Human MSC suppression correlates with cytokine induction of indoleamine 2,3-dioxygenase and bystander M2 macrophage differentiation

Clinical trials testing the use of either autologous or allogeneic human bone marrow-derived mesenchymal stromal cells (MSC) as a cell-based pharmaceutical for suppression of autoimmune and alloimmune ailments are underway. Reported results from completed trials vary in effectiveness within and between studies without any clear mechanistic explanation. We propose that these discrepancies may arise from intrinsic variability in the immunosuppressive potential of each MSC donor source. Here, we demonstrate that tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)-activated MSC derived from normal adult volunteers suppress T cell proliferation in vitro in a variegated manner, an observation linked to IFN-mediated indoleamine 2,3-dioxygenase (IDO) upregulation. We also demonstrate that MSC IDO activity is implicated in the differentiation of monocytes into interleukin (IL)-10-secreting M2 immunosuppressive macrophages (CD14(+)/CD206(+)). Those monocyte-derived M2 are in turn implicated in the suppression of T cell proliferation in an IL-10-independent manner, thus amplifying the immunosuppressive effect generated by MSC. In summary, the immune plasticity of IFN-γ and TNF-α licensed veto function of MSC vary among donors and defines a central role to inducible IDO activity and its bystander effect on lymphomyeloid immune effectors.     

CD40Ig treatment results in allograft acceptance mediated by CD8CD45RC T cells, IFN-gamma, and indoleamine 2,3-dioxygenase

Treatment with CD40Ig results in indefinite allograft survival in a complete MHC-mismatched heart allograft model in the rat. Here we show that serial second, third, and fourth adoptive transfers of total splenocytes from CD40Ig-treated recipients into secondary recipients led to indefinite donor-specific allograft acceptance. Purification of splenocyte subpopulations from CD40Ig-treated recipients demonstrated that only the adoptively transferred CD8(+)CD45RC(low) subset resulted in donor-specific long-term survival, whereas CD8(+)CD45RC(low) T cells from naive animals did not. Accepted grafts displayed increased indoleamine 2,3-dioxygenase (IDO) expression restricted in the graft to ECs. Coculture of donor ECs with CD8(+)CD45RC(low) T cells purified from CD40Ig-treated animals resulted in donor-specific IDO expression dependent on IFN-gamma. Neutralization of IFN-gamma or IDO triggered acute allograft rejection in both CD40Ig-treated and adoptively transferred recipients. This study demonstrates for what we believe to be the first time that interference in CD40-CD40 ligand (CD40-CD40L) interactions induces allospecific CD8(+) Tregs that maintain allograft survival. CD8(+)CD45RC(low) T cells act through IFN-gamma production, which in turn induces IDO expression by graft ECs. Thus, donor alloantigen-specific CD8(+) Tregs may promote local graft immune privilege through IDO expression.     

Thermosensitive hydrogel PEG-PLGA-PEG enhances engraftment of muscle-derived stem cells and promotes healing in diabetic wound.

Regenerating new tissue using cell transplantation has relied on successful cell engraftment in the host; however, cell engraftment into the diabetic skin wound is not as successful as in many other tissues. We used a biodegradable and biocompatible triblock co-polymer poly(ethylene glycol-b-[DL-lactic acid-co-glycolic acid]-b-ethylene glycol) (PEG-PLGA-PEG), which forms a thermosensitive hydrogel, as a wound dressing and scaffold. We found that the thermosensitive hydrogel increased the engraftment of muscle-derived stem cells (MDSCs) by 20- to 30-fold until day 20, when the wound was completely closed in a db/db genetically diabetic mouse model. At day 9, 30% of the transplanted MDSCs were found to remain, and 15% remained at day 20 after transplantation. The increased engraftment resulted in enhanced wound healing, as indicated by the wound closure rate, epithelium migration, and collagen deposition. Using MDSCs stably expressing beta-gal and immunofluorescence, we found that 25% of MDSCs differentiated into fibroblasts, 10% into myofibroblasts, and 10% into endothelial cells. We conclude that using the thermosensitive hydrogel as a scaffold increased the engraftment of MDSCs, which leads to improved diabetic wound healing, possibly by retaining the cells at the wound site for longer.     

Amniotic epithelial cells promote wound healing in mice through high epithelialization and engraftment

Although human amniotic epithelial cells (AMEs) are an attractive source of stem cells, their therapeutic potential in wound healing has not been fully investigated. We evaluated the therapeutic potential of AMEs for wound healing. Real‐time PCR showed that the epithelialization growth factors epidermal growth factor (EGF), platelet‐derived growth factor (PDGF)‐B and chemotactic factors interleukin‐8 (IL‐8 or CXCL8) and neutrophil‐activating protein‐2 (NAP‐2 or CXCL7) were upregulated in AMEs compared with adipose‐derived mesenchymal stem cells (ADMs). In vitro scratch wound assays revealed that AME‐derived conditioned medium substantially accelerated wound closure. Wounds in NOD/SCID mice were created by skin excision, followed by AME transplantation. AMEs implantation significantly accelerated wound healing and increased cellularity and re‐epithelialization. Transplanted AMEs exhibited high engraftment rates and expressed keratinocyte‐specific proteins and cytokeratin in the wound area, suggesting direct benefits for cutaneous closure. Taken together, these data indicate that AMEs possess therapeutic capability for wound healing through the secretion of epithelialization growth factors and enhanced engraftment properties. Copyright © 2015 John Wiley & Sons, Ltd.     

Comparison of advanced therapy medicinal product gingiva and skin substitutes and their in vitro wound healing potentials

Skin and oral mucosa substitutes are a therapeutic option for closing hard‐to‐heal skin and oral wounds. Our aim was to develop bi‐layered skin and gingiva substitutes, from 3 mm diameter biopsies, cultured under identical conditions, which are compliant with current European regulations for advanced therapy medicinal products. We present in vitro mode of action methods to (i) determine viability: epithelial expansion, proliferation (Ki‐67), metabolic activity (MTT assay); (ii) characterize skin and gingiva substitutes: histology and immunohistochemistry; and (iii) determine potency: soluble wound healing mediator release (enzyme‐linked immunosorbent assay). Both skin and gingiva substitutes consist of metabolically active autologous reconstructed differentiated epithelium expanding from the original biopsy sheet on a fibroblast populated connective tissue matrix (donor dermis). Gingival epithelium expanded 1.7‐fold more than skin epithelium during the 3 week culture period. The percentage of proliferating Ki‐67‐positive cells located in the basal layer of the gingiva substitute was >1.5‐fold higher than in the skin substitute. Keratins 16 and 17, which are upregulated during normal wound healing, were expressed in both the skin and gingiva substitutes. Notably, the gingiva substitute secreted higher amounts of key cytokines involved in mitogenesis, motogenesis and chemotaxis (interleukin‐6 > 23‐fold, CXCL8 > 2.5‐fold) as well as higher amounts of the anti‐fibrotic growth factor, hepatocyte growth factor (>7‐fold), compared with the skin substitute. In conclusion, while addressing the viability, characterization and potency of the tissue substitutes, important intrinsic differences between skin and gingiva were discovered that may explain in part the superior quality of wound healing observed in the oral mucosa compared with skin.     

Virus-specific CD8+ T cells accumulate near sensory nerve endings in genital skin during subclinical HSV-2 reactivation

Cytotoxic CD8(+) T cells play a critical role in controlling herpes simplex virus (HSV) infection and reactivation. However, little is known about the spatiotemporal dynamics of CD8(+) T cells during HSV lesion evolution or about their involvement in immune surveillance after lesion resolution. Using quantum dot-conjugated peptide-major histocompatibility complex multimers, we investigated the in vivo localization of HSV-2-specific CD8(+) T cells in sequential biopsies of human genital skin during acute, resolving, and healed stages of HSV-2 reactivation. Our studies revealed that functionally active CD8(+) T cells selectively infiltrated to the site of viral reactivation. After lesion healing in concert with complete reepithelialization and loss of HSV DNA from skin biopsies, HSV-2-specific CD8(+) T cells persisted for more than two months at the dermal-epidermal junction, adjacent to peripheral nerve endings. In two out of the six sequentially studied individuals, HSV-2 DNA reappeared in clinically and histologically normal-appearing skin. Detection of viral DNA was accompanied by increased numbers of both HSV-specific and total CD8(+) T cells in the dermis. These findings indicate that the frequency and clinical course of HSV-2 reactivation in humans is influenced by virus-specific CD8(+) T cells that persist in peripheral mucosa and genital skin after resolution of herpes lesions.     

CD4^＋CD25^＋调节性T细胞在特发性血小板减少性紫癜发病中的研究新进展

CD4^＋CD25^＋调节性T细胞是一群具有免疫抑制功能的T细胞亚群，在小鼠和健康人体中约占外周CD4^＋T细胞的5％-10％，占人体外周单个核细胞的1％-2％，其通过多种途径对免疫反应具有抑制效应，能维持内环境的稳定。特发性血小板减少性紫癜（idiopathic thrombocytopcnic purpura，ITP）是一种自身免疫性疾病，以皮肤、黏膜或内脏出血为主要表现。近年来研究发现，CD4^＋CD25^＋调节性T细胞与ITP的发病有一定的联系，本文对CD4^＋CD25^＋调节性T细胞的特征和作用，特发性血小板减少性紫癜发病机制及CD4^＋CD25^＋调节性T细胞在特发性血小板减少性紫癜发病中的作用等的研究新进展作一综述。     

Reduced wound contraction after grafting of full-thickness burns with a collagen and chondroitin-6-sulfate (GAG) dermal skin substitute and coverage with biobrane

Full-thickness burns destroy both the epidermal and dermal tissues of the skin. This study evaluates a collagen and chondroitin-6-sulfate dermal skin substitute (graft) that was applied to excised full-thickness burns and covered with Biobrane. Experimental conditions included: (a) no burn, subcutaneous implantation of the graft; (b) burn, excision, graft, coverage with Biobrane and bandages; (c) burn, excision, no graft, coverage with Biobrane and bandages; (d) burn only. forty-one days post-surgery, subcutaneous implantation (N = 3) of the graft caused no detectable contraction or necrosis of the overlying skin, whereas all burn wounds contracted. Measurements of wounds (percentage of original wound size) showed statistically significant differences between the following treatments; (a) graft plus Biobrane (N = 10), 34%; (b) no graft plus Biobrane (N = 9), 25%; (c) untreated burns (N = 6), 16%. Semi-quantitative evaluation of time to healing indicated by spontaneous detachment of Biobrane from wounds showed that grafted, excised wounds healed in an average of 2.7 weeks, while ungrafted, excised wounds required an average of 4.3 weeks to heal. Histological appearance of healed wounds after grafting and coverage with Biobrane resembles undamaged skin without epidermal adnexal structures. Excision of full-thickness burn eschar, followed by grafting with a collagen and chondroitin-6-sulfate dermal skin substitute and coverage with Biobrane provides reduced wound contraction within a six-week period of observation compared to non-excised wounds. Both more rapid and more complete wound healing took place compared to excised wounds that were not grafted.     

Functional assessment of the engraftment potential of gammaretrovirus-modified CD34+ cells, using a short serum-free transduction protocol

The successful transduction and engraftment of human mobilized peripheral blood (MBP) CD34(+) cells are determined to a large extent by the ex vivo cell-processing conditions. In preparation for upcoming clinical trials, we investigated essential culture parameters and devised a short and efficient gammaretroviral transduction protocol entailing minimal manipulation of MBP CD34(+) cells. The engraftment potential and in vivo transgene expression in the progeny of repopulating CD34(+) cells were measured to assess the functionality of CD34(+) cells transduced under these conditions. Using a competitive in vivo repopulation assay in nonobese diabetic/severe combined immunodeficient mice, we demonstrate equivalent engraftment of CD34(+) cells transduced under serum-free conditions as compared with CD34(+) cells cultured with serum. We also took advantage of this in vivo model to demonstrate that ex vivo manipulation of CD34(+) cells can be shortened to 60 hr, using 36 hr of prestimulation and two cycles of transduction 12 hr apart. These minimally manipulated CD34(+) cells engraft in a manner similar to cells transduced under longer protocols and the vector-encoded transgene is expressed at the same frequency in cells derived from repopulating CD34(+) cells in vivo. We have thus developed a short and efficient human MBP CD34(+) transduction protocol under serum-free conditions that is suitable and broadly applicable for phase I clinical trials.     

Temporary skin transplantation for the treatment of extensive burns

Survival of the extensively burned patient depends upon rapid excision of necrotic tissue, and skin grafting to obtain wound closure. When a sufficient supply of autogenous skin is not available to provide wound coverage, allograft skin has been successfully substituted. Although burn patients have been noted to be immunologically hyporesponsive, their immune response to skin allografts has necessitated the administration of immunosuppressive therapy, to assure the retention of the allografts until sufficient autogenous skin can be utilized. The temporary transplantation of skin allografts has proved successful in the treatment of extensively burned children.     

Correlation of time to platelet engraftment with amount of transplanted CD34+CD41+ cells after allogeneic bone marrow transplantation

A major problem after autologous or allogeneic stem cell transplantation is prolonged thrombocytopenia. There are several studies published about correlations of the composition of the graft and time to platelet engraftment for autologous transplantation but only a few studies for allogeneic transplantation. In our study, we wanted to find out whether the correlation between the time to platelet engraftment and amount of transplanted CD34(+)CD41(+) cells described previously after autologous peripheral blood stem cell transplantation could be reproduced in the allogeneic bone marrow transplantation setting. We found correlations not only for the number of transplanted CD34(+) cells with the time to leukocyte engraftment (r = -0.32, p = 0.045) but also for the number of transplanted CD34(+)CD41(+) cells and time to platelet engraftment (r = -0.34, p = 0.038), which were both statistically significant. A significant correlation between transplanted CD34(+) cells versus platelet engraftment and transplanted CD34(+)CD41(+) cells versus leukocyte engraftment was not found. The finding that the amount of committed megakaryocyte progenitor cells in the graft is an important predictive factor for platelet engraftment after allogeneic bone marrow transplantation might be the base for future studies of ex vivo expansion of clonable megakaryocyte precursors.     

Resident CD141 (BDCA3)+ dendritic cells in human skin produce IL-10 and induce regulatory T cells that suppress skin inflammation

Human skin immune homeostasis, and its regulation by specialized subsets of tissue-residing immune sentinels, is poorly understood. In this study, we identify an immunoregulatory tissue-resident dendritic cell (DC) in the dermis of human skin that is characterized by surface expression of CD141, CD14, and constitutive IL-10 secretion (CD141(+) DDCs). CD141(+) DDCs possess lymph node migratory capacity, induce T cell hyporesponsiveness, cross-present self-antigens to autoreactive T cells, and induce potent regulatory T cells that inhibit skin inflammation. Vitamin D(3) (VitD3) promotes certain phenotypic and functional properties of tissue-resident CD141(+) DDCs from human blood DCs. These CD141(+) DDC-like cells can be generated in vitro and, once transferred in vivo, have the capacity to inhibit xeno-graft versus host disease and tumor alloimmunity. These findings suggest that CD141(+) DDCs play an essential role in the maintenance of skin homeostasis and in the regulation of both systemic and tumor alloimmunity. Finally, VitD3-induced CD141(+) DDC-like cells have potential clinical use for their capacity to induce immune tolerance.     

Tryptophan-derived catabolites are responsible for inhibition of T and natural killer cell proliferation induced by indoleamine 2,3-dioxygenase

Macrophages exposed to macrophage colony-stimulating factor acquire the capacity to suppress T cell proliferation; this effect is associated with de novo expression of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO). We have purified IDO and tested its activity in in vitro models of T cell activation. IDO was able to inhibit proliferation of CD4(+) T lymphocytes, CD8(+) T lymphocytes, and natural killer (NK) cells; proliferation of B lymphocytes was not affected. The inhibitory role of tryptophan and of its catabolites was then tested. In the presence of tryptophan, only L-kynurenine and picolinic acid inhibit cell proliferation. In a tryptophan-free medium cell proliferation was not affected. In the absence of tryptophan inhibition induced by L-kynurenine and picolinic acid was observed at concentrations below the lowest concentration that was effective in the presence of tryptophan, and quinolinic acid acquired some inhibitory capacity. Inhibition of cell proliferation induced by the tryptophan catabolites resulting from IDO activity was selective, applying only to cells undergoing activation. Resting cells were not affected and could subsequently activate normally. We suggest that IDO exerts its effect on cell proliferation by (i) starting the cascade of biochemical reactions that produce the three catabolites and by (ii) enhancing their inhibitory potential by depriving the extracellular microenvironment of tryptophan.     

Skin coverage with Biobrane biomaterial for the treatment of patients with toxic epidermal necrolysis.

Toxic epidermal necrolysis (TEN) is an exfoliative skin disorder that may involve a large body surface area and mucosal surfaces. The microscopic changes that occur with this condition are similar to those that occur with superficial dermal burns, such as dermal detachment from the underlying dermis. Complications of TEN are related to the loss of the epithelial skin barrier and include pain, fluid and electrolyte loss, and an increased risk of sepsis. The treatment of a patient with TEN is best accomplished in a burn unit, where expert treatment of these complications can be provided. Medical treatment includes the administration of immunosuppressive therapy and the discontinuation of any previous corticosteroid treatment. Surgical management includes the debridement of necrotic areas. In this article, the surgical management of 8 consecutive patients with TEN who were admitted to the intensive care burn unit at the Hospital Universitario de Getafe in Madrid, Spain, from 1996 to 1998 is described. These patients were treated with extensive early debridement of necrotic skin areas followed by wound coverage with Biobrane (Dow B. Hickam, Inc, Sugarland, Tex), a temporary semisynthetic skin substitute. Skin coverage with this material decreases pain and fluid loss, and it possibly facilitates epithelization and decreases the risk of sepsis, without adverse side effects. This semisynthetic material meets some standards of an ideal skin substitute: it is easy to use, provides several beneficial physiologic effects, and improves patients' comfort. In the 8 cases of patients with TEN that were studied, the use of Biobrane skin substitute for the coverage of massive areas of detached skin was found to be an important aspect of treatment.     

NK细胞对小鼠异基因骨髓移植造血及免疫重建的影响

目的　研究自然杀伤 (NK)细胞在小鼠异基因骨髓移植 (allo BMT)中对造血及免疫重建的影响。方法　以近交系小鼠C5 7BL/ 6 (H 2 b)为供鼠、BALB/c(H 2 d)为受鼠 ,在allo BMT同时输入供鼠外周T细胞和 (或 )NK细胞 ,计数受鼠移植后不同时间的白细胞数 ;用流式细胞仪检测骨髓CD34 细胞和外周淋巴细胞中CD3 和CD19 细胞及表达供鼠基因的H 2Kb 细胞百分率 ,比较不同移植组存活率、植入水平、造血及免疫重建等。结果　输入供鼠外周NK细胞移植组与不输入NK细胞组比较 ,存活率显著增高 (6 0d存活率为 70 %vs 0 % ) ;白细胞计数、CD19 细胞及骨髓CD34 细胞计数恢复快 ;H 2Kb 细胞表达水平高 (86 .6 8± 4 .4 5vs 4 .6 8± 0 .32 )。移植后第 2 8天 ( 2 8天 )输入NK细胞组CD3 细胞水平 [(33.6 9± 3.36 ) % ]低于未输入NK细胞组 [(5 0 .4 0± 5 .0 6 ) % ](P <0 .0 1) ,在 6 0天两组比较差异无显著性 (P >0 .0 5 )。结论　在小鼠allo BMT中 ,同种异基因反应性NK细胞可以提高造血干细胞的植入水平、促进造血及免疫重建、增高移植受鼠的生存率。     

Uncoupling of proliferative potential and gain of effector function by CD8(+) T cells responding to self-antigens

Professional antigen-presenting cells (APCs) are capable of transporting self-antigens from peripheral tissues to secondary lymphoid organs where they are presented to potentially autoreactive CD8(+) T cells. In the absence of an inflammatory response, this results in immune tolerance. The presence of activated, antigen-specific CD4(+) T cells converts this tolerogenic encounter into an immunogenic one by promoting extensive proliferation of CD8(+) T cells and their development into effectors. Surprisingly, activation of APCs with an agonistic antibody specific for CD40 could not substitute for CD4(+) help in this task. Anti-CD40 induced recruitment of dendritic cells expressing high levels of B7 costimulatory molecules into the lymph nodes, which in turn, greatly enhanced activation and expansion of CD8(+) T cells. However, these activated CD8(+) cells did not demonstrate effector function. We conclude that proliferative potential and gain of effector function are separable events in the differentiation program of CD8(+) T cells.     

Recent developments in the regulation of peripheral blood stem cell mobilization and engraftment by cytokines, chemokines, and adhesion molecules

Peripheral blood stem cells (PBSC) have become the preferred source of stem cells for autologous transplantation because of the technical advantage and the shorter time to engraftment. Administration of hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) results in mobilization of PBSCs into the peripheral blood. G-CSF and GM-CSF differ somewhat in the number and composition of CD34(+) cells and effector cells mobilized to the peripheral blood; however, the molecular mechanism underlying the release and engraftment of CD34(+) cells by these growth factors is poorly understood. This review provides a recent update on the involvement of hematopoietic growth factors, chemokines, adhesion molecules, and chemokine receptors in the regulation of stem cell release and engraftment. The involvement of very late antigen-4 (VLA-4), VLA-5, leukocyte function associated-1 molecule (LFA-1), and L-selectin and their receptors CXCR4 and its ligand SDF-1 will be discussed, and cross talk between these factors will also be reviewed in the context of stem cell release and engraftment. Finally, PBSC mobilization by chemokines will be reviewed in relation to hematopoietic growth factors.     

深低温冻存同种异体皮肤移植中转化生长因子β的表达

背景：皮肤移植和创面覆盖是创伤、烧伤治疗的重要措施。目前,同种异体皮仍然是可利用的最佳创面覆盖物。目的：通过检测转化生长因子β在深低温冻存后的大鼠同种异体皮肤移植后的表达,评估深低温贮存同种异体皮在创面上的应用。方法：取大鼠皮肤保存于低温-20℃（低温保存组）及80℃深低温（深低温保存组）,冻存1周、1,2个月后,皮片分组移植于同种大鼠背部进行实验,并以自体移植大鼠作为对照组。结果与结论：同低温保存组相比,深低温保存组转化生长因子β的表达被抑制,移植皮肤排斥反应出现时间延迟及存活时间延长,排斥反应评分也较低。同低温冻存相比,深低温冷冻保存能使同种异体移植物的转化生长因子β抗原表达降低。提示深低温冻存的异体皮作为一种创面临时覆盖物,在存在皮肤组织缺失或皮源不足的情况下具有广阔的应用前景。     

Role of Vernix caseosa in the neonate: potential application in the adult population

Vernix caseosa is a naturally occurring fetal barrier film produced in late pregnancy as a result of sebaceous and epidermal lipids combined with desquamation of maturing fetal corneocytes. Vernix lacks desmosomal interconnections between corneocytes as demonstrated in adult stratum corneum and is, therefore, referred to as a "mobile phase" stratum corneum. Vernix is proposed to have multiple fetal/newborn overlapping biological functions: moisturization, anti-infective, antioxidant, wound healing, and waterproofing. Patients with altered skin integrity due to burn injuries lack the protective qualities necessary for wound healing. Emerging research suggests that Vernix applied to skin cultures may enhance wound healing. Application of the fetal/neonatal skin science findings to the adult burn population offers the potential for a clinically relevant homologous substitute for impaired tissue integrity.     

人Stro-1~+间充质干细胞诱导小鼠皮肤移植免疫耐受的初步研究

本研究探讨人间充质干细胞(MSC)及其Stro-1+MSC亚群对小鼠皮肤移植模型的诱导移植免疫耐受作用。从健康成人骨髓单个核细胞中培养MSC,并筛选Stro-1+MSC。建立小鼠同种异体皮肤移植模型,供体为雌性C57BL/6小鼠,获取皮片,移植给受体雌性BALB/c小鼠。动物分为4组:①Stro-1+MSC组:照射受鼠移植前输注2×106Stro-1+MSC;②MSC组:照射受鼠移植前输注2×106MSC;③照射对照组:受鼠照射后直接进行皮肤移植;④同系对照组:BALB/c小鼠照射后接受同系小鼠皮肤移植。检测项目包括:移植皮片存活时间,HE染色观察移植皮片病理改变,ELISA检测移植前后受鼠血浆转化生长因子β1(TGF-β1)浓度的变化。结果显示:MSC组皮肤移植物存活时间为(12.13±3.34)d,较照射对照组(11.38±1.01)d未见明显延长(P>0.05);Stro-1+MSC组皮肤移植物存活时间为(30.68±5.89)d,较照射对照组及MSC组明显延长(P<0.05),移植皮肤病理检查显示皮片结构清晰。在同系对照组和照射对照组,移植前后受鼠血浆中TGF-β1浓度无显著变化,而在MSC组和Stro-1+MSC组移植后TGF-β1浓度均有显著增高(P<0.05)。结论:Stro-1+MSC较未分选的MSC具有更强的诱导移植免疫耐受的功能,在体内可显著延长小鼠皮片的存活时间,而这种作用似与TGF-β1的表达无关。