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1.
P. H. Lemaître K. A. Field O. Leo A. Le Moine 《American journal of transplantation》2012,12(9):2313-2321
Allograft acceptance and tolerance can be achieved by different approaches including inhibition of effector T cell responses through CD28‐dependent costimulatory blockade and induction of peripheral regulatory T cells (Tregs). The observation that Tregs rely upon CD28‐dependent signals for development and peripheral expansion, raises the intriguing possibility of a counterproductive consequence of CTLA4‐Ig administration on tolerance induction. We have investigated the possible negative effect of CTLA4‐Ig on Treg‐mediated tolerance induction using a mouse model of single MHC class II‐mismatched skin grafts in which long‐term acceptance was achieved by short‐term administration of IL‐2/anti‐IL‐2 complex. CTLA4‐Ig treatment was found to abolish Treg‐dependent acceptance in this model, restoring skin allograft rejection and Th1 alloreactivity. CTLA4‐Ig inhibited IL‐2‐driven Treg expansion, and prevented in particular the occurrence of ICOS+ Tregs endowed with potent suppressive capacities. Restoring CD28 signaling was sufficient to counteract the deleterious effect of CTLA4‐Ig on Treg expansion and functionality, in keeping with the hypothesis that costimulatory blockade inhibits Treg expansion and function by limiting the delivery of essential CD28‐dependent signals. Inhibition of regulatory T cell function should therefore be taken into account when designing tolerance protocols based on costimulatory blockade. 相似文献
2.
J. Yang L.V. Riella O. Boenisch J. Popoola S. Robles T. Watanabe V. Vanguri X. Yuan I. Guleria L. A. Turka M. H. Sayegh A. Chandraker 《American journal of transplantation》2009,9(12):2837-2844
Blockade of the B7: CD28 costimulatory pathway has emerged as a promising therapy to prevent allograft rejection. However, this pathway has also been demonstrated to be important for the generation and maintenance of regulatory T cells. In this study, we investigated the role of the B7: CD28 pathway in the ‘bm12 into B6’ MHC class II‐mismatched vascularized cardiac transplant model of chronic rejection. Allograft rejection was remarkably accelerated in B6 background B7DKO and CD28KO recipients compared with B6 wild‐type (WT) recipients. Allograft rejection was associated with a significantly enhanced Th1/Th2 alloreactivity and marked reduction in the ratio of regulatory T cells to CD4+ effector/memory cells. We noted that administration of anti‐B7‐1 and anti‐B7‐2 mAb prior to transplantation also accelerated allograft rejection. Furthermore, depleting CD25+ cells in B6 WT recipients of bm12 hearts prior to transplant also precipitated rejection at a similar rate. Neither B7/CD28 deficiency nor CD25 depletion affected graft survival in single MHC class I‐mismatched (bm1 into B6) recipients. This study highlights the paradoxical functions of B7: CD28 costimulation in a MHC class II‐mismatched model, in which the B7: CD28 pathway is demonstrated to be important in preventing rejection through the generation and maintenance of Tregs. 相似文献
3.
K. Yamaura T. Watanabe O. Boenisch M. Yeung S. Yang C. N. Magee R. Padera S. Datta T. Schatton Y. Kamimura M. Azuma N. Najafian 《American journal of transplantation》2010,10(10):2355-2362
B7 ligands deliver both costimulatory and coinhibitory signals to the CD28 family of receptors on T lymphocytes, the balance between which determines the ultimate immune response. Although B7‐H4, a recently discovered member of the B7 family, is known to negatively regulate T cell immunity in autoimmunity and cancer, its role in solid organ allograft rejection and tolerance has not been established. Targeting the B7‐H4 molecule by a blocking antibody or use of B7‐H4?/? mice as recipients of fully MHC‐mismatched cardiac allografts did not affect graft survival. However, B7‐H4 blockade resulted in accelerated allograft rejection in CD28‐deficient recipients. B7‐1/B7‐2‐double‐deficient recipients are truly independent of CD28/CTLA‐4:B7 signals and usually accept MHC‐mismatched heart allografts. Blockade of B7‐H4 in these mice also precipitated rejection, demonstrating regulatory function of this molecule independent of an intact CD28/CTLA‐4:B7 costimulatory pathway. Accelerated allograft rejection was always accompanied by increased frequencies of alloreactive IFN‐γ‐, IL‐4‐ and Granzyme B‐producing splenocytes. Finally, intact recipient, but not donor, B7‐H4 is essential for prolongation of allograft survival by blocking CD28/CTLA4:B7 pathway using CTLA4‐Ig. These data are the first to provide evidence of the regulatory effects of B7‐H4 in alloimmune responses in a murine model of solid organ transplantation. 相似文献
4.
Christoph Schwarz Benedikt Mahr Moritz Muckenhuber Anna Marianne Weijler Lukas Walter Unger Nina Pilat Michaela Latus Heinz Regele Thomas Wekerle 《American journal of transplantation》2021,21(11):3765-3774
CTLA4Ig has been shown to improve kidney allograft function, but an increased frequency of early rejection episodes poses a major obstacle for more widespread clinical use. The deleterious effect of CTLA4Ig on Treg numbers provides a possible explanation for graft injury. Therefore, we aimed at improving CTLA4Ig's efficacy by therapeutically increasing the number of Tregs. Murine cardiac allograft transplantation (BALB/c to B6) was performed under CTLA4Ig therapy modeled after the clinically approved dosing regimen and Tregs were transferred early or late after transplant. Neither early nor late Treg transfer prolonged allograft survival. Transferred Tregs were traceable in various lymphoid compartments but only modestly increased overall Treg numbers. Next, we augmented Treg numbers in vivo by means of IL2 complexes. A short course of IL2/anti-IL2-complexes administered before transplantation reversed the CTLA4Ig-mediated decline in Tregs. Of note, the addition of IL2/anti-IL2-complexes to CTLA4Ig therapy substantially prolonged heart allograft survival and significantly improved graft histology on day 100. The depletion of Tregs abrogated this effect and resulted in a significantly diminished allograft survival. The increase in Treg numbers upon IL2 treatment was associated with a decreased expression of B7 on dendritic cells. These results demonstrate that therapy with IL2 complexes improves the efficacy of CTLA4Ig by counterbalancing its unfavorable effect on Tregs. 相似文献
5.
A Pilot Trial Targeting the ICOS–ICOS‐L Pathway in Nonhuman Primate Kidney Transplantation
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D. J. Lo D. J. Anderson M. Song F. Leopardi A. B. Farris E. Strobert S. Chapin B. Devens E. Karrer A. D. Kirk 《American journal of transplantation》2015,15(4):984-992
6.
Expression of a Chimeric Antigen Receptor Specific for Donor HLA Class I Enhances the Potency of Human Regulatory T Cells in Preventing Human Skin Transplant Rejection
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D. A. Boardman C. Philippeos G. O. Fruhwirth M. A. A. Ibrahim R. F. Hannen D. Cooper F. M. Marelli‐Berg F. M. Watt G. Lombardi 《American journal of transplantation》2017,17(4):931-943
Regulatory T cell (Treg) therapy using recipient‐derived Tregs expanded ex vivo is currently being investigated clinically by us and others as a means of reducing allograft rejection following organ transplantation. Data from animal models has demonstrated that adoptive transfer of allospecific Tregs offers greater protection from graft rejection compared to polyclonal Tregs. Chimeric antigen receptors (CAR) are clinically translatable synthetic fusion proteins that can redirect the specificity of T cells toward designated antigens. We used CAR technology to redirect human polyclonal Tregs toward donor‐MHC class I molecules, which are ubiquitously expressed in allografts. Two novel HLA‐A2‐specific CARs were engineered: one comprising a CD28‐CD3ζ signaling domain (CAR) and one lacking an intracellular signaling domain (ΔCAR). CAR Tregs were specifically activated and significantly more suppressive than polyclonal or ΔCAR Tregs in the presence of HLA‐A2, without eliciting cytotoxic activity. Furthermore, CAR and ΔCAR Tregs preferentially transmigrated across HLA‐A2‐expressing endothelial cell monolayers. In a human skin xenograft transplant model, adoptive transfer of CAR Tregs alleviated the alloimmune‐mediated skin injury caused by transferring allogeneic peripheral blood mononuclear cells more effectively than polyclonal Tregs. Our results demonstrated that the use of CAR technology is a clinically applicable refinement of Treg therapy for organ transplantation. 相似文献
7.
目的 观察CD4+CD25+T细胞(Treg)对小鼠同种异体心脏移植的免疫调节作用.方法 流式细胞仪检测正常小鼠和胸腺切除+PC61小鼠淋巴结、脾脏和外周血的Treg的比例.将供体鼠BALB/C心脏移植到受体鼠B6腹腔内,观察对照组(n=6)、胸腺切除组(THY,n=8)、hCTLA4Ig组(n=8)、DST+hCTLA4Ig组(n=8)和THY+PC61+DST+hCTLA4Ig组(n=6)小鼠心脏移植后生存时间和移植心脏病理学检查.结果 正常B6小鼠淋巴结、脾脏和外周血的Treg的比例分别为5.1%、4.5%和1. 7%,明显高于胸腺切除+PC61处理组(1. 8%、1.7%、0.7%).移植心脏平均存活时间在对照组和胸腺切除组分别为(8.2±2.9)d和(7.6±3.0)d,两组间差异无统计学意义(P>0.05);而在hCTLA4Ig组和DST+hCTLA4Ig组分别为(43.0±11.8)d和(135.0±29.7)d,均较对照组或胸腺切除组明显延长(P<0.01);THY+PC61+DST+hCTLA4Ig组移植心脏平均存活时间(25.8±8.9)d,也明显较对照组明显延长,但短于hCTLA4Ig组和DST+hCTLA4Ig组(P<0.01).DST+hCTLA4Ig组移植的心脏存活时间(135.0±29.7)d明显高于其他各组(P<0.01),其病理组织学表现为间质内有较多的淋巴细胞浸润,伴毛细血管增生,管壁增厚,间质纤维化.结论 CD4+CD25+T细胞水平对同种异体心脏移植的免疫耐受具有免疫调节作用.Abstract: Objective To investigate the immunoregulation effects of CD4 + CD25 + T cells in mice heart allograft transplantation. Methods Flow cytometry was used to analyze the contents of CD4 + CD25 +T regulatory cells (Tregs) of the lymph nodes, spleen and blood in the normal mice group and the thymusectomy (THY) + PC61 group. BALB/C mice served as the donors and C57BL/6 (B6) mice as the recipients. Five groups were established, including control group ( n = 6 ), THY group ( n = 8 ), hCTLA4Ig group ( n = 8 ), DST ( donor-specific T-depleted spleen cells) + hCTLA4Ig group ( n = 8) and THY + PC61+ DST + hCTLA4Ig group (n = 6). The survival time after heart allograft transplantation was observed and pathological examination was done in different groups. Results In control group, the rate of Tregs in lymph nodes, spleen and blood was 5. 1%, 4. 5% and 1.7% respectively, which was significantly higher than in THY + PC61 group ( 1. 8% , 1. 7% and 0. 7% respectively). The average survival time of control and THY groups was 8. 2 ± 2.9 and 7.6 ± 3. 0 days respectively ( P > 0. 05 ). The average survival time of hCTLA4Ig and DST + hCTLA4Ig groups was 43.0 ± 11.8 and 135.0 ± 29. 7 days respectively, which was significantly longer than in control group or THY group ( P <0. 01 ). The average survival time of THY +PC61 + DST + hCTLA4Ig group was 25.8 ± 8.9 days, which was significantly longer than in control group,but shorter than in hCTLA4Ig group or DST + hCTLA4Ig group ( P < 0. 01 ). The survival time in DST +hCTLA4Ig group was 135.0 ± 29. 7 days, which was significantly longer than other groups ( P < 0. 01 ).The pathological examination revealed that there were more lymphocytes infiltration and capillary vessel proliferation in the desmohemoblast in the transplanted heart of DST + hCTLA4Ig group. Conclusion CD4 +CD25 +T cells regulate the immune tolerance in the allograft transplantation. 相似文献
8.
The Immunosuppressive Effect of CTLA4 Immunoglobulin Is Dependent on Regulatory T Cells at Low But Not High Doses
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C. Schwarz L. Unger B. Mahr K. Aumayr H. Regele A. M. Farkas K. Hock N. Pilat T. Wekerle 《American journal of transplantation》2016,16(12):3404-3415
B7.1/2‐targeted costimulation blockade (CTLA4 immunoglobulin [CTLA4‐Ig]) is available for immunosuppression after kidney transplantation, but its potentially detrimental impact on regulatory T cells (Tregs) is of concern. We investigated the effects of CTLA4‐Ig monotherapy in a fully mismatched heart transplant model (BALB/c onto C57BL/6). CTLA4‐Ig was injected chronically (on days 0, 4, 14, and 28 and every 4 weeks thereafter) in dosing regimens paralleling clinical use, shown per mouse: low dose (LD), 0.25 mg (≈10 mg/kg body weight); high dose (HD), 1.25 mg (≈50 mg/kg body weight); and very high dose (VHD), 6.25 mg (≈250 mg/kg body weight). Chronic CTLA4‐Ig therapy showed dose‐dependent efficacy, with the LD regimen prolonging graft survival and with the HD and VHD regimens leading to >95% long‐term graft survival and preserved histology. CTLA4‐Ig's effect was immunosuppressive rather than tolerogenic because treatment cessation after ≈3 mo led to rejection. FoxP3‐positive Tregs were reduced in naïve mice to a similar degree, independent of the CTLA4‐Ig dose, but recovered to normal values in heart recipients under chronic CTLA4‐Ig therapy. Treg depletion (anti‐CD25) resulted in an impaired outcome under LD therapy but had no detectable effect under HD therapy. Consequently, the immunosuppressive effect of partially effective LD CTLA4‐Ig therapy is impaired when Tregs are removed, whereas CTLA4‐Ig monotherapy at higher doses effectively maintains graft survival independent of Tregs. 相似文献
9.
Kulachelvy Ratnasothy Jacintha Jacob Sim Tung Dominic Boardman Robert Ian Lechler Alberto Sanchez-Fueyo Marc Martinez‐Llordella Giovanna Lombardi 《American journal of transplantation》2019,19(7):2092-2100
Regulatory T cells (Tregs) have unique immunosuppressive properties and are essential to ensure effective immunoregulation. In animal models, Tregs have been shown to prevent autoimmune disorders and establish transplantation tolerance. Therefore, the prospect of harnessing Tregs, either by increasing their frequency or by conferring allospecificity, has prompted a growing interest in the development of immunotherapies. Here, employing a well‐established skin transplant model with a single major histocompatibility complex mismatch, we compared the therapeutic efficacy of adoptively transfer Treg with or without donor specificity and the administration of IL‐2 to promote in vivo expansion of Treg. We showed that IL‐2 treatment preferentially enhances the proliferation of the allospecific Tregs adoptively transferred in an antigen‐dependent manner. In addition, donor‐specific Tregs significantly increased the expression of regulatory‐related marker, such as CTLA4 and inducible costimulator (ICOS), in the skin allograft and draining lymph nodes compared to endogenous and polyclonal transferred Tregs. Importantly, by combining IL‐2 with donor‐specific Tregs, but not with polyclonal Tregs, a synergistic effect in prolonging skin allograft survival was observed. Altogether, our data suggest that this combination therapy could provide the appropriate conditions to enhance the immunoregulation of alloimmune responses in clinical transplantation. 相似文献
10.
Rapamycin Interferes With Postdepletion Regulatory T Cell Homeostasis and Enhances DSA Formation Corrected by CTLA4‐Ig
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B. Oh J. Yoon A. Farris III A. Kirk S. Knechtle J. Kwun 《American journal of transplantation》2016,16(9):2612-2623
Previously, we demonstrated that alemtuzumab induction with rapamycin as sole maintenance therapy is associated with an increased incidence of humoral rejection in human kidney transplant patients. To investigate the role of rapamycin in posttransplant humoral responses after T cell depletion, fully MHC mismatched hearts were transplanted into hCD52Tg mice, followed by alemtuzumab treatment with or without a short course of rapamycin. While untreated hCD52Tg recipients acutely rejected B6 hearts (n = 12), hCD52Tg recipients treated with alemtuzumab alone or in conjunction with rapamycin showed a lack of acute rejection (MST > 100). However, additional rapamycin showed a reduced beating quality over time and increased incidence of vasculopathy. Furthermore, rapamycin supplementation showed an increased serum donor‐specific antibodies (DSA) level compared to alemtuzumab alone at postoperation days 50 and 100. Surprisingly, additional rapamycin treatment significantly reduced CD4+CD25+FoxP3+ T reg cell numbers during treatment. On the contrary, ICOS+PD‐1+CD4 follicular helper T cells in the lymph nodes were significantly increased. Interestingly, CTLA4‐Ig supplementation in conjunction with rapamycin corrected rapamycin‐induced accelerated posttransplant humoral response by directly modulating Tfh cells but not Treg cells. This suggests that rapamycin after T cell depletion could affect Treg cells leading to an increase of Tfh cells and DSA production that can be reversed by CTLA4‐Ig. 相似文献
11.
Abstract We have defined factors relevant for the induction of rejection by indirect recognition in a rat heart allograft model and analyzed the influence of CTLA4Ig treatment on indirect alloactivation induced by donor MHC I peptides in a DA → LEW heart allograft model. Indirect allorecognition of MHC I led to accelerated graft rejection and was accompanied by the induction of anti-peptide antibodies and donor pep-tide-activated T cells. In an attempt to block the B7-induced costimulatory signal of T cell activation, CTLA4Ig was administered to graft recipients in addition to MHC I peptide treatment. CTLA4Ig therapy, however, was not effective in preventing the humoral or cellular anti-donor immune response, nor did it prevent accelerated graft rejection. 相似文献
12.
S. Hayashi M. Guang‐Lin I. Yokoyama Y. Namii H. Hamada A. Nakao 《Transplant international》2000,13(Z1):S329-S332
Abstract It has been demonstrated that the administration of CTLA4Ig protein can induce the suppression of allograft and xenograft rejection. The purpose of this study is to determine the effect of adenovirus‐mediated gene transfer with CTLA4Ig gene on the transgene expression and suppression of alloimmune response in allogeneic cardiac transplantation of rats. Adenoviral vectors with β galactosidase or human CTLA4Ig cDNA (Adex/LacZ, Adex/hCTLA4Ig) were constructed. These vectors were transduced to the liver of Lewis (LEW) rats by intravenous injection. Then LEW rats received heterotopic cardiac transplantation from Dark Agouti rats. Experiments were performed using both CTLA4Ig gene transduction and/or immunosuppressant FK506. The transgene expression after adenovirus‐mediated transfer with CTLA4Ig cDNA lasted for several months, compared with several weeks after that in controls, which was proportional to the blood concentration of CTLA4Ig protein. By the administration of 1 × 109 PFU of Adex/hCTLA4Ig, the survival of cardiac grafts was significantly prolonged, compared with controls or the use of 1 × 108 PFU of Adex/hCTLA4Ig. In the rats with beating grafts over 100 days, the blood concentrations of CTLA4Ig were undetectable. The combination therapy using a low titer Adex/hCTLA4Ig and low‐dose of FK506 was synergistically effective on this cardiac transplantation model. In conclusion, adenovirus‐mediated gene transfer with CTLA4Ig gene was efficient for the prolongation of both transgene expression and allograft survival. 相似文献
13.
C. H. Lin W. Zhang T. W. Ng D. Zhang J. Jiang B. Pulikkottil F. Lakkis V. S. Gorantla W. P. A. Lee G. Brandacher X. X. Zheng 《American journal of transplantation》2013,13(8):2161-2168
14.
J. Chen H. Yin J. Xu Q. Wang K. L. Edelblum R. Sciammas A. S. Chong 《American journal of transplantation》2013,13(9):2280-2292
Alloantibodies mediate acute antibody‐mediated rejection as well as chronic allograft rejection in clinical transplantation. To better understand the cellular dynamics driving antibody production, we focused on the activation and differentiation of alloreactive B cells in the draining lymph nodes and spleen following sensitization to allogeneic cells or hearts. We used a modified staining approach with a single MHC Class I tetramer (Kd) bound to two different fluorochromes to discriminate between the Class I‐binding and fluorochrome‐streptavidin‐binding B cells with a high degree of specificity and binding efficiency. By Day 7–8 postsensitization, there was a 1.5‐ to 3.2‐fold increase in the total numbers of Kd‐binding B cells. Within this Kd‐binding B cell population, approximately half were IgDlow, MHC Class IIhigh and CD86+, 30–45% expressed a germinal center (Fas+GL7+) phenotype and 3–12% were IRF4hi plasma cells. Remarkably, blockade with anti‐CD40 or CTLA‐4Ig, starting on Day 7 postimmunization for 1 or 4 weeks, completely dissolved established GCs and halted further development of the alloantibody response. Thus MHC Class I tetramers can specifically track the in vivo fate of endogenous, Class I‐specific B cells and was used to demonstrate the ability of delayed treatment with anti‐CD154 or CTLA‐4Ig to halt established allo‐B cell responses. 相似文献
15.
Selective CD28 Blockade Results in Superior Inhibition of Donor‐Specific T Follicular Helper Cell and Antibody Responses Relative to CTLA4‐Ig
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I. R. Badell G. M. La Muraglia II D. Liu M. E. Wagener G. Ding M. L. Ford 《American journal of transplantation》2018,18(1):89-101
Donor‐specific antibodies (DSAs) are a barrier to improved long‐term outcomes after kidney transplantation. Costimulation blockade with CTLA4‐Ig has shown promise as a potential therapeutic strategy to control DSAs. T follicular helper (Tfh) cells, a subset of CD4+ T cells required for optimal antibody production, are reliant on the CD28 costimulatory pathway. We have previously shown that selective CD28 blockade leads to superior allograft survival through improved control of CD8+ T cells relative to CTLA4‐Ig, but the impact of CD28‐specific blockade on CD4+ Tfh cells is unknown. Thus, we identified and characterized donor‐reactive Tfh cells in a murine skin transplant model and then used this model to evaluate the impact of selective CD28 blockade with an anti‐CD28 domain antibody (dAb) on the donor‐specific Tfh cell–mediated immune response. We observed that the anti‐CD28 dAb led to superior inhibition of donor‐reactive CXCR5+PD‐1high Tfh cells, CD95+GL7+ germinal center B cells and DSA formation compared with CTLA4‐Ig. Interestingly, donor‐reactive Tfh cells differentially upregulated CTLA4 expression, suggesting an important role for CTLA4 in mediating the superior inhibition observed with the anti‐CD28 dAb. Therefore, selective CD28 blockade as a novel approach to control Tfh cell responses and prevent DSA after kidney transplantation warrants further study. 相似文献
16.
B. T. Stocks A. J. Wilhelm C. S. Wilson A. F. Marshall N. E. Putnam A. S. Major D. J. Moore 《American journal of transplantation》2016,16(1):334-341
The strongly immunogenic environment in autoimmune diseases such as lupus may pose a stringent barrier to transplantation. Despite available murine models of lupus, transplant tolerance in this setting has yet to be fully investigated in highly penetrant genetic models of disease. Such studies are of clear clinical importance because lupus is a transplant indication in which transplanted kidneys have a substantially increased risk of rejection including a role for recurrent nephritis. In the fully penetrant B6.SLE123 mouse, we determined that CD4 T follicular helper and germinal center B cells were significantly expanded compared with healthy controls. We traced this expansion to resistance of effector CD4 T and B cells in B6.SLE123 mice to regulation by either CD4 T regulatory cells (CD4Tregs) or CD8 T regulatory cells (CD8Tregs), despite demonstrating normal function by Tregs in this strain. Finally, we determined that B6.SLE123 mice resist anti‐CD45RB–mediated tolerance induction to foreign islet allografts, even in the absence of islet autoimmunity. Overall, B6.SLE123 lupus‐prone mice are highly resistant to transplant tolerance induction, which provides a new model of failed tolerance in autoimmunity that may elucidate barriers to clinical transplantation in lupus through further cellular and genetic dissection. 相似文献
17.
A. Medvec M. Laszkowska M. Wray M. A. Mintz E. Trotta G. L. Szot W. Liu A. Lares K. Lee A. Laing R. I. Lechler J. L. Riley J. A. Bluestone G. Lombardi Q. Tang 《American journal of transplantation》2013,13(11):3010-3020
Regulatory T cell (Treg) therapy has the potential to induce transplantation tolerance so that immunosuppression and associated morbidity can be minimized. Alloantigen‐reactive Tregs (arTregs) are more effective at preventing graft rejection than polyclonally expanded Tregs (PolyTregs) in murine models. We have developed a manufacturing process to expand human arTregs in short‐term cultures using good manufacturing practice‐compliant reagents. This process uses CD40L‐activated allogeneic B cells to selectively expand arTregs followed by polyclonal restimulation to increase yield. Tregs expanded 100‐ to 1600‐fold were highly alloantigen reactive and expressed the phenotype of stable Tregs. The alloantigen‐expanded Tregs had a diverse TCR repertoire. They were more potent than PolyTregs in vitro and more effective at controlling allograft injuries in vivo in a humanized mouse model. 相似文献
18.
Hyperlipidemia Alters Regulatory T Cell Function and Promotes Resistance to Tolerance Induction Through Costimulatory Molecule Blockade
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Recent work from our laboratory has shown that hyperlipidemia promotes accelerated rejection of vascularized cardiac allografts in mice by inducing anti‐donor Th17 reactivity and production of IL‐17. Here, we show that hyperlipidemia also affects FoxP3+ regulatory T cells (Tregs). Hyperlipidemia promotes the development of Tregs that express low levels of CD25. Hyperlipidemia also promotes a decrease in central Tregs and an increase in effector Tregs that appears to account for the increase in the frequency of CD25low Tregs. Alterations in Treg subsets also appear to lead to alterations in Treg function. The ability of FoxP3+, CD25high, CD4+ Tregs from hyperlipidemic mice to inhibit proliferation of effector T cells stimulated with anti‐CD3 and CD28 was reduced when compared with Tregs from control mice. Regulatory T cells isolated from hyperlipidemic recipients exhibit increased activation of Akt, and a reduction in Bim levels that permits the expansion of FoxP3+CD25lowCD4+ T cells. Hyperlipidemic mice were also resistant to tolerance induction using costimulatory molecule blockade consisting of anti‐CD154 and CTLA4Ig, a strategy that requires Tregs. Together, our data suggest that hyperlipidemia profoundly affects Treg subsets and function as well as the ability to induce tolerance. 相似文献
19.
A Novel,Blocking, Fc‐Silent Anti‐CD40 Monoclonal Antibody Prolongs Nonhuman Primate Renal Allograft Survival in the Absence of B Cell Depletion
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M. Audet L. Roth M. A. Schneider A. Kunkler N. Stuber M. Erard M. Ceci R. Baumgartner R. Apolloni A. Cattini G. Robert D. Ristig J. Munz L. Haeberli R. Grau D. Sickert C. Heusser P. Espie C. Bruns D. Patel J. S. Rush 《American journal of transplantation》2015,15(11):2825-2836
CD40–CD154 pathway blockade prolongs renal allograft survival in nonhuman primates (NHPs). However, antibodies targeting CD154 were associated with an increased incidence of thromboembolic complications. Antibodies targeting CD40 prolong renal allograft survival in NHPs without thromboembolic events but with accompanying B cell depletion, raising the question of the relative contribution of B cell depletion to the efficacy of anti‐CD40 blockade. Here, we investigated whether fully silencing Fc effector functions of an anti‐CD40 antibody can still promote graft survival. The parent anti‐CD40 monoclonal antibody HCD122 prolonged allograft survival in MHC‐mismatched cynomolgus monkey renal allograft transplantation (52, 22, and 24 days) with accompanying B cell depletion. Fc‐silencing yielded CFZ533, an antibody incapable of B cell depletion but still able to potently inhibit CD40 pathway activation. CFZ533 prolonged allograft survival and function up to a defined protocol endpoint of 98–100 days (100, 100, 100, 98, and 76 days) in the absence of B cell depletion and preservation of good histological graft morphology. CFZ533 was well‐tolerated, with no evidence of thromboembolic events or CD40 pathway activation and suppressed a gene signature associated with acute rejection. Thus, use of the Fc‐silent anti‐CD40 antibody CFZ533 appears to be an attractive approach for preventing solid organ transplant rejection. 相似文献
20.
R. Stott J. Soohoo M. R. O’Connor H. Yeh G. Zhao P. Eliades C. Fox N. Cheng S. Deng J. F. Markmann 《American journal of transplantation》2012,12(8):2072-2078
The role of B cells in transplant tolerance remains unclear. Although B‐cell depletion often prolongs graft survival, sometimes it results in more rapid rejection, suggesting that B cells may have regulatory activity. We previously demonstrated that tolerance induction by anti‐CD45RB antibody requires recipient B cells. Here, we show that anti‐CD45RB in combination with anti‐TIM‐1 antibody has a synergistic effect, inducing tolerance in all recipients in a mouse islet allograft model. This effect depends on the presence of recipient B cells, requires B‐cell IL‐10 activity, and is antigen‐specific. These data suggest the existence of a regulatory B‐cell population that promotes tolerance via an IL‐10‐dependent pathway. 相似文献