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Abstract
The human betaretrovirus and the closely related mouse mammary tumor virus have been linked with the development of cholangitis and mitochondrial antibody production in patients with primary biliary cholangitis (PBC) and mouse models of autoimmune biliary disease, respectively. In vitro, betaretroviruses have been found to stimulate the expression of mitochondrial autoantigens on the cell surface of biliary epithelial cells. In vivo, both mitochondrial autoantigens and viral proteins have been shown to be co-expressed in biliary epithelium and lymphoid tissue. Notably, both mice and humans make poor antibody responses to betaretrovirus infection, whereas proinflammatory responses to viral proteins have been observed in T lymphocyte studies. Furthermore, proviral integration studies have confirmed the presence of human betaretrovirus in biliary epithelium of patients with PBC. Preliminary proof of principal studies using combination antiretroviral therapy have shown that suppression of viral expression is associated with sustained biochemical response. As the previous regimen used was poorly tolerated, further randomized controlled trials are planned to determine whether betaretrovirus infection plays an important role in the development of PBC.
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Affiliation(s)
- Andrew L Mason
- Department of Medicine, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
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2
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Lytvyak E, Montano-Loza AJ, Mason AL. Combination antiretroviral studies for patients with primary biliary cirrhosis. World J Gastroenterol 2016; 22:349-360. [PMID: 26755881 PMCID: PMC4698497 DOI: 10.3748/wjg.v22.i1.349] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 08/12/2015] [Accepted: 11/09/2015] [Indexed: 02/07/2023] Open
Abstract
Following the characterization of a human betaretrovirus in patients with primary biliary cirrhosis (PBC), pilot studies using antiretroviral therapy have been conducted as proof of principal to establish a link of virus with disease and with the eventual aim to find better adjunct therapies for patients unresponsive to ursodeoxycholic acid. In the first open label pilot study, the reverse transcriptase inhibitor lamivudine had little demonstrable biochemical or histological effect after 1 year. Whereas, lamivudine in combination with zidovudine was associated with a significant reduction in alkaline phosphatase as well as improvement in necroinflammatory score, cholangitis and ductopenia over a 12 mo period. A double blind, multi-center randomized controlled trial using lamivudine with zidovudine for 6 mo confirmed a significant reduction in alkaline phosphatase, ALT and AST in patients on antiviral therapy. However, none of the patients achieved the stringent endpoint criteria for normalization of alkaline phosphatase. Furthermore, some patients developed biochemical rebound consistent with drug resistance. A major fault of these studies has been the inability to measure the viral load in peripheral blood and therefore, provide a direct correlation between improvement of hepatic biochemistry and reduction in viral load. Nevertheless, viral mutants to lamivudine with zidovudine were later characterized in the NOD.c3c4 mouse model of PBC that has been used to test other antiretroviral regimens to betaretrovirus. The combination of tenofovir and emtricitabine reverse transcriptase inhibitors and the HIV protease inhibitor, lopinavir were found to abrogate cholangitis in the NOD.c3c4 mouse model and the same regimen normalized the liver tests in a PBC patient with HIV and human betaretrovirus infection. This combination antiretroviral therapy has now been used in a double blind randomized controlled crossover study for patients with PBC followed by an open label extension study. Only a third of the PBC patients were able to tolerate the lopinavir but those maintained on tenofovir, emtricitabine and lopinavir experienced sustained and clinically meaningful reduction in hepatic biochemistry. While we await the histological and virological evaluation, it is clear that better tolerated regimens of antiretroviral treatment will be required in future clinical trials.
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Fujiomto K, Takano JI, Narita T, Hanari K, Shimozawa N, Sankai T, Yosida T, Terao K, Kurata T, Yasutomi Y. Simian betaretrovirus infection in a colony of cynomolgus monkeys (Macaca fascicularis). Comp Med 2010; 60:51-53. [PMID: 20158949 PMCID: PMC2826085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/05/2009] [Accepted: 10/11/2009] [Indexed: 05/28/2023]
Abstract
Of the 419 laboratory-bred cynomolgus macaques (Macaca fascicularis) in a breeding colony at our institution, 397 (95%) exhibited antibodies or viral RNA (or both) specific for simian betaretrovirus (SRV) in plasma. Pregnant monkeys (n= 95) and their offspring were tested to evaluate maternal-infant infection with SRV. At parturition, the first group of pregnant monkeys (n = 76) was antibody-positive but RNA-negative, the second group (n = 14 monkeys) was positive for both antibody and RNA, and the last group (n = 5) was antibody-negative but RNA-positive. None of the offspring delivered from the 76 antibody-positive/RNA-negative mothers exhibited viremia at birth. Eight of the offspring (including two newborns delivered by caesarian section) from the 14 dually positive mothers exhibited SRV viremia, whereas the remaining 6 newborns from this group were not viremic. All of the offspring (including 2 newborns delivered by caesarian section) of the 5 antibody-negative/RNA-positive mothers exhibited viremia at birth. One neonatal monkey delivered by CS and two naturally delivered monkeys that were viremic at birth remained viremic at 1 to 6 mo of age and lacked SRV antibodies at weaning. Family analysis of 2 viremic mothers revealed that all 7 of their offspring exhibited SRV viremia, 6 of which were also antibody-negative. The present study demonstrates the occurrence of transplacental infection of SRV in viremic dams and infection of SRV in utero to induce immune tolerance in infant monkeys.
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Affiliation(s)
- Koji Fujiomto
- National Institute of Biomedical Innovation, Tsukuba, Japan.
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4
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Abstract
Sheep betaretroviruses offer a unique model system to study the complex interaction between retroviruses and their host. Jaagsiekte sheep retrovirus (JSRV) is a pathogenic exogenous retrovirus and the causative agent of ovine pulmonary adenocarcinoma. The sheep genome contains at least 27 copies of endogenous retroviruses (enJSRVs) highly related to JSRV. enJSRVs have played several roles in the evolution of the domestic sheep as they are able to block the JSRV replication cycle and play a critical role in sheep conceptus development and placental morphogenesis. Available data strongly suggest that some dominant negative enJSRV proviruses (i.e. able to block JSRV replication) have been positively selected during evolution. Interestingly, viruses escaping the transdominant enJSRV loci have recently emerged (less than 200 years ago). Thus, endogenization of these retroviruses may still be occurring today. Therefore, sheep provide an exciting and unique system to study retrovirus-host coevolution. (Part of a multi-author review).
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MESH Headings
- Amino Acid Sequence
- Animals
- Betaretrovirus/genetics
- Betaretrovirus/pathogenicity
- Betaretrovirus/physiology
- Cell Transformation, Viral/genetics
- Cell Transformation, Viral/physiology
- Embryonic Development/physiology
- Evolution, Molecular
- Female
- Gene Expression Regulation, Viral
- Genes, Viral
- Host-Pathogen Interactions/genetics
- Models, Molecular
- Molecular Sequence Data
- Morphogenesis
- Placenta/virology
- Placentation
- Pregnancy
- Protein Conformation
- Proviruses/genetics
- Proviruses/physiology
- Pulmonary Adenomatosis, Ovine/virology
- Retroviridae Infections/veterinary
- Retroviridae Infections/virology
- Retroviridae Proteins, Oncogenic/genetics
- Retroviridae Proteins, Oncogenic/physiology
- Selection, Genetic
- Sequence Alignment
- Sequence Homology, Amino Acid
- Sheep/embryology
- Sheep/virology
- Sheep Diseases/virology
- Species Specificity
- Tumor Virus Infections/veterinary
- Tumor Virus Infections/virology
- Viral Interference
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Affiliation(s)
- F. Arnaud
- Institute of Comparative Medicine, University of Glasgow Veterinary School, 464 Bearsden Road, Glasgow, G61 1QH, Scotland (United Kingdom), Fax: +44 141 3302271
| | - M. Varela
- Institute of Comparative Medicine, University of Glasgow Veterinary School, 464 Bearsden Road, Glasgow, G61 1QH, Scotland (United Kingdom), Fax: +44 141 3302271
| | - T. E. Spencer
- Laboratory for Uterine Biology and Pregnancy, Department of Animal Science, Texas A&M University, College Station, Texas (USA)
| | - M. Palmarini
- Institute of Comparative Medicine, University of Glasgow Veterinary School, 464 Bearsden Road, Glasgow, G61 1QH, Scotland (United Kingdom), Fax: +44 141 3302271
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Xu L, Shen Z, Guo L, Fodera B, Keogh A, Joplin R, O'Donnell B, Aitken J, Carman W, Neuberger J, Mason A. Does a betaretrovirus infection trigger primary biliary cirrhosis? Proc Natl Acad Sci U S A 2003; 100:8454-9. [PMID: 12832623 PMCID: PMC166250 DOI: 10.1073/pnas.1433063100] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Patients with primary biliary cirrhosis develop progressive ductopenia associated with the production of antimitochondrial antibodies that react with a protein aberrantly expressed on biliary epithelial cells and peri-hepatic lymph nodes. Although no specific microbe has been identified, it is thought that an infectious agent triggers this autoimmune liver disease in genetically predisposed individuals. Previous serologic studies have provided evidence to suggest a viral association with primary biliary cirrhosis. Here we describe the identification of viral particles in biliary epithelium by electron microscopy and the cloning of exogenous retroviral nucleotide sequences from patients with primary biliary cirrhosis. The putative agent is referred to as the human betaretrovirus because it shares close homology with the murine mammary tumor virus and a human retrovirus cloned from breast cancer tissue. In vivo, we have found that the majority of patients with primary biliary cirrhosis have both RT-PCR and immunohistochemistry evidence of human betaretrovirus infection in lymph nodes. Moreover, the viral proteins colocalize to cells demonstrating aberrant autoantigen expression. In vitro, we have found that lymph node homogenates from patients with primary biliary cirrhosis can induce autoantigen expression in normal biliary epithelial cells in coculture. Normal biliary epithelial cells also develop the phenotypic manifestation of primary biliary cirrhosis when cocultivated in serial passage with supernatants containing the human betaretrovirus or the murine mammary tumor virus, providing a model to test Koch's postulates in vitro.
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MESH Headings
- Autoantigens/biosynthesis
- Autoantigens/immunology
- Autoimmune Diseases/immunology
- Autoimmune Diseases/virology
- Betaretrovirus/genetics
- Betaretrovirus/isolation & purification
- Betaretrovirus/pathogenicity
- Bile Ducts, Intrahepatic/ultrastructure
- Bile Ducts, Intrahepatic/virology
- Cloning, Molecular
- Coculture Techniques
- DNA, Viral/genetics
- DNA, Viral/isolation & purification
- Dihydrolipoyllysine-Residue Acetyltransferase
- Epithelial Cells/ultrastructure
- Epithelial Cells/virology
- Fluorescent Antibody Technique, Indirect
- Humans
- Liver Cirrhosis, Biliary/immunology
- Liver Cirrhosis, Biliary/virology
- Lymph Nodes/chemistry
- Lymph Nodes/virology
- Mammary Tumor Virus, Mouse/genetics
- Microscopy, Electron
- Molecular Sequence Data
- Phenotype
- Proviruses/genetics
- Proviruses/isolation & purification
- Pyruvate Dehydrogenase Complex/biosynthesis
- Pyruvate Dehydrogenase Complex/immunology
- Retroviridae Infections/immunology
- Retroviridae Infections/pathology
- Retroviridae Infections/virology
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology
- Tissue Extracts/pharmacology
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Affiliation(s)
- Lizhe Xu
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Zhiwei Shen
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Linsheng Guo
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Brent Fodera
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Adrian Keogh
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Ruth Joplin
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Barbara O'Donnell
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - James Aitken
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - William Carman
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - James Neuberger
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
| | - Andrew Mason
- Section of Gastroenterology and Hepatology,
Ochsner Clinic Foundation, New Orleans, LA 70121;
Liver Unit, Queen Elizabeth Hospital,
University of Birmingham, Birmingham B15 2TT, United Kingdom; and
Institute of Biomedical and Life Sciences,
Division of Virology, University of Glasgow, Glasgow G12 8QQ, United
Kingdom
- To whom correspondence should be sent at the present address: Division of
Gastroenterology, University of Alberta, College Plaza, Room 205, 8215 112th
Street, Edmonton, AB, Canada T6G 2C8. E-mail:
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Liu SL, Lerman MI, Miller AD. Putative phosphatidylinositol 3-kinase (PI3K) binding motifs in ovine betaretrovirus Env proteins are not essential for rodent fibroblast transformation and PI3K/Akt activation. J Virol 2003; 77:7924-35. [PMID: 12829832 PMCID: PMC161958 DOI: 10.1128/jvi.77.14.7924-7935.2003] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV) are simple betaretroviruses that cause epithelial cell tumors in the lower and upper airways of sheep and goats. The envelope (Env) glycoproteins of both viruses can transform rodent and chicken fibroblasts, indicating that they play an essential role in oncogenesis. Previous studies found that a YXXM motif in the Env cytoplasmic tail, a putative docking site for phosphatidylinositol 3-kinase (PI3K) after tyrosine phosphorylation, was necessary for rodent cell transformation but was not required for transformation of DF-1 chicken fibroblasts. Here we show that JSRV and ENTV Env proteins with tyrosine or methionine mutations in the YXXM motif can still transform rodent fibroblasts, albeit with reduced efficiency. Akt was activated in cells transformed by JSRV or ENTV Env proteins and in cells transformed by the proteins with tyrosine mutations. Furthermore, the PI3K-specific inhibitor LY294002 could inhibit Akt activation and cell transformation in all cases, indicating that Akt activation and transformation is PI3K dependent. However, we could not detect tyrosine phosphorylation of JSRV or ENTV Env proteins or an interaction between the Env proteins and PI3K in the transformed cells. We found no evidence for mitogen-activated protein kinase activation in cells that were transformed by the JSRV or ENTV Env proteins. We conclude that ovine betaretrovirus Env proteins transform the rodent fibroblasts by indirectly activating the PI3K/Akt pathway.
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Affiliation(s)
- Shan-Lu Liu
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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Abstract
Type B leukemogenic virus (TBLV) is highly related to mouse mammary tumor virus but induces rapidly appearing T-cell lymphomas in mice. Unlike other T-cell tumors induced by retroviruses, only 5 to 10% of TBLV-induced lymphomas have detectable viral integrations near c-myc by Southern blotting, whereas Northern blotting has shown that most tumors have two- to sixfold overexpression of c-myc RNA. In this report, PCR was used to demonstrate that at least 30% of these lymphomas have TBLV insertions near c-myc. Some tumors contained multiple TBLV proviruses in different locations and orientations, suggesting that the tumors are polyclonal. The integrated proviruses near c-myc had different numbers (two to four) of long terminal repeat (LTR) enhancer repeats, although LTRs with three-repeat enhancers dominated the proviral population. Passage of polyclonal tumors in immunocompetent mice and semiquantitative PCR revealed that only cells with particular integrations were selected for growth. In three of six tumors tested, proviruses containing four-repeat enhancers near c-myc were selected during tumor passage. Since tumor cell selection may be accomplished by overexpression of c-myc RNA due to proximity to the unique TBLV LTR enhancer, we inserted LTRs at various locations within a plasmid containing the entire c-myc locus and cellular flanking sequences. To quantitatively measure effects on transcription, the Renilla luciferase gene was substituted for most of c-myc exon 2, and transient transfections were performed with c-myc reporter constructs in two different T-cell lines. As expected, insertion of a TBLV LTR with three-repeat enhancers in either orientation, 5" and 3", of the myc gene elevated reporter activity from 2- to 160-fold, consistent with enhancer function, but four-repeat LTRs had lower levels of expression compared to three-repeat LTRs. Surprisingly, LTR insertions that gave maximal c-myc expression in transient-transfection assays declined in tumor cells selected for growth in vivo. Selection for clonal growth may occur in tumor cells that have modest c-myc overexpression after proviral insertion to prevent apoptosis.
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Affiliation(s)
- Dana R Broussard
- Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, 100 W. 24th Street, Austin, TX 78712, USA
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Hecht SJ, Stedman KE, Carlson JO, DeMartini JC. Distribution of endogenous type B and type D sheep retrovirus sequences in ungulates and other mammals. Proc Natl Acad Sci U S A 1996; 93:3297-302. [PMID: 8622932 PMCID: PMC39601 DOI: 10.1073/pnas.93.8.3297] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The jaagsiekte sheep retrovirus (JSRV), which appears to be a type B/D retrovirus chimera, has been incriminated as the cause of ovine pulmonary carcinoma. Recent studies suggest that the sequences related to this virus are found in the genomes of normal sheep and goats. To learn whether there are breeds of sheep that lack the endogenous viral sequences and to study their distribution among other groups of mammals, we surveyed several domestic sheep and goat breeds, other ungulates, and various mammal groups for sequences related to JSRV. Probes prepared from the envelope (SU) region of JSRV and the capsid (CA) region of a Peruvian type D virus related to JSRV were used in Southern blot hybridization with genomic DNA followed by low- and high-stringency washes. Fifteen to 20 CA and SU bands were found in all members of the 13 breeds of domestic sheep and 6 breeds of goats tested. There were similar findings in 6 wild Ovis and Capra genera. Within 22 other genera of Bovidae including domestic cattle, and 7 other families of Artiodactyla including Cervidae, there were usually a few CA or SU bands at low stringency and rare bands at high stringency. Among 16 phylogenetically distant genera, there were generally fewer bands hybridizing with either probe. These results reveal wide-spread phylogenetic distribution of endogenous type B and type D retroviral sequences related to JSRV among mammals and argue for further investigation of their potential role in disease.
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Affiliation(s)
- S J Hecht
- Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, 80523, USA
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