阻断共刺激信号途径对造血干细胞移植后致敏受者免疫耐受排斥的影响简

本研究旨在应用CTLA4Ig及anti-CD154分别阻断致敏小鼠的B7/CD28及CD40/CD154共刺激信号途径,探讨其对异基因造血干细胞（HSC）植入的影响,为临床应用异基因造血干细胞移植（HSCT）治疗致敏受者免疫排斥提供实验基础.实验将BALB/c小鼠分为4组：①移植前7d致敏组;②移植前7d致敏同时应用CTLA4Ig＋anti-CD154组;③正常小鼠应用CTLA4Ig及anti-CD154的鼠源性对照抗体;④正常小鼠空白对照组.每组15只,于移植当天给小鼠8 Gy照射,然后将荧光标记的C57BL/6小鼠骨髓干细胞经尾静脉注射小鼠体内进行移植,于不同时间点取血或器官组织用流式细胞术检测荧光细胞归巢,同时记录生存状况,监测其造血重建水平.结果表明,与致敏鼠相比,CTLA4Ig＋ anti-CD154能促进异基因HSC在致敏受者体内植入,诱导免疫耐受,延长其生存期并在28 d内完成造血重建.结论：应用CTLA4Ig及anti-CDl5能诱导致敏受者对异基因HSC的免疫耐受,促进其植入,并完成造血重建.

Effects of Blocking Co-stimulatory Signals on Immunotolerence Rejection of Sensitized Recipient after Hematopoietic Stem Cell Transplantation

This research was aimed to explore the effects of blocking B7/CD28 and CD40/CD154 co-stimulatory signals on engraftment of hematopoietic stem cell in the sensitized recipient so as to provide the experimental evidence for the treatment of sensitized recipient＇s immune rejection after clinical allogeneic hematopoietic stem cell transplantation （HSCT）.The BALB/c mice were divided into 4 groups：（1） mice sensitized on 7 day before transplant; （2） mice were sensitized on 7 day before transplent,and injected CTLA4Ig ＋ anti-CD154 applied; （3） normal mice injected by corresponding isotype control IgG of CTLA4Ig and anti-CD154; （4） normal blank control mice.Each group had 15 mice.On day 0,mice of each group were irradiated lethally 8 Gy by linear accelerator,and the bone marrow cells of C57BL/6 labeled by fluorescence staining were injected via the tail vein.The fluorescent cell level in peripheral blood and organ tissue at different time points were detected by flow cytometry （FCM） for homing assessment.Survival rates and hematopoietic reconstitution were also monitored and recorded.The results showed that application of CTLA4Ig antiCD154 could promote implantation of allogeneic HSC in sensitized recipients,induce the immune tolerance,prolong thek survival time and acceelarate the hematopoietic reconstitution within 28 days,compared with the sensitized group.It is concluded that applying CTLA4Ig and anti-CD154 can enhance the engraftment of HSCT and induce immune tolerance in the sensitized recipient after allogeneic HSCT and accelerate the hematopoietic reconstitution.