus/thymic tissue are immunocompetent.
- the present disclosure provides a method of restoring or inducing immunocompetence (or restoring or promoting the thymus -dependent ability for T cell progenitors to mature or develop into functional mature T cells) in a host or recipient, e.g., a primate host or recipient, e.g., a human, which is capable of producing T cell progenitors but which is thymus -function deficient and thus unable to produce a sufficient number of mature functional T cells for a normal immune response.
- the method includes the step of introducing into the recipient, a hybrid thymus/thymic tissue, so that host T cells can mature in the implanted hybrid thymus/thymic tissue.
- the recipient/host is a primate, e.g., a human, and the donor is swine, e.g., miniature swine.
- liver or spleen tissue such as fetal or neonatal liver or spleen tissue
- donor hematopoietic cells e.g., cord blood stem cells or fetal or neonatal liver or spleen cells
- recipient e.g., a suspension of fetal liver cells is administered intraperitoneally or intravenously.
- the recipient may be thymectomized, such as before or at the time the hybrid thymus/thymic tissue is introduced.
- the method includes: (preferably prior to or at the time of introducing the thymic tissue into the recipient) depleting, inactivating or inhibiting recipient natural killer (NK) cells, e.g., by introducing into the recipient an antibody capable of binding to NK cells of the recipient, to prevent NK mediated rejection of the thymic tissue; (preferably prior to or at the time of introducing the thymic tissue into the recipient) depleting, inactivating or inhibiting host T cell function, e.g., by introducing into the recipient an antibody capable of binding to T cells of the recipient; (preferably prior to or at the time of introducing the thymic tissue into the recipient) depleting, inactivating or inhibiting host CD4+ cell function, e.g., by introducing into the recipient an antibody capable of binding to CD4, or CD4+ cells of the recipient.
- NK natural killer
- Certain embodiments include the step of (preferably prior to thymic tissue or hematopoietic stem cell transplantation) creating hematopoietic space, e.g., by one or more of: irradiating the recipient mammal with low dose, e.g., between about 100 and 400 rads, whole body irradiation, the administration of a myelosuppressive drug, or the administration of a hematopoietic stem cell inactivating or depleting antibody, to deplete or partially deplete the bone marrow of the recipient (preferably prior to thymic tissue transplantation).
- low dose e.g., between about 100 and 400 rads, whole body irradiation
- the administration of a myelosuppressive drug e.g., or the administration of a hematopoietic stem cell inactivating or depleting antibody
- Certain embodiments include (preferably prior to thymic tissue or hematopoietic stem cell transplantation) inactivating thymic T cells by one or more of: irradiating the host with, e.g., about 700 rads of thymic irradiation, administering to the recipient one or more doses of an anti T cell antibody, e.g., an anti-CD4 and/or an anti-CD8 monoclonal antibody, or administering to the recipient a short course of an immunosuppressant.
- an anti T cell antibody e.g., an anti-CD4 and/or an anti-CD8 monoclonal antibody
- Certain embodiments include depleting or otherwise inactivating natural antibodies, e.g., by one or more of: the administration of a drug which depletes or inactivates natural antibodies, e.g., deoxyspergualin; the administration of an anti-IgM antibody, or the adsorption of natural antibodies from the host's blood, e.g., by contacting the host's blood with donor antigen, e.g., by hemoperfusion of a donor organ, e.g., a kidney or a liver, from the donor species.
- tolerance to the thymic tissue can also be induced by inserting a nucleic acid which expresses a donor antigen, e.g., a donor MHC gene, into a cell of the recipient, e.g., a hematopoietic stem cell, and introducing the genetically engineered cell into the recipient.
- a donor antigen e.g., a donor MHC gene
- human recipient stem cells can be engineered to express a swine MHC gene, e.g., a swine class I or class II MHC gene, or both a class I and class II gene, and the cells implanted in a human recipient who will receive the hybrid thymic tissue.
- a recipient primate e.g., a human
- expression of the donor MHC gene results in tolerance to subsequent exposure to donor antigen, and can thus induce tolerance to the thymic tissue.
- Methods of inducing tolerance e.g., by the implantation of hematopoietic stem cells, can also be combined with the methods disclosed herein.
- helper T cells which can be induced, e.g., by the administration of a short course of high dose immunosuppressant, e.g., cyclosporine, has been found to induce tolerance.
- helper T cells is suppressed for a comparatively short period just subsequent to implantation of a graft, and does not require or include chronic immunosuppression.
- the present disclosure provides a method of diminishing or inhibiting T cell activity, preferably the activity of thymic or lymph node T cells, in a recipient mammal, e.g., a primate, e.g., a human, which receives a graft from a donor mammal.
- the method includes, inducing tolerance to the graft; administering to the recipient a short course of an immunosuppressive agent, e.g., cyclosporine, sufficient to inactivate T cells, preferably thymic or lymph node T cells.
- an immunosuppressive agent e.g., cyclosporine
- Thymus-function deficient refers to a condition in which the ability of an individual's thymus to support the maturation of T cells is impaired as compared with a normal individual. Thymus deficient conditions include those in which the thymus or thymus function is essentially absent.
- Tolerance refers to the inhibition or decrease of a graft recipient's ability to mount an immune response, e.g., to a donor antigen, which would otherwise occur, e.g., in response to the introduction of a non self MHC antigen into the recipient. Tolerance can involve humoral, cellular, or both humoral and cellular responses. The concept of tolerance includes both complete and partial tolerance. In other words, as used herein, tolerance include any degree of inhibition of a graft recipient's ability to mount an immune response, e.g., to a donor antigen.
- Hematopoietic stem cell refers to a cell that is capable of developing into mature myeloid and/or lymphoid cells.
- a hematopoietic stem cell is capable of the long term repopulation of the myeloid and/or lymphoid lineages.
- Stem cells derived from the cord blood of the recipient or the donor can be used in methods of the disclosure.
- Miniature swine refers to completely or partially inbred miniature swine.
- “Graft”, as used herein, refers to a body part, organ, tissue, cells, or portions thereof.
- “Stromal tissue”, as used herein, refers to the supporting tissue or matrix of an organ, as distinguished from its functional elements or parenchyma.
- Restoring, inducing, or promoting immunocompetence means one or both of: (1) increasing the number of mature functional T cells in the recipient (over what would be seen in the absence of treatment with a method of the disclosure) by either or both, increasing the number of recipient-mature functional T cells or by providing mature functional donor-T cells, which have matured in the recipient; or (2) improving the immune-responsiveness of the recipient, e.g., as is measured by the ability to mount a skin response to a recall antigen, or improving the responsiveness of a T cell of the recipient, e.g., as measured by an in vitro test, e.g., by the improvement of a proliferative response to an antigen, e.g., the response to tetanus antigen or to an alloantigen.
- Restoring or inducing the thymus-dependent ability for T cell progenitors to mature into mature T cells means either or both, increasing the number of functional mature T cells of recipient origin in a recipient, or providing mature functional donor T cells to a recipient, by providing donor thymic tissue in which T cells can mature.
- the increase can be partial, e.g., an increase which does not bring the level of mature functional T cells up to a level which results in an essentially normal immune response or partial, e.g., an increase which falls short of bringing the recipient's level of mature functional T cells up to a level which results in an essentially normal immune response.
- preparation of the recipient for either organ transplantation or thymus replacement includes any or all of the following steps. They may be carried out in the following sequence.
- a preparation of horse anti-human thymocyte globulin is intravenously injected into the recipient.
- the antibody preparation eliminates mature T cells and natural killer cells. If not eliminated, mature T cells might promote rejection of both the thymic transplant and, after sensitization, the xenograft organ.
- the ATG preparation also eliminates natural killer (NK) cells. NK cells probably have no effect on an implanted organ, but might act immediately to reject the newly introduced thymic tissue.
- Anti-human ATG obtained from any mammalian host can also be used, e.g., ATG produced in pigs, although thus far preparations of pig ATG have been of lower titer than horse-derived ATG.
- ATG is superior to anti-NK monoclonal antibodies, as the latter are generally not lytic to all host NK cells, while the polyclonal mixture in ATG is capable of lysing all host NK cells.
- Anti-NK monoclonal antibodies can, however, be used. In a relatively severely immunocompromised individual this step may not be necessary.
- host (or donor) T cells mature in the xenogeneic thymus they will be tolerant of the thymic tissue. Alternatively, as the host immune system is progressively restored, it may be desirable to treat the host to induce tolerance to the thymic tissue.
- the recipient can be thymectomized.
- recipient T cells do not have an opportunity to differentiate in the recipient thymus, but must differentiate in the hybrid thymic tissue. In some cases, it may be necessary to splenectomize the recipient in order to avoid anemia.
- the recipient can be administered low dose radiation.
- this step is thought to be beneficial in bone marrow transplantation (by creating hematopoietic space for newly injected bone marrow cells), it is of less importance in thymic grafts which are not accompanied by bone marrow transplantation.
- a sublethal dose e.g., a dose about equal to 100, or more than 100 and less than about 400, rads, whole body radiation, plus 700 rads of local thymic radiation, can be used.
- natural antibodies can be adsorbed from the recipient's blood. Antibody removal can be accomplished by exposing the recipient's blood to donor or donor species antigens, e.g., by hemoperfusion of a liver of the donor species to adsorb recipient-natural antibodies.
- Pre-formed natural antibodies are the primary agents of graft rejection. Natural antibodies bind to xenogeneic endothelial cells and are primarily of the IgM class. These antibodies are independent of any known previous exposure to antigens of the xenogeneic donor. B cells that produce these natural antibodies tend to be T cell-independent, and are normally tolerized to self antigen by exposure to these antigens during development. Again, this step may not be required, at least initially, in a relatively severely immunocompromised patient.
- the hybrid thymic tissue is implanted in the recipient.
- Fetal or neonatal liver or spleen tissue can be included.
- One, or any combination including all, of these procedures may aid the survival of implanted thymic tissue or another xenogeneic organ.
- Methods of the present disclosure can be used to confer tolerance to xenogeneic grafts, e.g., wherein the graft donor is a nonhuman animal, e.g., a swine, e.g., a miniature swine, and the graft recipient is a primate, e.g., a human.
- the graft donor is a nonhuman animal, e.g., a swine, e.g., a miniature swine
- the graft recipient is a primate, e.g., a human.
- the donor of the xenograft and the individual that supplies the tolerance-inducing thymic tissue may be the same individual or may be as closely related as possible. For example, it is preferable to derive a xenograft from a colony of donors that is highly or completely inbred.
- the second mammalian species may be a non-human mammalian species, such as a swine species (e.g., a miniature swine species) or a non-human primate species.
- a swine species e.g., a miniature swine species
- a non-human primate species e.g., a non-human primate species.
- the first mammalian species include a swine, rodent, non-human primate, cow, goat, and horse.
- the second mammalian species is a miniature swine which is at least partially inbred (e.g., the swine is homozygous at swine leukocyte antigen (SLA) loci, and/or is homozygous at at least 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more, of all other genetic loci).
- SLA swine leukocyte antigen
- the genetic engineering can be made in wholly or partially inbred swine (e.g., miniature swine, transgenic swine, etc.).
- MGH Massachusetts General Hospital
- MGH miniature swine which have been inbred for over 40 years and are homozygous at all genetic loci.
- inbred SLA dd miniature swine may be used. Mezrich et al. and Sachs, Histocompatible miniature swine: An inbred large-animal model. Transplantation, 2003; 75:904- 907. Swine at National Swine Resource and Research Center (NSRRC, RADIL, University Missouri, Columbia MO) may also be used in the present methods.
- NSRRC National Swine Resource and Research Center
- the first mammalian species may be a primate, such as non-human primate (e.g., a baboon, or cynomolgus monkey) or human.
- the second species is human.
- the donor (second species) and recipient (first species) are of different species.
- the donor is a non-human animal, e.g., a miniature swine, and the recipient is a human.
- Also encompassed by the present disclosure are methods of transplanting a graft from such a donor animal of the second mammalian species into a recipient mammal of a first mammalian species (e.g., human).
- a first mammalian species e.g., human
- Cells, tissues, organs or body fluids of the present transgenic donor animal may be used for transplantation (e.g., xenotransplantation).
- the graft harvested from the donor animal for transplantation may include, but are not limited to, a heart, a kidney, a liver, a pancreas, a lung transplant, an intestine, skin, thyroid, bone marrow, small bowel, a trachea, a cornea, a limb, a bone, an endocrine gland, blood vessels, connective tissue, progenitor stem cells, blood cells, hematopoietic cells, Islets of Langerhans, brain cells and cells from endocrine and other organs, bodily fluids, and combinations thereof.
- the cell can be any type of cell.
- the cell is a hematopoietic cell (e.g., a hematopoietic stem cell, lymphocyte, a myeloid cell), a pancreatic cell (e.g., a beta-islet cell), a kidney cell, a heart cell, or a liver cell.
- hematopoietic cell e.g., a hematopoietic stem cell, lymphocyte, a myeloid cell
- pancreatic cell e.g., a beta-islet cell
- a kidney cell e.g., a heart cell, or a liver cell.
- Bone marrow cells BMC
- hematopoietic stem cells e.g., a fetal liver suspension or mobilized peripheral blood stem cells
- the method may also include one or more of the following treatments: a treatment which inhibits T cells, blocks complement, or otherwise down-regulates the recipient immune response to the graft.
- Treatments that promote tolerance and/or decrease immune recognition of the graft include use of immunosuppressive agents (e.g., cyclosporine, FK506), antibodies (e.g., anti-T cell antibodies such as polyclonal anti-thymocyte antisera (ATG), and/or a monoclonal anti-human T cell antibody, such as LoCD2b), irradiation, and methods to induce mixed chimerism.
- immunosuppressive agents e.g., cyclosporine, FK506
- antibodies e.g., anti-T cell antibodies such as polyclonal anti-thymocyte antisera (ATG), and/or a monoclonal anti-human T cell antibody, such as LoCD2b
- ATG polyclonal anti-thymocyte antisera
- the recipient is thymectomized and/or splenectomized. Thymic irradiation can be used.
- the recipient is administered low dose radiation (e.g., a sublethal dose of between 100 rads and 400 rads whole body radiation). Local thymic radiation may also be used.
- low dose radiation e.g., a sublethal dose of between 100 rads and 400 rads whole body radiation.
- Local thymic radiation may also be used.
- the recipient can be treated with an agent that depletes complement, such as cobra venom factor.
- Natural antibodies can be eliminated by organ perfusion, and/or transplantation of tolerance-inducing bone marrow. Natural antibodies can be absorbed from the recipient's blood by hemoperfusion of a liver of the donor species.
- the cells, tissues, or organs used for transplantation may be genetically modified such that they are not recognized by natural antibodies of the host (e.g., the cells are a-l,3-galactosyltransferase deficient).
- the methods include treatment with a human anti-human CD154 mAb, mycophenolate mofetil, and/or methylprednisolone.
- the methods can also include agents useful for supportive therapy such as anti-inflammatory agents (e.g., prostacyclin, dopamine, ganiclovir, levofloxacin, cimetidine, heparin, antithrombin, erythropoietin, and aspirin).
- anti-inflammatory agents e.g., prostacyclin, dopamine, ganiclovir, levofloxacin, cimetidine, heparin, antithrombin, erythropoietin, and aspirin.
- donor stromal tissue is administered.
- An immunosuppressant also referred to as an immunosuppressive agent, can be any compound that decreases the function or activity of one or more aspects of the immune system, such as a component of the humoral or cellular immune system or the complement system.
- immunosuppressants include, (1) antimetabolites, such as purine synthesis inhibitors (such as inosine monophosphate dehydrogenase (IMPDH) inhibitors, e.g., azathioprine, mycophenolate, and mycophenolate mofetil), pyrimidine synthesis inhibitors (e.g., leflunomide and teriflunomide), and antifolates (e.g., methotrexate); (2) calcineurin inhibitors, such as tacrolimus, cyclosporine A, pimecrolimus, and voclosporin; (3) TNF-alpha inhibitors, such as thalidomide and lenalidomide; (4) IL-l receptor antagonists, such as anakinra; (5) mammalian target of rapamycin (mTOR) inhibitors, such as rapamycin (sirolimus), deforolimus, everolimus, temsirolimus, zotarolimus, and biolim
- Non-limiting exemplary cellular targets and their respective inhibitor compounds include, but are not limited to, complement component 5 (e.g., eculizumab); tumor necrosis factors (TNFs) (e.g., infliximab, adalimumab, certolizumab pegol, afelimomab and golimumab); IL-5 (e.g., mepolizumab); IgE (e.g., omalizumab); BAYX (e.g., nerelimomab); interferon (e.g., faralimomab); IL-6 (e.g., elsilimomab); IL-12 and IL-13 (e.g., lebrikizumab and ustekinumab); CD3 (e.g., muromonab-CD3, otelixizumab, teplizumab, visilizumab); CD4 (e.g., clen
- Natural antibodies of the recipient may be eliminated by organ perfusion, and/or transplantation of tolerance-inducing bone marrow.
- maintenance therapy includes treatment with a human anti- human CD154 mAb.
- Mycophenolate mofetil MMF
- Methylprednisolone may also be administered, beginning on the day of transplantation, tapering thereafter over the next 3-4 weeks.
- agents useful for supportive therapy include anti-inflammatory agents such as prostacyclin, dopamine, ganiclovir, levofloxacin, cimetidine, heparin, antithrombin, erythropoietin, and aspirin.
- fetal liver can also serve as an alternative to bone marrow as a source of hematopoietic stem cells.
- Each organ includes an organ specific stromal matrix that can support differentiation of the respective undifferentiated stem cells implanted into the host.
- fetal liver cells can be administered in fluid suspension.
- Bone marrow cells or another source of hematopoietic stem cells, e.g., a fetal liver suspension, of the donor can be injected into the recipient.
- Donor BMC home to appropriate sites of the recipient and grow contiguously with remaining host cells and proliferate, forming a chimeric lymphohematopoietic population.
- BMC bone marrow cells
- donor antigens e.g., fetal liver suspension
- Tolerance to the donor is also observed at the T cell level in animals in which hematopoietic stem cell, e.g., BMC, engraftment has been achieved.
- the use of xenogeneic donors allows the possibility of using bone marrow cells and organs from the same animal, or from genetically matched animals.
- Thymus transplantation is a promising approach to induce T cell tolerance for xenotransplantation. It has previously been shown that humanized mice generated with human hematopoietic stem cells (HSCs) and swine (SW) thymus grafts are tolerant to both species. However, there are still several challenges to this approach. First, T cells selected on SW MHC in pig thymus may not optimally recognize antigens presented by human MHC (HLA) in the periphery.
- HSCs human hematopoietic stem cells
- SW swine
- SW thymic epithelial cells do not display human tissue-restricted antigens (TRAs)
- TRAs tissue-restricted antigens
- thymic stromal cells were isolated by digestion of human fetal (gestational age 20 weeks) and pediatric (4 month old) thymi with liberase followed by magnetic depletion of human CD45+ cells.
- the human CD45- cells were resuspended in Matrigel and injected into freeze/thawed fetal SW thymic tissue that had been treated with 2- deoxyglucose, which suppresses glycolysis, to reduce the numbers of pig thymocytes in the fetal SW thymus ( Figures 2A-C).
- SW thymi were then implanted into irradiated NOD scid common g chain knockout (NSG) mice followed by injection of human fetal liver-derived CD34+ HSCs from the same huTEC donor or an allogeneic donor.
- NSG common g chain knockout mice
- human fetal liver-derived CD34+ HSCs from the same huTEC donor or an allogeneic donor.
- the grafted thymi were removed, sectioned and stained to detect human TECs using two-photon confocal microscopy ( Figures 1A-1D).
- thymus-derived huTECs and thymic mesenchyme cells from a l7-year-old donor were expanded on a 2D Matrigel matrix and the cells injected into fetal swine thymic tissues, followed by transplantation to humanized mice ( Figures 1E - 1H).
- HuTEC-injected SW thymi were functional and supported human thymopoiesis in humanized mice.
- Cytokeratin (CK) 14+ HLA-DR+ cells and CK8+ HLA-DR+ cells as well as CK8+ CK14+ HLA-DR+ cells were detected in hybrid thymi generated by both human fetal and pediatric donors.
- These TECs were distributed widely and admixed with pig TECs ( Figures 1A- 1D).
- l7-year-old thymus EpCAM+ TECs were expanded 5-fold in a single passage.
- Hybrid thymi that were generated with the in vitro- panded human TECs and mesenchyme cells contained human TECs ( Figures 1E- 1H).
- PBMCs were resuspended in Matrigel to prevent them from leaking out of the pig thymus after injection.
- human PBMCs were used instead of human thymic epithelial cells.
- 10 million human PBMCs were stained with CFSE (2.5 mM) as a tracing dye.
- CFSE-stained PBMCs (8 million cells) were resuspended in 140 pl Matrigel on ice with a cell concentration of 50,000 cells per pl.
- Method A Injection using Hamilton syringe while the pieces were placed inside the wells of a V-bottom 96-well plate (5-8 pl);
- Method B Injection using PE50 tubing (20 pl);
- Method C Injection using Hamilton syringe while the pieces were kept outside the well with forceps until the Matrigel is solidified (4-6 m ⁇ ).
- Matrigel is the trade name for a gelatinous protein mixture secreted by Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells produced and marketed by Corning Life Sciences and BD Biosciences.
- EHS Engelbreth-Holm-Swarm
- a hybrid thymus was generated and tested in vivo. Specifically, two vials of fetal pig thymus were thawed. After pipetting up and down to release as many thymocytes as possible, half of the pieces were treated with 100 mM 2DG for 12 hours and the other half remained untreated.
- each piece was transferred to a well of a 96-well plate containing medium with 10% human serum. As a control, some pieces were not injected with human thymic stromal cells. After 10 minutes in the incubator, the plate was transferred on ice to the mouse facility for transplantation to immunodeficient NSG mice.
- the recipient mice were previously thymectomized, so they had no native mouse thymus and the only place for thymopoiesis was the grafted thymic fragments.
- the recipient NSG mice were first irradiated (100 cG), followed by injection of human fetal liver-derived CD34+ hematopoietic stem cells (HSCs). Then, one thymic piece was transplanted under the kidney capsule of each recipient mouse.
- HSCs human fetal liver-derived CD34+ hematopoietic stem cells
- mice were bled, and the level of human immune cell reconstitution was evaluated. As shown in Figure 5, treatment of pig thymic fragments with 2DG did not affect human thymopoiesis in grafted thymi.
- mice were euthanized and the grafted thymi removed and froze in OCT.
- the slides were stained with antibodies against human HLA-DR, cytokeratin 8 (CK8, as a marker of cortical thymic epithelial cells (TECs)) and CK14 (as a marker of medullary TECs).
- CK antibodies are cross-reactive for both human and pig
- HLA-DR was used to differentiate human and pig TECs.
- the injected human TECs admixed with pig TECs were detected within the grafted thymus.
- the HLA-DR+ cells that were negative for CKs were the HSC-derived antigen-presenting cells that migrated from bone marrow to the grafted thymi.
- Example 3 Increased responsiveness to human tissue restricted antigens (TRAs) (MART-1, NYESOl and islet antigen IA-2) among human T cells that develop in a pig thymus (SW/HU mice) compared to those developing in a human thymus (HU/HU mice)
- TRAs tissue restricted antigens
- mice were generated with the same human fetal liver CD34+ HSCs and either an autologous human fetal thymus (HU/HU) or a swine fetal thymus (SW/HU). See Figure 8A.
- the native mouse thymus was removed to insure that the thymopoiesis occured only in either human or swine thymus.
- the mice were euthanized and the pooled lymph node (FN) and spleen cells were depleted of mouse CD45+ cells using MACS. The remaining cells were co-cultured with autologous HSC-derived dendritic cells loaded with different human TRA proteins to measure the T cell proliferation in response to these TRAs.
- FN pooled lymph node
- spleen cells were depleted of mouse CD45+ cells using MACS.
- human peripheral T cells in SW/HU mice showed significantly increased proliferative responses to human TRAs (IA-2, MART-l and NYESOl) presented by autologous human DCs.
- the amino acid sequence of these TRAs is significantly different between human and pig. This finding supported the lack of negative selection of human TRA- specific T cells in swine thymus and demonstrated the need for using a hybrid thymus.
- Example 4 Lower survival of human Tregs and CD8 T cells develop in a pig thymus (SW/HU mice) compared to those developing in a human thymus (HU/HU mice)
- mice generated in Example 3 were euthanized at about 24 weeks post-transplantation.
- Grafted thymi and pooled spleen and lymph nodes were harvested.
- Thymocytes, spleen and LN cells were isolated by physical force (crushing the thymus tissue between two slides and crushing the spleen and LNs through a 70pm cell strainer using a syringe plunger).
- ACK lysis buffer Gibco was used to lyse RBCs in spleen cells. Isolates cells were counted using a hemocytometer.
- the number of spleen and LN cells as well as grafted thymic cells were significantly higher in HU/HU mice compared to SW/HU mice (Ligures 9A and 9G).
- the ratios of DP (double positive CD4+ CD8+) and SP cells (single positive either SP-CD4 or SP-CD8) were similar in the grafted thymi between the HU/HU and SW/HU mice (Ligure 9B).
- a functional thymus should have a higher ratio of DP than SP cells.
- SW/HU mice had lower proportions of CD8 cells among T cells and also Tregs among CD4 cells in the periphery (spleen and lymph nodes, Ligures 9I-9K). This finding showed that both these cell subsets need to interact with the same MHC that they have been selected on for their survival. It appeared that there was a higher rate of naive to memory conversion in both CD4 and CD8 cell subsets in the periphery of SW/HU mice (Ligures 9L and 9M).
- Ki67+ proliferating
- HLA- DR+ activated
- CD45RO+ Figure 9P
- CTLA-4+ cells Figure 9Q
- hu-TECs Human fetal or pediatric thymic stromal cells
- hPSC-TEC progenitors (1- 2xl0 5 TECs) were injected into fetal pig thymus tissue (SW THY) prior to implantation under the kidney capsule of thymonectisized, immunodeficient NSG (Nod/Scid/Ilr2g-/-) mice, that had been injected intravenously with 2xl0 5 human fetal liver-derived CD34+ cells. Controls were implanted with fetal pig thymus tissue not injected with human TECs.
- the grafted thymi were removed, sectioned, and stained to detect human TECs using two-photon confocal microscopy.
- the cells were then released from the stroma and the number of cells determined by flow cytometry.
- hES-TEC l-2xl0 5 TECs
- SW THY fetal pig thymus tissue
- thymectomized immunodeficient NSG Nod/Scid/Ilr2g- /- mice
- Controls were implanted with fetal pig thymus tissue not injected with human TECs.
- Splenocytes and thymocytes from thymic grafts were analyzed by flow cytometry 18-22 weeks post-transplant.
- the thymic grafts injected with the hES-TECs had higher absolute numbers of human splenic CD3 + T cells, CD8 + T cells, CD4 + T cells, and recent thymic emmigrant CD3 l + CD4 + naive cells defined as CD45RA + CCR7 + cells in mononuclear cells of the spleen.
- thymocytes were stained for expression of HuCD45, CD19, CD14, CD4, CD8, CD45RA and CD45RO.
- the thymic grafts injected with the hES-TECs had higher numbers of total thymocytes as well as higher numbers of human CD45 cells, double positive CD4+CD8+, single positive CD4+CD8- , CD4-CD8+, and immature CD45RO+.
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Priority Applications (8)
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CA3113202A CA3113202A1 (en) | 2018-09-20 | 2019-09-19 | Hybrid thymus. methods of making, and methods of using to induce xenograft tolerance, restore immunocompetence and thymic function |
EP19862245.8A EP3853355A4 (en) | 2018-09-20 | 2019-09-19 | Hybrid thymus. methods of making, and methods of using to induce xenograft tolerance, restore immunocompetence and thymic function |
CN201980066688.4A CN113330110A (en) | 2018-09-20 | 2019-09-19 | Hybrid thymus, preparation method and use method for inducing tolerance of xenograft, and recovering immunocompetence and thymus function |
JP2021515594A JP2022501042A (en) | 2018-09-20 | 2019-09-19 | Hybrid thymus for inducing xenograft tolerance and restoring immune eligibility and thymic function, how to make and use it |
BR112021005275-5A BR112021005275A2 (en) | 2018-09-20 | 2019-09-19 | production methods and methods of using hybrid thymus to induce xenograft tolerance, restore immunocompetence and thymic function |
MX2021003308A MX2021003308A (en) | 2018-09-20 | 2019-09-19 | Hybrid thymus. methods of making, and methods of using to induce xenograft tolerance, restore immunocompetence and thymic function. |
KR1020217010702A KR20210062030A (en) | 2018-09-20 | 2019-09-19 | Hybrid thymus, methods for its preparation, and methods of use to induce xenograft resistance and restore immunocompetence and thymus function |
US17/204,147 US20210207101A1 (en) | 2018-09-20 | 2021-03-17 | Hybrid Thymus, Methods of Making, and Methods of Using to Induce Xenograft Tolerance, Restore Immunocompetence and Thymic Function |
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US201862734019P | 2018-09-20 | 2018-09-20 | |
US62/734,019 | 2018-09-20 |
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US17/204,147 Continuation US20210207101A1 (en) | 2018-09-20 | 2021-03-17 | Hybrid Thymus, Methods of Making, and Methods of Using to Induce Xenograft Tolerance, Restore Immunocompetence and Thymic Function |
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US (1) | US20210207101A1 (en) |
EP (1) | EP3853355A4 (en) |
JP (1) | JP2022501042A (en) |
KR (1) | KR20210062030A (en) |
CN (1) | CN113330110A (en) |
BR (1) | BR112021005275A2 (en) |
CA (1) | CA3113202A1 (en) |
MX (1) | MX2021003308A (en) |
WO (1) | WO2020061272A1 (en) |
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CN114653226B (en) * | 2022-04-07 | 2022-08-23 | 浙江大学 | Surface multiple modification nanofiber composite membrane for blood perfusion and preparation method thereof |
Citations (2)
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US20160010055A1 (en) * | 2013-02-27 | 2016-01-14 | The Regents Of The University Of California | Generation of Thymic Epithelial Progenitor Cells In Vitro |
WO2017192602A1 (en) * | 2016-05-02 | 2017-11-09 | Emory University | Uses of epithelial-to-mesenchymal inhibitors in generating pacemaker cells |
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US6030833A (en) * | 1995-08-04 | 2000-02-29 | The General Hospital | Transgenic swine and swine cells having human HLA genes |
JPWO2010143529A1 (en) * | 2009-06-09 | 2012-11-22 | 国立大学法人名古屋大学 | Method for inducing differentiation of pluripotent stem cells into thymic epithelium |
JP2014503217A (en) * | 2010-12-31 | 2014-02-13 | ザ トラスティーズ オブ コロンビア ユニヴァーシティ イン ザ シティ オブ ニューヨーク | Generation of autologous T cells in mice |
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- 2019-09-19 BR BR112021005275-5A patent/BR112021005275A2/en unknown
- 2019-09-19 WO PCT/US2019/051865 patent/WO2020061272A1/en unknown
- 2019-09-19 EP EP19862245.8A patent/EP3853355A4/en active Pending
- 2019-09-19 MX MX2021003308A patent/MX2021003308A/en unknown
- 2019-09-19 JP JP2021515594A patent/JP2022501042A/en active Pending
- 2019-09-19 CN CN201980066688.4A patent/CN113330110A/en active Pending
- 2019-09-19 KR KR1020217010702A patent/KR20210062030A/en active Search and Examination
- 2019-09-19 CA CA3113202A patent/CA3113202A1/en active Pending
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Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US20160010055A1 (en) * | 2013-02-27 | 2016-01-14 | The Regents Of The University Of California | Generation of Thymic Epithelial Progenitor Cells In Vitro |
WO2017192602A1 (en) * | 2016-05-02 | 2017-11-09 | Emory University | Uses of epithelial-to-mesenchymal inhibitors in generating pacemaker cells |
Non-Patent Citations (4)
Title |
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KAZUHIKO YAMADA, MEGAN SYKES, DAVID H. SACHS: "Tolerance in Xenotransplantation", CURRENT OPINION IN ORGAN TRANSPLANTATION, vol. 22, no. 6, December 2017 (2017-12-01), pages 522 - 528, XP055695011, ISSN: 1087-2418, DOI: 10.1097/MOT.0000000000000466 * |
PENDINO KIMBERLY J, CHEPENIK K P, SCHMIDT R R: "Differential eicosanoid synthesis by murine fetal thymic non-lymphoid cells", IMMUNOLOGY AND CELL BIOLOGY, vol. 70, no. 4, 1 August 1992 (1992-08-01), pages 237 - 252, XP055791286, DOI: 10.1038/icb.1992.31 * |
See also references of EP3853355A4 * |
YASUHIRO FUDABA, ONOE TAKASHI, CHITTENDEN MEREDITH, SHIMIZU AKIRA, SHAFFER JUANITA M, BRONSON RODERICK, SYKES MEGAN: "Abnormal regulatory and effector T cell function predispose to autoimmunity following xenogeneic thymic transplantation", JOURNAL OF IMMUNOLOGY, vol. 181, no. 11, 1 December 2008 (2008-12-01), pages 1 - 22, XP055695010 * |
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Publication number | Publication date |
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EP3853355A1 (en) | 2021-07-28 |
US20210207101A1 (en) | 2021-07-08 |
KR20210062030A (en) | 2021-05-28 |
CN113330110A (en) | 2021-08-31 |
BR112021005275A2 (en) | 2021-06-15 |
MX2021003308A (en) | 2021-05-13 |
JP2022501042A (en) | 2022-01-06 |
CA3113202A1 (en) | 2020-03-26 |
EP3853355A4 (en) | 2022-07-27 |
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