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absence of transmission of potentially xenotic viruses in a prospective pig to primate islet xenotransplantation study.shortage of human donor organs for transplantation has prompted usage of animals as an alternative donor source. pigs are the most acceptable candidate animals but issues of xenozoonoses remain. despite careful monitoring of designated pathogen free pigs there is still a risk that their tissues may carry infectious agents. thus xenotransplantation requires extensive pre-clinical study on safety of the graft especially for those viruses that are either potentially oncogenic and/or immunosuppressi ...200818814261
absence of replication of porcine endogenous retrovirus and porcine lymphotropic herpesvirus type 1 with prolonged pig cell microchimerism after pig-to-baboon xenotransplantation.porcine endogenous retrovirus (perv), porcine cytomegalovirus (pcmv), and porcine lymphotropic herpesvirus (plhv) are common porcine viruses that may be activated with immunosuppression for xenotransplantation. studies of viral replication or transmission are possible due to prolonged survival of xenografts in baboon recipients from human decay-accelerating factor transgenic or alpha-1,3-galactosyltransferase gene knockout miniature swine. ten baboons underwent xenotransplantation with transgeni ...200818829759
no evidence for perv release by islet cells from german landrace pigs.islet cells from pig could be used as an alternative to the current treatment of diabetic patients. however, xenotransplantation from pig to humans may be associated with the risk of transmission of porcine endogenous retroviruses (pervs) that are present in the genome of all pigs and infect human cells in vitro. although transplantation of pig islet cells for treatment of diabetes may be not accompanied by immunosuppression that may facilitate virus survival, since islets will be used encapsula ...200819034225
porcine endogenous retrovirus (perv) and its transmission characteristics: a study of the new zealand designated pathogen-free herd.previously a strategy for monitoring of pigs intended for cell transplantation was developed and successfully applied to several representative herds in new zealand. a designated pathogen-free (dpf) herd has been chosen as a good candidate for xenotransplantation. this herd has previously tested free of infectious agents relevant to xenotransplantation and we present here an in depth study of porcine endogenous retrovirus (perv) transmission. a panel of assays that describes the constraints for ...200819364075
transmission of porcine endogenous retrovirus to human cells in nude mouse.xenotransplantation is associated with the risk of porcine endogenous retrovirus (perv) transmission, since it has been shown that perv can infect human cells in vitro (specke et al., virology 285, 177-180, 2001). we evaluated the possibility of perv infection of human cells in nude mice model. porcine kidney cells pk15 carrying perv and human liver cancer cells smmc-7721 were injected separately into the right and left axilla of nude mice, respectively. two months later, pig cytochrome oxidase ...200819143483
large-scale survey of porcine endogenous retrovirus in chinese miniature pigs.we conducted a large-scale survey on the existence and expression status of porcine endogenous retrovirus (perv) in seven breeds of chinese miniature pigs. genotyping of perv was examined by pcr using type-specific primers according to the env genotyping method. the presence and expression status of viral gag, pol and env genes were further analyzed in wuzhishan pigs (wzsp) and bama minipigs (bmp). the results showed that perv existed in all 348 genomic dna samples. the genotype distribution was ...200817689611
progress towards clinical xenotransplantation.xenotransplantation has progressed from early heroic experiments on the path to meet the ever increasing demands of tissue and organ transplantation in patients with end-stage organ failure. the pig species is regarded as the most promising donor species. however, due to the evolutionary distance, innovative approaches are to be developed to permit life-supporting function in humans. transplantation of organs from non-human primates has increased our knowledge on rejection mechanisms and provide ...200817981539
reappraisal of biosafety risks posed by pervs in xenotransplantation.donor materials of porcine origin could potentially provide an alternative source of cells, tissues or whole organs for transplantation to humans, but is hampered by the health risk posed by infection with porcine viruses. although pigs can be bred in such a way that all known exogenous microorganisms are eliminated, this is not feasible for all endogenous pathogens, such as the porcine endogenous retroviruses (pervs) which are present in the germline of pigs as proviruses. upon transplantation, ...200817987669
identification of two distinct structural regions in a human porcine endogenous retrovirus receptor, hupar2, contributing to function for viral entry.of the three subclasses of porcine endogenous retrovirus (perv), perv-a is able to infect human cells via one of two receptors, hupar1 or hupar2. characterizing the structure-function relationships of the two hupar receptors in perv-a binding and entry is important in understanding receptor-mediated gammaretroviral entry and contributes to evaluating the risk of zoonosis in xenotransplantation.200919144196
no in vivo infection of triple immunosuppressed non-human primates after inoculation with high titers of porcine endogenous retroviruses.porcine endogenous retroviruses (pervs) released from pig tissue can infect selected human cells in vitro and therefore represent a safety risk for xenotransplantation using pig cells, tissues, or organs. although pervs infect cells of numerous species in vitro, attempts to establish reliable animal models failed until now. absence of perv transmission has been shown in first experimental and clinical xenotransplantations; however, these trials suffered from the absence of long-term exposure (tr ...200919243559
comparison of the age-related porcine endogenous retrovirus (perv)expression using duplex rt-pcr.porcine endogenous retroviruses (pervs) are members of family retroviridae, genus gamma retrovirus, and transmitted by both horizontally and vertically like other endogenous retroviruses (ervs). perv was initially described in the 1970s having inserted its gene in the host genome of different pig breeds, and three classes, perv-a, perv-b, and perv-c are known. the therapeutic use of living cells, tissues, and organs from animals called xenotransplantation might relieve the limited supply of allo ...200919934597
studies on long-term infection of human cells with porcine endogenous retrovirus.a major concern in pig-to-human xenotransplantations is the potential risk of transmission of porcine endogenous retroviruses (pervs) integrated in the pig genome. our previous work has shown that perv provirus genes and gag protein can be detected in human embryonic kidney hek-293 cells during a long-term infection with perv (yu et al., transplant. proc. 37, 496-499, 2005). in this study, we continued studying the long-term (>6 months) perv infection of hek-293 cells. the results showed no sign ...200919941398
investigation of porcine endogenous retrovirus in the conservation population of ningxiang pig.porcine endogenous retrovirus (perv) varies between pig breeds. screening and analysis of perv in putative pig breeds may provide basic parameters to evaluate the biological safety of xenotransplantation from pigs to humans. in this study, perv was investigated among the conservation population of the ningxiang pig. the result revealed that the genotype of perv distribution was subtype a, 100%; subtype b, 100%; and subtype c, 100%. the env sequences of perv-a and -b showed 11 clones detected by ...200920005405
distribution and expression of porcine endogenous retroviruses in multi-transgenic pigs generated for xenotransplantation.multi-transgenic pigs produced for use in xenotransplantation have to be screened for the presence and expression of porcine endogenous retroviruses (perv) to select animals with low perv load. the production of transgenic pigs may also be associated with the integration of the transgene adjacent to or into the locus of a perv provirus, potentially leading to an enhanced virus expression.200919392721
inhibition of porcine endogenous retrovirus (perv) replication by hiv-1 gene expression inhibitors.porcine endogenous retrovirus (perv) is persistently integrated into the host genomic dna as a provirus and released from a variety of porcine cells. perv infects a certain range of human cells, which is a major concern in xenotransplantation. therefore, the use of viral gene expression inhibitors could be envisaged, if they reduce perv production from porcine organs and minimize viral transmission to human recipients. in the present study, four hiv-1 gene expression inhibitors were examined for ...200919414036
porcine endogenous retrovirus and other viruses in xenotransplantation.potential transmission of zoonotic porcine viruses is a major safety issue in xenotransplantation. this review will first summarize recent studies involving transmission and control of the major concern, porcine endogenous retrovirus (perv). second, the potential for zoonotic transfer and safety measures required against other viruses of concern will be discussed.200919469034
characterization of the replication-competent porcine endogenous retrovirus class b molecular clone originated from korean domestic pig.xenotransplantation from pigs offers an opportunity to resolve the shortage of human organs. the porcine endogenous retrovirus (perv) cannot be eliminated because of its presence in the germline dna. three subgroups of the replication-competent perv (perv-a, perv-b, and perv-c) have been identified in pigs. we constructed a molecular clone of perv-b from a korean domestic pig bac clone containing perv genomes, and its replication competency was characterized in human cells. the pol region of per ...200919543822
production of transgenic pigs that express porcine endogenous retrovirus small interfering rnas.the presence of multiple copies of porcine endogenous retrovirus (perv) within the pig genome, and the demonstration that replication competent perv, that infect human cells in culture, can be isolated from pig cells, directly impacts the drive towards the development of pigs for xenotransplantation. the development of technology to produce pigs that do not propagate perv has the potential to facilitate the development of xenotransplantation products for human use, and as such, is the focus of t ...200919566656
porcine endogenous retrovirus released by a bioartificial liver infects primary human cells.porcine endogenous retrovirus (perv) remains a safety risk in pig-to-human xenotransplantation. there is no evidence of in vivo productive infection in humans because perv is inactivated by human serum. however, perv can infect human cell lines and human primary cells in vitro and inhibit human immune functions.200919686312
the international xenotransplantation association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes-- executive summary.the international xenotransplantation association islet xenotransplantation consensus statement describes the conditions for undertaking clinical trials of porcine islet products in type 1 diabetes. chapter 1 reviews the key ethical requirements and progress toward the definition of an international regulatory framework for clinical trials of xenotransplantation. chapters 2 to 7 provide in depth and agreed-upon recommendations on source pigs, pig islet product manufacturing and release testing, ...200919799759
the international xenotransplantation association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes--chapter 2: source pigs.an islet xenotransplantation product includes live cells from a non-human source, in this study, a pig source. a live product cannot be subjected to conventional disinfection, and therefore the source pig must be depleted of infectious agents that can transmit to the recipient and cause disease. among other requirements, regulatory guidances specify that donor animals fulfill the designated pathogen-free (dpf) status. donor pigs fulfilling dpf status are generally bred and maintained in biosecur ...200919799761
the international xenotransplantation association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes--chapter 5: strategies to prevent transmission of porcine endogenous retroviruses.xenotransplantation using porcine cells, tissues, or organs may offer a potential solution for the shortage of allogeneic human organs. prior to the clinical use of porcine xenotransplants, three main hurdles must be overcome: immunologic rejection, physiologic incompatibility, and risk of transmission of porcine pathogens. designated pathogen-free breeding of pigs can prevent transmission of most porcine microbes. however, this is not possible in the case of porcine endogenous retroviruses (per ...200919799764
[receptors for animal retroviruses].diseases caused by animal retroviruses have been recognized since 19th century in veterinary field. most livestock and companion animals have own retroviruses. to disclose the receptors for these retroviruses will be useful for understanding retroviral pathogenesis, developments of anti-retroviral drugs and vectors for human and animal gene therapies. of retroviruses in veterinary field, receptors for the following viruses have been identified; equine infectious anemia virus, feline immunodefici ...200920218331
genome areas with high gene density and cpg island neighborhood strongly attract porcine endogenous retrovirus for integration and favor the formation of hot spots.porcine endogenous retroviruses (perv) are members of the gammaretrovirus genus and display integration preferences around transcription start sites, a finding which is similar to the preferences of the murine leukemia virus (mlv). our new genome-wide analysis of the integration profile of a recombinant perv (perv a/c), enabled us to examine more than 1,900 integration sites and identify 224 integration hot spots. investigation of the possible genome features involved in hot-spot formation revea ...200919036816
polymerase chain reaction in detection of porcine endogenous retrovirus (perv) from porcine tissues.pigs offer an unlimited source of xenografts for humans. the use of transplants from animal origin offers a potential solution to the limited supply of human organs and tissues. however, like many other mammalian species, pigs harbor porcine endogenous retrovirus (perv), which are encoded in their genomic dna and are assumed to have been integrated into the porcine germline. the ability of perv to infect human cells in vitro has heightened safety concerns regarding the transmission of perv to pi ...200923100752
identification of full-length proviral dna of porcine endogenous retrovirus from chinese wuzhishan miniature pigs inbred.existence of porcine endogenous retrovirus (perv) hinders pigs to be used in clinical xenotransplantation to alleviate the shortage of human transplants. chinese miniature pigs are potential organ donors for xenotransplantation in china. however, so far, an adequate level of information on the molecular characteristics of perv from chinese miniature pigs has not been available. we described here the cloning and characterization of full-length proviral dna of perv from chinese wuzhishan miniature ...201019070900
expression of complement regulatory protein on porcine endogenous retrovirus (perv) depends on molecular size.expression of complement regulatory proteins (crp) on pig cells is an effective means to avoid hyperacute rejection. however, pig endogenous retrovirus (perv) from pig cells transfected with crp may acquire resistance to human serum (hs). the present study investigated the size limitations of the transfected crp that can be easily expressed and function on perv particles. cdnas of various sized daf(cd55)s, including single-, double-, triple-, tetra-, as well as 2.1- and 2.2-daf, were prepared. p ...201020226243
real-time quantitative polymerase chain reaction with sybr green i detection for estimating copy numbers of porcine endogenous retrovirus from chinese miniature pigs.porcine endogenous retrovirus (perv) in the pig genome represents a potential infectious risk in xenotransplantation. chinese miniature pigs have been considered to be potential organ donors in china. however, an adequate level of information on perv from chinese miniature pigs has not been available. we established an sybr green i-based real-time quantitative polymerase chain reaction (pcr) assay for estimating copy numbers of perv integrated in the host genome. the assay was 100-fold more sens ...201020620553
characterisation of a human cell-adapted porcine endogenous retrovirus perv-a/c.porcine endogenous retroviruses (pervs) pose a potential risk for xenotransplantation using pig cells, tissues or organs. a special threat comes from viruses generated by recombination between human-tropic perv-a and ecotropic perv-c. serial passages of a recombinant perv-a/c on human 293 cells resulted in increased infectious titers and a multimerization of transcription factor binding sites in the viral long terminal repeat (ltr). in contrast to the ltr, the sequence of the env gene did not ch ...201020657519
simultaneous detection and subtyping of porcine endogenous retroviruses proviral dna using the dual priming oligonucleotide system.the purpose of this study was to develop a multiplex pcr that can detect porcine endogenous retrovirus (perv) proviral genes (pol, enva, envb, envc) and porcine mitochondrial dna, using a dual priming oligonucleotide (dpo) system. the primer specifically detected the perv proviral genes pol, enva, envb, envc, and porcine mitochondrial dna only in samples of pig origin. the sensitivity of the primer was demonstrated by simultaneous amplification of all 5 target genes in as little as 10 pg of pig ...201020706036
analysis of the molecular and regulatory properties of active porcine endogenous retrovirus gamma-1 long terminal repeats in kidney tissues of the nih-miniature pig.the pig genome contains the gamma 1 family of porcine endogenous retroviruses (pervs), which are a major obstacle to the development of successful xenotransplantation from pig to human. long terminal repeats (ltrs) found in pervs are known to be essential elements for the control of the transcriptional activity of single virus by different transcription factors (tfs). to identify transcribed perv ltr elements, rt-pcr and dna sequencing analyses were performed. twenty-nine actively transcribed lt ...201020811814
molecular characterization of long terminal repeat of porcine endogenous retroviruses in chinese pigs.pigs offer an unlimited source of xenografts for humans. however, vertically transmitted porcine endogenous retrovirus (perv) poses an infectious risk in the course of pig-to-human transplantation. in this study, we characterized perv long terminal repeat (ltr) sequences from three species of chinese pigs banna minipig inbred (bmi), wu-zhi-shan pig (wzsp), and neijiang pig (njp-a), and compared them with those of known pervs (perv-a, perv-b, perv-c, perv-nih, and 293-perv-43). genomic dna extrac ...201020822308
a newly cloned pig dolichyl-phosphate mannosyl-transferase for preventing the transmission of porcine endogenous retrovirus to human cells.porcine endogenous retrovirus (perv) is a major problem associated with successful clinical xenotransplantation. in our previous study, reducing the high mannose type of n-glycan content proved to be very effective in downregulating perv infectivity. in this study, dolichyl-phosphate mannosyltransferase (d-p-m), an enzyme related to the early stages of n-linked sugar synthesis was studied. the pig cdna of the encoding d-p-m was newly isolated. the rna interference (sirna) for the d-p-m was appli ...201019912589
unusual permeability of porcine endogenous retrovirus subgroup a through membrane filters.in xenotransplantation from pigs to humans, a bio-artificial endocrine pancreas (bio-aep), in which pancreatic endocrine cells are encapsulated within a semipermeable membrane of 100 nm pore size, has been developed. we evaluated the permeability of porcine endogenous retroviruses (pervs) through membrane filters using a pseudotype virus (lacz(perv-a)) containing a viral core derived from murine leukemia virus and an envelope (env) from perv subgroup a. contrary to our expectations, lacz(perv-a) ...201019915326
regulation of porcine endogenous retrovirus release by porcine and human tetherins.the risk of transmission of porcine endogenous retrovirus (perv) is one of the major safety issues in xenotransplantation. human tetherin, recently described as an antiviral protein able to inhibit the release of enveloped viruses, and its porcine homologue were shown to inhibit perv release from producer cells, establishing themselves as candidate molecules to suppress perv production in porcine xenografts by animal engineering.201020015985
no evidence of porcine endogenous retrovirus in patients with type 1 diabetes after long-term porcine islet xenotransplantation.xenotransplantation is a promising alternative for donor shortage to ameliorate physiologic and metabolic disorders. the major concern for xenotransplant is the risk of zoonosis mainly by the porcine endogenous retrovirus (perv), presentation in the piglet genome. twenty-three patients with type 1 diabetes were transplanted with porcine islets using collagen-generating devices which were implanted subcutaneously in the anterior wall of the abdomen. clinical characteristics and metabolic tests we ...201020029803
critical issues related to porcine xenograft exposure to human viruses: lessons from allotransplantation.xenotransplantation of tissues from swine into humans poses the threat of bidirectional transfer of porcine or human microorganisms to the recipient or to the xenograft, respectively. this review focuses on recipient-derived infection. recent data are reviewed that assess the susceptibility of porcine cells to human viruses. on the basis of the experience in allotransplantation, potential consequences for the xenograft are discussed.201020061950
an effective method for the quantitative detection of porcine endogenous retrovirus in pig tissues.xenotransplantation shows great promise for providing a virtually limitless supply of cells, tissues, and organs for a variety of therapeutical procedures. however, the potential of porcine endogenous retrovirus (perv) as a human-tropic pathogen, particularly as a public health risk, is a major concern for xenotransplantation. this study focus on the detection of copy number in various tissues and organs in banna minipig inbreed (bmi) from 2006 to 2007 in west china hospital, sichuan university. ...201020108128
islet cell transplantation for type 1 diabetes.islet transplantation is an attractive concept for the treatment of type 1 diabetes because of its potential high efficacy and minimal invasion to patients. the treatment may effectively control blood glucose for brittle type 1 diabetes, resulting in a marked reduction in hypoglycemic episodes and improvements in hba1c. in addition, approximately 70% of transplanted type 1 diabetic patients have achieved insulin independence. however, there are still important issues to be addressed before this ...201020923470
the rapid production of high-titer porcine endogenous retrovirus(perv)-b env pseudotype and construction of an egfp-expressing replication competent perv-a vector.porcine endogenous retroviruses (pervs) present a unique concern associated with xenotransplantation because they have been shown to infect certain human cells in vitro and it is also difficult to generate herds of pigs free of pervs. a simple system for the production of high-titer momlv-perv pseudotypes is reported; an egfp-expressing replication-competent molecular clone that allows direct measurement of titer was also constructed. to improve the mlv-based retroviral vector system, a 2.1-kb p ...201020933542
suboptimal porcine endogenous retrovirus infection in non-human primate cells: implication for preclinical xenotransplantation.porcine endogenous retrovirus (perv) poses a potential risk of zoonotic infection in xenotransplantation. preclinical transplantation trials using non-human primates (nhp) as recipients of porcine xenografts present the opportunity to assess the zoonosis risk in vivo. however, perv poorly infects nhp cells for unclear reasons and therefore nhp may represent a suboptimal animal model to assess the risk of perv zoonoses. we investigated the mechanism responsible for the low efficiency of perv-a in ...201020949092
epigenetic regulation on the 5'-proximal cpg island of human porcine endogenous retrovirus subgroup a receptor 2/gpr172b.porcine endogenous retroviruses (pervs) have been considered one of the major risks of xenotransplantation from pigs to humans. perv-a efficiently utilizes human perv-a receptor 2 (hupar-2)/gpr172b to infect human cells; however, there has been no study on the regulation mechanisms of hupar-2/gpr172b expression. in this study, we examined the expression of hupar-2/gpr172b from the standpoint of epigenetic regulation and discussed the risks of perv-a infection in xenotransplantation. quantitative ...201020951222
long-term absence of porcine endogenous retrovirus infection in chronically immunosuppressed patients after treatment with the porcine cell-based academic medical center bioartificial liver.clinical use of porcine cell-based bioartificial liver (bal) support in acute liver failure as bridging therapy for liver transplantation exposes the patient to the risk of transmission of porcine endogenous retroviruses (pervs) to human. this risk may be enhanced when patients receive liver transplant and are subsequently immunosuppressed. as further follow-up of previously reported patients (di nicuolo et al. 2005), an assessment of perv infection was made in the same patient population pharma ...201021158944
fluidized-bed bioartificial liver assist devices (blads) based on microencapsulated primary porcine hepatocytes have risk of porcine endogenous retroviruses transmission.bioartificial liver assist devices (blads) are expected to bridge liver failure patients to liver transplantation, but porcine endogenous retroviruses (pervs) still pose a potential risk in pig-to-human xenotransplantation and thereby limit the use of bioartificial liver therapy. in our lab, fluidized-bed blads based on microencapsulated primary porcine hepatocytes have been successfully used to treat liver failure pigs. we detected the risk of pervs transmission of microencapsulated primary por ...201021286347
restriction of porcine endogenous retrovirus by porcine apobec3 cytidine deaminases.xenotransplantation of porcine cells, tissues, and organs shows promise to surmount the shortage of human donor materials. among the barriers to pig-to-human xenotransplantation are porcine endogenous retroviruses (perv) since functional representatives of the two polytropic classes, perv-a and perv-b, are able to infect human embryonic kidney cells in vitro, suggesting that a xenozoonosis in vivo could occur. to assess the capacity of human and porcine cells to counteract perv infections, we an ...201121307203
detection of porcine endogenous retrovirus (perv) viremia in diseased versus healthy us pigs by qualitative and quantitative real-time rt-pcr.previous studies have linked levels of porcine endogenous retroviruses (perv) with poor health and disease in pigs. to determine the levels of expression of pervs and their potential association with disease expression, real-time reverse transcriptase (rt) pcr assays were used to assess perv-abc, perv-c and perv-a/c levels in three commercial swine operations in the united states. pigs (n = 204) aged 3-25 weeks were screened, and all 369 serum samples collected were found to be positive for perv ...201121396084
repression of porcine endogenous retrovirus infection by human apobec3 proteins.it has been shown that porcine endogenous retrovirus (perv) can infect human cells, indicating that perv transmission poses a serious concern in pig-to-human xenotransplantation. a number of recent studies have reported on retrovirus interference by antiviral proteins. the most potent antiviral proteins are members of the apobec family of cytidine deaminases, which are involved in defense against retroviral attack. these proteins are present in the cytoplasm of mammalian cells and inhibit retrov ...201121396348
evaluation of the potential risk of porcine endogenous retrovirus (perv) infection in nude mice.nude mice (balb/c) were grafted with human 293 cells and perv (porcine endogenous retrovirus)-ires-egfp (a packageable retroviral vector plasmid containing an internal ribosome entry site-enhanced green fluorescent protein)-producing pig pk15 cells in order to determine whether the pig cells could transmit perv-ires-egfp to mice and human 293 cells in vivo. none of the transplanted human 293 cell lines were infected by perv, but pcr analysis identified perv-b provirus integration into both the h ...201121532322
development of sensitive methods for detection of porcine endogenous retrovirus-c (perv-c) in the genome of pigs.porcine endogenous retroviruses (perv) represent a risk for xenotransplantation using pig cells, tissues or organs. perv-a and perv-b are present in the genome of all pigs and both infect human cells in vitro. perv-c infects only pig cells and it is integrated in the genome of most, but not all pigs. recombinants between perv-a and perv-c were described that infect human cells and replicate at high titres. to avoid such recombinations, perv-c positive animals should not be used for breeding anim ...201121539860
multiplex high resolution melting assay for estimation of porcine endogenous retrovirus (perv) relative gene dosage in pigs and detection of perv infection in xenograft recipients.porcine endogenous retrovirus (perv) poses an infectious risk in the field of xenotransplantation. this risk may be mitigated by breeding selectively animals bearing favorable perv genetic characteristics including pigs with low levels of perv integrated in the genome. a real-time quantitative polymerase chain reaction (pcr) assay employing the roche high resolution melting (hrm) master was used to estimate the relative gene dosage of perv pol integrated within the pig genome. when assessed acro ...201121545811
identification of developmental competence-related genes in mature porcine oocytes.oocyte competence is a key factor limiting female fertility, yet the underlying molecular mechanisms that contribute to oocyte competence remain unclear. the objective of this study was to elucidate specific genes whose function contributes to oocyte competence. we observed that 6 of 20 target genes examined were differentially expressed between adult (more competent) and prepubertal (less competent) porcine in vitro matured (ivm) oocytes. these genes were the cholesterol synthesis-related gene ...201121774025
no enhanced expression and infectivity of porcine endogenous retrovirus in primary porcine hepatocytes with chitosan nanofiber scaffold.our previous report suggested that chitosan nanofiber scaffold may find application in bioartificial livers for it could enhance the function of hepatocytes. this study was focused on its microbiological safety, that is, its influence on the expression and infectivity of porcine endogenous retrovirus (perv) in primary porcine hepatocytes. freshly isolated porcine hepatocytes were cultured with or without chitosan nanofiber scaffold (defined as exp group and ctr group) and porcine kidney 15 (pk15 ...201121830478
influence of chitosan nanofiber scaffold on porcine endogenous retroviral expression and infectivity in pig hepatocytes.to investigate the influence of chitosan nanofiber scaffold on the production and infectivity of porcine endogenous retrovirus (perv) expressed by porcine hepatocytes.201121734784
Rapid determination of perv copy number from porcine genomic DNA by real-time polymerase chain reaction.Here, we report the quantification of porcine endogenous retrovirus (PERV) copy numbers using real time PCR. After generating standard curves using plasmid DNA, copy numbers were determined for PERV pol and for a housekeeping gene, porcine estrogen receptor2 (ER2) with the same amount of genomic DNA. Using this method, we examined 6 pig breeds in Korea including two breeds of miniature pig, one domestic pig from Jeju, and imported pig breeds, Duroc, Landrace, and Yorkshire. All breeds showed PER ...201122132811
xenotransplantation of galactosyl-transferase knockout, cd55, cd59, cd39, and fucosyl-transferase transgenic pig kidneys into baboons.galactosyl-transferase knockout (gt-ko) pigs represent the latest major progress to reduce immune reactions in xenotransplantation. however, their organs are still subject to rapid humoral rejection involving complement activation requiring the ongoing development of further genetic modifications in the pig. in a pig-to-baboon renal transplantation setting, we have used donor pigs that are not only gt-ko, but also transgenic for human cd55 (hcd55), hcd59, hcd39, and fucosyl-transferase (hht). we ...201122099813
reduction of n-tropic mutant porcine endogenous retrovirus infectivity by human tripartite motif-containing 5-isoform alpha.in cases of retroviral infection, the host cell deploys antiviral proteins as a type of innate immunity. tripartite motif-containing 5-isoform alpha (trim5α) is a potent antiviral protein. trim5α has been reported to restrict human immunodeficiency virus (hiv) 1 infection in rhesus monkey cells by targeting the incoming viral capsid at the postentry or preintegration stage of the viral life cycle. as a consequence, virus replication and reverse transcription are interrupted. trim5α of human orig ...201121911161
mapping of a neutralizing epitope in the surface envelope protein of porcine endogenous retrovirus subgroup b.pigs are thought to be the most suitable donor animal for xenotransplantation. however, pigs harbour potentially hazardous infectious agents, termed porcine endogenous retroviruses (pervs), in their genome. in this study, we generated a mab against perv-b surface (su) envelope protein (env), designated krt1. krt1 binding was detected by an indirect immunofluorescence assay and flow cytometric analysis on cells infected with perv-b. krt1 neutralized perv-b pseudotype virus and specifically recogn ...201121228129
generation of neutralising antibodies against porcine endogenous retroviruses (pervs).antibodies neutralising porcine endogenous retroviruses (pervs) were induced in different animal species by immunisation with the transmembrane envelope protein p15e. these antibodies recognised epitopes, designated e1, in the fusion peptide proximal region (fppr) of p15e, and e2 in the membrane proximal external region (mper). e2 is localised in a position similar to that of an epitope in the transmembrane envelope protein gp41 of the human immunodeficiency virus-1 (hiv-1), recognised by the mo ...201121237477
genetic prevalence of porcine endogenous retrovirus in chinese experimental miniature pigs.pig-to-human xenotransplantation poses the potential risk of interspecies transmission of porcine endogenous retrovirus (perv). the chinese experimental miniature pig may be used as a pig-to-human xenograft donor. however, data for the distribution of perv provirus in genomic dna and perv expression at the rna level for the chinese experimental miniature pig population are lacking. in this study, perv was investigated in this regard using polymerase chain reaction (pcr), real-time quantitative p ...201121911159
a clinical trial of xenotransplantation of neonatal pig islets for diabetic patients.to ascertain the safety and function of the transplantation of neonatal pig islets (npis) for diabetic patients.201122246351
increased neutralizing antibody response after simultaneous immunization with leucogen and the feline leukemia virus transmembrane protein.to develop improved vaccination strategies against feline leukemia virus (felv), rats were immunized with the transmembrane envelope protein p15e of felv alone or in combination with the commercial vaccine leucogen® comprising the nonglycosylated felv surface envelope protein. binding and neutralizing antibodies were induced in both groups and in the group immunized with leucogen alone. higher titers of antibodies neutralizing felv were induced by simultaneous immunization with leucogen and p15e ...201120829603
transmission of zoonoses in xenotransplantation: porcine endogenous retroviruses from an immunological and molecular point of view.background and objectives: pigs offer an unlimited source of xenografts for humans. the use of transplants from animal origin offers a potential solution to the limited supply of human organs and tissues. however, like many other mammalian species, pigs harbor porcine endogenous retrovirus (perv), which are encoded in their genomic dna and are assumed to have been integrated into the porcine germ line more than 7.6 × 106 years ago and showing that the age correlates with the time of separation b ...201223897566
xenotransplantation-associated infectious risk: a who consultation.xenotransplantation carries the potential risk of the transmission of infection with the cells or tissues of the graft. the degree of risk is unknown in the absence of clinical trials. the clinical application of xenotransplantation has important implications for infectious disease surveillance, both at the national and international levels. preclinical data indicate that infectious disease events associated with clinical xenotransplantation from swine, should they occur, will be rare; data in h ...201222497509
viral metagenomic analysis of bushpigs (potamochoerus larvatus) in uganda identifies novel variants of porcine parvovirus 4 and torque teno sus virus 1 and 2.as a result of rapidly growing human populations, intensification of livestock production and increasing exploitation of wildlife habitats for animal agriculture, the interface between wildlife, livestock and humans is expanding, with potential impacts on both domestic animal and human health. wild animals serve as reservoirs for many viruses, which may occasionally result in novel infections of domestic animals and/or the human population. given this background, we used metagenomics to investig ...201222967311
emerging and re-emerging swine viruses.in the past two decades or so, a number of viruses have emerged in the global swine population. some, such as porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus type 2 (pcv2), cause economically important diseases in pigs, whereas others such as porcine torque teno virus (ttv), now known as torque teno sus virus (ttsuv), porcine bocavirus (pbov) and related novel parvoviruses, porcine kobuvirus, porcine toroviruses (ptov) and porcine lymphotropic herpesviruses (pl ...201222225855
carbohydrate antigens.purpose of review: to summarize the current knowledge of carbohydrate antigens as related to xenotransplantation. the emphasis is on non-gal carbohydrate antigens identified in many institutes. in addition, several topics such as glycosyltransferase-transgenic pigs, innate cell receptors and porcine endogenous retrovirus (perv) will be discussed. recent findings: studies related to igb3 and neoantigens after knocking out galt (ggta1) were reviewed. available data do not support the conclusion th ...201222262104
Characterization of porcine endogenous retrovirus clones from the NIH miniature pig BAC library.Pigs have been considered as donors for xenotransplantation in the replacement of human organs and tissues. However, porcine endogenous retroviruses (PERVs) might transmit new infectious disease to humans during xenotransplantation. To investigate PERV integration sites, 45 PERV-positive BAC clones, including 12 PERV-A, 16 PERV-B, and 17 PERV-C clones, were identified from the NIH miniature pig BAC library. The analysis of 12 selected full-length sequences of PERVs, including the long terminal r ...201221912484
characterization of molecular clones of porcine endogenous retrovirus-a containing different numbers of u3 repeat boxes in the long terminal repeat region.when full-length molecular clones of porcine endogenous retrovirus (perv)-a and porcine endogenous retrovirus (perv)-b were passaged on human cells, an increase in the length of the long terminal repeat (ltr) was reported. a 39-bp repeat box in the ltr u3 region was multimerized dynamically upon replication, acting as a viral enhancer element that contains binding sites for nuclear transcription factor nf-y. to analyze the optimum number of 39-bp repeats for viral replication, molecular clones o ...201222343070
evaluation of a novel hybrid bioartificial liver based on a multi-layer flat-plate bioreactor.to evaluate the efficacy and safety of a hybrid bioartificial liver (hbal) system in the treatment of acute liver failure.201222851870
binding of transcription factor activating protein 2 γ on the 5'-proximal promoter region of human porcine endogenous retrovirus subgroup a receptor 2/gpr172b.xenotransplantation is one of the solutions for the shortage of organ donors, and pigs have been considered to be the most suitable animal donors. specific pathogen-free pigs are utilized in the xenotransplantation; however, pigs have infectious gammaretroviruses, named porcine endogenous retroviruses (pervs) in their genome. of them, perv-a and perv-b can infect human cells in vitro and potentially induce diseases like other gammaretroviruses. the human cellular receptors for perv-a were identi ...201222702469
detailed mapping of determinants within the porcine endogenous retrovirus envelope surface unit identifies critical residues for human cell infection within the proline-rich region.replication-competent porcine endogenous retroviruses (pervs) are either human cell tropic (perv-a and perv-b) or non-human cell tropic (perv-c). we previously demonstrated that perv in vitro cell tropism is modulated by 2 residues within the c terminus of su and that the perv receptor binding domain (rbd) extends beyond the variable regions a and b (vra and vrb, respectively), to include the proline rich-region (prr) of su (m. gemeniano et al., virology 346:108-117, 2000; t. argaw et al., j. vi ...201222696659
potential zoonotic infection of porcine endogenous retrovirus in xenotransplantation.porcine endogenous retrovirus (perv) is considered the major biosafety issue in xenotransplantation. several techniques have been employed for the analysis of the perv status in the animal donor and for the assessment of perv transmission/infection in the xenograft recipient. in this chapter, methods to assess the expression of perv and the potential for perv transmission from a donor animal are described in addition to the identification of relevant loci within the porcine genome.perv detection ...201222566002
[new evidence of porcine endogenous retrovirus transmission with new bio-artificial liver system: a experimental study].to investigate the potential transmissibility of porcine endogenous retrovirus (perv) from a newly-developed porcine hepatocyte bioartificial liver (bal) system prior to human clinical trial by using a live canine model.201222464706
porcine endogenous retrovirus copy number in different pig breeds is not related to genetic diversity.the risk of zoonoses is a major obstacle to xenotransplantation. porcine endogenous retrovirus (perv) poses a potential risk of zoonotic infection, and its control is a prerequisite for the development of clinical xenotransplantation. the copy number of perv varies among different breeds, and it has been suggested that the perv integrations number is increased by inbreeding. the purpose of this study was (i) to examine the copy number of perv in different spanish pig breeds, spanish wild boar an ...201222348392
degradation effect of diepoxide fixation on porcine endogenous retrovirus dna in heart valves: molecular aspects.xenotransplantations of porcine cells, tissues, and organs involve a risk of zoonotic viral infections in recipients, including by porcine endogenous retroviruses (pervs), which are embedded the genome of all pigs. an appropriate preparation of porcine heart valves for transplantation can prevent retroviral infection. therefore, the present study focuses on the effect of epoxy compounds and glutaraldehyde on the perv presence in porcine heart valves prepared for clinical use.201222307333
the sequence and analysis of a chinese pig genome.the pig is an economically important food source, amounting to approximately 40% of all meat consumed worldwide. pigs also serve as an important model organism because of their similarity to humans at the anatomical, physiological and genetic level, making them very useful for studying a variety of human diseases. a pig strain of particular interest is the miniature pig, specifically the wuzhishan pig (wzsp), as it has been extensively inbred. its high level of homozygosity offers increased ease ...201223587058
comparison of the convergent receptor utilization of a retargeted feline leukemia virus envelope with a naturally-occurring porcine endogenous retrovirus a.in vitro screening of randomized felv envelope libraries identified the cp isolate, which enters cells through hupar-1, one of two human receptors utilized by porcine endogenous retrovirus-a (perv-a), a distantly related gammaretrovirus. the cp and perv-a envs however, share little amino acid homology. their receptor utilization was examined to define the common receptor usage of these disparate viral envs. we demonstrate that the receptor usage of cp extends to hupar-2 but not to the porcine re ...201222405627
porcine endogenous retrovirus infection changes the expression of inflammation-related genes in lipopolysaccharide-stimulated human dermal fibroblasts.the present study focuses on explaining the interaction between porcine endogenous retroviruses (pervs) and human cells in inflammatory conditions. the differences in expression of selected inflammation-related genes in human dermal fibroblasts (nhdf) infected with pervs with and without lipopolysaccharide stimulation were identified.201324157628
long-term igg response to porcine neu5gc antigens without transmission of perv in burn patients treated with porcine skin xenografts.acellular materials of xenogenic origin are used worldwide as xenografts, and phase i trials of viable pig pancreatic islets are currently being performed. however, limited information is available on transmission of porcine endogenous retrovirus (perv) after xenotransplantation and on the long-term immune response of recipients to xenoantigens. we analyzed the blood of burn patients who had received living pig-skin dressings for up to 8 wk for the presence of perv as well as for the level and n ...201323945141
susceptibility of human liver cells to porcine endogenous retrovirus.the risk of porcine endogenous retrovirus infection is a major barrier for pig-to-human xenotransplant. porcine endogenous retrovirus, present in porcine cells, can infect many human and nonhuman primate cells in vitro, but there is no evidence available about in vitro infection of human liver cells. we investigated the susceptibility of different human liver cells to porcine endogenous retrovirus.201323901808
construction and characterization of an infectious replication competent clone of porcine endogenous retrovirus from chinese miniature pigs.xenotransplantation from animals has been considered to be a preferable approach to alleviate the shortage of human allografts. pigs are the most suitable candidate because of the anatomical and physiological similarities shared with humans as well as ethical concerns. however, it may be associated with the risk of transmission of infectious porcine pathogens. porcine endogenous retroviruses (pervs) are of particular concern because they have been shown to infect human cells in vitro. to date, r ...201323837947
promoter activity analysis and methylation characterization of ltr elements of pervs in nih miniature pig.the potential risk of porcine endogenous retrovirus (perv) transmission is an important issue in xenotransplantation (pig-to-human transplantation). long terminal repeats (ltrs) in perv elements show promoter activity that could affect neighboring functional genes. the methylation status and promoter activities of 3 ltr structures (perv-ltr1, ltr2, and ltr3 elements) belonging to the perv-a family were examined using luciferase reporter genes in human liver cell lines (hepg2 and hep3b). the perv ...201323832305
neutralization of porcine endogenous retrovirus by antibodies against the membrane-proximal external region of the transmembrane envelope protein.immunization of different species including goats, rats, hamsters and guinea pigs with the recombinant ectodomain of the transmembrane envelope (tm) protein p15e of porcine endogenous retrovirus (perv) has been shown to result in the production of virus-neutralizing antibodies. the sera recognize two groups of epitopes, one located in the fusion peptide-proximal region (fppr) and the second in the membrane-proximal external region (mper) of p15e. most interestingly, the epitopes in the mper are ...201323223617
improved pig donor screening including newly identified variants of porcine endogenous retrovirus-c (perv-c).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 ge ...201323053520
ethical and regulatory guidelines in clinical trials of xenocorneal transplantation in korea; the korean xenocorneal transplantation consensus statement.to establish the consensus about the conditions for undertaking clinical trials in xenocorneal transplantation in korea, specific issues regarding the xenocorneal transplantation on ethical and regulatory aspects are addressed, and the guidelines to conduct clinical trial of the xenocorneal transplantation are proposed.201323683073
knockdown of porcine endogenous retroviruses by rna interference in chinese experimental miniature pig fibroblasts.the clinical application of porcine-derived xenotransplants is limited by the potential risk of infection due to the presence of porcine endogenous retrovirus (perv) in tissues, organs, and cells. the establishment of pig fibroblasts with low perv expression and without perv-c can provide a nuclear donor to generate a safer transgenic pig.201323498816
preparation of immunogen-reduced and biocompatible extracellular matrices from porcine liver.decellularized biologic matrices are plausible biomedical materials for the bioengineering in liver transplantation. however, one of the concerns for safe medical application is the lack of objective assessment of the immunogen within the materials and the in vivo immune responses to the matrices. the purpose of this study was the production of immunogen-reduced and biocompatible matrices from porcine liver. in the present study, 0.1% sds solution was effective for removing dna fragments and seq ...201323068617
immunising with the transmembrane envelope proteins of different retroviruses including hiv-1: a comparative study.the induction of neutralizing antibodies is a promising way to prevent retrovirus infections. neutralizing antibodies are mainly directed against the envelope proteins, which consist of two molecules, the surface envelope (su) protein and the transmembrane envelope (tm) protein. antibodies broadly neutralizing the human immunodeficiencvy virus-1 (hiv-1) and binding to the tm protein gp41 of the virus have been isolated from infected individuals. their epitopes are located in the membrane proxima ...201323249763
koala retroviruses: characterization and impact on the life of koalas.koala retroviruses (korv) have been isolated from wild and captive koalas in australia as well as from koala populations held in zoos in other countries. they are members of the genus gammaretrovirus, are most closely related to gibbon ape leukemia virus (galv), feline leukemia virus (felv) and porcine endogenous retrovirus (perv) and are likely the result of a relatively recent trans-species transmission from rodents or bats. the first korv to be isolated, korv-a, is widely distributed in the k ...201324148555
molecular evolution of the porcine type i interferon family: subtype-specific expression and antiviral activity.type i interferons (ifns), key antiviral cytokines, evolve to adapt with ever-changing viral threats during vertebrate speciation. due to novel pathogenic pressure associated with suidae speciation and domestication, porcine ifns evolutionarily engender both molecular and functional diversification, which have not been well addressed in pigs, an important livestock species and animal model for biomedical sciences. annotation of current swine genome assembly sscrofa10.2 reveals 57 functional gene ...201425372927
optimization of virus detection in cells using massively parallel sequencing.massively parallel sequencing (mps)-based virus detection has potential regulatory applications. we studied the ability of one of these approaches, based on degenerate oligonucleotide primer (dop)-polymerase chain reaction (pcr), to detect viral sequences in cell lines known to express viral genes or particles. dop-pcr was highly sensitive for the detection of small quantities of isolated viral sequences. detected viral sequences included nodavirus, bracovirus, and endogenous retroviruses in hig ...201424309095
quantitative detection of residual porcine host cell dna by real-time pcr.all biological products are derived from complex living systems and are often mixed with large numbers of impurities. for reasons of safety, residual host-cell dna must be eliminated during processing. to assay host-cell dna content in biopharmaceutical products derived from porcine sources, this study applies the quantitative real-time polymerase chain reaction (q-pcr) method. the optimized assay in this study is based on the pol region of the porcine endogenous retrovirus (perv). assay validat ...201424394374
novel neutralising antibodies targeting the n-terminal helical region of the transmembrane envelope protein p15e of the porcine endogenous retrovirus (perv).previously, immunising different species with the transmembrane envelope protein p15e of the porcine endogenous retrovirus (perv), neutralising antibodies were induced which recognised epitopes in the fusion peptide proximal region (fppr) and in the membrane-proximal external region (mper). only the mper-specific antibodies were shown to neutralise and these antibodies targeted epitopes in the mper similarly localised as the epitopes recognised by antibodies broadly neutralising hiv-1 such as 2f ...201423729215
inhibition of porcine endogenous retrovirus in pk15 cell line by efficient multitargeting rna interference.to effectively suppress porcine endogenous retroviruses (perv)s, rnai technique was utilized. rnai is the up-to-date skill for gene knockdown which simultaneously multitargets both gag and pol genes critical for replication of pervs. previously, two of the most effective sirnas (gag2, pol2) were found to reduce the expression of pervs. concurrent treatment of these two sirnas (gag2+pol2) showed knockdown efficiency of up to 88% compared to negative control. however, despite the high initial knoc ...201424138389
clinical porcine islet xenotransplantation under comprehensive regulation.xenotransplantation with porcine islets is a promising approach to overcome the shortage of human donors. this is the first report of phase 1/2a xenotransplantation study of encapsulated neonatal porcine islets under the current framework of regulations for xenotransplantation in new zealand.201425131091
microarray analysis of retroviral restriction factor gene expression in response to porcine endogenous retrovirus infection.microarray analysis has been used for screening genes involved in specific biological processes. many studies have shown that restriction factors may play an important role in xenotransplantation safety, but it is still unclear whether porcine endogenous retroviruses (pervs) may be inhibited by these factors. therefore, the present study focused on the microarray analysis retroviral restriction factors gene expression in normal human dermal fibroblasts (nhdfs) in response to pervs. perv infectiv ...201425115112
differential expression of tripartite motif-containing family in normal human dermal fibroblasts in response to porcine endogenous retrovirus infection.antiretroviral restriction factors may play an essential role in the safety of xenotransplantation. therefore, the present study focused on investigation of the changes in the tripartite motif-containing family (trim) gene expression in normal human dermal fibroblasts with and without lipopolysaccharide stimulation in response to porcine endogenous retrovirus infection. analysis of the expression profile of trims was performed using oligonucleotide microarrays and qrt-pcr. nine (trim1, trim2, tr ...201425056437
no expression of porcine endogenous retrovirus after pig to monkey xenotransplantation.this study was performed to investigate the expression of two porcine endogenous retrovirus (perv) elements, perv gag and full-length conserved perv, in blood cells collected periodically from organ-recipient monkeys that underwent pig to non-human primate xenotransplantation. the heart and kidney-respectively acquired from α-1,3-galactosyltransferase knockout (gt-ko) pigs that survived for24 and 25 days-were xenografted into cynomolgus monkeys. the two perv elements expressed in the xenografted ...201424999364
inhibition of budding/release of porcine endogenous retrovirus.perv is integrated into the genome of all pigs. perv-a and perv-b are polytropic and can productively infect human cell lines, whereas perv-c is ecotropic. recombinant perv-a/c can infect human cells and exhibits high titer replication. therefore, use of pigs for human xenotransplantation raises concerns about the risks of transfer of this infectious agent from donors to xenotransplantation recipients. to establish strategies to inhibit perv production from cells, in the present study, we invest ...201424931347
lack of antibody response in pigs immunized with the transmembrane envelope protein of porcine endogenous retroviruses.recently, we immunized different mammalian species (goats, mice, rats, rabbits, guinea pigs and hamsters) with the recombinant ectodomain of the transmembrane envelope (tm) protein p15e of porcine endogenous retrovirus (perv). in all cases, neutralizing immune sera were induced, which recognized epitopes in the fusion peptide proximal region and the membrane proximal external region of p15e. in order to analyse whether pigs are also able to produce such antibodies, and whether such antibodies ca ...201424828332
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