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Noguchi K, Majima R, Takahashi K, Iwase Y, Yamada S, Satoh K, Koshizuka T, Inoue N. Identification and functional analyses of a cell-death inhibitor encoded by guinea pig cytomegalovirus gp38.1 in cell culture and in animals. J Gen Virol 2020; 101:1270-1279. [PMID: 32915127 DOI: 10.1099/jgv.0.001493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytomegaloviruses (CMVs) employ an array of strategies designed to interfere with host defence responses against pathogens. Studies on such evasion mechanisms are important for understanding the pathogenesis of CMV diseases. Although guinea pig CMV (GPCMV) provides a useful animal model for congenital CMV infection, its evasion strategies are not fully elucidated. Here, we analysed a genome locus that may encode gene products for the GPCMV evasion mechanisms and found the following. (1) RACE analyses identified five transcripts in the GP38-gp38.4 locus, one of which was a spliced product encoding gp38.1. Similarities in the splicing pattern and gene position of gp38.1 to human CMV UL37 and its exon 1 encoding vMIA (viral mitochondria-localized inhibitor of apoptosis) suggest that the gp38.1 gene encodes an apoptosis inhibitor. (2) In a transient transfection assay, gp38.1 localized in the mitochondria and relocated BAX from the cytoplasm to the mitochondria, although its co-localization with BAK was not evident. Further, the expression of gp38.1 partially reduced staurosporine-induced apoptosis. (3) GPCMV defective in the gp38.1 ORF (Δ38.1) and the virus that rescues the defect (r38.1) were generated. Guinea pig fibroblast cells infected with Δ38.1 died earlier than r38.1-infected cells, which resulted in the lower yields of Δ38.1. (4) In animals, viral loads in the spleens of r38.1-infected guinea pigs were higher than those in the spleens of Δ38.1-infected animals. In conclusion, although GPCMV gp38.1 exerts a vMIA-like function, its inhibitory effect was not robust, suggesting the presence of additional inhibitory molecule(s), such as a BAK-specific inhibitor.
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Affiliation(s)
- Kazuma Noguchi
- Present address: Kaken Pharmaceutical, Tokyo, Japan
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Ryuichi Majima
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Keita Takahashi
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Yoshihiko Iwase
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Souichi Yamada
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Keisuke Satoh
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Tetsuo Koshizuka
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Naoki Inoue
- Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
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Roark HK, Jenks JA, Permar SR, Schleiss MR. Animal Models of Congenital Cytomegalovirus Transmission: Implications for Vaccine Development. J Infect Dis 2020; 221:S60-S73. [PMID: 32134481 PMCID: PMC7057791 DOI: 10.1093/infdis/jiz484] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although cytomegaloviruses (CMVs) are species-specific, the study of nonhuman CMVs in animal models can help to inform and direct research aimed at developing a human CMV (HCMV) vaccine. Because the driving force behind the development of HCMV vaccines is to prevent congenital infection, the animal model in question must be one in which vertical transmission of virus occurs to the fetus. Fortunately, two such animal models-the rhesus macaque CMV and guinea pig CMV-are characterized by congenital infection. Hence, each model can be evaluated in "proof-of-concept" studies of preconception vaccination aimed at blocking transplacental transmission. This review focuses on similarities and differences in the respective model systems, and it discusses key insights from each model germane to the study of HCMV vaccines.
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Affiliation(s)
- Hunter K Roark
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Jennifer A Jenks
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Sallie R Permar
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Mark R Schleiss
- Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, Department of Pediatrics, Division of Pediatric Infectious Diseases and Immunology, Minneapolis, Minnesota, USA
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Roles of GP33, a guinea pig cytomegalovirus-encoded G protein-coupled receptor homolog, in cellular signaling, viral growth and inflammation in vitro and in vivo. PLoS Pathog 2018; 14:e1007487. [PMID: 30571759 PMCID: PMC6319746 DOI: 10.1371/journal.ppat.1007487] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 01/04/2019] [Accepted: 11/27/2018] [Indexed: 11/23/2022] Open
Abstract
Cytomegaloviruses (CMVs) encode cellular homologs to evade host immune functions. In this study, we analyzed the roles of GP33, a guinea pig CMV (GPCMV)-encoded G protein-coupled receptor (GPCR) homolog, in cellular signaling, viral growth and pathogenesis. The cDNA structure of GP33 was determined by RACE. The effects of GP33 on some signaling pathways were analyzed in transient transfection assays. The redET two-step recombination system for a BAC containing the GPCMV genome was used to construct a mutant GPCMV containing an early stop codon in the GP33 gene (Δ33) and a rescued GPCMV (r33). We found the following: 1) GP33 activated the CRE- and NFAT-, but not the NFκB-mediated signaling pathway. 2) GP33 was dispensable for infection in tissue cultures and in normal animals. 3) In pregnant animals, viral loads of r33 in the livers, lungs, spleens, and placentas at 6 days post-infection were higher than those of Δ33, although the viruses were cleared by 3 weeks post-infection. 4) The presence of GP33 was associated with frequent lesions, including alveolar hemorrhage in the lungs, and inflammation in the lungs, livers, and spleens of the dams. Our findings suggest that GP33 has critical roles in the pathogenesis of GPCMV during pregnancy. We hypothesize that GP33-mediated signaling activates cytokine secretion from the infected cells, which results in inflammation in some of the maternal organs and the placentas. Alternatively, GP33 may facilitate transient inflammation that is induced by the chemokine network specific to the pregnancy. Cytomegalovirus (CMV) is a major pathogen that causes congenital diseases, including birth defects and developmental abnormalities in newborns. Better understanding of the immune evasion mechanisms may open the way to the development of new types of live attenuated vaccines for congenital CMV infection. In contrast to murine and rat CMVs, guinea pig CMV (GPCMV) causes infection in utero, which makes GPCMV animal models a useful tool for understanding the pathogenesis of congenital infection and evaluation of vaccine strategies. By constructing a GPCMV mutant lacking GP33, a viral G protein-coupled receptor homolog, this study found that GP33 was involved in the induction of significant inflammatory responses in pregnant but not in normal animals. As GP33 activated the NFAT- and CRE-, but not the NFκB-signal pathway, it is plausible that GP33 enhanced cytokine expression, which results in pathogenic outcomes in the maternal organs and placentas.
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Jackson JW, Sparer T. There Is Always Another Way! Cytomegalovirus' Multifaceted Dissemination Schemes. Viruses 2018; 10:v10070383. [PMID: 30037007 PMCID: PMC6071125 DOI: 10.3390/v10070383] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 12/12/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a β-herpes virus that is a significant pathogen within immune compromised populations. HCMV morbidity is induced through viral dissemination and inflammation. Typically, viral dissemination is thought to follow Fenner's hypothesis where virus replicates at the site of infection, followed by replication in the draining lymph nodes, and eventually replicating within blood filtering organs. Although CMVs somewhat follow Fenner's hypothesis, they deviate from it by spreading primarily through innate immune cells as opposed to cell-free virus. Also, in vivo CMVs infect new cells via cell-to-cell spread and disseminate directly to secondary organs through novel mechanisms. We review the historic and recent literature pointing to CMV's direct dissemination to secondary organs and the genes that it has evolved for increasing its ability to disseminate. We also highlight aspects of CMV infection for studying viral dissemination when using in vivo animal models.
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Affiliation(s)
- Joseph W Jackson
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN 37996, USA.
| | - Tim Sparer
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN 37996, USA.
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Coleman S, Choi KY, McGregor A. Cytomegalovirus UL128 homolog mutants that form a pentameric complex produce virus with impaired epithelial and trophoblast cell tropism and altered pathogenicity in the guinea pig. Virology 2017. [PMID: 28651121 DOI: 10.1016/j.virol.2017.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Guinea pig cytomegalovirus (GPCMV) encodes a homolog pentameric complex (PC) for specific cell tropism and congenital infection. In human cytomegalovirus, the PC is an important antibody neutralizing target and GPCMV studies will aid in the development of intervention strategies. Deletion mutants of the C-terminal domains of unique PC proteins (UL128, UL130 and UL131 homologs) were unable to form a PC in separate transient expression assays. Minor modifications to the UL128 homolog (GP129) C-terminal domain enabled PC formation but viruses encoding these mutants had altered tropism to renal and placental trophoblast cells. Mutation of the presumptive CC chemokine motif encoded by GP129 was investigated by alanine substitution of the CC motif (codons 26-27) and cysteines (codons 47 and 62). GP129 chemokine mutants formed PC but GP129 chemokine mutant viruses had reduced epitropism. A GP129 chemokine mutant virus pathogenicity study demonstrated reduced viral load to target organs but highly extended viremia.
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Affiliation(s)
- Stewart Coleman
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States
| | - K Yeon Choi
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States
| | - Alistair McGregor
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, Health Science Center, College of Medicine, College Station, TX, United States.
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Heo J, Dogra P, Masi TJ, Pitt EA, de Kruijf P, Smit MJ, Sparer TE. Novel Human Cytomegalovirus Viral Chemokines, vCXCL-1s, Display Functional Selectivity for Neutrophil Signaling and Function. THE JOURNAL OF IMMUNOLOGY 2015; 195:227-36. [PMID: 25987741 DOI: 10.4049/jimmunol.1400291] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/27/2015] [Indexed: 12/16/2022]
Abstract
Human CMV (HCMV) uses members of the hematopoietic system including neutrophils for dissemination throughout the body. HCMV encodes a viral chemokine, vCXCL-1, that is postulated to attract neutrophils for dissemination within the host. The gene encoding vCXCL-1, UL146, is one of the most variable genes in the HCMV genome. Why HCMV has evolved this hypervariability and how this affects the virus' dissemination and pathogenesis is unknown. Because the vCXCL-1 hypervariability maps to important binding and activation domains, we hypothesized that vCXCL-1s differentially activate neutrophils, which could contribute to HCMV dissemination, pathogenesis, or both. To test whether these viral chemokines affect neutrophil function, we generated vCXCL-1 proteins from 11 different clades from clinical isolates from infants infected congenitally with HCMV. All vCXCL-1s were able to induce calcium flux at a concentration of 100 nM and integrin expression on human peripheral blood neutrophils, despite differences in affinity for the CXCR1 and CXCR2 receptors. In fact, their affinity for CXCR1 or CXCR2 did not correlate directly with chemotaxis, G protein-dependent and independent (β-arrestin-2) activation, or secondary chemokine (CCL22) expression. Our data suggest that vCXCL-1 polymorphisms affect the binding affinity, receptor usage, and differential peripheral blood neutrophil activation that could contribute to HCMV dissemination and pathogenesis.
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Affiliation(s)
- Jinho Heo
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996; and
| | - Pranay Dogra
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996; and
| | - Tom J Masi
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996; and
| | - Elisabeth A Pitt
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996; and
| | - Petra de Kruijf
- Division of Medicinal Chemistry, VU University Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - Martine J Smit
- Division of Medicinal Chemistry, VU University Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - Tim E Sparer
- Department of Microbiology, The University of Tennessee, Knoxville, TN 37996; and
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7
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Proudfoot AEI, Bonvin P, Power CA. Targeting chemokines: Pathogens can, why can't we? Cytokine 2015; 74:259-67. [PMID: 25753743 DOI: 10.1016/j.cyto.2015.02.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 12/19/2022]
Abstract
Chemoattractant cytokines, or chemokines, are the largest sub-family of cytokines. About 50 distinct chemokines have been identified in humans. Their principal role is to stimulate the directional migration of leukocytes, which they achieve through activation of their receptors, following immobilization on cell surface glycosaminoglycans (GAGs). Chemokine receptors belong to the G protein-coupled 7-transmembrane receptor family, and hence their identification brought great promise to the pharmaceutical industry, since this receptor class is the target for a large percentage of marketed drugs. Unfortunately, the development of potent and efficacious inhibitors of chemokine receptors has not lived up to the early expectations. Several approaches to targeting this system will be described here, which have been instrumental in establishing paradigms in chemokine biology. Whilst drug discovery programs have not yet elucidated how to make successful drugs targeting the chemokine system, it is now known that certain parasites have evolved anti-chemokine strategies in order to remain undetected by their hosts. What can we learn from them?
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Affiliation(s)
- Amanda E I Proudfoot
- Geneva Research Centre, Merck Serono S.A., 9 chemin des Mines, 1202 Genève and NovImmune S.A., 14 chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland.
| | - Pauline Bonvin
- Geneva Research Centre, Merck Serono S.A., 9 chemin des Mines, 1202 Genève and NovImmune S.A., 14 chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland.
| | - Christine A Power
- Geneva Research Centre, Merck Serono S.A., 9 chemin des Mines, 1202 Genève, Switzerland.
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An attenuated cytomegalovirus vaccine with a deletion of a viral chemokine gene is protective against congenital CMV transmission in a guinea pig model. Clin Dev Immunol 2013; 2013:906948. [PMID: 24000289 PMCID: PMC3755440 DOI: 10.1155/2013/906948] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/24/2013] [Accepted: 06/05/2013] [Indexed: 01/05/2023]
Abstract
Development of a vaccine against congenital cytomegalovirus (CMV) infection is a public health priority, but CMVs encode immune evasion genes that complicate live virus vaccine design. To resolve this problem, this study employed guanosyl phosphoribosyl transferase (gpt) mutagenesis to generate a recombinant guinea pig CMV (GPCMV) with a knockout of a viral chemokine gene, GPCMV MIP (gp1). MIP deletion virus replicated with wild-type kinetics in cell culture but was attenuated in nonpregnant guinea pigs, demonstrating reduced viremia and reduced inflammation and histopathology (compared to a control virus with an intact GPCMV MIP gene) following footpad inoculation. In spite of attenuation, the vaccine was immunogenic, eliciting antibody responses comparable to those observed in natural infection. To assess its protective potential as a vaccine, either recombinant virus or placebo was used to immunize seronegative female guinea pigs. Dams were challenged in the early 3rd trimester with salivary gland-adapted GPCMV. Immunization protected against DNAemia (1/15 in vaccine group versus 12/13 in the control group, P < 0.01). Mean birth weights were significantly higher in pups born to vaccinated dams compared to controls (98.7 g versus 71.2 g, P < 0.01). Vaccination reduced pup mortality, from 35/50 (70%) in controls to 8/52 (15%) in the immunization group. Congenital GPCMV infection was also reduced, from 35/50 (70%) in controls to 9/52 (17%) in the vaccine group (P < 0.0001). We conclude that deletion of an immune modulation gene can attenuate the pathogenicity of GPCMV while resulting in a viral vaccine that retains immunogenicity and demonstrates efficacy against congenital infection and disease.
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Schleiss MR, McVoy MA. Guinea Pig Cytomegalovirus (GPCMV): A Model for the Study of the Prevention and Treatment of Maternal-Fetal Transmission. Future Virol 2010; 5:207-217. [PMID: 23308078 DOI: 10.2217/fvl.10.8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A major public health challenge today is the problem of congenital cytomegalovirus (CMV) transmission. Maternal-fetal CMV infections are common, occurring in 0.5-2% of pregnancies, and these infections often lead to long-term injury of the newborn infant. In spite of the well-recognized burden that these infections place on society, there are as yet no clearly established interventions available to prevent transmission of CMV. In order to study potential interventions, such as vaccines or antiviral therapies, an animal model of congenital CMV transmission is required. The best small animal model of CMV transmission is the guinea pig cytomegalovirus (GPCMV) model. This article summarizes the GPCMV model, putting it into the larger context of how studies in this system have relevance to human health. An emphasis is placed on how the vertical transmission of GPCMV recapitulates the pathogenesis of congenital CMV in infants, making this a uniquely well-suited model for the study of potential CMV vaccines.
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Affiliation(s)
- Mark R Schleiss
- Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, 2001 6 Street SE, Minneapolis, MN 55455,
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Miller-Kittrell M, Sparer TE. Feeling manipulated: cytomegalovirus immune manipulation. Virol J 2009; 6:4. [PMID: 19134204 PMCID: PMC2636769 DOI: 10.1186/1743-422x-6-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 01/09/2009] [Indexed: 02/03/2023] Open
Abstract
No one likes to feel like they have been manipulated, but in the case of cytomegalovirus (CMV) immune manipulation, we do not really have much choice. Whether you call it CMV immune modulation, manipulation, or evasion, the bottom line is that CMV alters the immune response in such a way to allow the establishment of latency with lifelong shedding. With millions of years of coevolution within their hosts, CMVs, like other herpesviruses, encode numerous proteins that can broadly influence the magnitude and quality of both innate and adaptive immune responses. These viral proteins include both homologues of host proteins, such as MHC class I or chemokine homologues, and proteins with little similarity to any other known proteins, such as the chemokine binding protein. Although a strong immune response is launched against CMV, these virally encoded proteins can interfere with the host's ability to efficiently recognize and clear virus, while others induce or alter specific immune responses to benefit viral replication or spread within the host. Modulation of host immunity allows survival of both the virus and the host. One way of describing it would be a kind of "mutually assured survival" (as opposed to MAD, Mutually Assured Destruction). Evaluation of this relationship provides important insights into the life cycle of CMV as well as a greater understanding of the complexity of the immune response to pathogens in general.
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Affiliation(s)
- Mindy Miller-Kittrell
- Department of Microbiology, University of Tennessee, 1414 Cumberland Ave, Knoxville, TN, USA.
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Nozawa N, Yamamoto Y, Fukui Y, Katano H, Tsutsui Y, Sato Y, Yamada S, Inami Y, Nakamura K, Yokoi M, Kurane I, Inoue N. Identification of a 1.6 kb genome locus of guinea pig cytomegalovirus required for efficient viral growth in animals but not in cell culture. Virology 2008; 379:45-54. [PMID: 18656220 DOI: 10.1016/j.virol.2008.06.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 03/10/2008] [Accepted: 06/10/2008] [Indexed: 11/17/2022]
Abstract
Guinea pig cytomegalovirus (GPCMV) provides a useful model for studies of congenital CMV infection. During characterization of the GPCMV genome sequence, we identified two types of strains in a virus stock purchased from ATCC. One of them, GPCMV/del, lacks a 1.6 kb locus that positionally corresponds to murine CMV (MCMV) M129-M133. Growth of GPCMV/del in cell culture was marginally better than that of the other strain, GPCMV/full, which harbors the 1.6 kb locus. However, in animals infected intraperitoneally with virus stocks containing both strains, GPCMV/full disseminated more efficiently than GPCMV/del, including 200-fold greater viral load in salivary glands. Viral DNA, transcripts of the immediate-early 2 gene homolog, and viral antigens were more abundant in animals infected with GPCMV/full than in those infected with GPCMV/del. Although the observed phenomena have some similarity with the growth properties of MCMV strains defective in mck-1/mck-2(M129/131) and those defective in sgg(M132), no M129-M132 homologs were found in the 1.6 kb locus. Since one of the ORFs in the locus has a weak sequence similarity with HCMV UL130, which relates to cell tropism, further studies will be required to learn the mechanism for efficient GPCMV growth in animal.
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Affiliation(s)
- Naoki Nozawa
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
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Beisser PS, Lavreysen H, Bruggeman CA, Vink C. Chemokines and chemokine receptors encoded by cytomegaloviruses. Curr Top Microbiol Immunol 2008; 325:221-42. [PMID: 18637509 DOI: 10.1007/978-3-540-77349-8_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
CMVs carry several genes that are homologous to genes of the host organism. These include genes homologous to those encoding chemokines (CKs) and G protein-coupled receptors (GPCRs). It is generally assumed that these CMV genes were hijacked from the host genome during the long co-evolution of virus and host. In light of the important function of the CK and GPCR families in the normal physiology of the host, it has previously been hypothesized that the CMV homologs of these proteins, CMV vCKs and vGPCRs, may also have a significant impact on this physiology, such that lifelong maintenance and/or replication of the virus within the infected host is guaranteed. In addition, several of these homologs were reported to have a major impact in the pathogenesis of infection. In this review, the current state of knowledge on the CMV vCKs and vGPCRs will be discussed.
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Affiliation(s)
- P S Beisser
- Department of Medical Microbiology, Cardiovascular Research Institute Maastricht, University Hospital Maastricht, PO Box 5800, AZ, Maastricht, The Netherlands
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Schleiss MR. Comparison of vaccine strategies against congenital CMV infection in the guinea pig model. J Clin Virol 2007; 41:224-30. [PMID: 18060834 DOI: 10.1016/j.jcv.2007.10.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 10/03/2007] [Indexed: 12/01/2022]
Abstract
Vaccines are urgently needed to protect newborns against the devastating sequelae of congenital cytomegalovirus infection. Evaluation of candidate vaccines in the guinea pig model of congenital infection can shed light on potentially useful strategies for humans, since guinea pig CMV (GPCMV) is transmitted to the fetus transplacentally, causing infection and disease in utero. A number of vaccine strategies have been evaluated in this model, including DNA vaccines, live attenuated vaccines, and recombinant glycoprotein vaccines. Induction of virus-neutralizing antibody appears to play a key role in protection of the fetus. Recently, a vectored vaccine based on the GPCMV homolog of the UL83 (pp65) protein has also been shown to be effective when used as a preconceptual vaccine in this model, suggesting that strategies designed to elicit T-cell responses may be of value in protection of the fetus.
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Affiliation(s)
- Mark R Schleiss
- Division of Pediatric Infectious Diseases and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School, 2001 6th Street SE, Minneapolis, MN 55455, USA.
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14
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Schleiss MR. Nonprimate models of congenital cytomegalovirus (CMV) infection: gaining insight into pathogenesis and prevention of disease in newborns. ILAR J 2006; 47:65-72. [PMID: 16391432 DOI: 10.1093/ilar.47.1.65] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Congenital and perinatal infections with cytomegalovirus (CMV) are responsible for considerable short- and long- term morbidity in infants. CMV is the most common congenital viral infection in the developed world, and is a common cause of neurodevelopmental injury, including mental retardation and sensorineural hearing loss (SNHL). Antiviral therapy has been shown to be valuable in ameliorating the severity of SNHL, but CMV disease control in newborns ultimately depends on successful development of a vaccine. Because CMVs are extremely species specific, preclinical evaluation of vaccines must be performed in animal models using the appropriate CMV of the animal being studied. Several small animal models available for CMV vaccine and pathogenesis research are described. The discussion focuses on the guinea pig model because guinea pig cytomegalovirus (GPCMV), which crosses the placenta and causes infection in utero, is uniquely useful. Examination of vaccines in the GPCMV and other nonprimate models should provide insights into the determinants of the host response that protect the fetus, and may help to prioritize potential vaccine strategies for use in human clinical trials related to this important public health problem.
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Affiliation(s)
- Mark R Schleiss
- Division of Pediatric Infectious Diseases, University of Minnesota Children's Hospital, and School of Medicine, Department of Pediatrics, Minneapolis, MN, USA
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15
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van Cleef KWR, Smit MJ, Bruggeman CA, Vink C. Cytomegalovirus-encoded homologs of G protein-coupled receptors and chemokines. J Clin Virol 2006; 35:343-8. [PMID: 16406796 DOI: 10.1016/j.jcv.2005.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 10/06/2005] [Accepted: 10/15/2005] [Indexed: 11/29/2022]
Abstract
BACKGROUND Cytomegaloviruses (CMVs) have developed various sophisticated strategies to manipulate and evade the defense mechanisms of their hosts. Among the CMV genes that are predicted to be involved in these strategies are genes that encode mimics of cellular proteins, such as G protein-coupled receptors (GPCRs) and chemokines (CKs). These genes may have been pirated from the host genome during the long co-evolution of virus and host. OBJECTIVES In this report, the putative functions of the CMV-encoded homologs of GPCRs and CKs in the pathogenesis of infection will be discussed. STUDY DESIGN In order to present an overview of the current state of knowledge, the literature on the CMV-encoded homologs of GPCRs and CKs was reviewed. RESULTS The GPCR and CK homologs that are encoded by the CMVs represent immunomodulatory proteins with crucial roles in the pathogenesis of infection. CONCLUSIONS In light of their function as well as accessibility on the cell surface, the CMV-encoded GPCR homologs are attractive targets for the development of new anti-viral therapies.
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Affiliation(s)
- Koen W R van Cleef
- Department of Medical Microbiology, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
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Voigt S, Sandford GR, Hayward GS, Burns WH. The English strain of rat cytomegalovirus (CMV) contains a novel captured CD200 (vOX2) gene and a spliced CC chemokine upstream from the major immediate-early region: further evidence for a separate evolutionary lineage from that of rat CMV Maastricht. J Gen Virol 2005; 86:263-274. [PMID: 15659745 DOI: 10.1099/vir.0.80539-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sequence data for eight genes, together with time-course Northern blotting and 3′- and 5′-RACE (rapid amplification of cDNA ends) analysis for some mRNAs from a 12 kb region upstream from the major immediate-early (MIE) genes of the English isolate of rat cytomegalovirus (RCMV), are presented. The results identified important differences compared to both murine cytomegalovirus (MCMV) and the Maastricht isolate of RCMV. A striking finding is the presence of a highly conserved, rightwards-oriented homologue of the rat cellular CD200 (OX2) gene immediately to the right of the MIE region, which replaces either the leftwards-oriented AAV REP gene of RCMV (Maastricht) or the upstream spliced portions of the immediate-early 2 gene (ie2) in MCMV. From the presence of other homologues of MCMV- and RCMV-specific genes, such as the β-chemokine MCK-2, SGG1 and an Fcγ receptor gene, as reported here, the basic architecture of the MIE region (reported previously) and the level of IE2 and DNA polymerase (POL) protein conservation in phylogenetic analyses, it is clear that the English strain of RCMV is also a member of the genus Muromegalovirus, but is a β-herpesvirus species that is very distinct from both MCMV and RCMV (Maastricht). Both the lack of a CD200 homologue in the other two rodent viruses and the depth of sequence divergence of the rodent CMV IE2 and POL proteins suggest that these three viruses have evolved as separate species in the genus Muromegalovirus since very early in the host rodent lineage.
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Affiliation(s)
- Sebastian Voigt
- Bone Marrow Transplant Program, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Laboratory for Molecular Biology, Department of Pediatrics, Charité, 10098 Berlin, Germany
| | - Gordon R Sandford
- Viral Oncology Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
- Bone Marrow Transplant Program, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Gary S Hayward
- Viral Oncology Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - William H Burns
- Bone Marrow Transplant Program, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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