CD86在排斥反应和前房相关免疫偏离过程中的作用

The effects of CD86 in rejection after penetrating keratoplasty and ACAID in rats

目的检测大鼠角膜共刺激分子CD86(B7-2)的原位表达,探讨CD86分子与角膜移植排斥反应和前房相关免疫偏离(ACAID)过程的关系。方法制作穿透角膜移植排斥反应和同一供体前房内注射脾细胞诱导ACAID的大鼠模型;角膜移植组进行排斥反应指数(RI)评分;ACAID组进行迟发型超敏反应(DTH)评价;采用免疫组织化学的方法检测CD86在角膜中的原位表达(以脾脏的表达为阳性对照)。结果角膜移植组植片均出现不同程度的新生血管、角膜水肿、混浊、增厚;ACAID组角膜透明,房水清,DTH评价术后2周及4周诱导成功率100%;免疫组织化学检测CD86在正常大鼠角膜组织全层无阳性表达,在移植后出现急性排斥反应的大鼠角膜上皮层中有大量阳性细胞表达,在ACAID诱导成功的大鼠角膜中未见阳性细胞表达。结论共刺激分子CD86参与移植后的急性排斥反应,但可能不参与免疫赦免过程。

Objective To investigate the expression of CD86,a co-stimulatory molecule,during corneal allograft rejection and anterior chamber associated immune deviation （ACAID）. Methods Corneal transplantation was performed orthotopically from 15 Wistar donor rats to 70 SD recipients rats. The SD rats were divided into corneal transplantation group（30 rats ） ,ACAID group（30 rats） and ACAID control group（ 10 rats, group Ⅰ ）. ACAID was induced by injection of splenocytes suspension from the same Wistar donor rats into anterior chamber of the right eyes. Three female Wistar rats and 3 male SD normal rats were used as normal controls. Rejection index were determined under the slit-lamp biomicroscope at transplantation group based on the score of edema,opacity and neovaseularization of graft. DTH response to alloantigen were evaluated by measuring an ear swelling hight at ACAID group. The cornea of those rats was enueleated at 1,2,4 weeks after operation,and the expression of CD86 on the cornea whole-mounts was detected using immunohistochemistry,and spleen tissue was as positive control. Results The corneal grafts rejection occurred after transplantation and peaked in 7 - 11 days with the RI ≥ 6. Cornea was clear in ACAID group during the observed period. The edema, vacuolar degeneration of cornea epithelial cells,infiltration of inflammatory cells and new blood vessel were found in graft of transplantation group,but the corneal structure was normal in ACAID group. No CD86 ^＋ cell was seen in normal cornea,however,a lots of CD86 ^＋ positive cells were found in corneal epithelium in allograft rejection of transplantation group. ACAID was induced successfully at two or four weeks after injection of splenoeytes, and no CD86 ^＋ cell was detected in corneal epithelia. The edema of ear edge was significantly mild in ACAID group compared with negative control group. Conclusion Expression of eostimulatory molecules CD86 in cornea in situ may be related to the acute immune rejection after penetrating keratoplasty. CD86 ^＋ cells are not presented on corneal epithelium of ACAID eye. This result suggests that CD86 may have no relationship with immune privilege.