小鼠角膜移植排斥反应中植片内细胞因子表达水平的变化

背景研究表明细胞因子在角膜移植免疫调节中起重要的作用,但关于角膜移植术后角膜植片内细胞因子表达的变化报道较少。目的探讨角膜移植术后不同时间点细胞因子的表达变化。方法采用雌性6～8周龄BALB／c小鼠及C57BL／6小鼠分别建立小鼠自体角膜移植和同种异体角膜移植模型,每组各10只,自体角膜移植术组供体和受体同为BALB／c小鼠,同种异体角膜移植术组供体为C57BL／6小鼠,受体为BALB／c小鼠。于术后1d开始临床观察角膜植片并对炎症程度进行评分,当植片评分总和≥5分或植片混浊≥2分时为发生植片排斥反应。将BALB／c小鼠随机分为正常对照组3只和同种异体角膜移植术组15只,后者分别于术后6h及1、3、7、14d对角膜植片行逆转录PCR（RT—PCR）检测植片中细胞因子白细胞介素4（IL-4）、γ-干扰素（IFN-γ）、IL-10、肿瘤坏死因子α（TNF—α）表达的变化。结果在60d的观察期中,自体角膜移植术后小鼠角膜植片混浊评分均〈2分,植片的炎症评分之和均〈5分,植片存活率为100％,但同种异体角膜移植术后角膜植片水肿、混浊,伴有角膜新生血管形成,至术后24d角膜植片排斥反应评分之和均≥5分,植片混浊评分≥2分,全部发生排斥反应,角膜植片平均存活时间为（17．80±4．66）d。RT—PCR检测结果表明,正常角膜中IL-4和IFN-γ呈阳性表达,IL-10和TNF-α表达阴性。同种异体角膜移植术后6h可检测到IL-4呈阳性表达,IFN-γ和IL-10表达呈强阳性,而未检测到TNF—α的表达。术后1～3d角膜植片中IL-4呈强阳性表达,IFN-γ阳性表达,TNF—α表达增强,IL-10表达逐渐消失。角膜移植术后7d,可见IL-4表达阴性,而IFN-γ、IL-10和TNF—α仍呈强阳性表达。至术后14d,角膜植片中IL-4、IFN-γ和TNF—α．均未见表达,仅检测到IL-10呈阳性表达。结论TNF-α是角膜移植术后局部参与调控的主要因子。     

小鼠异基因角膜移植术后调节性T细胞与相关因子的表达研究

目的 探讨在小鼠异基因角膜移植免疫排斥中,调节性T细胞(Treg)及其下游细胞因子的表达变化.方法 实验研究.实验组以BALB/c(H-2~d)小鼠为受体、C3H/He(H-2~k)小鼠为供体,建立小鼠异基因角膜移植模型48只;对照组的受体与供体均为BALB/c,建立小鼠同基因角膜移植模型48只.观察术后植片的存活率、排斥反应发生时间;组织病理学检查术后3 d、7 d,4周及8周各时间点角膜植片中炎症细胞浸润与角膜新生血管生成;流式细胞仪检测术前、术后3 d、7 d、4周及8周各时间点受体外周血和脾脏中CD4~+CD25~+Treg及CD103~+CD8~+Treg的表达变化;同时酶联免疫吸附试验检测血清与房水中白细胞介素10(IL-10)、IL-4、γ干扰素(IFN-γ)及II-1β的表达变化.应用Kaplan-Meier生存曲线、两独立样本t检验、非参数秩和检验进行统计学分析.结果 实验组角膜植片免疫排斥发生时间为7 d至4周,平均存活时间为(14.79±1.02)d,对照组术后植片保持透明,观察期(8周)内未发生排斥反应,存活时间显著长于实验组,差异有统计学意义(x~2=46.934,P=0.000).流式细胞仪检测显示对照组外周血CD4~+CD25~+Treg术后各时间点的表达分别为(3.36±0.29)%、(4.09±0.44)%、(5.44±0.35)%、(5.73±0.53)%,显著高于实验组的(2.50±0.39)%、(3.24±0.25)%、(4.20±0.45)%、(4.18±0.14)%,差异有统计学意义(t=3.828、2.898、3.780、4.892,均P＜0.05),两组脾脏中CD4~+CD25~+Treg的表达上调先于外周血;术后各时间点实验组外周血内CD8+CD103+Treg的表达分别为(2.20±0.33)%、(2.79±0.57)%、(4.55±1.03)%、(4.31±0.07)%,显著高于对照组的(0.73±0.12)%、(1.10±0.19)%、(1.43±0.14)%、(2.10±0,14)%,差异有统计学意义(t=7.133、4,876、5.196、19.960,均P＜0,05),两组脾脏中CD8~+CD103~+Treg的表达上调先于外周血.实验组术后各时间点血清内IL-10与IL-4水平均显著低于对照组,差异有统计学意义(t=3.203、3.141、3.012、2.869与2.340、6.681、8.839、8.574.P=0.011、0.012、0.013、0.019与0.053、0.000、0.000、0.000);实验组术后血清内IFN-γ与IL-1β含量上调,各时间点的表达水平均高于对照组(除术后4周、8周的IL-1β,余差异有统计学意义,t=3.508、3.265、4.402、5.539与3.630、5.796、1.728、0.660,P=0.006、0.011、0.002、0.000与0.005、0.000、0.115、0.524).房水中各细胞因子的表达改变与血清中变化相似.结论　小鼠同种异基因角膜移植免疫排斥中,CD4~+CD25~+Treg表达下调并伴随血清与房水中IL-10、IL-4表达下调,而CD8~+CD103~+Treg的表达上调伴随IFN-γ、IL-1β的含量增加,可能参与了角膜移植免疫排斥反应的过程.     

ICOS共刺激通路参与角膜移植免疫排斥反应的研究

目的研究可诱导共刺激分子（ICOS）共刺激通路与角膜移植急性免疫排斥反应的关系。方法建立大鼠同种异体穿透角膜移植模型,分别于术后7d、14d取植片进行病理学观察,采用RT-PCR法检测植片组织ICOS mRNA的表达情况,免疫组织化学法检测植片组织淋巴细胞ICOS蛋白水平;同时采用流式细胞术检测外周血CD3^＋ICOS^＋T／CD3^＋T的表达情况。均以正常大鼠作为正常对照。结果正常大鼠角膜组织未检测到ICOS蛋白及ICOS mRNA的表达,移植术后植片组织可以检测到ICOS蛋白及ICOS mRNA的表达,且术后14d高于术后7d（P=0．000）;与正常大鼠外周血CD3^＋ICOS^＋T／CD3^＋T的表达相比术后表达皆升高（方差齐性,P=0．156）,且术后14d外周血CD3^＋ICOS^＋T／CD3^＋T的表达高于术后7d的表达（P=0．000）。结论共刺激分子ICOS与角膜移植急性免疫排斥反应密切相关。     

ResolvinE1对高危角膜移植免疫排斥反应的抑制作用

背景 以往防治角膜移植术后排斥反应的药物存在诱发局部或全身不良反应的风险,研究表明resolvinE1(RyE1)能够调节辅助性T细胞1(Th1)型免疫反应,但其对高危角膜移植术后的植片排斥反应有无抑制作用尚不清楚. 目的 观察高危角膜移植动物模型局部应用RvE1对植片免疫排斥反应的抑制作用.方法 以BALB/c小鼠为受体、C57BL/6小鼠为供体行角膜移植术.采用随机数字表法将90只BALB/c小鼠随机分成异体角膜移植组、异体角膜移植+RvE1组和自体角膜移植组,每组各30只.BALB/c小鼠右眼先用缝线法刺激2周以建立高危角膜移植眼模型,然后行穿透角膜移植术.异体角膜移植组和异体角膜移植+RvE1组小鼠右眼行异体角膜移植,自体角膜移植组小鼠将右眼角膜植片旋转180°后缝合于植床上.异体角膜移植组及自体角膜移植组小鼠术后每日用生理盐水10μl结膜下注射1次,异体角膜移植+RvE1组小鼠术后同法注射终质量浓度为0.1 μg/μl的RvE1 10μl,连续7d.术后裂隙灯显微镜下观察小鼠角膜植片反应并对其排斥反应进行评分.术后21 d处死各组小鼠各20只,收集小鼠术眼角膜、眼球和术眼侧颈部淋巴结,采用苏木精-伊红染色法观察各组小鼠角膜植片的组织病理学变化;采用免疫组织化学法检测术眼角膜中CD4及γ干扰素(IFN-γ)的表达;采用流式细胞术检测术眼侧颈部淋巴结淋巴细胞中Th1细胞(CD3+ CD8a-IFN-γ+)比例;采用荧光定量PCR法检测Th1细胞相关因子白细胞介素-2(IL-2)、肿瘤坏死因子-α(TNF-c)、IFN-γ及T-bet mRNA的相对表达水平.结果 异体角膜移植+RvE1组小鼠角膜植片存活时间为(28.5±1.7)d,明显长于异体角膜移植组的(14.0±1.6)d,差异有统计学意义(t=4.14,P＜0.001),自体角膜移植组小鼠植片在术后50 d存活率为100％.苏木精-伊红染色显示,异体角膜移植+RvE1组和自体角膜移植组小鼠角膜植片水肿及炎性细胞浸润程度均轻于异体角膜移植组.免疫组织化学法检测显示,各组角膜全层均有CD4表达,而IFN-γ主要表达于角膜上皮层,异体角膜移植组小鼠角膜组织中CD4和IFN-γ阳性细胞数均明显多于异体角膜移植+RvE1组和自体角膜移植组.流式细胞术检测显示,异体角膜移植+RvE1组和自体角膜移植组小鼠淋巴细胞中Th1细胞比例分别为(1.07±0.25)％和(0.85±0.12)％,明显低于异体角膜移植组的(1.56±0.20)％,差异均有统计学意义(均P＜0.05).荧光定量PCR检测显示,异体角膜移植组小鼠角膜中IL-2、TNF-α、IFN-γ及T-bet mRNA的相对表达量明显高于异体角膜移植+RvE1组和自体角膜移植组,差异均有统计学意义(均P＜0.05).结论 RvE1可抑制小鼠高危角膜移植排斥反应,作用机制可能与其下调角膜植片和淋巴细胞中Th1细胞及相关细胞因子的表达有关.     

环孢素A缓释系统植入前房抑制鼠角膜移植免疫排斥反应机制的研究

目的　探讨前房植入环孢素A(cyclosporineA ,CsA)缓释系统抑制鼠角膜移植免疫排斥反应的机制。方法　 (1)环孢素A缓释系统的制备 :为CsA粉剂与已交酯 丙交酯 已内酯的三元共聚物混合体 ,每粒含环孢素A 0 5mg。 (2 )对 90只 (90只眼 )BALB c鼠 (受体 )行穿透性角膜移植术 ,将其分为A、B、C组 ,每组 30只。供体为C5 7BL 6鼠。A组术中鼠前房植入CsA缓释系统 ;B组术中鼠前房植入不含CsA的空白缓释系统 ;C组术后不作任何处理作为正常对照组。术后 3d用裂隙灯显微镜观察角膜植片情况 ,记录角膜植片免疫排斥反应发生的时间和程度。各组分别于术后 1、2、4及 6周随机取 2只鼠眼行组织病理学检查 ,并用CD4、CD8及CD11B单克隆抗体行免疫组织化学染色 ,观察各组T淋巴细胞的迁移和数量。结果　A组鼠角膜植片排斥时间平均 (35± 3)d ,较B、C组 (14± 3)d明显延长 (P <0 0 0 1)。前房植入的CsA缓释系统体积缩小前 ,A组角膜植片均保持透明 ;当前房植入的CsA缓释系统消失后 ,角膜出现免疫排斥反应 ,植片逐渐混浊、增厚、血管化。B、C组免疫排斥反应均在术后 2周发生。组织病理学和免疫组织化学检查 :A组在术后 14d仅于植床角膜可见少量CD+ 4 　和CD+ 8　细胞浸润 ,在虹膜和睫状体中未见CD+ 11B、CD+ 4 、CD+ 8　T淋     

Role of CD4+ T cells in immunobiology of orthotopic corneal transplants in mice.

PURPOSE: To determine, with the use of mice genetically deficient in expression of CD4 or CD8 molecules, which T cells are responsible for rejection of orthotopic corneal allografts in mice. METHODS: Corneas were prepared from major histocompatibility complex (MHC)-only incompatible, minor histocompatibility (H)- only incompatible, and MHC-plus-minor H incompatible donors and grafted orthotopically to eyes of CD4 knockout (KO), CD8KO, and wild-type control mice. Graft survival patterns were assessed clinically and compared. Mice that retained healthy corneal allografts beyond 8 weeks were evaluated for evidence of donor-specific tolerance and anterior-chamber-associated immune deviation (ACAID) using local adoptive transfer reactions and challenge with orthotopic skin allografts. RESULTS: Corneas grafted to CD8KO mice were rejected with an incidence and tempo indistinguishable from that in wild-type control animals. By contrast, MHC-only, and minor-H-only incompatible corneal grafts survived indefinitely in eyes of CD4KO mice. Approximately 50% of corneal grafts that confronted CD4KO recipients with both MHC and minor H alloantigens experienced delayed rejection, whereas similar grafts in wild-type recipients were rejected acutely. CD4KO mice with long-accepted grafts displayed neither donor-specific ACAID nor allograft tolerance. CONCLUSIONS: CD8+ T cells play little or no role in acute rejection of orthotopic corneal allografts. Instead, acute rejection is mediated almost exclusively by CD4+ T cells. Moreover, when corneal allografts survive for 8 weeks without acute rejection, CD4+ T cells promote donor-specific ACAID thereby insuring long-term graft acceptance.     

CD4+CD25+调节性T细胞参与大鼠角膜移植免疫耐受的研究

目的 探讨超抗原金黄色葡萄球菌肠毒素B(SEB)诱导大鼠高危角膜移植免疫耐受时CD4+CD25+调节性T细胞在眼局部及全身的表达情况.方法 本实验采用对照设计,以13只SD大鼠作为供体,26只Wistar大鼠作为受体建立高危穿透性角膜移植模型.所有受体大鼠抽签法随机分为2组,对照组和SEB组分别腹腔注射生理盐水和SEB(75 μg/kg体重),1次/4 d,共3次,末次注射后1 d行右眼穿透性角膜移植术.术后观察大鼠角膜植片的存活时间,并采用免疫荧光染色分析CD4+CD25+T细胞在大鼠角膜植片和虹膜的表达,使用流式细胞学方法分析外周血中的CD4+CD25+T细胞百分数.结果 对照组大鼠角膜植片平均存活时间为(11.63±2.83)d,SEB组为(14.13±0.99)d,两组间比较差异有统计学意义(P＜0.05).组织病理学检查可见发生排斥的角膜植片有大量炎性细胞浸润,炎性细胞数量与排斥反应程度呈正相关性.直接免疫荧光染色检查可见术前两组角膜组织均不表达CD4+CD25+T细胞,而术后20 d两组均有表达.虹膜铺片直接免疫荧光染色检查术前对照组未见CD4+CD25+T细胞表达,而SEB组(首次注射SEB后第10天)虹膜片可见CD4+CD25+T细胞表达,术后第20天两组大鼠虹膜铺片均可见CD4+CD25+T细胞表达,并且SEB组阳性细胞数更多.流式细胞学方法分析显示手术前后、对照组大鼠外周血中CD4+CD25+T细胞的百分数无变化,而SEB组呈先升高、后降低的变化趋势.结论 CD4+CD25+调节性T细胞参与超抗原SEB诱导大鼠高危角膜移植术后免疫耐受的形成.     

角膜共焦显微镜早期诊断兔高危角膜移植排斥反应的价值

目的:角膜共焦显微镜检查对兔碱烧伤角膜移植排斥反应进行研究,找寻排斥反应早期诊断的客观指标。方法:制作兔角膜碱烧伤模型,36d后行穿透性角膜移植,于角膜移植术后4,9,14,21~28d诊断排斥反应时,角膜共焦显微镜检查角膜。结果:排斥反应时角膜共焦显微镜检查见角膜植片炎性细胞浸润,角膜细胞丢失,新生血管生长。结论:角膜共焦检查有助于早期诊断排斥反应。     

Corneal epithelial rejection in the rat

PURPOSE: To investigate clinical and histologic changes in the epithelium during corneal graft rejection in the rat. METHODS: LEW (RT1(l)) or PVG (RT1(c)) strain corneas were transplanted to PVG strain recipients and examined by slit lamp for clinical signs of rejection. Recipients were killed, and corneal epithelial sheets were removed and examined by adenosine diphosphatase (ADPase) staining for Langerhans cells (LC) and by immunohistology for leukocytes and adhesion molecules (T cells, macrophages, granulocytes, major histocompatibility complex [MHC] class II, CD2 and CD54 intercellular adhesion molecule [ICAM]-1) at a range of time points before, during, and after rejection, depending on the cell type sought. Normal and contralateral eyes were examined for ADPase(+) and MHC class II(+) cells. RESULTS: Clinical rejection, as defined by stromal opacity, occurred between days 10 and 15 after transplantation. In 94% of allografts, a curved clinical epithelial rejection line was observed in which ADPase(+)/MHC class II(+), CD4(+), or CD8(+) T cells were identified. There were significantly more infiltrating cells of all types in epithelia of allografts than in those of isografts. The most numerous cells were CD4(+) and CD8(+) T cells, suggesting preferential migration of these cells into the epithelium from underlying layers. Expression of MHC class II and ICAM-1 was induced on epithelial cells. CONCLUSIONS: Epithelial rejection in rats is clinically similar to that in humans and occurs simultaneously with stromal infiltration. It may be mediated by T cells rather than macrophages. In isolation, its recognition in humans may be a useful indication that the patient is at high risk of endothelial rejection.     

Prolongation of corneal allograft survival by CTLA4-FasL in a murine model

Background To investigate the therapeutic effect of CTLA4-FasL—B7 costimulatory pathway blockage—on graft survival in a murine model of corneal transplantation. Methods Orthotopic penetrating keratoplasty was performed on BALB/c mice. The mice were randomized into four groups: the isograft group, untreated allograft group, cyclosporine A drug delivery system (CsA DDS)-anterior chamber implanted group, and 10 μg/mL CTLA4-FasL-treated group. Allografts were from C57BL/6 mice. Survival time of corneal grafts was evaluated. Immunohistological method and TdT-mediated dUTP Nick End Labeling (TUNEL) were applied for the detection of CD4+ T cells and apoptotic cells in corneal transplants. To assess whether peripheral immune tolerance appeared after the treatment of CTLA4-FasL, CsA DDS-implanted- and CTLA4-FasL-treated BALB/c mice with clear grafts received skin allografts at 4 weeks after keratoplasty, and the status of corneal transplants were observed when skin grafts were rejected. Results Allografts in the CTLA4-FasL group (median survival time [MST] = 106 days, p = 0.0042) and the CsA DDS group (MST = 60 days, p = 0.0037) revealed extending survival time, compared with that in the untreated allograft group (MST = 14 days). There were significantly fewer CD4-positive T cells in both the isograft group and the CsA DDS group. In the untreated allograft group, the number of CD4+ T cells gradually increased from day 1 until the final day of observation (day 21). By contrast, it reached a peak on day 7 and then absolutely reduced in the CTLA4-FasL group. Many apoptotic cells were detected on day 7 in the CTLA4-FasL group, but very few were seen in the other groups. Within 30 days of skin-graft rejection, previously healthy and long-standing corneal grafts became rejected in the CsA DDS group but remained clear in the CTLA4-FasL group. Conclusions CTLA4-FasL can prolong the survival time of corneal allografts in mice, exerting a negative regulation on T-cell activation simultaneously by blocking B7 costimulatory signals and inducing Fas-FasL apoptotic pathway. Due to the adjunctive role of FasL, it also appears to be a potential activity of tolerance induction through T-cell apoptotic pathways.     

Preliminary findings in corneal allograft rejection in patients with keratoconus

PURPOSE: Classically, corneal allograft rejection is thought to be a T(H)1-mediated phenomenon. However, T(H)2-mediated allograft rejection has been reported in other transplanted organ systems, including the heart and kidney. We previously reported a form of T(H)2-mediated corneal allograft rejection in a murine model with a T(H)2 immune bias. In this study we sought to determine if there was any evidence for this form of corneal allograft rejection in humans. DESIGN: Experimental study with an interventional case series. METHODS: The clinical records of all keratoconus patients undergoing penetrating keratoplasty at the University of Texas, Southwestern Medical Center from 1994 to 1999 were reviewed. Careful attention was paid to a clinical history of atopy. Atopic patients were selected, because these patients have been shown to have a "T(H)2 immune bias." The corneal graft rejection rate in these patients and the number of repeat corneal transplants performed was determined. The experimental group consisted of patients with a clinical history of atopy and keratoconus who had at least one repeat penetrating keratoplasty for an immunologically rejected corneal transplant. Any patient with evidence of primary allograft failure was excluded from this study. Tissue specimens from these patients were embedded in paraffin, serially sectioned, stained with Giemsa stains, and examined histologically. The control group consisted of patients without a clinical history of allergy (and therefore no T(H)2 immune bias) who underwent corneal transplantation for Fuch corneal endothelial dystrophy, or aphakic/pseudophakic bullous keratopathy. Failed grafts from these control patients were also paraffin embedded, serially sectioned, stained, and examined histologically. The human experimental and control corneal specimens were compared with data obtained in a murine model of T(H)2-mediated corneal allograft rejection. Briefly, full-thickness penetrating C57BL/6ByJ corneal allografts were transplanted onto Balb/cByJ and Balb/c-IFN-gamma(tm1Ts) (Balb/c-IFN-gamma knockout) mice. Additionally, full-thickness Balb/cByJ corneal allografts were transplanted onto C57BL/6ByJ and C57BL/6ByJ-IFN-gamma(tm1Ts) mice. Corneal allograft rejection rates and mean rejection times were calculated and compared between wild-type and interferon gamma (IFN-gamma) knockout hosts. The rejected allografts were examined histologically by the same methods used in the human tissue. RESULTS: There were 84 penetrating keratoplasties performed from 1994 to 1999 for keratoconus. Seven of these 84 patients rejected their corneal grafts. Of the 7 patients who rejected their corneal allografts, 4 had repeat penetrating keratoplasty. Of these 4 repeat corneal allografts, 3 showed eosinophilia when compared with rejected grafts in control patients. Atopic keratoconus patients had a mixed inflammatory cellular infiltrate in the rejected corneal tissue specimen with a significantly greater density of eosinophils (P =.001) compared with patients who did not have a pre-existing T(H)2 bias. The inflammatory infiltrate in these patients without a T(H)2 immune bias was mononuclear. In the murine model, corneal allograft rejection did occur in the absence of IFN-gamma, a critical T(H)1 cytokine in both fully allogeneic donor-host combinations. Histologically, rejection in these ("T(H)2 mice") was characterized by a predominant eosinophilic infiltrate in the rejected graft bed when compared with wild-type animals ("T(H)1 mice") that had a predominantly mononuclear infiltrate in the rejected corneal graft bed. CONCLUSIONS: Preliminary findings show that corneal allograft rejection in patients with a pre-existing T(H)2 phenotype is similar to what is seen in the murine model of T(H)2-mediated corneal allograft rejection. Based on this small sample, it appears that eosinophils may play a role in corneal allograft rejection in this group of patients. However, further study is necessary to determine the importance of these cells in allograft rejection.     

细胞毒T淋巴细胞相关抗原4免疫球蛋白抑制鼠高危角膜移植免疫排斥反应的实验研究

目的　探讨细胞毒T淋巴细胞相关抗原 4免疫球蛋白 (CTLA4 Ig)对小鼠高危角膜移植免疫排斥反应的抑制作用及局部抗免疫排斥反应机制。方法　建立 5 0只BALB/c小鼠穿透性角膜移植动物模型。治疗组 (2 5只 ) :取C5 7BL/ 6小鼠角膜片 ,放置于 10 μg/mlCTLA4 Ig保存液中浸泡 2 4h后 ,移植到BALB/c小鼠。对照组 (2 5只 ) :植片不行任何处理。术后每 3d用裂隙灯显微镜检查植片情况 ,每周应用组织学和免疫组织化学方法检测植片中各种炎性细胞和淋巴细胞的变化。对出现排斥反应的角膜植片应用逆转录PCR(RT PCR)方法检测部分细胞因子的表达。另外 ,选择经CTLA4 Ig治疗、植片保持透明 6周以上的小鼠作为受体 ,接受来自C5 7BL/ 6小鼠皮肤的移植 ,当移植皮肤发生排斥时 ,进行迟发性超敏反应 (DTH)分析。结果　CTLA4 Ig治疗组角膜植片保持透明 >10 0d。对照组小鼠术后 14d内均发生免疫排斥反应。组织病理学检查显示 ,角膜移植术后 2周 ,CTLA4 Ig治疗组植片保持正常细胞结构 ,无明显炎性细胞和T淋巴细胞浸润 ;对照组的排斥植片有大量炎性细胞和T淋巴细胞浸润 (包括CD 4 ,CD 8及CD 11细胞 )。术后 2周发生免疫排斥的角膜植片中检测到白细胞介素 10 (IL 10 ) ,肿瘤坏死因子α(TNF α) ,γ干扰素 (IFN γ) ,B7及C     

CD4＋ NK T细胞在超抗原SEB诱导大鼠高危角膜移植免疫耐受中的作用

目的研究超抗原金黄色葡萄球菌肠毒素B亚单位（SEB）治疗高危角膜移植免疫排斥反应与CD4＋自然杀伤（NK）T细胞的相关性。方法Fisher 344大鼠21只作为供体,Lewis大鼠42只作为受体。缝线法诱导角膜新生血管,建立高危角膜移植动物模型。将受体大鼠随机分为3组,每组14只。SEB组在角膜移植术前腹腔内注射75μg/kgSEB 0.2 mL,每4日1次,共3次;SEB联合地塞米松组除按上述方法注射SEB外,在角膜移植术后每日结膜下注射5 g/L地塞米松0.1 mL,每日1次,共3次;生理盐水组按SEB组的方法腹腔内注射等体积生理盐水。术后观察植片混浊、水肿和新生血管指标并进行评分。术后第10天,每组取3只受体大鼠进行组织病理学和免疫学检测。结果SEB组植片平均存活时间为（12.50±1.41）d,较SEB联合地塞米松组（10.38±3.07）d和生理盐水组（7.30±0.67）d明显延长（P〈0.05）。SEB组淋巴细胞的增生能力明显降低,脾脏和颌下淋巴结中的CD4＋NK T细胞百分数明显升高。SEB联合地塞米松组脾脏和颌下淋巴结中的CD4＋和CD8＋细胞百分数均明显降低。SEB组房水和血清中IL-2质量浓度均明显降低,而IL-10质量浓度均明显升高。结论超抗原SEB能够明显延长大鼠高危角膜移植手术植片的存活时间,其作用机制与上调了CD4＋NK T细胞有关,CD4＋NK T细胞对于免疫耐受的形成有重要作用。     

Promotion of murine orthotopic corneal allograft survival by systemic administration of anti-CD4 monoclonal antibody.

A mouse model of orthotopic corneal allograft rejection was used to examine the efficacy of anti-CD4 and anti-CD8 monoclonal antibodies in preventing immunologic rejection of corneal allografts. Although it is believed by many that corneal graft rejection is mediated, at least in part, by CD8-positive cytotoxic T-lymphocytes, systemic administration of anti-CD8 antibody did not reduce the rejection rate of corneal allografts that differed from the host at the entire major histocompatibility complex. By contrast, systemic administration of anti-CD4 monoclonal antibody reduced the rejection rate from 83% (untreated controls) to 33%. Fluorocytometric analysis of residual lymphoid populations showed that neither monoclonal antibody eliminated the inappropriate subset of T-cells in antibody-treated animals. In vitro cell-mediated cytotoxicity assays showed that both antibodies eliminated allospecific cytotoxic T-lymphocyte populations; however, only anti-CD4 antibody promoted graft survival. Thus, these results indicate that anti-CD4 monoclonal antibody is a powerful immunosuppressive agent for promoting corneal graft survival and that CD8-positive T-cells alone do not cause rejection of corneal allografts.     

CTLA4-Ig抑制兔角膜移植排斥反应的作用

目的:建立兔角膜移植高危及非高危模型,通过阻断CD28,探讨CTLA4-Ig对高危角膜移植排斥反应的影响。方法:实验分为新生血管化模型组及非新生血管化组,每组随机分成:空白对照组(空白保存液)、实验组(浸入含有CTLA4-Ig10mg/L保存液4℃孵育18h),每组10只兔。观察术后受体植片角膜混浊情况和植片病理改变,原位杂交方法检测角膜植片TNF mRNA的表达情况,比较植片生存时间。结果:非新生血管化角膜移植组:对照组和实验各组的植片排斥时间或平均植片存活时间上无统计学意义,超过半数植片(16/30,53%)存活时间超过100d。新生血管化角膜移植组:实验组生存时间较长69±34d,对照组26±4d,原位杂交检测移植术后4wk或排斥反应发生时对照组角膜植片上皮下基质层浸润细胞有明显的TNF mRNA的表达,实验组未见TNF mRNA表达。结论:在兔角膜移植排斥反应中应用CTLA4-Ig阻断CD28,可以明显抑制兔高危角膜移植排斥反应,提高移植的存活率。     

Corneal allograft rejection in rabbits

We performed a phase I study to assess the therapeutic efficacy of an anti-T cell monoclonal antibody conjugated with ricin A-chain in a corneal graft rejection model. Corneal allografts were exchanged between Dutch and New Zealand rabbits. Rejections occurred within 16-22 days in untreated animals. Graft rejection was delayed by topical or retrobulbar cyclosporine, but not by subconjunctival injections of a murine anti-rabbit T cell monoclonal antibody, nor by either subconjunctival or intravenous F(ab')2-ricin conjugate.     

Prolongation of rat corneal graft survival by treatment with anti-CD4 monoclonal antibody.

A rat model of orthotopic corneal graft rejection was used to investigate the effect of depletion of subpopulations of immune cells by treatment with monoclonal antibodies. Though CD4+ cells were not eliminated completely by anti-CD4 monoclonal antibodies there was a profound delay in the rejection times of orthotopic corneal allografts. Furthermore a third of the CD4+ depleted animals failed to reject corneal allografts by 100 days post grafting. Despite an almost complete depletion of circulating CD8+ cells, the anti-CD8 antibody treated animals rejected corneal allografts in a similar time course to allografted controls treated with a non-reactive control antibody OX21. These results demonstrate that CD8+ T-cells are not required for rejection of corneal allografts whereas CD4+ T-cells play a critical role in the rejection response. Treatment with anti-CD4 antibodies may have a useful clinical application.     

Lymphocyte infiltration and activation in iris-ciliary body and anterior chamber of mice in corneal allograft rejection

AIM: To investigate the infiltration and activation of lymphocyte in iris-ciliary body and anterior chamber after allogenic penetrating keratoplasty (PK), for further revealing the role of iris-ciliary body in corneal allograft immune rejection. METHODS: In the mice models of PK, BALB/C mice received orthotopic isografts (n =35) or C57BL/6 donor allografts (n =25). Grafts were examined daily for 3 weeks by slit-lamp microscopy and scored for opacity. The infiltration of CD4+ T lymphocyte in iris-ciliary body and anterior chamber was examined by immunohistology and the mRNA of CD80 and CD86 in both cornea graft and iris-ciliary body by RT-PCR was analyzed in allograft recipient at days 3, 6, 10 and the day when graft rejection occurred. Isograft recipients were examined as control at the corresponding time points. Transmission electron microscope was used to study the ultrastructure, especially cell infiltration, of iris-cilary body and corneal graft at day 3, 7 and the day when rejection occurred after allogenic PK. RESULTS: Rejection was observed in all the allograft recipients followed more than 10 days, at a median time of 15 days (range 12-18 days), but not in any of isografts. CD4+ T cells were first detected at day 6 after transplantation in limbus and Ciliary body, and then in the stroma of recipient, iris, anterior chamber and corneal allograft with an increased number until graft rejection occurred. CD80 and CD86 mRNA were detected under RT-PCR examination in both graft and iris-ciliary body of allograft recipient, but not in any of isograft recipient. Three days after operation, lymphocytes and monocytes macrophages were visible in iris blood vessels and the anterior chamber, and vascular endothelial cell proliferation and activation were significant under transmission electron microscopy examination. At day 7, corneal endothelial cells became thinner. Lymphocytes and mononuclear macrophages were found with great number in the anterior chamber and adhered to the corneal endothelium. Blood vessels in iris increased and were filled with lymphocytes. And lymphocytes were detected to migrate through endothelial cell gap out of vessels. When allograft rejection occurred, macrophages attached to endothelial cells with large number of lymphocytes and macrophages infiltrating in iris. CONCLUSION: Lymphocyte infiltration and activation occurred in iris-ciliary body after allogenic PK, and the lymphocytes could migrate from iris blood vessel to the anterior chamber, which might play an important role in corneal allograft immune rejection.