未成熟树突状细胞诱导建立异基因嵌合体及延长移植物存活的可能机制

目的：研究应用供体来源的未成熟树突状细胞(inDCs)注射受体小鼠后，诱导形成异基因嵌合体及延长移植物存活的机制。方法：(1)应用供体(C57BL／6)来源的骨髓细胞，在体外培养出imDCs，灭活后体内输注或体外直接刺激受体小鼠(Balb/C)的脾细胞，观察脾细胞对供体细胞的应答反应；(2)取已建立异基因嵌合体并有效延长移植物存活的受体小鼠的脾细胞，观察其对供体细胞刺激的应答反应；(3)通过半定量RT—PCR检测不同免疫状态下Th1／Th2型细胞因子的表达情况。结果：应用imDCs体外预刺激脾细胞或体内注射imDCs受鼠的脾细胞，均呈现对供鼠脾细胞刺激的特异性低应答，这种低应答主要出现在受鼠脾细胞在供鼠脾细胞刺激后的72小时内；建立异基因嵌合体并延长移植物存活的受鼠对来自供鼠脾细胞的刺激也表现为低应答，而对于无关第三者脾细胞的刺激仍保持较高水平，二者比较，统计学处理有显著性差异(P＜0．05)；在诱导形成异基因嵌合体及延长移植物存活的过程中，一定程度上显示出Th1／Th2模式的偏移。结论：应用供体来源的imDCs注射给受体，诱导形成异基因嵌合体和延长移植物存活的机制可能与imDCs诱导受体T细胞无能有关，而且此过程中在一定程度上表现为Th1向Th2方向的免疫偏移。

The possible mechanisms of establishing allogeneic chimerism and prolonging allograft survival by immature dendritic cells

Objective:To explore the possibly mechanisms of inducing allogeneic chimerism and prolonging allografts survival in recipients by immature dendritic cells (imDCs) Methods:Bone marrow cells (BMCs) derived from donor (C57BL/6) were used to generate imDCs The splenocytes of recipients were pretreated by inactivated imDCs in vitro, or the recipients (Balb/C) were injected of inactivated imDCs via vein in vivo Then collected the splenocytes mixed with the inactivated splenocytes from donor to detect the responsiveness Mixed lymphocyte reaction was also used to evaluate the reactivity of the chimerism mice to the donor splenocytes At the same time the diversion of Th1/Th2 paradigm was studied by semi quantitative RT PCR Results:The splenocytes conditioned with imDCs pretreatment expressed hypo responsiveness to the donor stimulation, and the immunized mice also proliferated less degree compared with the naive mice The hyporeactivity was evidently seen within 72 hours after stimulation by donor splenocytes There was significant difference between them The chimerism mice showed unresponsiveness to donor antigens, while reactivity to the third party antigens was retained The result of RT PCR suggested, to some extent, there was a diversion of Th1/Th2 paradigm in the establishment of chimerism in the model Conclusion:The putative mechanism of immature dendritic cells inducing the generation of allogeneic chimerism may based on the hypo responsiveness produced by imDCs, and there may also exist some kinds of diversion of Th1/Th2 paradigm