Improved pig donor screening including newly identified variants of porcine endogenous retrovirus-C (PERV-C)

Abstract

Porcine endogenous retroviruses (PERV) are widely distributed in the genomes of pigs. PERV-A and PERV-B are present in all pigs. They infect human cells in vitro and therefore represent a risk for xenotransplantation when pig cells, tissues or organs are used. PERV-C infects only pig cells and is not present in the genomes of all pigs. However, PERV-A/C recombinants infecting human cells and characterized by high replication titers were found in pigs. To select PERV-C-free animals that cannot generate such recombinants, PCR-based assays were developed (Kaulitz et al., J Virol Methods, 175:60, 2011). When screening for PERV-C in German wild boars (Sus scrofa scrofa), applying these methods, a new variant of PERV-C was identified. Whereas in all 125 wild boar only the new variant of PERV-C was found, different variants were present in some landrace pigs, and most importantly, some pigs were totally free of PERV-C.

Virus safety of islet cell transplantation from transgenic pigs to marmosets

“…1). In addition, using primers and probes specific for PERV-C and for a recently described new variant of PERV-C, PERVCnv (Kaulitz et al, 2013), all animals were also found positive in a real-time PCR (data not shown), indicating that all known PERV subtypes are present in the genome of the pigs analysed in this study. Using a cloned PERV-C specific amplicon, the copy number of PERV-C was estimated: 45 copies/cell.…”

Translational Animal Models for Regenerative Medicine Research

“…In theory, this can be used to eliminate the pig hepatocytes in favor of the human hepatocytes. The application of this approach was delayed over concerns about pig endogenous retrovirus [77].…”

Recent Progress in Xenotransplantation, with Emphasis on Virological Safety

“…Such recombinant PERV-A/C are characterized by an increased replication competence compared with the parenteral virus [84][85][86][87]. Sensitive and specific methods have been developed to screen for PERV-Cpositive animals [88,89]. Third, RNA interference technology has been successfully used in transgenic pigs to reduce the expression of PERV in vitro [90][91][92] and in vivo [93][94][95].…”