中文摘要：

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。

英文摘要：

Background Immune rejection is a main reason of failure of corneal allografts.Staphylococcal enterotoxin B（SEB） can prolong the survival of the allografts.CD4~＋ nature kill（NK） T cells are very important in the formation of immune tolerance of corneal allografts,but the relationship between SEB and CD4~＋NK T cells is still unclear.ObjectiveThis study is to investigate the correlation of CD4~＋NK T cells with Staphylococcal enterotoxin B（SEB） treating high-risk corneal reject after transplantation.MethodTwenty-one corneas from 21 Fisher 344 donor rats were transplanted into the 42 Lewis recipients.Corneal neovascularization was induced by suturing to establish the animal models of high risk corneal transplantation in the right eyes.All the recipients were divided into three groups randomly and 14 rats for each group.The SEB of 75μg/kg（0.2mL） was intraperitoneally injected at 3-day interval for 3 times in SEB group.SEB was used at the same way and dexamethasone（Dex） of 5mg/mL（0.1mL） was injected conjunctivally once per day for 3 days in SEB＋Dex group.The same volume of normal saline solution was used in normal saline solution group.All transplants were evaluated for consecutive 30 days.The opacity,edema and neovascularization of grafts were scored according to Dana＇s standard.Ten days after transplantation,three recipient rats in each group were sacrificed and spleen and lymphaden suspension was prepared for the proliferation detect of lymphcytes with ELIASA and CD4~＋/CD8＋ and CD4~＋/CD161＋ were detected by Western blot.Interleukin（IL）-2 and IL-10 levels in aqueous humor was determined by ELISA.ResultsThe survival time of the allografts in the SEB group was（12.50±1.41） days,showing a significant prolong in comparison with that of the normal saline solution group（7.30±0.67days）（P=0.00） and the SEB＋Dex group（10.38±3.07 days）（P=0.00）.Grafts reject occurred in all the rats of normal saline solution group,majority of rats of SEB group and fewer of rat