过继转发IRBP致敏脾细胞诱发EAU、EAP的实验研究

将光感受器间维生素A类结合蛋白(IRBP)免疫鼠的脾细胞单独或与IRBP一起培养后注射至6只Lewis鼠的腹腔内(每鼠3×10⁷个细胞),发现经IRBP刺激的脾细胞既可转移特异性免疫反应，又可使受鼠发生实验性自身免疫性葡萄膜视网膜(EAU)、实验性自身免疫性松果体炎(EAP)；而未用IRBP刺激的脾细胞则不能诱发EAU、EAP和特异性免疫反应。此结果表明细胞免疫在EAU、EAP发生中起决定性作用，并证明过继转移前用特异性抗原刺激是不可缺少的。 （中华眼底病杂志，1993，9：210-213）     

视网膜S抗原的制备和提纯方法的改进

实验性自身免疫性葡萄膜炎(EAU)是由CD4+T淋巴细胞介导的器官特异性炎症,可由多种视网膜蛋白诱发,主要有视网膜可溶性抗原(S-Ag)、光感受器间维生素A类结合蛋白(IRBP)和视紫红质等,其中以S抗原诱发的葡萄膜炎更具有临床意义[1]。由于S抗原所致葡萄膜炎的活性与其纯度呈正相关,所以S抗原的纯化尤为重要。我们将Al-Mahdawi等[2]的方法进行改进简化,获得了较高纯度的牛视网膜S抗原,并免疫Lewis大鼠成功地复制出EAU模型。现将结果报告如下。1材料和方法冰浴下暗室解剖新鲜牛眼,沿角膜缘环行切开眼球,挤出晶状体和玻璃体,用毛笔刷轻取…     

实验性自身免疫性葡萄膜视网膜炎中浸润细胞的表型及其凋亡的研究

目的探讨实验性自身免疫性葡萄膜视网膜炎(experimental autoimmune uveoretinitis,EAU)中参与的细胞表型及其凋亡。方法用光感受器间维生素A类结合蛋白(interphotoreceptor retinoid-binding protein,IRBP)免疫16只Lewis鼠后，于眼组织切片和平片上进行免疫组织化学染色和原位 凋亡染色，所用抗体为抗单核细胞、巨噬细胞(EDI)、MHC-II类抗原(OX6)、T淋巴细胞(R73)的单克隆抗体，所用原位凋亡试剂盒为TACS1 Klenow。结果用IRBP免疫Lewis鼠后，16只鼠中12只发生了临床可见的葡萄膜炎，炎症平均得分为1.29±0.7级；免疫组织化学染色发现葡萄膜和视网膜中有大量的单核细胞、淋巴细胞及MHC-II⁺细胞浸润，这些组织中均可见浸润细胞的凋亡，虹膜睫状体中凋亡细胞明显多于脉络膜和视网膜中的凋亡细胞。结论单核巨噬细胞、淋巴细胞和MHC-II⁺细胞均参与了EAU的形成，在EAU早期即有浸润细胞发生凋亡，此可能是导致这种炎症迅速消退的重要机制。（中华眼底病杂志，2000，16：1-70）     

抗肿瘤坏死因子-α单克隆抗体治疗实验性自身免疫性葡萄膜视网膜炎的研究

目的 观察抗肿瘤坏死因子-α单克隆抗体（TNF-α MCAb）对于实验性自身免疫性葡萄膜视网膜炎（EAU）的治疗作用。方法 合成光感受器间维生素A类结合蛋白（IRBP）R16多肽片段，联合免疫佐剂诱导EAU动物模型。按照注射次数不同将大鼠分为2组，分别于IRBP R16免疫后的第6天和第4、6、8天自大鼠尾静脉注入TNF-α MCAb，裂隙灯显微镜观察其眼部临床表现，同时设未治疗组大鼠作为对照。于IRBP R16免疫后第13天测量迟发型超敏反应（DTH），并于第14天处死大鼠，取眼球行组织病理检查。应用酶联免疫吸附试验（ELISA）检测抗体注射后14 d 时大鼠血清中Th1类细胞因子γ-干扰素（IFN-γ）、Th2类细胞因子白细胞介素-4（IL-4）水平以及房水中IFN-γ水平。测量引流淋巴结细胞的抗原特异性淋巴细胞增生反应。结果 TNF-αMCAb治疗组大鼠的眼部炎症较未治疗组明显减轻，病理分级下降；房水和血清中IFN-γ水平降低，血清中IL-4增高；DTH反应下降；引流淋巴结细胞对IRBP R16多肽刺激的增生反应下降，差异均有统计学意义（P＜0.01）。与单次注射相比，3次注射的治疗效果更显著（P＜0.05）。结论 TNF-αMCAb能够有效减轻EAU大鼠眼部的炎症反应和特异性细胞免疫反应，改变Th1/Th2细胞因子平衡；多次应用作用更显著。     

实验性自身免疫性葡萄膜视网膜炎中可诱导的共刺激分子的表达及意义

目的探讨可诱导的共刺激分子（ICOS）在实验性自身免疫性葡萄膜视网膜炎(EAU)中的表达及意义。方法Lewis大鼠28只，用视网膜S抗原（50 μg）和福完全佐剂免疫24只大鼠以诱导EAU模型（免疫组），另外4只作为正常对照。裂隙灯显微镜每日观察大鼠眼部变化。免疫组大鼠分别于免疫后第7、12、15、21天被处死，摘除其脾脏后制作冰冻连续切片并提取组织蛋白。使用多克隆抗ICOS抗体，用免疫组织化学细菌蛋白过氧化物酶（SP）法在上述组织切片上进行免疫组织化学染色，并对提取的蛋白进行Western blotting检测。对照组大鼠在相应各时间点做同样处理。结果正常脾组织中可见少量ICOS阳性细胞；分别在免疫后第7、12 d，脾脏中ICOS阳性细胞数量明显增加，免疫后第15天时阳性细胞数量最多，21 d时阳性细胞数量减少，但仍显著高于正常组；Western blotting检测结果显示，ICOS蛋白的动态变化与免疫组织化学显示的阳性细胞数量变化一致。结论脾脏ICOS表达升高出现于EAU发生之前，随炎症的出现和加重而升高，在EAU消退期其表达有所降低，提示ICOS参与EAU的形成、发展和消退，在EAU发病中有重要意义。(中华眼底病杂志,2005,21:114-117)     

实验性自身免疫性葡萄膜炎炎性因子表达的动态观察

背景 C57BL/6 (B6)小鼠是实验性自身免疫性葡萄膜炎(EAU)动物模型常用的小鼠种系,以往研究证明葡萄膜炎的发病机制与辅助性T(Th)细胞分泌的炎性细胞因子相关,但各种Th细胞在EAU发病中的相互作用并不十分清楚. 目的 研究光感受器间维生素A类结合蛋白(IRBP)诱导不同天数后EAU小鼠脾脏和血清中炎性因子的动态变化,探讨各种炎性因子在EAU病理过程中的作用. 方法 用IRBP及完全弗氏佐剂(CFA)的乳化液在小鼠的尾根部及躯干部均匀注射5个点以免疫B6小鼠44只,免疫后每周3次用间接检眼镜观察小鼠的EAU发病情况,并参照Thurau的评分标准进行炎症评分.于注射后第30天摘取20只模型小鼠眼球,于瞳孔视神经平面制备切片行组织病理学检测.分别于注射前,注射后第2、5、10、15、20、25、30天取模型小鼠脾脏,提取RNA,逆转录扩增并行凝胶电泳,检测白细胞介素-17(IL-17)、γ干扰素(IFN-γ)、肿瘤坏死因子-α(TN F-α)和IL-10等因子的mRNA含量,同时收集相同时间点小鼠的血清,采用酶联免疫吸附试验(ELISA)检测血清中上述因子的质量浓度. 结果 IRBP及CFA乳化液免疫B6小鼠后第12天可见轻度葡萄膜炎症,炎症评分为0.5分,炎症反应在免疫后第13～ 15天最重,评分为1.0分,至第30天炎症明显减轻,评分为0.5.组织病理学检查显示,注射后第30天模型鼠眼部反应与间接检眼镜检查结果吻合,病理评分为0.5.模型鼠血清炎性因子检测结果显示,注射后第5天,小鼠血清中IL-17的质量浓度达到峰值,为(51.85±2.42) ng/L,随着时间的延长开始降低.到第15天时降到最低,为(4.01 ±0.06)ng/L,但在第25天时再次升高至(25.00±0.94) ng/L,之后逐渐下降,第30天时,血清中IL-17的质量浓度为(6.01±0.21)ng/L,与免疫前的(0.98±0.05) ng/L相比差异有统计学意义(P=0.000).小鼠免疫前血清中IFN-γ的质量浓度为(1.02±0.09) ng/L,在注射后第5天达到(50.54±0.48)ng/L,于注射后第10天达到峰值,为(73.21±0.12) ng/L,然后逐渐降低.到第30天时,血清中IFN-γ的质量浓度为(5.15±0.18) ng/L,与免疫前相比差异仍有统计学意义(P=0.000).注射后模型鼠血清中TNF-α质量浓度升高迅速,免疫后第2天质量浓度较免疫前明显升高,第5天达到峰值,质量浓度为(134.25±0.59) ng/L,但至第15天降到最低.注射后第20天再次升高,达到(60.54±0.62)ng/L,之后又逐渐下降,第30天时和免疫前相比差异无统计学意义(P=0.660).IL-10在免疫后第5天可以被检测到,并且随着注射后时间的延长逐渐升高.到第15天时达到高峰,随后开始降低,第30天与免疫前相比差异有统计学意义(P=0.000).脾脏中IL-10、IL-17、TNF-α、IFN-γ 4种炎性因子mRNA表达变化趋势和血清中的变化一致. 结论 在B6小鼠的EAU中,Th1、Th2、Th17相关炎性因子IFN-γ、TNF-α、IL-10及IL-17具有特征性变化规律,IFN-γ可能与EAU的急性期病理过程相关;IL-17、TNF-α可能与葡萄膜炎的慢性化、复发性有关;IL-10可缓解EAU的病理过程.     

IL-17在实验性自身免疫性葡萄膜炎大鼠模型眼部的表达

目的研究IL-17阳性细胞在实验性自身免疫性葡萄膜炎（EAU）大鼠模型眼部的表达。方法用光感受器间维生素A类结合蛋白（IRBP）和氟氏完全佐剂等量混合注射于20只Lewis大鼠的右后足底部为实验组,于建模后第7、10、11、12、13、14、21、28天用裂隙灯显微镜进行眼前节检查,并根据de Smet的标准对炎症进行分级。用0.3 mL肝素（5 000 U/mL）注射至左心室以抗凝血,然后取眼球制作冰冻切片。免疫组织化学染色观察IL-17多克隆抗体在眼组织中的表达,5只正常Lewis大鼠作为对照。结果用IRBP免疫Lewis鼠后第10天,裂隙灯显微镜下可见眼前节炎症表现,免疫后第7、14、21、28天各组大鼠眼部炎症平均得分为0.4、3.2、1.6和0.2。实验组大鼠眼组织切片的苏木精-伊红染色可见炎性细胞浸润和光感受器细胞破坏。免疫组织化学染色发现,实验组虹膜、睫状体和视网膜部位可见IL-17蛋白表达,而正常组未见IL-17蛋白表达。第7、14、21、28天各组大鼠眼部组织切片染色的平均得分分别为0.6、4、2、0.4。EAU大鼠眼部炎症表现的严重程度与IL-17的表达量呈正相关（r=0.968,P〈0.01）。结论IL-17蛋白在Lewis大鼠EAU模型中呈高表达,表明IL-17阳性表达细胞在EAU的发病过程中起一定作用。     

龙胆泻肝汤对葡萄膜炎大鼠关键炎症细胞因子表达的影响

目的 探讨龙胆泻肝汤对实验性自身免疫性葡萄膜炎(experimental autoimmune uveitis,EAU)大鼠关键炎症细胞因子表达的影响.方法 Lewis大鼠随机分为对照组(6只)、EAU组(18只)和LXT组(18只).光感受器间维生素A结合蛋白(interphotoreceptor retinoid-binding protein,IRBP)免疫EAU组和LXT组大鼠,对照组大鼠注射等量不含IRBP的乳化液.使用实时荧光定量PCR及ELISA方法检测血液、淋巴结和脾脏中IFN-γ、IL-17、TNF-α和IL-10细胞因子在EAU大鼠体内治疗前后的变化情况.结果 LXT组大鼠全血中IFN-γ mRNA表达在第8天虽然高于对照组(P=0.000),但已显著低于EAU组(P=0.000);LXT组IL-17 mRNA在第12天达峰值,显著低于EAU组(P=0.000),且均显著高于对照组(P=0.000);TNF-α mRNA仅在第12天显著高于对照组(P=0.000),但低于EAU组(p=0.000);IL-10 mRNA表达在第16天高于EAU组(P =0.042).LXT组大鼠淋巴结和脾脏中IFN-y、IL-17和TNF-α mRNA表达在第12天显著低于EAU组(均为P =0.000);LXT组淋巴结中IL-10 mRNA表达在第8天开始显著高于对照组(P=0.001),且在整个炎症期均维持在较高水平;LXT组脾脏IL-10 mRNA表达在第12天达峰值,且高于对照组和EAU组(均为P=0.000).LXT组大鼠血清中IFN-y、IL-17和TNF-α蛋白表达水平在第12天和第16天均低于EAU组(均为P＜0.05);EAU组和LXT组血清中IL-10蛋白表达在第12天均高于对照组(均为P ＜0.05),第16天达峰值,但LXT组IL-10蛋白含量更高.结论 龙胆泻肝汤通过抑制IFN-γ、IL-17和TNF-oα相关炎症因子的表达发挥其抗炎作用,促进IL-10的表达,加速自身免疫炎症的恢复.龙胆泻肝汤可通过多种途径在EAU的治疗中发挥免疫调节作用.     

γδ T细胞在实验性自身免疫性葡萄膜炎小鼠脾脏中的动态表达及作用机制

背景 以往研究证明葡萄膜炎的发病机制与γδ T细胞相关,γδ T细胞在实验性自身免疫性葡萄膜炎(EAU)中的作用尚不完全清楚. 目的 研究γδ T细胞在EAU小鼠脾脏中的动态变化,探讨γδ T细胞在EAU病程进展中的作用机制.方法 应用随机数字表法将45只C57 BL/6(B6)小鼠随机分为正常对照组6只和模型组39只.用抗原肽光感受器间维生素A类结合蛋白1-20(IRBP1-20)及完全弗氏佐剂(CFA)的乳化液在B6小鼠的足垫、尾根部及躯干部均匀注射6个点,用Genesis-D动物眼部照相机观察并记录正常小鼠及免疫后不同时间点(4、8、12、16、20、24、28、32和36 d)EAU小鼠的发病情况,参照Thurau的评分标准进行炎症评分.颈椎脱臼法处死小鼠后摘取右侧眼球,切片后行组织病理学评分.同时在相同时间点分离模型小鼠脾脏淋巴细胞,流式细胞仪检测γδ T细胞数量和激活状态.免疫磁珠分选γδ T细胞,并用流式细胞仪检测其细胞内表达白细胞介素-17A(IL-17A)的变化.向EAU小鼠回输激活的γδ T细胞,观察炎症变化. 结果 经IRBP1-20及CFA乳化液免疫后小鼠于第12天可见轻度葡萄膜炎症,炎症反应在免疫后第16 ～20 d达峰,至第28天炎症明显减轻.组织病理学观察发现,免疫小鼠视网膜外核层皱褶,玻璃体、视网膜全层炎性细胞浸润及内界膜层增厚.造模后不同时间点的炎症症状评分和病理学炎症评分的总体比较,差异均有统计学意义(F=51.399,P=0.000;F=47.342,P=0.000).流式细胞仪检测发现,EAU发病高峰期小鼠的脾脏中γδ T细胞数量增加,造模后16 d和20 d分别为(5.67±0.49)％和(5.78±0.55)％,与造模前的(1.53±0.14)％比较,差异均有统计学意义(均P＜0.05),且呈活化状态.EAU发病高峰期小鼠的脾脏中γδ T细胞分泌的IL-17A明显增多,造模后16d和20 d分别为(13.40±0.50)％和(17.80±2.37)％,与正常对照小鼠的(1.53±0.19)％比较,差异均有统计学意义(P=0.000、0.001).体内回输激活的γδ T细胞后EAU炎症加重,炎症症状评分为1.00(1.00,2.00),明显高于未回输激活的γδ T细胞的0.75(0.05,1.00),二者比较差异有统计学意义(Z=27.00,P=0.03).结论 EAU中γδ T细胞比例在炎症的高峰期明显升高,且呈激活状态;活化性Yδ T细胞在EAU模型中发挥的免疫调节作用可能是通过分泌IL-17A进行的.     

大鼠自身免疫性葡萄膜视网膜炎眼部细胞因子信号抑制因子的表达

目的:大鼠自身免疫性葡萄膜视网膜炎(experimentalautoimmune uveoretinitis,EAU)大鼠模型眼部研究细胞因子信号抑制因子(suppressor of cytokine signaling,SOCS)的表达。方法:用光感受器间维生素A类结合蛋白(interphotoreceptorretinoid-binding protein,IRBP)免疫Lewis鼠160只后,在眼组织切片上应用SOCS多克隆抗体进行免疫组织化学染色,观察其在眼组织中的表达并与正常大鼠40只做对照。结果:用IRBP免疫Lewis鼠后,免疫组织化学染色发现在虹膜、睫状体和视网膜部位可见SOCS-1和SOCS-5蛋白表达;而在正常Lewis鼠未见SOCS蛋白表达。统计学结果显示,SOCS-1和SOCS-5蛋白表达与EAU严重程度呈正相关(r1=0.954,r2=0.963,P<0.01)。结论:自身免疫性葡萄膜视网膜炎Lewis鼠出现SOCS阳性表达细胞在EAU的发病过程中起了一定的作用。     

Antigen-specific suppressor cells induced by FK506 in experimental autoimmune uveoretinitis in the rat.

The authors previously reported that FK506 effectively suppressed the induction of experimental autoimmune uveoretinitis (EAU) in rats with much lower doses than cyclosporine A. This study was aimed at analyzing the immune status of the FK506-treated and EAU-suppressed rats and examining the hypothesis whether the agent could induce antigen-specific suppressor T (Ts) cells. It was found that spleens from S-antigen-immunized and FK506-treated rats contained a population of Ts cells inhibiting the proliferative responses of S-antigen-sensitized lymphocytes to S-antigen, yet these cells did not affect the proliferative responses of interphotoreceptor retinoid-binding protein (IRBP)-sensitized lymphocytes to IRBP. The helper T (Th) cells did not exhibit such suppressor activities. Furthermore, transfer of Ts cells from S-antigen-immunized and FK506-treated rats to naive syngenic rats induced partial inhibition of EAU induction or delay of EAU onset after immunizing the recipient rats with S-antigen. Lymphocytes from the EAU-suppressed recipients showed low proliferative response to S-antigen and low levels of antibody to S-antigen. These data thus indicate that FK506 treatment after S-antigen immunization induces an activation of Ts cells specific to S-antigen and that the Ts cells might contribute, at least in part, to the uniquely prolonged and intensive immunosuppression by FK506.     

Experimental autoimmune uveoretinitis in brown Norway rats induced by bovine interphotoreceptor retinoid-binding protein and renal cryosurgery

In Brown Norway (BN) rats, it is known to be difficult to induce experimental autoimmune uveoretinitis (EAU) by the injection of retinal S-antigen (S-Ag) or interphotoreceptor retinoid-binding protein (IRBP) together with complete Freund's adjuvant (CFA), unless intravenous Bordetella Pertussis is used as an additional adjuvant. In the present study it was found that the rate of onset of EAU could be increased in BN rats immunized with IRBP and CFA by simultaneous cryosurgery to the renal cortex. There was no evidence of retinal vasculitis, pinealitis or nephritis in the rats with EAU except for renal inflammatory infiltrates as a reaction to the cryosurgery. Affected eyes eventually showed destruction of most retinal components and prominent infiltration of the retina by macrophages, with the changes being more severe than those previously reported in Lewis rats with EAU induced by IRBP. Data suggesting the existence of an antibody that cross-reacts with the proximal renal tubules and the retinal pigment epithelium were also obtained.     

Experimental autoimmune uveoretinitis (EAU) in rats: isolation of S-antigen, EAU susceptibility of rat strains, genetic control of EAU induction, and effects of cyclophosphamide and irradiation on EAU

Highly purified S-antigen was isolated from bovine retinas by high performance liquid chromatography (HPLC), and was used to induce experimental autoimmune uveoretinitis (EAU) in various rat strains. Studies were then made of the genetic control of EAU, the effects of cyclophosphamide or irradiation on EAU, and the correlation between the EAU incidence and the serum levels of antibody to S-antigen. Lewis rats were the most susceptible to EAU followed by Wistar rats. F344 rats and BN rats were resistant to EAU. (Lewis X BN)F1 rats and (LBNF1 X Lewis) rats were susceptible to EAU, while (LBNF1 X BN) rats were resistant. These results indicate that susceptibility to EAU was inherited as an autosomal dominant trait. Treatment of rats with cyclophosphamide or irradiation (200 rad/rat) on the day before immunization markedly suppressed EAU development. On the other hand, the same dose of irradiation 7 days after the immunization did not affect the disease induction, yet the antibody levels to S-antigen were very high in the rats. In addition, BN rats resistant to EAU exhibited very high levels of antibody to S-antigen. Therefore, the antibody to S-antigen seems to play a minor role, if any, in the immunopathogenic mechanisms of EAU.     

Differential expression of nitric oxide synthase in experimental uveoretinitis.

PURPOSE: To investigate the site and the cellular source of inducible nitric oxide synthase (iNOS) expression in human S-antigen peptide-induced experimental autoimmune uveoretinitis (EAU). METHODS: Twenty-one Lewis rats were sensitized with human S-antigen peptides. Three rats were killed each consecutive day from day 6 through day 12 after sensitization. Frozen sections of the enucleated eyes were analyzed for iNOS by the dual immunohistochemical method. Primary antibodies included rabbit anti-mouse iNOS combined with anti-human endothelium NOS, anti-rat lysosomal protein (ED1), or anti-rat major histocompatibility complex class II molecule (OX6) monoclonal antibodies. Secondary antibodies were fluorescein-conjugated anti-mouse IgG and streptavidin rhodamine-labeled anti-rabbit IgG. The adjacent sections were separately stained with ED1, iNOS, and glial fibrillary acidic protein (GFAP). The mouse macrophage cell line RAW 264.7 was exposed to either interferon (IFN)gamma/lipopolysaccharide (LPS) or S-antigen and to interphotoreceptor retinoid-binding protein (IRBP), myelin basic protein, and bovine serum albumin for 12 hours. Cells were harvested for detection of iNOS expression by northern blot analysis hybridization and detection of protein by immunohistochemistry. RESULTS: In the retina of eyes with EAU, ED1+/iNOS+ and OX6+/iNOS+ cells were first detected on day 9 after sensitization. These iNOS+ cells increased in number on subsequent days in parallel with the increasing severity of retinal damage. Most of the cells localized around the outer retina. In contrast, a large number of ED1+ and OX6+ cells that were localized in the uvea and conjunctiva were negative for iNOS. Retinal pigment epithelial cells did not stain for iNOS. Macrophages exposed to IFNgamma/LPS, S-antigen, and IRBP showed expression of iNOS mRNA and the protein. CONCLUSIONS: Macrophages are an important source of NO production in eyes with EAU. These macrophages preferentially express iNOS in the retina. Such a differential expression of iNOS by the macrophages appears to be related to retinal soluble proteins.     

Murine experimental autoimmune uveoretinitis induced by interphotoreceptor retinoid-binding protein and Klebsiella pneumoniae 03 lipopolysaccharide (K03-LPS): a relation between H-2 haplotype and EAU induction

The pathogenicity of interphotoreceptor retinoid-binding protein (IRBP) in the mouse and H-2 restriction of IRBP-induced experimental autoimmune uveoretinitis (EAU) was tested by repeated immunization using Klebsiella pneumoniae 03 lipopolysaccharide (K03-LPS) as an adjuvant. It was shown that IRBP had a greater capacity to induce EAU than S-antigen. Based on the incidence of EAU induction using B10 congenic mice and other strains, the susceptibility to EAU was, at least in part, controlled by the I-A^k haplotype of the H-2 subregion. The results also indicated that non-major histocompatibility complex (MHC) genes play some role in disease susceptibility.     

The purification of bovine IRBP and its uveitogenic action]

The interphotoreceptor retinoid-binding protein, IRBP, shuttles the retinoid between photoreceptor cells and the pigment epithelium. It also induces experimental autoimmune uveoretinitis (EAU). The authors first purified IRBP in China by Con A Sepharose affinity chromatography in conjunction with the purification of bovine retinal S-antigen by ion-exchange chromatography. EAU was successfully induced by injection of emulsified IRBP 50 micrograms with Freund's complete adjuvant into the footpad of Lewis rats. It was characterized by panophthalmia with severe damage to the posterior retina, and lymphocytes predominated the inflammatory infiltration that included mononuclear and polymorphonuclear cells.     

Humoral autoimmune response against S-antigen and IRBP in ocular onchocerciasis

Autoimmune mechanisms are thought to play a role in the pathogenesis of the chorioretinal changes in ocular onchocerciasis. In this study, the involvement of autoimmunity against retinal antigens in developing chorioretinitis was investigated. Serum levels of autoantibodies, directed against human S-antigen and interphotoreceptor retinoid-binding protein (IRBP), were determined in patients with onchocerciasis (n = 46) and endemic controls (n = 38) from Sierra Leone with the use of an enzyme immunoassay. In both groups high levels of anti-human S-antigen and IRBP antibodies were detected. No relationship could be demonstrated between the antiretinal antibody level and the occurrence of chorioretinitis in onchocerciasis. The levels of both anti-human S-antigen and IRBP antibodies were significantly higher in patients with onchocerciasis compared with endemic controls (P less than 0.001). Cross-reactivity of antiretinal antibodies with parasitic antigens could not be demonstrated as a possible explanation for the higher levels in patients with onchocerciasis. No correlation was found between the levels of antibodies of different classes against the crude Onchocerca volvulus, the egg antigen, or the microfilariae and the antiretinal antibody levels. Furthermore, in a panel of 13 different monoclonal antibodies directed against O. volvulus, only one showed a slight anti-human IRBP reactivity and none reacted with S-antigen. The immune response against the two retinal antigens investigated was not specific for onchocerciasis because high antibody levels were also found in patients with Bancroftian filariasis from Papua, New Guinea, and Surinam.(ABSTRACT TRUNCATED AT 250 WORDS)     

Experimental autoimmune uveoretinitis (EAU) in rats: abrogation of resistance to the induction and augmentation of the inflammation by pertussis toxin

The effect of pertussis toxin (PT) on experimental autoimmune uveoretinitis (EAU) induced by immunization with S-antigen was examined in rats. Intravenous administration of PT (2 micrograms/rat) initiated the development of EAU in rats that had been made resistant to the induction of EAU by immunization with S-antigen and complete Freund's adjuvant (CFA). The capacity of PT to promote EAU was also demonstrated by a marked augmentation of the inflammation in EAU eyes of rats susceptible to the induction of EAU. PT was most effective when it was given from the day before to the day after immunization with S-antigen. However the induction of EAU was promoted by the injection of PT even 7 days before and 14 days after immunization. The clinical and histopathological findings of the EAU produced by the additional PT treatment were described and the mechanisms by which PT augmented the induction of EAU were discussed.     

Interphotoreceptor retinoid binding protein is a potent tolerogen in Lewis rat: suppression of experimental autoimmune uveoretinitis is retinal antigen specific

AIMS—Administration of unfractionated retinal antigen(s) (retinal extract, RE) suppresses RE induced experimental autoimmune uveoretinitis (EAU) and offers a potential therapeutic alternative to non-specific immunosuppressive therapies for posterior uveitis and autoimmune diseases. S-Ag and interphotoreceptor retinoid binding protein (IRBP) are two major autoantigens within soluble RE. It was aimed to assess, firstly, as has previously been shown with S-Ag, if IRBP can induce intranasal tolerance and, secondly, the contribution of both these major autoantigens to tolerance induction by whole RE.
METHODS—Animals were tolerised by intranasal administration with S-Ag or IRBP, either alone or in combination, or RE before immunisation with either IRBP or RE. Control animals were administered nasally either PBS or MBP. Daily clinical responses were recorded biomicroscopically and histological grades were obtained using a semiquantitative scoring system. Weekly serum antibody levels to retinal antigens were measured by ELISA and delayed hypersensitivity responses (DTH) were assessed by skin reactivity to intradermal inoculation with retinal or non-specific antigens.
RESULTS—Microgram doses of IRBP successfully suppressed both clinically and histologically IRBP induced EAU. This suppression was accompanied by reduced antigen specific DTH reactivity but maintained T cell dependent (IgG2a) antibody responses. Furthermore, combined S-Ag and IRBP administration afforded equal suppression of RE induced EAU when compared with RE therapy alone. Suppression of RE induced EAU was not achieved with administration of a non-retinal specific autoantigen, MBP. Although individually, both S-Ag and IRBP suppressed RE induced EAU, whole RE was unable to protect against IRBP induced disease.
CONCLUSIONS—Intranasal administration of IRBP suppressed IRBP induced EAU in the Lewis rat. S-Ag and IRBP are the major contributors to the tolerogenicity within RE, despite the known uveogenicity of other retinal antigens within RE and induction of tolerance was retinal antigen specific. Furthermore, suppression induced by single antigen administration is antigen specific although concomitant bystander suppression may also play a role. RE was unable to protect against IRBP induced disease despite tolerogenic levels of antigen within RE. Although this may be due in part to a dose effect of either tolerising or immunising antigen, further investigation into the possible antigen dominance of IRBP or mucosal processing of combinations of antigens is necessary so that the full efficacy of mucosal tolerance therapy can be assessed.