| identification of exogenous forms of human-tropic porcine endogenous retrovirus in miniature swine. | the replication of porcine endogenous retrovirus subgroup a (perv-a) and perv-b in certain human cell lines indicates that perv may pose an infectious risk in clinical xenotransplantation. we have previously reported that human-tropic pervs isolated from infected human cells following cocultivation with miniature swine peripheral blood mononuclear cells (pbmc) are recombinants of perv-a with perv-c. here, we report that these recombinants are exogenous viruses in miniature swine; i.e., they are ... | 2004 | 14963150 |
| guided tissue regeneration: porcine matrix does not transmit perv. | for cardiovascular tissue engineering, acellularized scaffolds of porcine matrices have been successfully used. however, the possibility of porcine endogenous retrovirus (perv) transmission remains debatable. in this study, we investigated whether acellularized porcine vascular scaffolds cause cross-species transmission of perv in a xenogenic model. | 2004 | 15020135 |
| prevalence of porcine endogenous retrovirus in domestic pigs in japan and its potential infection in dogs xenotransplanted with porcine pancreatic islet cells. | the prevalence of porcine endogenous retrovirus (perv) proviral dna among various pig breeds raised in japan was investigated by polymerase chain reaction (pcr). moreover, potential infection of perv was investigated by pcr and reverse transcriptase-polymerase chain reaction (rt-pcr) in experimentally induced diabetic dogs (n=5) implanted with the diffusion chamber type bio-artificial endocrine pancreas (bio-aep) containing porcine pancreatic endocrine (pe) cells. no immunosuppressant was used a ... | 2004 | 15031539 |
| porcine endogenous retroviruses (pervs) and xenotransplantation: screening for transmission in several clinical trials and in experimental models using non-human primates. | xenotransplantation may develop into a medical technology able to save or improve the quality of life. porcine endogenous retroviruses (pervs), because they are integrated in the genome of all pig strains, because they are produced by normal pig cells, and because they can infect human cell in vitro, are considered to be the main microbiological risk if pig cells, tissues or organs are to be transplanted. indeed, serial passaging of perv on human cells, simulating the situation during xenotransp ... | 2003 | 15114938 |
| porcine endogenous retrovirus transmission characteristics of galactose alpha1-3 galactose-deficient pig cells. | galactose alpha1-3 galactose (gal) trisaccharides are present on the surface of wild-type pig cells, as well as on viruses particles produced from such cells. the recognition of gal sugars by natural anti-gal antibodies (nab) in human and old world primate serum can cause the lysis of the particles via complement-dependent mechanisms and has therefore been proposed as an important antiviral mechanism. recently, pigs have been generated that possess disrupted galactosyl-transferase (ggta1) genes. ... | 2004 | 15140978 |
| reduced sensitivity to human serum inactivation of enveloped viruses produced by pig cells transgenic for human cd55 or deficient for the galactosyl-alpha(1-3) galactosyl epitope. | complement activation mediated by the major xenogeneic epitope in the pig, galactosyl-alpha(1-3) galactosyl sugar structure (alpha-gal), and human natural antibodies could cause hyperacute rejection (har) in pig-to-human xenotransplantation. the same reaction on viruses bearing alpha-gal may serve as a barrier to zoonotic infection. expressing human complement regulatory proteins or knocking out alpha-gal epitopes in pig in order to overcome har may therefore pose an increased risk in xenotransp ... | 2004 | 15140979 |
| establishing the reactivity of monoclonal antibodies against porcine endogenous retrovirus envelope protein. | xenotransplantation of pig organs may be associated with a risk of transmission of microorganisms. porcine endogenous retroviruses (perv) are of particular concern since in vitro experiments have demonstrated that human cells are susceptible to such microorganisms. to monitor the transmission of perv, highly sensitive and specific immunoassays must be developed for clinical surveillance. this report describes the production, preliminary characterization and application of a monoclonal antibody ( ... | 2004 | 15192273 |
| xenografts are an achievable breakthrough. | the objective of this communication is to show that pig-to-human organ transplantation could be feasible through genetic engineering. by introducing into donor pigs several different tolerance promoting genetic modifications there can be a synergistic effect to produce extended tolerance for xenografted organs in human recipients. nuclear-transfer cloning allows production of pigs with knockout mutations in the galactose-alpha-1,3-galactosyl transferase gene, in principle eliminating hyperacute ... | 2004 | 15193356 |
| porcine endogenous retroviral nucleic acid in peripheral tissues is associated with migration of porcine cells post islet transplant. | porcine islets represent an alternative source of insulin-producing tissue, however, porcine endogenous retrovirus (perv) remains a concern. in this study, scid mice were transplanted with nonencapsulated (non-ec), microencapsulated (ec) or macroencapsulated (in a theracyte trade mark device) neonatal porcine islets (npis), and peripheral tissues were screened for presence of viral dna and mrna. to understand the role of an intact immune system in perv incidence, mice with established npi grafts ... | 2004 | 15196061 |
| no transmission of porcine endogenous retrovirus after transplantation of adult porcine islets into diabetic nude mice and immunosuppressed rats. | the aim of this study was to investigate whether transmission of porcine endogenous retrovirus (perv) occurs in a model of diabetes reversal by the xenotransplantation of adult porcine islets (apis) into immunoincompetent diabetic rodents. | 2004 | 15196128 |
| porcine cell microchimerism but lack of productive porcine endogenous retrovirus (perv) infection in naive and humanized scid-beige mice treated with porcine peripheral blood mononuclear cells. | pigs are considered a suitable source of cells and organs for xenotransplantation. all known strains of pigs contain porcine endogenous retrovirus (perv) and perv released by porcine cells may infect human cells in vitro and severe-combined immunodeficient (scid) mice in vivo. humanized scid (hu-scid) mice develop immune response to porcine antigens. here we investigated perv transmission in humanized scid-beige mice using porcine peripheral blood mononuclear cells (pbmc) as the donor tissue (an ... | 2004 | 15203124 |
| human immune responses to porcine endogenous retrovirus-derived peptides presented naturally in the context of porcine and human major histocompatibility complex class i molecules: implications in xenotransplantation of porcine organs. | porcine endogenous retroviruses (perv) have been shown to infect human cells, raising concerns regarding safety of xenotransplantation. in patients exposed to porcine tissues, no perv infection has been observed. this study was designed to develop human cd8+ cytotoxic t lymphocytes (ctl) against perv-derived peptides presented in the context of human leukocyte antigen (hla) or swine leukocyte antigen (sla) class i molecules and to define dominant epitopes contributed by perv. | 2004 | 15239626 |
| porcine endogenous retroviruses infect cells lacking cognate receptors by an alternative pathway: implications for retrovirus evolution and xenotransplantation. | a phq motif near the amino termini of gammaretroviral envelope glycoprotein surface (su) subunits is important for infectivity but not for incorporation into virions or binding to cognate receptors. the h residue of this motif is most critical, with all substitutions we tested being inactive. interestingly, porcine endogenous retroviruses (pervs) of all three host-range groups, a, b, and c, lack full phq motifs, but most members have an h residue at position 10. h10a perv mutants are noninfectio ... | 2004 | 15280495 |
| identification of a neutralizing epitope in the betae-betaf loop of vp1 of equine rhinitis a virus, defined by a neutralization-resistant variant. | equine rhinitis a virus strain 393/76 (erav.393/76) was passaged in the presence of post-infection erav.393/76 equine polyclonal antiserum (epa). viruses with increased resistance to neutralization by epa were obtained after 15 passages. compared with the parent virus, five plaque-purified, neutralization-resistant mutant viruses, in addition to the non-plaque-purified viruses that were examined, had a glu-->lys change at position 658, which is located in the predicted betae-betaf (ef) loop of v ... | 2004 | 15302948 |
| xenotransplantation: infectious risk revisited. | xenotransplantation is a possible solution for the shortage of tissues for human transplantation. multiple hurdles exist to clinical xenotransplantation, including immunologic barriers, metabolic differences between pigs--the source species most commonly considered--and humans, and ethical concerns. since clinical trials were first proposed almost 10 years ago, the degree of risk for infection transmitted from the xenograft donor to the recipient has been extensively investigated. a number of po ... | 2004 | 15307825 |
| mouse retrovirus mediates porcine endogenous retrovirus transmission into human cells in long-term human-porcine chimeric mice. | porcine endogenous retrovirus (perv) is a potential pathogen in clinical xenotransplantation; transmission of perv in vivo has been suggested in murine xenotransplantation models. we analyzed the transmission of perv to human cells in vivo using a model in which immunodeficient nod/scid transgenic mice were transplanted with porcine and human lymphohematopoietic tissues. our results demonstrate, we believe for the first time, that human and pig cells can coexist long-term (up to 25 weeks) withou ... | 2004 | 15343388 |
| phylogenetic relationship of porcine endogenous retrovirus (perv) in chinese pigs with some type c retroviruses. | pcr amplification of proviral dna extracted from peripheral blood lymphocytes of three chinese pigs (banna minipig inbreed (bmi), wu-zhi-shan pig (wzsp) and neijiang pig (njp)), using primers corresponding to highly conserved regions of reverse transcriptase (rt) of pol gene and nucleocapsid sequence of gag gene. pcr products were then extracted and cloned into pgem-t vector. phylogenetic analysis of the nucleotide sequences of perv-bmi, perv-wzsp and perv-wzsp revealed that they were of retrovi ... | 2004 | 15351490 |
| [studies on the infectivity by porcine endogenous retrovirus with porcine skin fibroblast in vitro and in vivo]. | to understand the infectivity by porcine endogenous retrovirus with porcine skin fibroblast cell in vitro and in vivo, porcine skin fibroblast cell established by our laboratory were co-cultured with neo/hek293 cell for the infection of perv in vitro, and were subcutaneously transplantated to scid (severe combined immuno-deficiency) mice for the infection of perv in vivo, laying the foundation for valuation of biologic safety of xenotransplantation. the event of neo/hek293 cells infected by perv ... | 2004 | 15481536 |
| screening and analysis of porcine endogenous retrovirus in chinese banna minipig inbred line. | pigs have been the most likely animal as the source of cells, tissues, and organs for xenotransplantation. but the use of pigs in xenotransplantation is associated with the risk of porcine endogenous retrovirus (perv) transmission. previous studies have identified that the proviruses are integrated into the genome of normal pigs and that virus particles released from the porcine cells can infect human cells in vitro. as a unique inbred pig, banna minipig inbred (bmi) has a huge potential value f ... | 2004 | 15561290 |
| phylogenetic analysis of porcine endogenous retrovirus variation in three chinese pigs. | pcr amplification was performed on genomic dna extracted from peripheral blood lymphocytes of three species of chinese pigs (banna minipig inbreed [bmi], wu-zhi-shan pig [wzsp], and nei jiang pig [njp]), using primers corresponding to the highly conserved regions of polymerase (pol) gene. extracted pcr products were then cloned in a pgem-t vector. phylogenetic analysis of the nucleotide sequences of bmi-perv, njjp-perv, and wzsp-perv revealed them to be a novel category of perv. in comparison to ... | 2004 | 15561294 |
| determinants of high titer in recombinant porcine endogenous retroviruses. | porcine endogenous retroviruses (pervs) pose a potential stumbling block for therapeutic xenotransplantation, with the greatest threat coming from viruses generated by recombination between members of the perv subgroup a (perv-a) and perv-c families (perv-a/c recombinants). perv-a and perv-b have been shown to infect human cells in culture, albeit with low titers. perv-c has a more restricted host range and cannot infect human cells. a recombinant perv-a/c virus (perv-a14/220) contains the perv- ... | 2004 | 15564495 |
| evidence and consequence of porcine endogenous retrovirus recombination. | the genetic nature and biological effects of recombination between porcine endogenous retroviruses (perv) were studied. an infectious molecular clone was generated from a high-titer, human-tropic perv isolate, perv-a 14/220 (b. a. oldmixon, et al. j. virol. 76:3045-3048, 2002; t. a. ericsson et al. proc. natl. acad. sci. usa 100:6759-6764, 2003). to analyze this sequence and 15 available full-length perv nucleotide sequences, we developed a sequence comparison program, loha(tm) to calculate loca ... | 2004 | 15564496 |
| the screening and identification of endogenous retrovirus free cemps. | the provirus dna sequence of porcine endogenous retrovirus (perv) distributed in the pig genome is the major obstacle that restricts the swine as the organ donors in xenotransplantation, and the copy number of perv varies greatly among different breeds and individuals. in the experiment, 67 healthy, female chinese experimental mini-pigs (cemps) aged at 3-6 months were selected from the animal husbandry station of china agricultural university, the copy number of perv and types of envelope protei ... | 2004 | 15620113 |
| [analysis of presence and difference of sequence of porcine endogenous retrovirus in dna genomes from peripheral blood white cells of pig and mrna in tissues from mini-pigs]. | the aim is to investigate biological features of porcine endogenous retrovirus (perv) of pigs in china and to provide basic parameters for evaluation of biological safety of xenotransplantation from pig to human. in this study, basic biologic features of perv of dna of peripheral blood white cells of 12 species of domestic pigs in china were examined by polymerase chain reaction; analysis of difference of perv gene sequence was investigated by sliver-stained single stranded conformational polymo ... | 2004 | 15636362 |
| characterization of a monoclonal antibody specific to the gag protein of porcine endogenous retrovirus and its application in detecting the virus infection. | the porcine endogenous retrovirus (perv) has drawn extensive attention recently, due to the widespread use of biomaterials of porcine origin in organ transplantation. this virus is present in all pig strains and has been demonstrated to be capable of infecting human cells in vitro. therefore, it is imperative to develop a highly sensitive and specific immunoassay for clinical surveillance in patients receiving xenotransplantation. we describe here the generation of a monoclonal antibody (mab) na ... | 2005 | 15681064 |
| absence of perv infection in baboons after transgenic porcine liver perfusion. | xenotransplantation offers great promise to supplement the shortage of human organs available for transplant, but cross-species infection is a substantial concern. porcine endogenous retrovirus (perv), in particular, is thought to pose a risk as a potential pathogen to humans. we evaluated whether perv is capable of infecting nonhuman primates in vivo after extracorporeal porcine liver perfusion (eclp). | 2005 | 15734478 |
| transplantation of neonatal porcine islets and sertoli cells into nonimmunosuppressed nonhuman primates. | a mexican group reported transplantation of cocultured neonatal porcine islets and sertoli cells resulting in insulin independence in nonimmunosuppressed type 1 diabetes patients. we have transplanted similar islets alone (naked islets) or cocultured islets with sertoli cells (islet/sertoli cells) into an omental site and other locations of seven nondiabetic, nonimmunosuppressed, nonhuman primates. porcine endogenous retrovirus was not detected in recipient blood 8 weeks after porcine islet graf ... | 2005 | 15808684 |
| long-term effects on hek-293 cell line after co-culture with porcine endogenous retrovirus. | xenotransplantation of pig organs, tissues, and cells bears the risk of interspecies transmission of porcine endogenous retrovirus (perv). to evaluate the long-term effect of perv infection on human cells, human embryonic kidney cell line hek-293 cells were co-cultured with perv produced by the porcine kidney pk15 cell line for 24 hours and the infected hek-293 cells were continually cultured for 6 months. perv-gag, pol gene and gag protein were detected in infected hek-293 cells by pcr and immu ... | 2005 | 15808688 |
| the effect of complement regulatory protein expression on pig endothelial cells to porcine endogenous retrovirus lyses by human sera. | expression of human complement regulatory proteins (crp) on pig endothelial cells (pec) has been useful to avoid hyperacute rejection by human sera. on the other hand, porcine endogenous retrovirus (perv) from pec transfectants with crp may acquire resistance to human sera. in this study, we investigated the effects of the transfected crp on perv neutralization and/or lysis by human sera. | 2005 | 15808690 |
| porcine endogenous retroviruses perv-a and perv-b infect neither mouse cells in vitro nor scid mice in vivo. | porcine endogenous retroviruses (pervs) pose a risk for xenotransplantations using pig materials as they are present in the genome of all pigs and are able to infect human cells in vitro. until recently, transmission of pervs in vivo was only described in severe combined immunodeficient (scid) and nude mice inoculated with perv-producing cells. however, in this series of experiments microchimerism could not be excluded. to overcome this problem, the risk of perv infection was addressed in a simi ... | 2005 | 15812191 |
| lack of cross-species transmission of porcine endogenous retrovirus in pig-to-baboon xenotransplantation with sustained depletion of anti-alphagal antibodies. | nonhuman primates are potential permissive animals for studying the risk of in vivo infection with porcine endogenous retrovirus (perv). anti-alphagal natural antibodies are considered one of the barriers for preventing perv infection, and it has been postulated that reduction of these antibodies could increase the risk of this infection. the aim of this study was to investigate the role of gas 914, which depletes anti-alphagal antibodies, in the potential in vivo transfer of perv after pig-to-b ... | 2005 | 15818319 |
| neutralising antibodies against the transmembrane protein of feline leukaemia virus (felv). | neutralising antibodies specific for feline leukaemia virus (felv) were induced by immunisation with recombinant felv transmembrane envelope protein p15e. epitope mapping revealed two epitopes located in similar regions to those previously identified for the porcine endogenous retrovirus (perv). one of the epitopes has partial homology and both are located in regions corresponding to epitopes recognised by neutralising antibodies in patients infected with hiv-1. | 2005 | 15837241 |
| characterization of a hollow fiber bioartificial liver device. | a three-compartment bioartificial liver (bal) has been developed for potential treatment of fulminant hepatic failure. it has been shown previously that viability and liver-specific functions were maintained in laboratory-scale bioreactors of such design. in this study, the performance of hepatocytes in a clinical-scale bioartificial liver was verified by sustained specific production rates of albumin and urea, along with oxygen consumption rates for up to 56 h and liver-specific gene expression ... | 2005 | 15854219 |
| [construction and evaluation of the property of decellular porcine aortic valve]. | to construct decellular porcine aortic valve (pav) and to observe the existence of porcine endogenous retrovirus (perv) and valve scaffold structure before and after implantation. | 2005 | 15854509 |
| prevention of perv infections in pig to human xenotransplantation by the rna interference silences gene. | the possibility of preventing the transmission of porcine endogenous retrovirus (perv) to human cells using short interfering rnas (sirna) was investigated. the sirna for the p30 of perv gag region was cloned into psuper, the polymerase-iii h1-rna gene promoter. a green fluorescence protein (gfp) was also cloned into psuper to establish psxgh. pig endothelial cells (pec) were transduced with the lacz gene by pseudotype infection, and infected with perv subtype b, resulting in the formation of pe ... | 2005 | 15858174 |
| analysis of pig-to-human porcine endogenous retrovirus transmission in a triple-species kidney xenotransplantation model. | clinical pig-to-human xenotransplantation might be associated with the risk of transmission of xenozoonoses, especially porcine endogenous retroviruses (pervs). we have established a pig-to-humanised-cynomolgus monkey xenotransplantation model allowing the analysis of potential perv-transmission from normal or transgenic porcine organs to human vascular tissue. pig-to-human kidney xenotransplantation was performed in cynomolgus monkeys. an interposition graft constructed from a human saphena vei ... | 2005 | 15864489 |
| cell-binding properties of the envelope proteins of porcine endogenous retroviruses. | to examine the binding properties of the envelope glycoproteins of porcine endogenous retrovirus subgroups a and b (perv-a and perv-b), we produced two forms of soluble envelope proteins, termed env-st and env-su, using a baculovirus expression system. env-st and env-su encompass one-third of the n-terminal and the entire surface unit (su) of the envelope protein, respectively. using these proteins, binding assays were performed in various mammalian cell lines. the binding properties of the env- ... | 2005 | 15876545 |
| no evidence of in vitro and in vivo porcine endogenous retrovirus infection after plasmapheresis through the amc-bioartificial liver. | currently a number of bioartificial livers (bal) based on porcine liver cells have been developed as a treatment to bridge acute liver failure patients to orthotopic liver transplantation or liver regeneration. these xenotransplantation related treatments hold the risk of infection of treated patients by porcine endogenous retrovirus (perv) released from the porcine cells, as in vitro infection experiments and transplantations in immunocompromised mice have shown that perv is able to infect huma ... | 2005 | 15943777 |
| porcine endogenous retrovirus encodes xenoantigens involved in porcine cellular xenograft rejection by mice. | identification of the antigens that stimulate transplant rejection can help develop graft-specific antirejection strategies. the xenoantigens recognized during rejection of porcine cellular xenografts have not been clearly defined, but it has been assumed that major histocompatibility complex (mhc) xenoantigens are involved. | 2005 | 15973168 |
| pseudotyping of porcine endogenous retrovirus by xenotropic murine leukemia virus in a pig islet xenotransplantation model. | the potential of porcine endogenous retrovirus (perv) as a human pathogen, particularly as a public health risk, is a major concern for xenotransplantation. in vitroperv transmission to human cells is well established. evidence from human/pig hematopoietic chimeras in immunodeficient mice suggests perv transmission from pig to human cells in vivo. however, recently yang et al. demonstrated in such a model that perv-c, a nonhuman-tropic class, could be transmitted via pseudotyping by xenotropic m ... | 2005 | 15996230 |
| [preliminary study on human embryonic kidney cell line hek-293 after porcine endogenous retrovirus infection]. | to assess the infectivity of porcine endogenous retrovirus (perv) via in vitro infection of human embryonic kidney cell line hek-293. | 2005 | 16091176 |
| prevalence of porcine endogenous retrovirus in chinese pig breeds and in patients treated with a porcine liver cell-based bioreactor. | to determine the prevalence of porcine endogenous retrovirus (perv) in various pig breeds raised in china including chinese experimental mini-pigs by perv-reverse transcriptase (perv-rt enzyme). moreover, the potential for infection of perv was investigated in patients treated with a bioreactor based on porcine liver cells (n = 3). | 2005 | 16094718 |
| the ethics debate in relation to xenotransplantation. | xenotransplantation is the transplantation of organs and cells from one species to another: it has enormous potential to increase the supply of organs and tissues to alleviate human disease. recent scientific progress has eliminated the obstacle of hyperacute rejection, which is the massive destruction of the transplanted organ within 24 h. despite this progress and the tremendous clinical potential, a number of ethical issues require careful consideration. these issues involve the human recipie ... | 2005 | 16110900 |
| xenotransplantation of porcine neonatal islets of langerhans and sertoli cells: a 4-year study. | porcine islets of langerhans for xenotransplantation into humans have been proposed as a solution to the shortage of human donors. rejection is one of the main constraints. this study presents the results of a clinical trial using a novel method for transplanting and immunoprotecting porcine islets in type 1 diabetic patients. | 2005 | 16131605 |
| induction of neutralizing antibody against human immunodeficiency virus type 1 (hiv-1) by immunization with gp41 membrane-proximal external region (mper) fused with porcine endogenous retrovirus (perv) p15e fragment. | the membrane-proximal external region (mper) of hiv-1 gp41 is recognized by all three anti-hiv antibodies 2f5, 4e10 and z13 that were directly derived from aids patients and have broader anti-hiv neutralizing activities. thus, the mper has been the focus of anti-hiv vaccine design and development. however, it has been unsuccessful to generate anti-hiv neutralizing antibodies targeting this region. one possible reason is that the mper-containing immunogens have failed to maintain the correct conf ... | 2006 | 16143433 |
| pig islet xenotransplantation: activation of porcine endogenous retrovirus in the immediate post-transplantation period. | porcine endogenous retroviruses (perv) are considered as the main infectious barrier in islet xenotransplantation. perv has been shown to infect, but not to cause symptomatic disease in mice after islet transplantation. in vivo activation of perv have so far not been examined. expression of perv was examined in adult and fetal porcine islets with or without the presence of known retroviral inducers or after transplantation to rats. | 2005 | 16202068 |
| [effects of modified acellularization process on porcine endogenous retroviruses in porcine aorta valves]. | to study the effect of modified acellularization process on porcine endogenous retrovirus (perv) in porcine aorta valves (pavs). | 2005 | 16253188 |
| the use of pancreas biopsy scoring provides reliable porcine islet yields while encapsulation permits the determination of microbiological safety. | for clinical xenogenic islet transplantation to be successful, several requirements must be met. among them is a sizeable and reliable source of fully functional and microbiologically safe islets. the inherent variability among porcine pancreases, with respect to islet yield, prompted us to develop a biopsy score technique to determine the suitability of each pancreas for islet isolation processing. the biopsy score consists of an assessment of five variables: warm ischemia time, pancreas color, ... | 2005 | 16285251 |
| intraperitoneal alginate-encapsulated neonatal porcine islets in a placebo-controlled study with 16 diabetic cynomolgus primates. | a nonhuman primate model of diabetes is valuable for assessing porcine pancreatic islet transplants that might have clinical benefits in humans. | 2005 | 16298643 |
| the infectivity and host range of the ecotropic porcine endogenous retrovirus, perv-c, is modulated by residues in the c-terminal region of its surface envelope protein. | endogenous retroviral genetic material serves as a reservoir for the generation of retroviral pathogens by recombination between activated endogenous or exogenous infectious agents. some porcine tissues actively express infectious porcine endogenous retroviruses (pervs). of the three classes of perv characterized to date, two, perv-a and b, are capable of infecting human cells in vitro, whereas perv-c cannot. here, we demonstrate that the perv-c envelope surface protein (su) when disassociated f ... | 2006 | 16309725 |
| [intergration and epression of porcine endogenous retrovinus in the immortal cell line of banna minipig inberd line-mesenhymal stem cells]. | to detect the integration and expression of porcine endogenous retrovirus (perv) in the immortal cell line of banna minipig inbred line-mesenchymal stem cells (bmi-mscs). | 2005 | 16334548 |
| variation of host cell tropism of porcine endogenous retroviruses expressed in chinese banna minipig inbred. | a serious donor-organ shortage urges the use of animal donors to treat a wide appropriate variety of major health problems including organ failure and diabetes. however, the promise of clinical xenotransplantation is offset at the present time by the potential of a public health risk due to the cross-species transmission of pathogens from animal donors to human patients. in particular, the transmission of porcine endogenous retrovirus (perv) is a major concern. in this study, cell tropism of per ... | 2006 | 16407655 |
| antibodies neutralizing feline leukaemia virus (felv) in cats immunized with the transmembrane envelope protein p15e. | the feline leukaemia virus (felv) vaccines that are currently in wide use are generally poor inducers of virus-neutralizing antibodies, although such antibodies appear after recovering from challenge. however, the presence of neutralizing antibodies in cats recovering from natural felv infection clearly correlates with resistance to subsequent infection and passive transfer of antibodies can protect other animals. after demonstrating the induction of neutralizing antibodies in rats and goats imm ... | 2006 | 16423059 |
| an69 hollow fiber membrane will reduce but not abolish the risk of transmission of porcine endogenous retroviruses. | as the risk of porcine endogenous retrovirus (perv) infection is a major obstacle to the xenotransplantation of porcine tissue, we investigated whether an an69 hollow fibre membrane, used for islets of langerhans transplantation, could prevent the transfer of pervs and thus reduce the risk of perv infection. pk15 cells were used as a perv source. a specific and highly sensitive rcr was used for detection of a perv provirus dna (gag region) and a porcine mtdna. human u293 cells were incubated in ... | 2005 | 16454349 |
| long-term survival of neonatal porcine islets in nonhuman primates by targeting costimulation pathways. | we evaluated the ability of neonatal porcine islets to engraft and restore glucose control in pancreatectomized rhesus macaques. although porcine islets transplanted into nonimmunosuppressed macaques were rapidly rejected by a process consistent with cellular rejection, recipients treated with a cd28-cd154 costimulation blockade regimen achieved sustained insulin independence (median survival, >140 days) without evidence of porcine endogenous retrovirus dissemination. thus, neonatal porcine isle ... | 2006 | 16501570 |
| phylogeny, recombination and expression of porcine endogenous retrovirus gamma2 nucleotide sequences. | endogenous retroviral sequences in the pig genome represent a potential infectious risk in xenotransplantation. porcine endogenous retrovirus (perv) gamma sequences described to date have been classified into several families. the known infectious, human-tropic pervs have been assigned to the perv gamma1 subfamilies a, b and c. high copy numbers and full-length clones have also been observed for an additional family, designated perv gamma2. the aim of this study was to examine the perv gamma2 fa ... | 2006 | 16528048 |
| detection of perv by polymerase chain reaction and its safety in bioartificial liver support system. | to establish a method detecting porcine endogenous retrovirus (perv) in china experimental minipigs and to evaluate the safety of perv in three individuals treated with bioartificial liver support systems based on porcine hepatocytes. | 2006 | 16534887 |
| mice transgenic for a human porcine endogenous retrovirus receptor are susceptible to productive viral infection. | porcine endogenous retrovirus (perv) is considered one of the major risks in xenotransplantation. no valid animal model has been established to evaluate the risks associated with perv transmission to human patients by pig tissue xenotransplantation or to study the potential pathogenesis associated with perv infection. in previous work we isolated two genes encoding functional human perv receptors and proved that introduction of these into mouse fibroblasts allowed the normally nonpermissive mous ... | 2006 | 16537582 |
| a novel strategy for preventing perv transmission to human cells by remodeling the viral envelope glycoprotein. | porcine endogenous retrovirus (perv) released from pig cells is a main problem associated with clinical xenotransplantation. in a previous study, we demonstrated that the high mannose type of n-glycan of the envelope glycoprotein is closely related to perv infectivity with respect to human cells. in this study, we addressed the effects of reducing the high mannose type of n-glycan on perv infectivity. | 2006 | 16756569 |
| [research of porcine endogenous retrovirus in shaziling pigs]. | to provide basic parameters of evaluating the biological safety of xenotransplantation from pig to human, ear tissues from 31 individuals were randomly collected from a shazi ling pig population. pcr and rt-pcr were performed to detect porcine endogenous retrovirus (perv) proviral dna and mrna respectively. the sensitivity of the pcr was evaluated using a positive control. to study tissue distribution, rt-pcr of pol, gag and env was performed in the kidney, heart, liver, lung and spleen of 3 ind ... | 2006 | 16825165 |
| journey from hepatocyte transplantation to hepatic stem cells: a novel treatment strategy for liver diseases. | acute liver failure (alf) carries high morbidity and mortality (>80%) even in the best centres. orthotopic liver transplantation (oltx) is the only viable approach to the treatment of alf. this has significantly improved the survival in these patients. the major limitations of oltx are non availability of the donor liver, requirement of a major surgical procedure, high cost and longterm immunosuppression. isolated hepatocyte transplantation is emerging as an appealing method for the treatment of ... | 2006 | 16873904 |
| porcine endogenous retrovirus integration sites in the human genome: features in common with those of murine leukemia virus. | porcine endogenous retroviruses (perv) are a major concern when porcine tissues and organs are used for xenotransplantation. perv has been shown to infect human cells in vitro, highlighting a potential zoonotic risk. no pathology is associated with perv in its natural host, but the pathogenic potential might differ in the case of cross-species transmission and can only be inferred from knowledge of related gammaretroviruses. we therefore investigated the integration features of the perv dna in t ... | 2006 | 16928752 |
| phylogenetic analysis of porcine endogenous retroviruses expressed in chinese pigs based on envelope sequences. | the promise of successful clinical xenotransplantation is now offset by the potential risk of transmission of porcine endogenous retrovirus (perv). perv consists of three subtypes according to the varieties of env sequences. we analyzed perv subtypes in two species of chinese pigs (banna minipig inbred, bmi, and wu-zhi-shan pig, wzsp). positive a and b were detected while positive c was absent in the analyzed chinese pigs. the polymerase chain reaction products were then cloned into a pgem-t vec ... | 2006 | 16980057 |
| the lack of inhibition of porcine endogenous retrovirus by small interference rna designed from the long terminal regions. | xenotransplantation from pigs may offer a potential solution to the organ shortage. however, there remains the risk of xenoinfection by porcine endogenous retroviruses (pervs) that cannot be eliminated by breeding pigs under specified pathogen-free conditions. rna interference is a new method to inhibit the expression of a specific gene. here, we designed two sirnas from the long terminal repeat of perv. our results showed that these sirnas had no inhibitory effects. the possible reasons for thi ... | 2006 | 16980058 |
| in vivo screening of porcine endogenous retrovirus in chinese banna minipig inbred. | the risk of porcine endogenous retrovirus (perv) infection is one of the major barriers in clinical trials of pig-to-human xenotransplantation. previous experiments showed that perv could infect many types of human and nonhuman primate cells, but there is no reported evidence of in vivo infection. in this study, extracted genomic dna from tissues of seventeen pigs was analyzed using specific sequence primers for gag, pol, and env. the results suggested that perv exist in the genomes of all tissu ... | 2006 | 16980059 |
| isolation and characterization of an infectious replication-competent molecular clone of ecotropic porcine endogenous retrovirus class c. | xenotransplantation of pig organs is complicated by the existence of polytropic replication-competent porcine endogenous retroviruses (perv) capable of infecting human cells. the potential for recombination between ecotropic perv-c and human-tropic perv-a and perv-b adds another level of infectious risk. proviral perv-c were characterized in max-t cells derived from d/d haplotype miniature swine. three proviruses were cloned from a genomic library. clone perv-c(1312) generated infectious particl ... | 2006 | 17005704 |
| genomic presence of recombinant porcine endogenous retrovirus in transmitting miniature swine. | the replication of porcine endogenous retrovirus (perv) in human cell lines suggests a potential infectious risk in xenotransplantation. perv isolated from human cells following cocultivation with porcine peripheral blood mononuclear cells is a recombinant of perv-a and perv-c. we describe two different recombinant perv-ac sequences in the cellular dna of some transmitting miniature swine. this is the first evidence of perv-ac recombinant virus in porcine genomic dna that may have resulted from ... | 2006 | 17081300 |
| molecular characterization of the porcine endogenous retrovirus subclass a and b envelope gene from pigs. | xenotransplantation of porcine organs has the potential to overcome the current critical shortage of allogenic organs for transplantation in humans. however, the existence of porcine endogenous retroviruses (pervs) presents a problem for the clinical use of xenografts from pigs. in an attempt to understand the molecular characteristics of pervs, we cloned the perv env gene from six pig breeds (ie, berkshire, duroc, landrace, yorkshire, and two types of miniature pigs) in korea. a total of 141 en ... | 2006 | 17112901 |
| [porcine endogenous retrovirus in daweizi pigs in hunan]. | to detect porcine endogenous retrovirus (perv) in daweizi pigs and to provide basic parameters of evaluating the biological safety for xenotransplantation from pigs to humans. | 2006 | 17213579 |
| lack of evidence for perv expression after apoptosis-mediated horizontal gene transfer between porcine and human cells. | evidence for porcine endogenous retrovirus (perv) infection of human cells has provoked a public health debate over the proposed use of porcine xenografts to alleviate the worldwide shortage of human allografts. nevertheless, the potential relevance of perv transmission by apoptosis-mediated horizontal dna transfer, a documented means of infection-independent retrovirus delivery, appears to have been overlooked in this discussion. to examine the hypothesis that apoptotic cell death during porcin ... | 2007 | 17214701 |
| functional epitopes on porcine endogenous retrovirus envelope protein interacting with neutralizing antibody combining sites. | porcine cell and organ transplantation provides promise for maintaining normal physiological conditions in patients with end-stage organ failure. the approach however poses serious risk of transmitting pig pathogens to humans. among many potential pathogens, porcine endogenous retroviruses (perv) are of particular concern due to their ubiquitous nature in pigs and capability of infecting human cells. major antigenic determinants and receptor binding domains on perv remain unclear until now. two ... | 2007 | 17222436 |
| transient transmission of porcine endogenous retrovirus to fetal lambs after pig islet tissue xenotransplantation. | evidence for the in vivo transmission of porcine endogenous retrovirus (perv) from porcine xenografts to various recipient animals has been inconsistent. to characterize the contribution of the host immune system to the potential for perv transmission from pig islet tissue xenografts to host tissues, we examined two immunoincompetent animal models, thymectomizsed fetal lambs and nodscid mice. pig proislets were grafted into fetal lambs or adult nodscid mice. conventional, nested and real-time pc ... | 2007 | 17228325 |
| novel method of decellularization of porcine valves using polyethylene glycol and gamma irradiation. | recent tissue-engineered valves are in need of a breakthrough to overcome several limitations against clinical applications. we have developed a new method of decellularization using polyethylene glycol and gamma irradiation. | 2007 | 17383366 |
| expression of porcine endogenous retroviruses (pervs) in melanomas of munich miniature swine (mms) troll. | porcine endogenous retroviruses (pervs) are integrated in the genome of all pig breeds. since some of them are able to infect human cells, they might represent a risk for xenotransplantation using pig cells or organs. however, the expression and biological role of pervs in healthy pigs as well as in porcine tumours is largely unknown. since we and others have recently shown overexpression of a human endogenous retrovirus, herv-k, in human melanomas, we studied the expression of pervs in melanoma ... | 2007 | 17418507 |
| selective inhibition of porcine endogenous retrovirus replication in human cells by acyclic nucleoside phosphonates. | several anti-human immunodeficiency virus type 1 reverse transcriptase inhibitors were evaluated for their antiviral activities against porcine endogenous retrovirus in human cells. among the test compounds, zidovudine was found to be the most active. the order of potency was zidovudine > phosphonylmethoxyethoxydiaminopyrimidine = phosphonylmethoxypropyldiaminopurine > tenofovir > or = adefovir > stavudine. | 2007 | 17470654 |
| three-yr follow-up of a type 1 diabetes mellitus patient with an islet xenotransplant. | in order to alleviate the shortage of human donors, the use of porcine islets of langerhans for xenotransplantation in diabetic patients has been proposed as a solution. to overcome rejection, we have developed a procedure for protecting the islets by combining them with sertoli cells and placing them in a novel subcutaneous device, that generates an autologous collagen covering. a type 1 diabetic woman was closely monitored for 10 months, and then transplanted in two devices with two months of ... | 2007 | 17488384 |
| some ethical issues regarding xenotransfusion. | the use of porcine red blood cells has recently been proposed as a possible solution to the shortage of blood for human transfusion. | 2007 | 17489861 |
| pre-screening of miniature swine may reduce the risk of transmitting human tropic recombinant porcine endogenous retroviruses. | it has been reported that peripheral blood mononuclear cells from miniature swine are capable of transmitting human tropic porcine endogenous retrovirus (perv) recombinants to both human and pig cells. it has been suggested that these recombinants are exogenous and/or driven by one or more critical loci present in the pig genome. | 2007 | 17489862 |
| [clinical xenotransplantation]. | the growing numerical gap between the number of patients and available human donor organs have led to a revival interest in xenotransplantation. this review will mainly focus on the clinical affairs of xenotransplantation and the project of producing the gene modified pigs. trials, designed to overcome xenogenic rejection by the expression of human complement regulatory protein (crp), such as daf (cd55), on the pig organ and knocking out the alpha-gal epitope(galalpha1-3galbeta1-4glcnac-r), whic ... | 2007 | 17603258 |
| no evidence of perv infection in healthcare workers exposed to transgenic porcine liver extracorporeal support. | clinical xenotransplantation holds great promise by providing one solution to the shortage of human organs for transplantation, while also posing a potential public health threat by facilitating transmission of infectious disease from source animals to humans. one potential vector for infectious disease transmission is healthcare workers (hcw) who are involved in administering xenotransplantation procedures. | 2007 | 17669172 |
| 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 ... | 2008 | 17689611 |
| lack of cross-species transmission of porcine endogenous retrovirus (perv) to transplant recipients and abattoir workers in contact with pigs. | this study investigated the potential transmission of porcine endogenous retrovirus (perv) to solid-organ transplant recipients and abattoir workers in contact with pigs. blood samples were obtained from volunteer healthy blood donors (group a; n=33); pig-breeding farmers who had undergone a liver transplant (group b; n=14); and pig abattoir workers (group c; n=49). a second blood sample was obtained 1 year after the first sample from 10 of the abattoir workers (group d). tests included investig ... | 2007 | 17713442 |
| the restriction of zoonotic perv transmission by human apobec3g. | the human apobec3g protein is an innate anti-viral factor that can dominantly inhibit the replication of some endogenous and exogenous retroviruses. the prospects of purposefully harnessing such an anti-viral defense are under investigation. here, long-term co-culture experiments were used to show that porcine endogenous retrovirus (perv) transmission from pig to human cells is reduced to nearly undetectable levels by expressing human apobec3g in virus-producing pig kidney cells. inhibition occu ... | 2007 | 17849022 |
| 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 ... | 2008 | 17981539 |
| 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, ... | 2008 | 17987669 |
| [potential risk of porcine endogenous retrovirus cross-species transmission in neonatal pig islets under xenotransplanted condition]. | to evaluate the potential risk of porcine endogenous retrovirus (perv) cross-species transmission xenotransplanted with microencapsulated neonatal pig islets (npis). | 2007 | 18007064 |
| [cloning and bioinformatics analysis of sla-dr genes in hunan shaziling pigs]. | in order to clone class ii dra and drb genes of swine leukocyte antigen (sla) in hunan shaziling pigs, to analyze their characteristics and polymorphism and to provide immunological basic parameters for xenotransplantation from pigs to humans. sla-dra and sla-drb genes in two shaziling pigs with the absence of porcine endogenous retrovirus (perv) env-c were amplified by rt-pcr, cloned into pucm-t vectors, sequenced and analyzed through blast in ncbi and related software in expasy. the obtained s ... | 2007 | 18065385 |
| differential resistance to cell entry by porcine endogenous retrovirus subgroup a in rodent species. | the risk of zoonotic infection by porcine endogenous retroviruses (perv) has been highlighted in the context of pig-to-human xenotransplantation. the use of receptors for cell entry often determines the host range of retroviruses. a human-tropic perv subgroup, perv-a, can enter human cells through either of two homologous multitransmembrane proteins, hupar-1 and hupar-2. here, we characterised human pars and their homologues in the perv-a resistant rodent species, mouse and rat (mupar and ratpar ... | 2007 | 18081925 |
| knockdown of porcine endogenous retrovirus (perv) expression by perv-specific shrna in transgenic pigs. | xenotransplantation using porcine cells, tissues or organs may be associated with the transmission of porcine endogenous retroviruses (pervs). more than 50 viral copies have been identified in the pig genome and three different subtypes of perv were released from pig cells, two of them were able to infect human cells in vitro. rna interference is a promising option to inhibit perv transmission. | 2008 | 18333912 |
| no transmission of porcine endogenous retroviruses (pervs) in a long-term pig to rat xenotransplantation model and no infection of immunosuppressed rats. | 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 that infect human cells in vitro. however, it remains unclear whether pervs infect transplant recipients in vivo and, if so, whether they are pathogenic. it is therefore essential to perform in vivo infection studies in animal models. | 2008 | 18344940 |
| functional hierarchy of two l domains in porcine endogenous retrovirus (perv) that influence release and infectivity. | the porcine endogenous retrovirus (perv) gag protein contains two late (l) domain motifs, pppy and p(f/s)ap. using viral release assays we demonstrate that pppy is the dominant l domain involved in perv release. pfap represents a novel retroviral l domain variant and is defined by abnormal viral assembly phenotypes visualized by electron microscopy and attenuation of early perv release as measured by viral genomes. psap is functionally dominant over pfap in early perv release. psap virions are 3 ... | 2008 | 18355887 |
| is porcine endogenous retrovirus (perv) transmission still relevant? | xenotransplantation using porcine cells or organs may be associated with the risk of transmission of zoonotic microorganisms. porcine endogenous retroviruses (pervs) pose a potentially high risk because they are integrated into the genome of all pigs and perv-a and perv-b at least, which are present in all pigs, can infect human cells. however, perv transmission could not be demonstrated in the first recipients of clinical xenotransplantation or after numerous experimental pig-to-non-human prima ... | 2008 | 18374136 |
| porcine endogenous retrovirus transmission characteristics from a designated pathogen-free herd. | previously, a strategy for monitoring pigs intended for cell transplantation was developed and successfully applied to several representative herds in new zealand. a better understanding of porcine viruses' epidemiology in new zealand has been achieved, and, as a result, a designated pathogen-free (dpf) herd has been chosen as a good candidate for xenotransplantation. this herd is free of all infectious agents relevant to xenotransplantation. the presented study of pig endogenous retrovirus (per ... | 2008 | 18374137 |
| retrotransposition: another obstacle for xenotransplantation? | to overcome the shortage of human organs for transplantation, pigs are considered as xenogeneic donors. however, primarily immunological and virological barriers exist. one of the main virological obstacles, represented by the presence of functional and infectious porcine endogenous retroviruses (perv) in the genome of the pigs, may be excluded by conventional breeding. in contrast, there are truncated proviral sequences that have the capacity to retrotranspose, causing insertional mutagenesis i ... | 2008 | 18374139 |
| analysis of natural recombination in porcine endogenous retrovirus envelope genes. | human tropic porcine endogenous retroviruses (pervs) are the major concern in zoonosis for xenotransplantation because pervs cannot be eliminated by specific pathogen-free breeding. recently, a perv a/c recombinant with perv-c bearing perv-a gp70 showed a higher infectivity (approximately 500-fold) to human cells than perv-a. additionally, the chance of recombination between pervs and hervs is frequently stated as another risk of xenografting. overcoming zoonotic barriers in xenotransplantation ... | 2008 | 18388481 |
| no infection with porcine endogenous retrovirus in recipients of acellular porcine aortic valves: a two-year study. | engineered tissue heart valves may become a promising therapeutics for heart valve disease. compared with synthetic materials, acellular porcine scaffolds are considered as suitable matrices for tissue-engineered heart valves for the mechanical and structural properties of native tissue. whether acellular porcine scaffolds can cause infection in recipients with porcine endogenous retrovirus (perv) is critical for evaluating the safety of transplantation of tissue-engineered heart valves based on ... | 2008 | 18447885 |
| identification of residues outside of the receptor binding domain that influence the infectivity and tropism of porcine endogenous retrovirus. | identification of determinants of human tropism of porcine endogenous retrovirus (perv) is critical to understanding the risk of transmission of perv to recipients of porcine xenotransplantation products. previously, we showed that a chimeric envelope cdna encoding the 360 n-terminal residues of the human-tropic perv envelope class a (perv-a) su and the 130 c-terminal residues of the pig-tropic perv-c su and all of tm (perv-a/c) showed a 100-fold decrease in infectivity titer on human cells (m. ... | 2008 | 18508891 |
| recombinant porcine endogenous retroviruses (perv-a/c): a new risk for xenotransplantation? | pervs are integrated in the genome of all pigs. some of them infect human cells and represent therefore a potential risk for xenotransplantation using pig cells or organs. three replication-competent subtypes have been described, perv-a, perv-b and perv-c. whereas perv-a and perv-b are polytropic viruses and infect, among others, human cells, perv-c is an ecotropic virus, infecting only pig cells. recombinant perv-a/c are able to infect human cells, they are characterised by high-titre replicati ... | 2008 | 18584115 |
| strategies to enhance the safety profile of xenotransplantation: minimizing the risk of viral zoonoses. | pig-to-human xenotransplantation has taken steps closer to reality through advances in animal engineering to address immunological as well as microbial problems. the most highlighted problem in xenotransplantation safety has been the potential risk for zoonotic infection mediated by porcine endogenous retroviruses. safety issues regarding viral zoonosis, particularly porcine endogenous retroviruses, are summarized and commented upon. | 2008 | 18685301 |
| existence of proviral porcine endogenous retrovirus in fresh and decellularised porcine tissues. | swine are expected to be utilized as xenograft donors for both whole organ and cellular transplantation. a major concern in using porcine organs for transplantation is the potential of transmission of porcine endogenous retrovirus (perv). tissue-engineered or decellularised heart valves have already been implanted in humans and have been marketed by certain companies after food and drug administration (fda) approval. the aim of this study was to examine the existence of porcine endogenous retrov ... | 2008 | 18695319 |