超抗原金黄色葡萄球菌肠毒素B亚单位防治大鼠高危角膜移植免疫排斥反应的研究

目的探讨超抗原金黄色葡萄球菌肠毒素B亚单位(SEB)对大鼠高危角膜移植免疫排斥反应的防治作用机制。方法实验供体为30只Fisher344和4只Lewis大鼠,受体为64只Lewis大鼠。将实验受体大鼠按随机数字表法随机分为4个治疗组和1个对照组,每组12只;同时设4只Lewis大鼠行同种同体移植。治疗组术前分别用02ml不同浓度的SEB(25、50、75、100μg/kg)腹腔注射诱导免疫耐受。对照组用02ml生理盐水腹腔注射。缝线法诱导受体角膜新生血管,然后行穿透性角膜移植术,术后观察记录植片的存活状况并对受体全身免疫状态进行免疫组化染色,流式细胞分析和淋巴细胞增殖能力检测。结果对照组大鼠角膜植片的平均存活时间为(730±067)d,SEB治疗组(25、50、75、100μg/kg)植片存活时间分别为(643±127)d、(1070±250)d、(1250±141)d、(883±194)d。免疫组织化学染色和流式细胞检测显示SEB治疗组大鼠角膜植片中淋巴细胞的浸润以及外周免疫器官中淋巴细胞亚群百分数较对照组明显降低。此外,SEB治疗组中受体淋巴细胞对供体抗原刺激的反应性降低,外周血中白细胞介素(IL)2浓度降低而IL10浓度升高,其中以SEB75μg/kg组作用最明显。结论在一定剂量范围内,SEB可以诱导大鼠免疫耐受形成,减少局部和全身淋巴细胞数量,并有效防治高危角膜移植免

Immune tolerance induced by staphylococcal enterotoxin B for the treatment of rat high-risk corneal transplantation rejection

OBJECTIVE: To determine the mechanism of staphylococcal enterotoxin B (SEB) induced immune tolerance in the treatment of high-risk corneal transplantation in the rat. METHODS: Fisher 344 rats were used as donors and Lewis rats were used as recipients. Corneal neovascularization was induced by sutures. The rats were divided randomly into five groups in a masked fashion. In the 4 SEB-treated groups, 0.2 ml SEB were intraperitoneally injected before the keratoplasty at concentrations of 25 microg/kg, 50 microg/kg, 75 microg/kg and 100 microg/kg, respectively. The control group received a saline buffer injection intraperitoneally. All allografts were observed and scored for 30 days. Meanwhile, the infiltration of lymphocytes in the allografts, the percentage of lymphocyte subpopulations in the immune organs, the proliferation ability of the lymphocytes and the cytokines in the serum were measured. RESULTS: The SEB at the concentration of 25 microg/kg did not prolong the survival time of the allografts as compared to the control group. With the increase of the concentration of SEB, the survival time in the other three SEB-treated groups were prolonged significantly and the 75 microg/kg group showed the best results. The infiltration of the lymphocytes in the allografts and the percentages of CD4+ and CD8+ lymphocytes in the immune organs in the SEB treated groups were reduced. The proliferation ability of the lymphocytes in SEB treated groups was decreased; the concentration of IL-2 was lower while the concentration of IL-10 was higher in the serum in the SEB treated groups. CONCLUSIONS: SEB at an optimal concentration is effective in inhibiting immune rejection in high-risk corneal transplantation. The mechanism of SEB induced immune tolerance is related to the reduction of the number and the immune tolerance status of the lymphocytes.