CD28/B7和CD134/CD134L共刺激通路阻断与免疫抑制剂联合治疗对移植心脏存活时间影响

Blockade of CD28/Bq and CD134/CD134L Co-stimulation in Combination with Additional Immunosuppressive Agents Enhances Cardiac Allograft Survival in Rat

目的探讨CD28-B7、CD134-CD134L共刺激信号通路阻断以及雷帕霉素、供体特异性脾细胞输注(DST)等联合治疗对心脏移植排斥反应的影响。方法将DA大鼠心脏移植到LEW大鼠的腹腔内,用CTLA4-Ig融合蛋白、CD134L抗体分别阻断CD28-B7、CD134-CD134L共刺激信号通路,以及雷帕霉素、DST等不同治疗组合观察对移植心脏存活时间的影响,并利用免疫组化方法观察炎症细胞浸润情况。结果CD134-CD134L、CD28-B7共刺激信号通路单独阻断和雷帕霉素单独治疗后心脏存活时间分别为7.6+0.5d、12+3.5d和19.1+6d;CD134-CD134L、CD28-B7共刺激信号通路阻断与雷帕霉素联合治疗心脏存活时间分别为25.2+2.2d和31.5+4.6d。CD134-CD134L、CD28-B7共刺激信号通路共同阻断与雷帕霉素、DST联合治疗心脏存活时间明显延长,为59.1±10.4d,另外有2例存活时间超过120d。结论单独雷帕霉素、CD134-CD134L和CD28-B7通路阻断对移植心脏炎症细胞浸润和组织坏死程度无明显改善,而两个共刺激通路同时阻断与雷帕霉素、DST联合治疗时改善效果最明显。

Objective CD28 is the primary co-stimulatory signal, but additional pathways such as CD134 may have selective roles in T cell activation. Here we investigated the effect of CD134 and CD28 blockade combined with additional immunosuppressive agents on allograft survival and cell infiltrations in a rat cardiac transplant model. Methods Mouse CTLA4-Ig and monoclonal antibody to CD134L were used to block the CD28 and CD134 costimulatory pathways respectively. Rapamyein and DST were used as combined treatments. Graft survival and histology were monitored. Results CD134 blockade alone did not prolong allograft survival （ 7.6 ＋ 0.5 d） compared with untreated controls （7 ＋ 1.4 d）. CD28 blockade alone and rapamycin treatment alone mildly improved allograft survival （12＋3.5d,19.1＋6d） respectively. Costimulatory blockade combined with rapamycin treatment improved allograft survival （CD134 blockade ＋ rapamycin, 25.2 ＋ 2.2d; CD28 blockade ＋ rapamycin, 31.5 ＋ 4.6d）. A double costimulatory blockade in combination with rapamycin and DST significantly prolonged allograft survival （59.1 ± 10.4d）, two of the recipients with 120d long term survival. Single treatments with anti-CD134L antibody CTLA4Ig or rapamycin did not improve pathological changes, including leukocyte infiltration and cardiac muscle necrosis in the allografts. Cellular infiltration, particularly macrophages, in the graft was significantly reduced following the inhibition of both CD134 and CD28 combined with rapamycin and DST. Conclusions The data presented here demonstrate the roles of the CD28 and CD134 costimulatory pathways in allograft rejection. A costimulatory blockade in combination with appropriate immunosuppression achieved prolonged survival.