<scp>PERV</scp> inactivation is necessary to guarantee absence of pig‐to‐patient <scp>PERV</scp>s transmission in xenotransplantation

Güell, Marc; Niu, Dong; Kan, Yinan; George, Haydy; Wang, Tao; Lee, I-Hsiu; Wang, Gang; Church, George M.; Yang, Luhan

doi:10.1111/xen.12366

Cited by 27 publications

(30 citation statements)

References 15 publications

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“…27 It is also possible to insert inactivating mutations into multiple PERVs by CRISPR/CAS9 gene editing and then generate viable pigs, 60 but whether such wholesale modification of the porcine genome will be required for xenotransplantation to proceed to clinical trials is as yet undecided. 61…”

Section: S Ite-s Pecific Recomb Ina S E Smentioning

confidence: 99%

Assembling multiple xenoprotective transgenes in pigs

Fischer

Kind

Schnieke

2018

Xenotransplantation

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This review gives a brief overview of the genetic modifications necessary for grafted porcine tissues and organs to overcome rejection in human recipients. It then focuses on the problem of generating and breeding herds of donor pigs carrying modified endogenous genes and multiple xenoprotective transgenes. A xenodonor pig optimised for human clinical use could well require the addition of ten or more xenoprotective transgenes. It is impractical to produce the required combination of transgene by cross-breeding animals bearing individual transgenes at unlinked genetic loci, because independent segregation means that huge numbers of pigs would be required to produce relatively few donor animals. A better approach is to colocate groups of transgenes at a single genomic locus. We outline current methods to assemble transgene arrays and consider their pros and cons. These include polycistronic expression systems, in vitro recombination of large DNA fragments in PAC and BAC vectors, transposon vectors, classical gene targeting by homologous recombination at permissive loci such as ROSA26, targeted transgene placement aided by gene editing systems such as CRISPR/Cas9, and transgene placement by site-specific recombination such as Min-tagging using the Bxb1recombinase.

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Section: S Ite-s Pecific Recomb Ina S E Smentioning

confidence: 99%

Assembling multiple xenoprotective transgenes in pigs

Fischer

Kind

Schnieke

2018

Xenotransplantation

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“…Some studies utilize "human cells" as targets for infection using the HEK293T cell line, which lacks certain innate restriction mechanisms. Further studies are needed to define the susceptibility of primary human cells to PERV infection and any mechanisms serving to limit productive infection despite the presence of functional PERV receptors 75. Further studies are needed to define the susceptibility of primary human cells to PERV infection and any mechanisms serving to limit productive infection despite the presence of functional PERV receptors 75.…”

mentioning

confidence: 99%

“…Evidence of infection of human cells by porcine endogenous retrovirus after islet xenotransplantation in SCID (severe combined immunodeficiency disorder) mice was found to be erroneous and an artifact of pseudotyping of PERV by murine leukemia virus (MLV) 60,71,72. Most primary human cells have not been infectable by PERV; human vascular endothelial cells (HUVEC) and peripheral blood mononuclear cells are infectable by certain strains of PERV in vitro 39,47,49,50,[73][74][75]. Some studies utilize "human cells" as targets for infection using the HEK293T cell line, which lacks certain innate restriction mechanisms.…”

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confidence: 99%

“…Human APOBEC3 and other cellular restriction factors may inhibit PERV replication 68,76. Further studies are needed to define the susceptibility of primary human cells to PERV infection and any mechanisms serving to limit productive infection despite the presence of functional PERV receptors 75. To date, all preclinical and clinical xenotransplantation studies using pig cells, tissues, and organs have failed to demonstrate transmission of PERV to humans including transplantation of porcine pancreatic islets and over 200 individuals exposed to pig cells or tissues or ex vivo perfusion of pig organs or pig cell-based bioreactors 64,65.…”

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confidence: 99%

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Infectious disease risks in xenotransplantation

Fishman

2018

American Journal of Transplantation

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Hurdles exist to clinical xenotransplantation including potential infectious transmission from nonhuman species to xenograft recipients. In anticipation of clinical trials of xenotransplantation, the associated infectious risks have been investigated. Swine and immunocompromised humans share some potential pathogens. Swine herpesviruses including porcine cytomegalovirus (PCMV) and porcine lymphotropic herpesvirus (PLHV) are largely species-specific and do not, generally, infect human cells. Human cellular receptors exist for porcine endogenous retrovirus (PERV), which infects certain human-derived cell lines in vitro. PERV-inactivated pigs have been produced recently. Human infection due to PERV has not been described. A screening paradigm can be applied to exclude potential human pathogens from "designated pathogen free" breeding colonies. Various microbiological assays have been developed for screening and diagnosis including antibody-based tests and qualitative and quantitative molecular assays for viruses. Additional assays may be required to diagnose pig-specific organisms in human xenograft recipients. Significant progress has been made in the evaluation of the potential infectious risks of clinical xenotransplantation. Infectious risk would be amplified by intensive immunosuppression. The available data suggest that risks of xenotransplant-associated recipient infection are manageable and that clinical trials can be performed safely. Possible infectious risks of xenotransplantation to the community at large are undefined but merit consideration.

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“…This approach should be balanced with the fact that PERV has not been transferred in vivo with the selected pig lines used. 16,18 We have known and unknown infectious agents to consider, so to try to address all aspects of the guidance and these testing if animals are to be cloned, then this virus is not an issue when a skin biopsy is utilized; in addition, husbandry procedures involving hysterotomy derivation of the offspring is a suitable approach to eliminate this pathogen. 6 Looking at the pathogen status in the cell product, PERV RNA was located the endocrine fraction of the pancreas and neonatal islets had significantly lower levels of PERV RNA than adult islets.…”

mentioning

confidence: 99%