同种异体牙移植的免疫抑制功能研究

目的探讨不同方法处理的同种异体牙移植后免疫抑制功能反应。方法未根管处理的28只白鼠的上颌第1磨牙分别移植,术后1、2、4、8周时间段进行免疫组织化学技术分析。结果同种异体牙均诱发免疫排斥反应,宿主主抗体-补体介导细胞杀伤、细胞介导的细胞杀伤与同基因移植牙差异有统计学意义（P〈0.01）。结论异体牙引起免疫排斥反应,如果新型免疫抑制剂药物得到改善,将来异体牙移植的临床应用是可行的。     

大鼠同种异体肢体移植急性排斥反应的实验研究

目的通过大鼠同种异体肢体移植模型,旨在分析大鼠同种异体肢体移植中各种不同组织的急性排斥反应特点,确定反映肢体移植排斥反应最具有代表性的组织类型.方法将29只Sprague-Dawley成年大鼠随机分成2组,对照组15只为自体肢体再植组,实验组14只为Wistar→SD同种异体肢体移植组,术后不用免疫抑制剂,观察急性排斥反应出现的时间及表现,并对移植肢体中各组织进行组织病理学检查.结果异体肢体移植术后第(3.36±1.15)d开始出现皮下水肿和皮肤红斑,这是最早的急性排斥反应表表现;移植肢体的平均存活时间为(7±0.78)d;移植肢体中皮肤组织的排斥反应程度最强.结论Wistar→SD同种异体肢体移植中皮肤是最具有代表性的、最易于观察排斥反应的组织类型.     

同种异体复合组织移植的免疫研究进展

目的了解同种异体复合组织移植的免疫研究进展。方法查阅相关文献,对同种异体复合组织移植的免疫特点、实验进展、临床经验等进行总结。结果同种异体复合组织位于体表,包含组织成分复杂,抗原性高。其移植后在免疫抑制剂用药方案、排斥反应的诊断以及慢性排斥反应发生率等许多方面同内脏器官移植有不同的特点。结论在下一步研究中,应吸取同种异体复合组织移植独特的经验教训,在诱导耐受、局部用药、排斥诊断等方面树立同种异体复合组织的独特标准。     

FK506和RS-61443对大鼠异体肢体移植的联合免疫抑制作用

目的　通过大鼠异体肢体移植模型 ,旨在分析 FK5 0 6和 RS- 6 14 4 3对大鼠异体肢体移植中急性排斥反应的免疫抑制作用。　方法　选择雄性 Wistar和 SD大鼠为供、受体 ,以 FK5 0 6和 RS- 6 14 4 3为免疫抑制剂 ,对照组为术后不用药组 ,实验组根据用药剂量和药物不同分为 6组 ,各组用药时间均为 5周 (每日 1次共 2周 ,然后每周 2次共 3周 ) ,进行了 10 1例异体肢体移植动物实验。观察大鼠一般情况、移植肢体排斥反应及存活时间。　结果　对照组肢体平均存活时间为 (7.0 0± 0 .78)天 ;实验组 1～ 6组移植肢体平均存活时间分别为 (17.0 8± 4 .5 0、2 3.2 0± 5 .0 5、11.19±2 .2 8、16 .33± 1.83、13.33± 3.2 2和 5 8.76± 6 .81)天。　结论　 FK5 0 6和 RS- 6 14 4 3能抑制大鼠同种异体肢体移植术后急性移植排斥反应的发生 ,并能延长移植肢体的存活时间。     

大鼠T细胞疫苗的制备及其抗移植皮肤排斥作用的实验研究

目的 探讨T细胞疫苗(TCV)的制备方法及其抗移植皮肤排斥反应的作用.方法 制备针对特定SD大鼠的供体特异性T细胞疫苗,将其免疫受体Wistar大鼠;然后取免疫前和每次免疫后第五天的受体Wistar的淋巴细胞(反应细胞)与供体SD的淋巴细胞(刺激)进行体外单向混合淋巴细胞反应(MLR),以MTT法检测细胞免疫增值反应情况,比较疫苗接种后诱导淋巴细胞反应受抑制的情况:再将SD大鼠皮肤移植到TCV免疫后的Wistar大鼠,观察皮肤移植反应并统计移植物存活的时间.排斥反应的移植物行病理检查.结果 TCV组受体淋巴细胞反应程度比接种前显著减弱(P＜0.05);特异性TCV组皮肤移植物存活时间较非特异性TCV组及对照组延长(P＜0.05).移植皮肤排斥反应病理表现更轻.结论 TCV经腹腔接种可以诱导出针对同种抗原特异性免疫耐受,TCV能够延长同种异体移植皮肤的存活时间,有一定抗移植排斥反应作用.     

国外美容医学最新动态

1灵长类动物面部复合组织同种异体移植1：延长移植体存活的技术及免疫抑制疗法 目的：由于排斥反应及传统的免疫抑制剂的应用带来的风险,阻碍了复合组织同种异体移植手术的广泛开展。本文作者为了给临床应用提供更多的实验资料,用灵长类动物进行面部复合组织同种异体研究,并观察其长期的效果。方法：在匹配不良的猕猴间,施行面部复合组织（包括皮肤、肌肉、骨骼）异体移植实验。从供体切取面部复合组织,保留供血的颈总动脉,和颈内、颈外两条引流静脉。将移植体转移至另一猕猴的下腹部-异位移植。供体的颈总动脉与受体的股动脉进行端-端吻合,两条颈静脉分别与股静脉吻合。受体动物接受单一的tacrolimus免疫抑制剂治疗。术后不间断地观察,适时取活体组织检查或直行核磁共振检查。结果：在13个移植体中,两例于术后3～5天因一条静脉栓塞而失效,与排斥无关,其余移植体均成活良好。单一的免疫抑制疗法有效,未发生并发症。移植体的无排斥反应存活期为60～177天。结论：作者利用灵长类动物猕猴施行面部复合组织同种异体移植获得成功。保持两条引流静脉的畅通是成功的要点,采用tocrolimus单项免疫抑制剂可获长期的抑制排斥反应的效果,未出现早期并发症。此模型可作为进一步研究复合组织同种异体移植的研究工具。     

小剂量环孢素A对大鼠同种异体肢体移植的免疫抑制作用

目的通过大鼠同种异体肢体移植模型,分析小剂量环孢素A(cyvlosporinA ,CsA)对大鼠同种异体肢体移植急性排斥反应的免疫抑制作用。方法采用雄性Wistar和SD大鼠为供、受体,以CsA为免疫抑制剂。对照组14只,将Wistar大鼠肢体移植至SD大鼠,术后不用药。实验组术后按用药剂量的不同分为2组( 2mg/kg组17只大鼠和CsA 6mg/kg组18只大鼠)。2组术后用药时间均为4周(每日1次共2周,然后每周2次共2周)。术后观察大鼠一般情况、移植肢体排斥反应及存活时间;用免疫荧光染色流式细胞仪检测各组手术前后T细胞亚群的变化。结果对照组移植肢体平均存活时间为[( 7.0 0±0 .78)d , x±s ,下同] ;CsA 2mg/kg组为( 3 7.18±0 .5 1)d ,CsA 6mg/kg组为( 3 3 .2 0±1.0 5 )d。术后第3天,对照组的CD4/CD8比值显著增高,移植肢体开始出现肿胀、皮肤红斑等表现。实验组的CD4/CD8较术前无明显变化。结论小剂量CsA能抑制大鼠同种异体肢体移植术后急性排斥反应的发生,并能延长移植肢体的存活时间。     

猪肝肠联合移植免疫耐受的实验研究

目的 研究猪肝肠联合移植中肝移植物对同源小肠移植物免疫耐受的作用.方法 70头杂交长白猪分为4组,A、B、C组为辅助性同种异体肝肠联合移植(每组20头);D组为节段性间种异体小肠移植(10头).移植后A、D组未用免疫抑制剂治疗,B、C组分别采用常规剂量和小剂量的环孢素和甲基强的松龙治疗.结果 A组术后小肠移植物较D组排斥反应时间延迟,程度明显减轻(P＜0.05).常规剂量的B组与小剂量的C组在术后存活时间、排斥反应开始时间以及排斥反应程度方面差异无统计学意义(P＞0.05).结论 猪同种异体肝肠联合移植中肝移植物可以诱导同源小肠移植物免疫耐受.     

脂肪干细胞在同种异体复合组织移植中的作用及其临床应用展望

同种异体复合组织移植是临床修复重建的重要手段,但术后长期应用免疫抑制剂所导致的副作用仍是亟待解决的难题,细胞治疗联合传统免疫抑制剂治疗有望解决这一难题。间质干细胞,特别是脂肪干细胞,被认为可用于延长移植物存活及改善免疫排斥情况的发生。其在同种异体复合组织移植中发挥的作用包括旁分泌免疫调节因子抑制免疫排斥反应、诱导调节性T细胞产生、形成嵌合体诱导免疫耐受,以及改善移植过程中缺血再灌注损伤等。但是,该方法要真正应用于临床前,相关问题如使用剂量、时机及安全性等仍需经过进一步深入研究。     

转化生长因子β1质粒对新鲜异体神经移植排斥反应的影响

自体神经移植是目前修复周围神经缺损的最佳方式,但存在增加手术创伤、造成供体神经支配区域的功能障碍及供体有限等缺点.同种异体神经移植可克服这一困难,但存在免疫排斥反应,移植后的免疫排斥反应是影响神经移植效果的重要因素[1].如何有效地抑制或减弱移植排斥反应是提高移植成功率,延长存活时间的根本问题.转化生长因子-1(TGF-β1)是一种强效细胞生长增殖调节蛋白,在移植免疫的抗排斥反应中扮演重要角色,已成为近年细胞,组织,器官移植的研究热点.我们通过局部注射TGF-β1质粒,观察其对大鼠异体神经移植后排斥反应的影响.     

Allergic Conjunctivitis Renders CD4+ T Cells Resistant to T Regulatory Cells and Exacerbates Corneal Allograft Rejection

Allergic diseases rob corneal allografts of immune privilege and increase immune rejection. Corneal allograft rejection in BALB/c allergic hosts was analyzed using a short ragweed (SWR) pollen model of allergic conjunctivitis. Allergic conjunctivitis did not induce exaggerated T‐cell responses to donor C57BL/6 (B6) alloantigens or stimulate cytotoxic T lymphocyte (CTL) responses. Allergic conjunctivitis did affect T regulatory cells (Tregs) that support graft survival. Exogenous IL‐4, but not IL‐5 or IL‐13, prevented Treg suppression of CD4⁺ effector T cells isolated from naïve mice. However, mice with allergic conjunctivitis developed Tregs that suppressed CD4⁺ effector T‐cell proliferation. In addition, IL‐4 did not inhibit Treg suppression of IL‐4Rα^?/? CD4⁺ T‐cell responses, suggesting that IL‐4 rendered effector T cells resistant to Tregs. SRW‐sensitized IL‐4Rα^?/? mice displayed the same 50% graft survival as nonallergic WT mice, that was significantly less than the 100% rejection that occurred in allergic WT hosts, supporting the role of IL‐4 in the abrogation of immune privilege. Moreover, exacerbation of corneal allograft rejection in allergic mice was reversed by administering anti‐IL‐4 antibody. Thus, allergy‐induced exacerbation of corneal graft rejection is due to the production of IL‐4, which renders effector T cells resistant to Treg suppression of alloimmune responses.     

他汀类药物在同种异体全厚皮片移植中的作用

目的：研究他汀类药物在同种异体全厚皮片移植中作用。方法：荷兰黑兔作为供体,日本白兔作为受体。实验分为三组（n=8）：1组,空白对照组;2组,小剂量他汀类药物（术后给于2mg／kg／天）;3组,大剂量他汀类药物（术后给于4mg／kg／d）。通过临床评估和病理组织活检来计算皮片的存活时间以及他汀类药物抑制炎性细胞浸润的作用,通过免疫组织化学检测和外周血IL-2水平测定来观察他汀类药物在对抗急性炎症反应的作用。结果：全厚皮片的存活时间：1组,（7．0±1．07）天;2组,（8．13±1．13）天;3组,（13．25±0．71）天。3组的存活时间长于1组和2组,但1组和2组之间比较没有统计学差异．大剂量阿托伐他汀延长了皮片的存活时间,阻止了淋巴细胞的浸润,而且在对抗急性排斥反应中有很大的作用。结论：阿托伐他汀延长了同种异体全厚皮片移植的存活时间,抑制了炎性细胞的浸润,有效的对抗急性排斥反应。     

Graft produced interleukin-6 functions as a danger signal and promotes rejection after transplantation

BACKGROUND: Interleukin (IL)-6 is a pleiotropic cytokine that functions in both the innate and adaptive immune responses. However, the role of IL-6 in allograft rejection remains poorly understood. METHODS: In this study, we demonstrate a critical role for graft-produced IL-6 in allograft rejection in a murine model of cardiac allograft transplantation. RESULTS: The results show that IL-6-deficient grafts transplanted into allogeneic wild-type recipients have significantly prolonged survival, approximately three times the survival time of wild-type controls. In contrast, allogeneic cardiac transplants into IL-6-deficient recipients do not have prolonged graft survival, indicating that donor graft cells are the relevant source of IL-6. Our investigation of potential mechanisms shows that graft-produced IL-6 promotes the activation of peripheral CD4 and CD8 T cells. Furthermore, we show that IL-6 deficiency prolongs graft survival only in the presence of CD25+ T cells that have a phenotype consistent with regulatory T cells. Interestingly, IL-6 production by the graft is triggered by antigen-independent innate immune mechanisms. CONCLUSIONS: Thus, our results suggest the paradigm that graft rejection versus tolerance is determined by a balance between the activation of effector T cells versus immune suppression by regulatory T cells, and that after transplantation, IL-6 functions as a systemic danger signal that overcomes constitutive immune suppression mediated by regulatory T cells and promotes the activation of effector T cells.     

Macrophages play a role in the early phase of corneal allograft rejection in rats

BACKGROUND: Rat corneal allograft rejection is delayed by repeated local injection of liposomes filled with clodronate (dichloromethylene diphosphonate), which selectively deplete macrophages. Various administration schedules of liposomes were tested to determine the optimum schedule for prevention of graft rejection. Cell subpopulations in the anterior segment of the eye were studied at different time points after transplantation to assess the kinetics of the immune response. METHODS: AO rats were grafted orthotopically with corneal buttons from PVG rats. Postoperatively, rats remained untreated or received clodronate liposomes subconjunctivally. Clodronate liposomes were injected five times on postoperative days (PODs) 0, 2, 4, 6, and 8; or once, on POD 0 or 6; or twice on PODs 0 and 2 or PODs 0 and 6. Grafts were examined for signs of rejection clinically and immunohistologically. RESULTS: All untreated rats rejected their grafts as did all five rats that received clodronate liposomes once on POD 6. In all the other administration schedules tested, graft survival was prolonged compared with the untreated control group (P <0.01). Injections of clodronate liposomes on PODs 0 and 2 proved to be the most effective treatment. Histologically reduced influx of virtually all cell types tested was found in this group. CONCLUSIONS: To prevent or delay graft rejection, it is necessary to administer clodronate liposomes in the early phase after corneal transplantation. These results suggest a role for macrophages in the afferent phase of corneal graft rejection.     

Expression of the chemokine antagonist vMIP II using a non-viral vector can prolong corneal allograft survival

BACKGROUND: The expression of chemokines is central to the recruitment of inflammatory cells for graft rejection, and modulation of chemokine action is of potential in preventing graft rejection. We have examined chemokine expression in a murine model of corneal allograft rejection, and also determined the effect of expressing a broad acting chemokine antagonist, viral macrophage inflammatory protein II (vMIP II), on graft survival. METHOD: The expression of chemokines in a murine model of corneal transplantation was determined by real time RT-PCR and, in the case of regulated on activation normal T-cell expressed and secreted, by ELISA. The plasmid encoding the virally derived chemokine antagonist, vMIP II, was introduced into the corneal endothelial cells using a non-viral vector consisting of liposomes and transferrin. The expression and activity of vMIP II was determined by ELISA and functional assays, and the effect on graft survival noted. RESULTS: After allotransplantation, there was up-regulation of all 11 chemokines examined. After gene delivery, there was expression of active vMIP II for more than 14 days and considerable prolongation of graft survival. This was associated with a decrease in leukocyte infiltration of the stroma of the cells. CONCLUSION: As expected there was considerable up-regulation of chemokines during allograft rejection. The expression of vMIP II showed considerable prolongation of graft survival. This is the first time we have observed prolongation of graft survival after a non-viral (as opposed to viral) means of gene delivery and indicates the potential of interfering with chemokine action to prevent corneal graft failure.     

In vivo Treg expansion under costimulation blockade targets early rejection and improves long-term outcome

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.     

Regulatory T cells induce transplant immune tolerance

Organ transplantation is the preferred treatment option for end-stage organ failure. Although immunosuppressants are effective for preventing the occurrence of acute rejection, they also cause a series of side effects in transplant recipients. To improve the quality of patient survival, a new therapeutic strategy that has fewer side effects than current immunosuppressive regimens and can induce allograft immune tolerance and effectively prevent transplant rejection is needed. In this context, regulatory T cells (Tregs) are considered to be promising research targets. With the increasing understanding of the immunomodulatory role of Tregs, the use of Treg-based cellular therapies has shifted from prevention/treatment of autoimmune diseases to clinical trials for organ transplantation. This review describes the phenotype and in vitro expansion of Tregs and the mechanisms by which they exert immunomodulatory effects in transplantation immunity, highlights recent clinical trial data on Treg-based cellular therapies in transplantation, and describes future directions and limitations.     

Analysis of therapeutic potential of monocytic myeloid-derived suppressor cells in cardiac allotransplantation

BackgroundMyeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) are attractive immune cells to induce immune tolerance. To explore a strategy for improving the efficacy of MDSC therapies, we examined the impact of adoptive transfer of several types of MDSCs on graft rejection in a murine heart transplantation model.MethodsWe analyzed the effects of induced syngeneic and allogeneic bone marrow-derived MDSCs (BM-MDSCs) on graft survival and suppressive capacity. We also compared the ability of syngeneic monocytic MDSCs (Mo-MDSCs) and polymorphonuclear MDSCs (PMN-MDSCs) to inhibit graft rejection and investigated the suppression mechanisms.ResultsBoth syngeneic and allogeneic donor- or allogeneic third-party-derived BM-MDSCs prolonged graft survival, although syngeneic BM-MDSCs inhibited anti-donor immune responses most effectively in vitro. Syngeneic Mo-MDSCs, rather than PMN-MDSCs, were responsible for immune suppression through downregulating inducible nitric oxide synthase (iNOS) and expanded naturally occurring thymic originated Treg (nTreg) in vitro. Adoptive transfer of Mo-MDSCs, but not PMN-MDSCs, prolonged graft survival and increased Treg infiltration into the graft heart.ConclusionRecipient-derived Mo-MDSCs are most effective in prolonging graft survival via inhibiting T cell response and nTreg infiltration.     

Allergic Airway Hyperreactivity Increases the Risk for Corneal Allograft Rejection

Corneal allografts transplanted into hosts with allergic conjunctivitis experience an increased incidence and swifter tempo of immune rejection compared to corneal allografts transplanted to nonallergic hosts. Previous findings suggested that increased risk for rejection was not a local effect produced by an inflamed eye, but was due to perturbation of the systemic immune responses to alloantigens on the corneal allograft. We tested the hypothesis that another allergic disease, airway hyperreactivity (AHR), would also increase the risk for corneal allograft rejection. Induction of AHR with either ovalbumin (OVA) or short ragweed (SRW) extract prior to keratoplasty resulted in a steep increase in the speed and incidence of corneal allograft rejection. Delayed-type hypersensitivity (DTH) responses to corneal alloantigens were closely associated with corneal allograft rejection. However, the deleterious effect of AHR on corneal allograft survival was not reflected in a heightened magnitude of allospecific DTH, cytotoxic T lymphocyte and lymphoproliferative responses to the alloantigens on the corneal allograft. Unlike Th2-based immediate hypersensitivity, CD8⁺ T-cell-based contact hypersensitivity to oxazolone did not increase the risk for corneal allograft rejection. Thus, Th2-based allergic diseases significantly reduce the immune privilege of the corneal allograft and represent important risk factors for consideration in the atopic patient.     

Targeting NF-κB c-Rel in regulatory T cells to treat corneal transplantation rejection

The relevance of Tregs in the induction of tolerance against corneal allografts has been well established. Although it is well known that the conversion of Tregs into effector-like cells contributes to the loss of corneal immune privilege, the underlying mechanism is still not fully understood. Using heterologous penetrating keratoplasty model, we found that Tregs from corneal allograft rejected mice (inflam-Tregs) exhibit impaired function and characteristics of effector T cells. Further study showed that the expression of NF-κB c-Rel, a key mediator of effector T cell function, was significantly increased in inflam-Tregs. Mechanistic study revealed that elevated NF-κB c-Rel level in inflam-Tregs impaired Treg function through the promotion of inflammatory cytokine production and glycolysis. More importantly, we demonstrated that targeting NF-κB c-Rel was able to improve the immune suppressive function of inflam-Tregs in vitro and enhance the potential of them to suppress corneal transplantation rejection. Therefore, our current study identified NF-κB c-Rel as a key mediator of the conversion of Tregs into effector-like cells when under inflammatory environment.