异种输血——猕猴受输猪红细胞的初步研究

Preliminary Study on Xenotransfusion from Porcine Red Blood Cell into Rhesus Monkey

本研究的目的是改造猪红细胞(pRBC)表面抗原,使之与灵长类动物相容,以探讨异种输血的可能性。结合使用α半乳糖苷酶(AGL)酶解和甲氧基聚乙二醇(mPEG)修饰改造猪红细胞表面异种抗原,并输注给猕猴,观察pRBC在猕猴体内活存时间及安全性;使用免疫抑制剂(蛇毒因子CVF和地塞米松)延长pRBC在猕猴体内的存活时间;建立失血性贫血猕猴模型,观察输注pRBC治疗失血性贫血猕猴的可能性。结果表明:AGL酶解能够去除猪红细胞表面主要异种抗原(α-Gal抗原),减弱其与猕猴血清的凝集反应,酶解技术与mPEG修饰技术结合可以使猪红细胞与猕猴血清更为相容。异种输血试验表明,双修饰的pRBC在猕猴体内存活时间为12小时,使用免疫抑制剂后,可延长至40小时;pRBC在猕猴体内8小时的存活率为38%,在输注pRBC的8小时内,失血猕猴的血红蛋白和红细胞压积可维持在失血前的正常水平。结论:改造后的pRBC可安全地输注给猕猴,改善失血猕猴的贫血症状,提示用猪红细胞进行异种输血是可能的。

In order to study the possibility of xenαransfusion from porcine red blood cell （pRBC） to primate, the antigens on pRBC surface were modified to make it more compatible to primate sera. Porcine RBCs were subjected to bαh enzymatic removal of membrane α-Gal antigens with recombinant α-galactosidase （AGL） and covalent attachment of succinimid propionate-linked methoxypolyethyleneglycol （mPEG-SPA） to camouflage non-αGal antigens. The effects of double modifications were determinated by hemagglutination and clinical cross-match testing with rhesus sera. In vivo clearance rates and safety of modified pRBCs were measured after it was transfused into Rhesus monkey with or without immunosuppressant treatment . The validity of pRBC was detected in exsanguine Rhesus monkey model. The results showed that AGL could effectively remove α-Gal xenoantigens on pRBC membrane and reduce hemagglutination. The combination of mPEG modification with AGL treatment could significantly increased compatibility between pRBCs and Rhesus monkey sera. Modified pRBCs were detectable in Rhesus monkey blood at 12 hours after transfusion, and their survival time was 40 hours in the immunosuppressant-treated Rhesus monkey. In vivo survival rates of pRBCs were 38% in exsanguine Rhesus monkey at 8 hours after transfusion, and during that time, the hemoglobin and hematocrit of Rhesus monkey were maintained at the same level as before it lost blood. It is concluded that the modified pRBC can be safely transfused into Rhesus monkey and relieve the anemic symptom exsanguine Rhesus monkey . It suggested that pRBC can be hopefully used as a blood substitute for primate and human in the future.