Robert Koch Institute, HIV and Other Retroviruses, Berlin, Germany.
Xenotransplantation. 2013 May-Jun;20(3):148-56. doi: 10.1111/xen.12032. Epub 2013 Apr 2.
To establish the safety of xenotransplantation when cells, tissues, or organs of pigs are used, an effective screening for potential zoonotic microorganisms has to be performed. In doing so, special attendance has to be paid to porcine endogenous retroviruses (PERVs) that are widely distributed as proviruses in the genome of pigs. PERV-A and PERV-B are present in all pigs, they infect human cells in vitro and therefore represent a direct risk. PERV-C infects only pig cells; however, recombinant PERV-A/C infecting human cells and replicating at a higher rate were found in pigs indicating an indirect risk. To prevent the transmission of PERV, it was suggested to use animals characterized by a low expression of PERV-A and PERV-B that are free of PERV-C and cannot generate recombinants. Göttingen minipigs are used for numerous biomedical investigations and they are well characterized; however, the prevalence and the expression of PERV in these animals were not yet investigated.
The presence and expression of all PERVs including a new variant (nv) of PERV-C and PERV-A/C were analyzed using PCR and real-time PCR methods. Altogether, 15 animals belonging to different families were analyzed. To make a low expression better measurable, peripheral blood mononuclear cells (PBMCs) of the animals were stimulated with phytohaemagglutinin generally increasing the expression of PERV and allowing a better classification into animals with high and low expression. As a major end point, the release of virus particles able to infect susceptible human 293 cells was investigated.
PERV-A, PERV-B, PERV-C, and PERV-Cnv were found in the genome of all investigated Göttingen minipigs, but recombinant PERV-A/Cs were not found. When the expression of PERV was compared with that in previously analyzed pig strains, it was higher than in German landrace and some other pigs, but lower than in Yucatan miniature pigs. Virus particles able to infected human 293 cells were not detected even after mitogen treatment of the PBMCs.
The Göttingen minipigs are well defined concerning their physiologic parameters, their health status, and their genetics, and therefore, they may be considered as donor animals for at least cell xenotransplantation. When the prevalence and the expression of PERVs were analyzed in these animals, it was demonstrated that although PERV-A, -B, and -C proviruses were found in all animals, their expression was low. Additional investigations are required to assess the suitability of Göttingen minipigs and other animals for xenotransplantation in terms of microbiological safety.
为了确定在使用猪的细胞、组织或器官进行异种移植时的安全性，必须对潜在的人畜共患病微生物进行有效的筛选。在这样做的时候，必须特别注意广泛分布在猪基因组中的猪内源性逆转录病毒（PERVs）。PERV-A 和 PERV-B 存在于所有的猪中，它们可以在体外感染人类细胞，因此构成了直接的风险。PERV-C 仅感染猪细胞；然而，在猪中发现了能够感染人类细胞并以更高速率复制的重组 PERV-A/C，这表明存在间接风险。为了防止 PERV 的传播，有人建议使用 PERV-A 和 PERV-B 表达水平较低、不携带 PERV-C 且不能产生重组体的动物。哥廷根小型猪被用于许多生物医学研究，它们的特征得到了很好的描述；然而，这些动物中 PERV 的流行情况和表达情况尚未得到研究。
使用 PCR 和实时 PCR 方法分析了所有 PERV 的存在和表达，包括 PERV-C 的一种新变体（nv）和 PERV-A/C。总共分析了来自不同家族的 15 只动物。为了更好地测量低表达，用植物血球凝集素刺激动物的外周血单核细胞（PBMCs），通常会增加 PERV 的表达，从而更好地将高表达和低表达的动物进行分类。作为一个主要的终点，研究了能够感染易感人类 293 细胞的病毒颗粒的释放。
在所研究的所有哥廷根小型猪的基因组中都发现了 PERV-A、PERV-B、PERV-C 和 PERV-Cnv，但未发现重组 PERV-A/Cs。当比较 PERV 的表达与之前分析的猪株的表达时，它高于德国长白猪和其他一些猪，但低于尤卡坦微型猪。即使在用植物血球凝集素处理 PBMCs 后，也未检测到能够感染人类 293 细胞的病毒颗粒。
哥廷根小型猪在生理参数、健康状况和遗传学方面都有很好的定义，因此它们可以被认为是至少细胞异种移植的供体动物。当在这些动物中分析 PERV 的流行情况和表达情况时，结果表明，尽管所有动物都发现了 PERV-A、-B 和 -C 前病毒，但它们的表达水平较低。需要进一步的研究来评估哥廷根小型猪和其他动物在微生物安全性方面用于异种移植的适宜性。
