etiologic relationship of skin tumors (skin leukosis) of chickens to marek's disease. 197011515057
glycoproteins e and i of marek's disease virus serotype 1 are essential for virus growth in cultured cells.the role of glycoprotein e (ge) and gi of marek's disease virus serotype 1 (mdv-1) for growth in cultured cells was investigated. mdv-1 mutants lacking either ge (20deltage), gi (20deltagi), or both ge and gi (20deltagei) were constructed by rece/t-mediated mutagenesis of a recently established infectious bacterial artificial chromosome (bac) clone of mdv-1 (d. schumacher, b. k. tischer, w. fuchs, and n. osterrieder, j. virol. 74:11088-11098, 2000). deletion of either ge or gi, which form a comp ...200111689611
functional characterization of marek's disease virus (mdv) origin-binding protein (obp): analysis of its origin-binding previous studies, we identified a marek's disease virus (mdv) origin-binding protein (obp) gene that is highly homologous to the herpes simplex virus type 1 ul9 gene that encodes an obp and functions as an initiator protein for viral dna replication. in this study, a protein of 95 kda was produced in coupled in vitro transcription-translation reaction with the plasmid containing the wild type mdv obp gene. the in vitro synthesized protein was detected by immunoprecipitation with a penta-histi ...200111724278
marek's disease virus genome separation from feather tip extracts by pulsed field gel electrophoresis.marek's disease virus is an oncogenic herpes virus of poultry that is highly cell associated. in the infected tissues and tumors the virus replicates in a low copy number. the propagation and dissemination of the virus takes place at the feather follicle epithelium, where the viral genome is produced in high copy number. as the viral genome is a large circular dna molecule (200 kbp), pulsed field gel electrophoresis was used for separation of the viral genome directly from the infected chicken. ...200211849695
improving dna vaccine potency by linking marek's disease virus type 1 vp22 to an antigen.we have previously employed an intercellular spreading strategy using herpes simplex virus type 1 (hsv-1) vp22 protein to enhance dna vaccine potency because dna vaccines lack the intrinsic ability to amplify in cells. recently, studies have demonstrated that the protein encoded by ul49 of marek's disease virus type 1 (mdv-1) exhibits some degree of homology to the hsv-1 vp22 protein and features the property of intercellular transport. we therefore generated a dna vaccine encoding mdv-1 vp22 li ...200211861834
marek's disease virus vp22: subcellular localization and characterization of carboxyl terminal deletion mutations.marek's disease virus (mdv) is an alphaherpesvirus that causes t cell lymphoma and severe immunosuppression in chickens. the mdv ul49 gene, which encodes the tegument viral protein 22 (vp22), has been expressed as a green fluorescent protein (gfp) fusion protein in chicken embryonic fibroblasts to examine its subcellular localization. as with both human herpesvirus 1 and bovine herpesvirus 1vp22-gfp fusion proteins, the mdv vp22-gfp product binds to microtubules and heterochromatin. in addition, ...200211878926
resistance and susceptibility to marek's disease: nitric oxide synthase/arginase activity balance.the metabolic no pathway, catalyzed by the enzyme no synthase in macrophages, is a key defense element against viruses and tumors. however, arginase is an other enzyme able to metabolize the substrate l-arginine, and the two enzymes are alternatively regulated by th1 and th2 cytokines in murine macrophages. marek's disease is characterized by strong immunosuppression and development of t-cell lymphomas in chickens. inoculation of the very virulent strain of mdv rb-1b induced strong and long-last ...200211900957
antiviral activity of ovotransferrin discloses an evolutionary strategy for the defensive activities of lactoferrin.ovotransferrin (formerly conalbumin) is an iron-binding protein present in birds. it belongs to the transferrin family and shows about 50% sequence homology with mammalian serum transferrin and lactoferrin. this protein has been demonstrated to be capable of delivering iron to cells and of inhibiting bacterial multiplication. however, no antiviral activity has been reported for ovotransferrin, although the antiviral activity of human and bovine lactoferrins against several viruses, including hum ...200211908636
rescue of a pathogenic marek's disease virus with overlapping cosmid dnas: use of a pp38 mutant to validate the technology for the study of gene function.marek's disease virus (mdv) genetics has lagged behind that of other herpesviruses because of the lack of tools for the introduction of site-specific mutations into the genome of highly cell-associated oncogenic strains. overlapping cosmid clones have been successfully used for the introduction of mutations in other highly cell-associated herpesviruses. here we describe the development of overlapping cosmid dna clones from a very virulent oncogenic strain of mdv. transfection of these cosmid clo ...200211997455
molecular identification of the marek's disease virus vaccine strain cvi988 in vaccinated chickens.the study describes three polymerase chain reaction (pcr) systems for the cvi988 vaccine virus: the meq gene, the mdv bamhi-d/h 132 bp tandem repeat fragment and the mdv-gb gene. whereas the pcr product of virulent mdv strains and of the cvi988 virus strain with the meq and the 132 bp primer sets differed for the two templates, the mdv-gb pcr products were similar. the sensitivity of the three pcrs was determined for the two templates: the cvi988 dna was detected up to 2.48 plaque forming units, ...200212002424
molecular indications for in vivo integration of the avian leukosis virus, subgroup j-long terminal repeat into the marek's disease virus in experimentally dually-infected chickens.marek's disease virus, a herpesvirus, and avian leukosis virus, subgroup j, a retrovirus, are oncogenic viruses of poultry. both viruses may infect the same flock, the same bird and the same cell. in a double-infected cell, the retroviral dna can integrate into the cellular or the marek's disease virus (mdv) genome. the retroviral-long terminal repeat (ltr) integration into mdv was first described by isfort et al., (proc natl acad sci 89, 991-995, 1992) following tissue culture co-infection. the ...200212018709
evaluation of an early granulocytic response of chick embryos inoculated with herpesvirus of turkeys.1. early granulocytic response was evaluated in chick embryos inoculated with herpesvirus of turkeys (hvt). 2. fifty 10-d-old specific pathogen-free embryos were divided into two groups, inoculated via yolk sac. group 1 were inoculated with a complete dose of hvt and group 2 with vaccinediluent only. 3. samples were taken for histological evaluation of yolk sac, liver, chorioallantoic membrane, brain and heart from 5 embryos per group on days 12, 14, 16, 18 and 20 of embryonic life. 4. increases ...200212047084
generation of a permanent cell line that supports efficient growth of marek's disease virus (mdv) by constitutive expression of mdv glycoprotein e.a recombinant cell line (soge) was established, which was derived from the permanent quail muscle cell line qm7 and constitutively expressed the glycoprotein e (ge) gene of marek's disease virus serotype 1 (mdv-1). the soge cell line supported growth of virulent (rb-1b) and vaccine (cvi988, 584ap80c) mdv-1 strains at a level comparable with that of primary chicken embryo cells (cec). the soge cell line was used to produce a vaccine against marek's disease. chickens were immunized at 1 day old wi ...200212124462
immunosuppressive effects of marek's disease virus (mdv) and herpesvirus of turkeys (hvt) in broiler chickens and the protective effect of hvt vaccination against mdv challenge.much of the impact of marek's disease in broiler chickens is considered to be due to immunosuppression induced by marek's disease virus (mdv). the present study evaluates the effects of an australian isolate of pathogenic mdv (strain mpf 57) and a non-pathogenic vaccinal strain of herpesvirus of turkeys (hvt) (strain fc 126) on the immune system of commercial broiler chickens for 35 days following challenge at days 0 or 3 of age. it also investigates the extent of protection provided by hvt vacc ...200212427339
monocytosis is associated with the onset of leukocyte and viral infiltration of the brain in chickens infected with the very virulent marek's disease virus strain c12/130.marek's disease (mdv) virus is mainly known for the induction of visceral lymphomas and lymphoid infiltration of peripheral nerves. recently, additional tropism for the central nervous system has been recognised as a distinct feature of disease induced by very virulent mdv isolates. during the analysis of changes in the peripheral blood leukocyte subpopulations in chickens infected with either a virulent (hprs-16) or a very virulent (c12/130) strain of mdv, we observed a marked monocytosis in ch ...200312745364
marek's disease virus reactivation from latency: changes in gene expression at the origin of replication.marek's disease is a contagious lymphoma of chickens caused by marek's disease virus (mdv). mdv replicates in chicken lymphocytes and establishes latency within and transforms chicken cd4+ t-cells. transformed t-cells are seen as skin leukosis or as lymphomas in visceral organs. a major focus of our laboratory is the functional study of genes flanking the origin of replication. this origin (orilyt) is contained within the repeats flanking the unique long (ul) region of the genome (irl and trl). ...200312817443
replication-competent bacterial artificial chromosomes of marek's disease virus: novel tools for generation of molecularly defined herpesvirus vaccines.marek's disease (md), a highly infectious disease caused by an oncogenic herpesvirus, is one of the few herpesvirus diseases against which live attenuated vaccines are used as the main strategy for control. we have constructed bacterial artificial chromosomes (bacs) of the cvi988 (rispens) strain of the virus, the most widely used and effective vaccine against md. viruses derived from the bac clones were stable after in vitro and in vivo passages and showed characteristics and growth kinetics si ...200312885890
novel applications of feather tip extracts from mdv-infected chickens; diagnosis of commercial broilers, whole genome separation by pfge and synchronic mucosal infection.marek's disease virus (mdv) productive replication occurs in the feather follicle epithelium and the feather tips are valuable both for research and disease diagnosis. three novel applications of feather tip extracts are described now: (a). as a source of dna for amplifying either mdv and/or alv-j. in two clinical situations a marked advantage was obtained compared to blood and organs; in broiler breeder flocks with a mixed mdv and alv-j infection, and in young broilers with neurological marek's ...200314522455
characterization of the chromosomal binding sites and dimerization partners of the viral oncoprotein meq in marek's disease virus-transformed t cells.marek's disease virus (mdv) is an acute transforming alphaherpesvirus that causes t-cell lymphomas in chickens. we previously reported the identification of a putative oncogene, meq, that is encoded only by the oncogenic serotype of mdv. the gene product, meq, is a latent protein that is consistently expressed in mdv-transformed lymphoblastoid cells and tumor cells. meq has a bzip (basic leucine zipper) structure resembling the family of jun/fos. the mechanism whereby meq transforms t cells rema ...200314610205
influence of a reovirus-antibody complex vaccine on efficacy of marek's disease vaccine administered in ovo.two experiments determined the influence of an experimental reovirus-antibody complex vaccine on mareks disease virus (mdv) vaccine when used in ovo. designs were the same except that specific-pathogen-free (spf) broiler eggs were used in experiment 1 and commercial broiler eggs with maternal antibodies against reovirus were used in experiment 2. at 18 days of incubation, embryos were separated into four groups and inoculated with either diluent, mdv vaccine, reovirus-antibody complex vaccine, o ...200314708983
titration of marek's disease cell-associated vaccine virus (cvi 988) of reconstituted vaccine and vaccine ampoules from dutch hatcheries.thirty-one outbreaks of marek's disease (md) were reported in the netherlands and retrospectively analyzed. the outbreaks occurred mostly in vaccinated commercial layer and a few breeder flocks of several breeds; however, the cause of the outbreaks could not be established. therefore, in a prospective study, the occurrence of true vaccine failures was assessed onfive hatcheries. the plaque-forming units (pfu) of md vaccine per chicken dose were determined through in vitro assays on vacine ampoul ...200314708997
the chicken telomerase rna gene: conservation of sequence, regulatory elements and synteny among viral, avian and mammalian genomes.telomerase rna (tr) is essential for telomerase activity and the maintenance of telomere length in proliferating cell populations. the objective of the present research was to define the cytogenetic and molecular genomic organization of chicken tr (chtr). the chtr exists as a single copy gene (terc, alias tr), mapping to chromosome 9 (gga9). the loci on the q arm of gga9 map to three chromosomes in human with five of the nine gga9q loci mapping to hsa3q. sequencing of the chterc locus (3,763 bp) ...200314970722
an enzyme-linked immunosorbent assay (elisa) for detection of marek's disease virus-specific antibodies and its application in an experimental vaccine enzyme-linked immunosorbent assay (elisa) for the detection of marek's disease virus (mdv)-specific antibodies was developed. chicken embryo cells (cec) or chicken kidney cells (ckc) were infected with mdv vaccine strain cvi988/rispens, and infected-cell lysates were prepared at day 5 post-infection by freeze-thawing. uninfected-cell lysates served as negative controls. sera were used at a 1 : 100 dilution and were added in parallel to wells containing the infected and uninfected cell lysates ...200415030602
a comprehensive screen for chicken proteins that interact with proteins unique to virulent strains of marek's disease virus.genetic resistance to marek's disease (md) has been proposed as a method to augment current vaccinal control of md. although it is possible to identify qtl and candidate genes that are associated with md resistance, it is necessary to integrate functional screens with linkage analysis to confirm the identity of true md resistance genes. to help achieve this objective, a comprehensive 2-hybrid screen was conducted using genes unique to virulent marek's disease virus (mdv) strains. potential mdv-h ...200415285502
comparative analysis of marek's disease virus (mdv) glycoprotein-, lytic antigen pp38- and transformation antigen meq-encoding genes: association of meq mutations with mdvs of high virulence.marek's disease (md) is a highly contagious lymphoproliferative and demyelinating disorder of chickens. md is caused by marek's disease virus (mdv), a cell-associated, acute-transforming alphaherpesvirus. for three decades, losses to the poultry industry due to md have been greatly limited through the use of live vaccines. mdv vaccine strains are comprised of antigenically related, apathogenic mdvs originally isolated from chickens (mdv-2), turkeys (herpesvirus of turkeys, hvt) or attenuated-onc ...200415327791
marek's disease is a natural model for lymphomas overexpressing hodgkin's disease antigen (cd30).animal models are essential for elucidating the molecular mechanisms of carcinogenesis. hodgkin's and many diverse non-hodgkin's lymphomas overexpress the hodgkin's disease antigen cd30 (cd30(hi)), a tumor necrosis factor receptor ii family member. here we show that chicken marek's disease (md) lymphoma cells are also cd30(hi) and are a unique natural model for cd30(hi) lymphoma. chicken cd30 resembles an ancestral form, and we identify a previously undescribed potential cytoplasmic signaling do ...200415356338
association between rate of viral genome replication and virulence of marek's disease herpesvirus strains.the early pathogenesis of marek's disease virus (mdv) infection is characterized by a lytic infection followed by the induction of latency. genetically resistant n2a and susceptible p2a chickens were infected with the less virulent jm-16 or the very virulent plus (vv+) rk-1 mdv strains to examine the relationship between virulence and resistance on virus replication during 1-10 days postinfection (dpi) using real-time quantitative polymerase chain reaction (qpcr) and quantitative reverse transcr ...200415380365
construction and characterization of marek's disease viruses having green fluorescent protein expression tied directly or indirectly to phosphoprotein 38 expression.marek's disease (md) is caused by marek's disease virus (mdv), a highly cell-associated alphaherpesvirus. md is primarily characterized by lymphocyte infiltration of the nerves and the development of lymphomas in visceral organs, muscle, and skin. mdv encodes two phosphoproteins, pp24 and pp38, that are highly expressed during lytic infection. these proteins were initially identified in mdv-induced tumors but are now known to be linked primarily to mdv lytic infection. despite the recent charact ...200415529969
oncogenicity of virulent marek's disease virus cloned as bacterial artificial chromosomes.marek's disease virus (mdv) is an oncogenic alphaherpesvirus that induces t-cell lymphomas in poultry. we report the construction of bacterial artificial chromosome (bac) clones of the highly oncogenic rb-1b strain by inserting mini-f vector sequences into the u(s)2 locus. mdv reconstituted from two bac clones induced rapid-onset lymphomas similar to those induced by the wild-type virus. virus reconstituted from another bac clone that showed a 7.7-kbp deletion in the internal and terminal unique ...200415542691
absolute quantitation of marek's disease virus genome copy number in chicken feather and lymphocyte samples using real-time pcr.a real-time pcr method was developed, optimised and validated, to enable quantitation of marek's disease virus genomes as copy number per million host cells. the duplex pcr measured the virus meq gene and host ovotransferrin gene in a single reaction enabling correction for differences in amount of sample dna added. a bacterial artificial chromosome (bac) clone of the virus genome, and a plasmid (pgem-t-ovo) bearing a fragment of the chicken ovotransferrin gene, were used to quantify virus and h ...200515582699
abundance of ifn-alpha and ifn-gamma mrna in blood of resistant and susceptible chickens infected with marek's disease virus (mdv) or vaccinated with turkey herpesvirus; and mdv inhibition of subsequent induction of ifn gene transcription.the effects of the very virulent rb-1b strain of marek's disease virus (mdv) and turkey herpesvirus (hvt), a vaccinal strain, on abundance of ifn mrna in the blood were investigated. mdv and hvt infection did not change the circulating level of ifn-gamma mrna 1 and 7 days p.i., but they increased ifn-alpha mrna levels slightly in genetically susceptible (to tumour development) b(13)/b(13) chickens. the total number of circulating leukocytes was unchanged and increase in message was accompanied b ...200415592893
anatomical distribution of t- and b-lymphocytes in marek's disease--an immunohistochemical study.neural lesions of marek's disease, marek's disease tumours in the ovary, liver, and kidney, as well as spleen and bursa of fabricii of chickens bearing marek's disease tumorous infiltrations, were examined by a new immunohistochemical technique basing upon sternbergers unlabelled antibody enzyme method which allows the exact localization of lymphoid cells based on their surface antigens. type c neural lesions contained t-lymphocytes almost exclusively. type b neural lesions had relatively high p ...198015612258
quail cell lines supporting replication of marek's disease virus serotype 1 and 2 and herpesvirus of turkeys.marek's disease virus (mdv), a highly cell-associated alphaherpesvirus, can be isolated and propagated in chicken kidney cells (ckc) and chicken or duck embryo fibroblast cells (cef or def, respectively). two recently developed cell lines, cu447 and cu453, developed from methylcholanthrene-induced tumors in japanese quail, were examined for their suitability to propagate the three serotypes of mdv. the mdv strain rb-1b (serotype 1) was passaged for more than 30 passages in cu447 without causing ...200415666861
successful control of marek's disease by vaccination.marek's disease (md) is a neoplastic disease of poultry caused by the highly contagious marek's disease virus (mdv). vaccination with live attenuated vaccines forms the cornerstone of the current md control programmes. the widespread use of the vaccines in the last 30 years has significantly reduced the losses from md. despite the huge success of the vaccination policy, the continuing trend in virulence increase of field strains of mdv has forced the introduction of new generations of vaccines t ...200415742626
fowlpox virus as a recombinant vaccine vector for use in mammals and vaccines against fowlpox virus, which causes moderate pathology in poultry and is the type species of the avipoxvirus genus, were developed in the 1920s. development of recombinant fowlpox virus vector vaccines began in the 1980s, for use not only in poultry, but also in mammals including humans. in common with other avipoxviruses, such as canarypox virus, fowlpox virus enters mammalian cells and expresses proteins, but replicates abortively. the use of fowlpox virus as a safe vehicle for e ...200515757474
use of marek's disease vaccines: could they be driving the virus to increasing virulence?marek's disease (md) is an economically important neoplastic disease of poultry. md almost devastated the poultry industry in the 1960s but the disease was brought under control after marek's disease herpesvirus (mdv) was identified and vaccines were developed. this is the first effective use of an antiviral vaccination to prevent a naturally occurring cancer in any species. mdv infection has many effects. initially causing a cytolytic infection in b-lymphocytes, mdv infects activated t-lymphocy ...200515757475
pro-inflammatory responses in chicken spleen and brain tissues after infection with very virulent plus marek's disease chickens infected with virulent (v) or very virulent (vv) marek's disease (md) virus (mdv) strains, small to moderate increases in plasma nitric oxide (no) levels are seen, respectively, whereas very virulent plus (vv+) strains induce very high levels in vivo. the data presented in this report show that chickens presenting with clinical neurological disease following infection with the vv+ rk-1 strain have significantly higher in vivo no levels compared to rk-1-infected non-symptomatic chicke ...200515802959
comparative functional study of the viral telomerase rna based on natural mutations.telomerase activity is present in most malignant tumors and provides a mechanism for the unlimited potential for division of neoplastic cells. we previously characterized the first identified viral telomerase rna (vtr) encoded by the marek's disease virus (mdv) (fragnet, l., blasco, m. a., klapper, w., and rasschaert, d. (2003) j. virol. 77, 5985-5996). this avian herpesvirus induces t-lymphomas. we demonstrated that the vtr subunit of the oncogenic mdv-rb1b strain is functional and would be mor ...200515811851
antiviral activity of ovotransferrin derived peptides.ovotransferrin and lactoferrin are iron-binding proteins with antiviral and antibacterial activities related to natural immunity, showing marked sequence and structural homologies. the antiviral activity of two hen ovotransferrin fragments dqkdeyell (hotrf(219-227)) and kdllfk (hotrf(269-301) and hotrf(633-638)) towards marek's disease virus infection of chicken embryo fibroblasts is reported here. these fragments have sequence homology with two bovine lactoferrin fragments with antiviral activi ...200515845359
high-level expression of marek's disease virus glycoprotein c is detrimental to virus growth in vitro.expression levels of marek's disease virus (mdv) glycoprotein c (gc) are significantly reduced after serial virus passage in cell culture. reduced gc expression coincides with enhanced mdv growth in vitro and attenuation. to analyze this phenomenon in detail, a full-length infectious mdv clone was modified by red-based and shuttle mutagenesis in escherichia coli. besides a gc-negative deletion mutant harboring a kanamycin resistance gene, a markerless mutant with the u(l)44 gene deleted was cons ...200515857974
vlip, a viral lipase homologue, is a virulence factor of marek's disease virus.the genome of marek's disease virus (mdv) has been predicted to encode a secreted glycoprotein, vlip, which bears significant homology to the alpha/beta hydrolase fold of pancreatic lipases. here it is demonstrated that mdv vlip mrna is produced via splicing and that vlip is a late gene, due to its sensitivity to inhibition of dna replication. while vlip was found to conserve several residues essential to hydrolase activity, an unfavorable asparagine substitution is present at the lipase catalyt ...200515890938
[study on the characterization of the bi-directional promoter between pp38 gene and 1.8kb mrna transcripts of marek's disease viruses].the bi-directional promoter between pp38 gene and 1.8kb mrna transcripts of marek's disease viruses (mdv) was divided into two single-direction promoters from the replication of mdv genomic dna. the pp38 gene was cloned into puc18 vector for plasmid puc-pp38. then the complete bi-directional promoter was cloned into puc-pp38 in two directions to form plasmids ppro(f)pp38 and ppro(r)pp38, and the divided two single directional promoters were cloned in puc-pp38 for plasmids pdpro(f)pp38 and pdpro( ...200515989227
attenuation of marek's disease virus by deletion of open reading frame rlorf4 but not rlorf5a.marek's disease (md) in chickens is caused by the alphaherpesvirus md virus (mdv) and is characterized by the development of lymphoblastoid tumors in multiple organs. the recent identification and cloning of rlorf4 and the finding that four of six attenuated strains of mdv contained deletions within rlorf4 suggested that it is involved in the attenuation process of mdv. to assess the role of rlorf4 in md pathogenesis, its coding sequence was deleted in the prb-1b bacterial artificial chromosome ...200516140742
novel criteria for the diagnosis of marek's disease virus-induced lymphomas.several novel criteria have been tested to assist in the differential diagnosis of tumours induced by marek's disease virus (mdv) from those induced by avian leukosis virus (alv) and reticuloendotheliosis virus (rev). a collection of tumours induced by inoculation of specific strains of mdv, alv and rev, alone or in combination, were tested for quantification of mdv dna by real-time polymerase chain reaction, expression of the mdv oncogene meq, expression of several cell markers associated with ...200516147570
classification of marek's disease viruses according to pathotype: philosophy and methodology.the concept of pathotype in marek's disease (md) probably dates from the recognition of a more virulent form of the disease in the late 1950s (benton & cover, 1957). distinctions between md virus strains were further expanded with the description of the vv pathotype in the early 1980s and of the vv+ pathotype in the 1990s. pathotype designations reflect important biological properties that correlate with the break-through of vaccinal immunity in the field. however, pathotyping methods applied by ...200516191686
replication kinetics of marek's disease vaccine virus in feathers and lymphoid tissues using pcr and virus isolation.cvi988 (rispens), an avirulent strain of marek's disease virus, is the most widely used vaccine against marek's disease. the kinetics of replication of cvi988 was examined in tissues of chickens vaccinated at either 1 day or 14 days of age and sampled regularly up to 28 days post-vaccination. age at vaccination had no significant effect on the kinetics of cvi988 virus replication. during the cytolytic phase of infection (1-7 days), virus levels peaked in the spleen, bursa and thymus with very cl ...200516227220
is ms an auto-immune disease or a chronic gammaherpesvirus infection?the geographical-epidemiological findings of ms over the past 75 years are reviewed. evidence concerning pr latitude-gradients, clusters, migration patterns, and enhancement-protective factors are critically reviewed and analyzed. the evidence in genetics, twin-studies and auto-immune theories are also thoroughly scrutinized as to their possible involvement as causative factors in ms- and found to be somewhat lacking. environmental discoveries in the faroes and key west clusters are reviewed for ...199616296264
[high level expression of recombinant chicken interferon-gamma in insect cells].the recombinant transfer vector pfastbacl-chifn-y was constructed by plasmid pcdna-chifn-gamma digested with ecor i and not i enzymes and cloned into pfastbacl. then the transfer vector was transformed into e. coli competent cells dh10bac which contained the bacmid with amini-atttn7 target site and the helper plasmid. the recombinant bacmid-chifn-gamma was generated by transposing themini-tn7 element located in pfastbacl-chifn-gamma to themini-atttn7 attachment site on the bacmid. subsequently t ...200516342758
interaction of meq protein and c-terminal-binding protein is critical for induction of lymphomas by marek's disease virus.marek's disease virus (mdv) is an oncogenic herpesvirus that induces fatal t cell lymphomas in chickens. with more than 20 billion doses of vaccine used annually, vaccination constitutes the cornerstone of marek's disease control. despite the success of vaccination, evolution of virulence among mdv strains continues to threaten the effectiveness of the current marek's disease vaccines. mdv-encoded protein meq (mdv ecori q) probably acts as a transcription factor and is considered to be the major ...200616446447
marek's disease virus: from miasma to model.marek's disease virus (mdv) is an oncogenic herpesvirus that causes various clinical syndromes in its natural host, the chicken. mdv has long been of interest as a model organism, particularly with respect to the pathogenesis and immune control of virus-induced lymphoma in an easily accessible small-animal system. recent advances in mdv genetics and the determination of the chicken genome sequence, aided by functional genomics, have begun to dramatically increase our understanding not only of ly ...200616541136
the enhancement effect of pp38 gene product on the activity of its upstream bi-directional promoter in marek's disease virus.there was a bi-directional promoter between gene 38 kd phosphorylated protein (pp38) gene and 1.8-kb mrna transcript gene family in the genome of marek's disease virus (mdv). in this study, enhanced green fluorescence protein (egfp) reporter plamids, pp(pp38)-egfp and pp(1.8-kb)-egfp, were constructed under this bi-directional promoter in two directions. the two plasmids were transfected into uninfected chicken embryo fibroblast (cef), mdv clone rmd5 infected cef (rmd5-cef) and pp38-deleted deri ...200616544576
rapid identification of non-essential genes for in vitro replication of marek's disease virus by random transposon mutagenesis.marek's disease virus (mdv) is a highly oncogenic alphaherpesvirus that induces rapid-onset t-cell lymphomas in poultry. the mdv genome encodes more than 100 genes. however, the role of many of these genes in virus replication is not known. the construction of an infectious bacterial artificial chromosome (bac) clone of the highly oncogenic rb-1b strain of mdv has been described previously. virus reconstituted from the bac clone induced rapid-onset lymphomas in chickens very similar to the wildt ...200616650486
a virus-encoded telomerase rna promotes malignant t cell lymphomagenesis.telomerase is a ribonucleoprotein complex consisting of two essential core components: a reverse transcriptase and an rna subunit (telomerase rna [tr]). dysregulation of telomerase has been associated with cell immortalization and oncogenesis. marek's disease herpesvirus (mdv) induces a malignant t cell lymphoma in chickens and harbors in its genome two identical copies of a viral tr (vtr) with 88% sequence identity to chicken tr. mdv mutants lacking both copies of vtr were significantly impaire ...200616651385
telomerase flies the coop: the telomerase rna component as a viral-encoded oncogene.telomerase, the enzyme that elongates our telomeres, is crucial for cancer development based on extensive analyses of human cells, human cancers, and mouse models. new data now suggest that a viral telomerase rna gene encoded by marek's disease virus (mdv), an oncogenic herpesvirus of chickens, promotes tumor formation. these findings highlight the importance of telomerase in cancer and raise new questions regarding the mechanisms by which the telomerase rna component supports tumorigenesis.200616682501
h2a.z stabilizes chromatin in a way that is dependent on core histone acetylation.the functional and structural chromatin roles of h2a.z are still controversial. this work represents a further attempt to resolve the current functional and structural dichotomy by characterizing chromatin structures containing native h2a.z. we have analyzed the role of this variant in mediating the stability of the histone octamer in solution using gel-filtration chromatography at different ph. it was found that decreasing the ph from neutral to acidic conditions destabilized the histone comple ...200616707487
[construction and immunological characterization of recombinant marek's disease virus expressing ibdv vp2 fusion protein].a transfer plasmid vector puc18-us10-vp2 was first constructed by inserting the gene of the enhancer green fluorescent protein(egfp) fused to the vp2 gene of very virulent infectious bursal disease virus (ibdv) js strain into the us10 fragment of the marek's disease virus (mdv) cv1988/rispens. the recombinant virus, designated as rmdv, was developed by co-transfecting cef with the transfer plasmid vector and simultaneously infecting with the cvi988/rispens virus. the pcr and ifa results indicate ...200616755916
relationship between marek's disease and the time course of viral genome proliferation in feather tips.a total of 114 male chickens from three sire families of a commercial cross of white leghorn chickens were infected with rb-1b marek's disease (md) virus at 21 days of age by exposing them to chickens previously inoculated with md virus. the presence of virus in feather tips, feather pulp, and md viral antibodies indicated all chickens became infected. the first virus-positive chickens were observed at 12 days postexposure (dpe). the frequency reached a maximum at 27 dpe and then decreased. at 8 ...200616863063
psittacid herpesvirus 1 and infectious laryngotracheitis virus: comparative genome sequence analysis of two avian alphaherpesviruses.psittacid herpesvirus 1 (pshv-1) is the causative agent of pacheco's disease, an acute, highly contagious, and potentially lethal respiratory herpesvirus infection in psittacine birds, while infectious laryngotracheitis virus (iltv) is a highly contagious and economically significant avian herpesvirus which is responsible for an acute respiratory disease limited to galliform birds. the complete genome sequence of pshv-1 has been determined and compared to the iltv sequence, assembled from publis ...200616873243
marek's disease virus up-regulates major histocompatibility complex class ii cell surface expression in infected cells.many herpesviruses modulate major histocompatibility complex (mhc) expression on the cell surface as an immune evasion mechanism. we report here that marek's disease virus (mdv), a lymphotrophic avian alphaherpesvirus, up-regulates mhc class ii cell surface expression in infected cells, contrary to all other herpesviruses examined to date. this mdv-induced class ii up-regulation was detected both in vitro and in vivo. this effect was not solely an indirect effect of interferon, which is a highly ...200717028059
susceptibility of adult chickens, with and without prior vaccination, to challenge with marek's disease virus.marek's disease (md) outbreaks can occur in previously healthy adult layer or breeder flocks. however, it is not clear whether such outbreaks are caused by recent challenge with highly virulent (vv and vv+) strains of md virus (mdv; i. e., new infection hypothesis) or by exacerbation of an earlier mdv infection (i. e., old infection hypothesis). to discriminate between these hypotheses, adult white leghorn chickens of laboratory strains or commercial crosses with or without prior vaccination or ...200617039834
real-time quantitative pcr for marek's disease vaccine virus in feather samples: applications and opportunities.marek's disease, an economically-important lymphoid neoplasm of chickens, is controlled by vaccination with cvi988 strain of marek's disease herpesvirus. sub-optimal vaccinal protection can have multiple causes. accurate quantification of cvi988 in vaccinated chickens will assist in understanding the causes of these vaccine breaks. we developed, optimised and validated a real-time pcr assay for quantification of cvi988 vaccine virus (in terms of cvi988 genomes per 10,000 cells) in the feather ti ...200617058503
marek's disease virus: lytic replication, oncogenesis and control.marek's disease (md) is caused by a ubiquitous, lymphotropic alphaherpesvirus, md virus (mdv). md has been a major concern in the poultry industry owing to the emergence of increasingly virulent strains over the last few decades that were isolated in the face of comprehensive vaccination. the disease is characterized by a variety of clinical signs; among them are neurological symptoms, chronic wasting and, most notably, the development of multiple lymphomas that manifest as solid tumors in the v ...200617184215
transcriptional analysis of host responses to marek's disease viral infection.this study was aimed at investigating the genes that control host responses to marek's disease virus (mdv). spleen tissues from infected and age-matched uninfected control chickens were examined 4, 7, 14, and 21 d postinfection for gene expression differences, using both microarray and quantitative real-time polymerase chain reaction (pcr) methodologies. up to 51% of genes assayed during microarray analysis showed a significant change (p < or = 0.05) in expression after mdv infection, of which c ...200617201670
effects of reticuloendotheliosis virus and marek's disease virus infection and co-infection on ifn-gamma production in spf chickens.two experiments were used to examine the potential role of ifn-gamma in chickens infected with reticuloendotheliosis virus (rev) and marek's disease virus (mdv). first, chickens were infected with rev and/or mdv at 5 days of age and examined from 3 to 50 days post-infection (dpi). in rev+mdv co-infection chickens, ifn-gamma elisa demonstrated a 3-fold increase at 7 dpi compared to the controls, while rev alone caused a 5-fold increase, the ifn-gamma levels peaked, and then gradually decreased. i ...200717339769
expression of chicken interleukin-2 by turkey herpesvirus increases the immune response against marek's disease virus but fails to increase protection against virulent marek's disease virus continues to evolve towards greater virulence, more efficacious vaccines will be required in the future. we expressed chicken interleukin-2 (il-2) from a turkey herpesvirus (hvt) in an attempt to increase the efficacy of hvt as a vaccine against marek's disease. the recombinant il-2/hvt was safe for in ovo vaccination, although it replicated less in the birds compared with the parent hvt strain. expression of il-2 increased the neutralizing antibody response against hvt ...200717364512
comparative full-length sequence analysis of oncogenic and vaccine (rispens) strains of marek's disease virus.the complete dna sequence of the marek's disease virus serotype 1 vaccine strain cvi988 was determined and consists of 178 311 bp with an overall gene organization identical to that of the oncogenic strains. in examining open reading frames (orfs), nine differ between vaccine and oncogenic strains. a 177 bp insertion was identified in the overlapping genes encoding the meq, rlorf6 and 23 kda proteins of cvi988. three orfs are predicted to encode truncated proteins. one, designated 49.1, overlaps ...200717374751
expression and intercellular trafficking of the vp22 protein of cvi988/rispens vaccine strain of marek's disease virus.the viral protein 22 (vp22) in the tegument of marek's disease virus serotype 1 (mdv-1) plays an important role in cell-to-cell spread and viral propagation. antiserum against the carboxyl terminus of vp22 was prepared by immunizing mice with recombinant vp22 expressed in e. coli, and used to investigate its expression in chicken embryo fibroblast (cef) cells infected with different mdv-1 strains. at an infection dose of pfu=50, intercellular trafficking of the vp22 into the nuclei of the surrou ...200717393086
marek's disease virus type 2 (mdv-2)-encoded micrornas show no sequence conservation with those encoded by mdv-1.micrornas (mirnas) are increasingly being recognized as major regulators of gene expression in many organisms, including viruses. among viruses, members of the family herpesviridae account for the majority of the currently known virus-encoded mirnas. the highly oncogenic marek's disease virus type 1 (mdv-1), an avian herpesvirus, has recently been shown to encode eight mirnas clustered in the meq and lat regions of the viral genome. the genus mardivirus, to which mdv-1 belongs, also includes the ...200717459919
a full ul13 open reading frame in marek's disease virus (mdv) is dispensable for tumor formation and feather follicle tropism and cannot restore horizontal virus transmission of rrb-1b in vivo.marek's disease virus (mdv) is an oncogenic alphaherpesvirus that is highly contagious in poultry. recombinant rb-1b (rrb-1b) reconstituted from an infectious genome cloned as a bacterial artificial chromosome (bac) is unable to spread horizontally, quite in contrast to parental rb-1b. this finding suggests the presence of one or several mutations in cloned relative to parental viral dna. sequence analyses of the prb-1b bacmid identified a one-nucleotide insertion in the ul13 orthologous gene th ...200717506972
marek's disease virus research in the post-sequencing era: new tools for the study of gene functions and virus-host interactions.despite the fact that the causative agent of marek's disease was described more than 30 years ago, and that subsequently many classical biological studies have been carried out on the marek's disease virus (mdv), detailed analysis of its gene functions has been hampered by lack of suitable research tools. information on the primary structure of mdv-1 and its serologically related viruses, mdv-2 and herpesvirus of turkeys, is now available. this review focuses on the introduction of the modern an ...200317585455
marek's disease virus unique genes pp38 and pp24 are essential for transactivating the bi-directional promoters for the 1.8 kb mrna transcripts.the pp38 and pp24 genes of marek's diseases virus (mdv) share the same promoter, which controls the transcription of pp38 or pp24 and a 1.8-kb mrna bi-directionally. to understand the trans-activating activity of pp38 and pp24 on the bi-directional promoter, both genes were cloned into pcdna-3 or pbudce4.1 vectors either singly or in combination. these plasmids were expressed in transfected chicken embryonic fibroblast (cef) cells. chloramphenicol acetyltransferase (cat) activity expressed under ...200717619133
identification and characterization of a novel spliced form of the meq transcript in lymphoblastoid cell lines derived from marek's disease tumour cell lines established from marek's disease (md) lymphomas l-meq is consistently expressed. it contains a 180 bp insertion encoding additional copies of the proline-rich repeat in the meq open reading frame and its product may contribute to the maintenance of md virus (mdv) latency. in this study, we identified a novel spliced form of the meq transcript in md-derived lymphoblastoid cell lines and in mdv-infected cells. this transcript, termed deltameq, encodes an n-terminal 98 aa of th ...200717622612
quantitative profiling of the shedding rate of the three marek's disease virus (mdv) serotypes reveals that challenge with virulent mdv markedly increases shedding of vaccinal viruses.the shedding profile of marek's disease virus serotype 1 (mdv1, virulent), serotype 2 (mdv2, vaccinal) and herpesvirus of turkeys (hvt, vaccinal) in commercial broiler chickens was determined by measuring the daily rate of production of feather dander from chickens housed in isolators and by quantifying the viral load of each of these serotypes in the dander using quantitative real-time pcr (qpcr). mdv1 and hvt viruses were detectable in dander filtered from isolator exhaust air from day 7 and m ...200717622613
horizontal transmission of marek's disease virus requires us2, the ul13 protein kinase, and gc.marek's disease virus (mdv) causes a general malaise in chickens that is mostly characterized by the development of lymphoblastoid tumors in multiple organs. the use of bacterial artificial chromosomes (bacs) for cloning and manipulation of the mdv genome has facilitated characterization of specific genes and genomic regions. the development of most mdv bacs, including prb-1b-5, derived from a very virulent mdv strain, involved replacement of the us2 gene with mini-f vector sequences. however, w ...200717634222
evidence for widespread epistatic interactions influencing marek's disease virus viremia levels in chicken.marek's disease (md), a t cell lymphoma induced by the marek's disease virus (mdv), is the main chronic infectious disease concern threatening the poultry industry. enhancing genetic resistance to md in commercial poultry is an attractive method to augment md vaccines, which is currently the control method of choice. in order to implement this control strategy through marker-assisted selection (mas), it is necessary to identify quantitative trait loci (qtl) or genes that influence md incidence. ...200717675873
genomics and marek's disease virus.marek's disease virus (mdv), a lymphotrophic alphaherpesvirus of chickens, causes a disease that is characterized by tumor formation, immunosuppression and neurological disorders. recent developments in chicken genomics have been applied to studies of mdv and have advanced our understanding of both the virus and the disease it causes. we have constructed and used microarrays to identify host genes that are up-regulated in chicken embryo fibroblasts infected with mdv as a first step to catalog th ...200717675881
molecular characterization of the herpes simplex virus 1 (hsv-1) homologues, ul25 to ul30, in duck enteritis virus (dev).a 16.6-kilo-base pair (kb) sequence was amplified from the duck enteritis virus (dev) clone-03 strain genome using 'targeted gene walking polymerase chain reaction (pcr)'. seven complete open reading frames (orfs) were predicted, and designated herpes simplex virus 1 (hsv-1) homologues, unique long (ul) 25, ul26, ul26.5, ul27, ul28, ul29, and ul30. sequence analysis revealed that the arrangement of seven genes in dev clone-03 strain was collinear to that from hsv-1. in addition, mrna transcripti ...200717706377
morphogenesis of a highly replicative egfpvp22 recombinant marek's disease virus in cell culture.marek's disease virus (mdv) is an alphaherpesvirus for which infection is strictly cell associated in permissive cell culture systems. in contrast to most other alphaherpesviruses, no comprehensive ultrastructural study has been published to date describing the different stages of mdv morphogenesis. to circumvent problems linked to nonsynchronized infection and low infectivity titers, we generated a recombinant mdv expressing an enhanced green fluorescent protein fused to vp22, a major tegument ...200717855520
molecular evaluation of responses to vaccination and challenge by marek's disease viruses.a real-time quantitative polymerase chain reaction was utilized to study the in vivo replication of marek's disease vaccine viruses and of virulent oncogenic strains. in the first of four experiments, the growth of the herpes virus of turkeys (hvt) vaccine was detectable in various organs of infected chicken embryos, with the highest viral loads being present in the spleen. no evidence was obtained for replication of serotype-1 marek's disease viruses in embryos. in the second experiment, viral ...200717899458
creation of diversity in the animal virus world by inter-species and intra-species recombinations: lessons learned from poultry viruses.the biological diversity within viruses is one of the largest found in all other forms of nature. many mechanisms contribute to virus diversity and include incorporating genetic material from the host, recombination between viruses belonging to the same or to a different family, and even recombination between viruses normally infecting different hosts. in particular, avian viruses can utilize all three of these mechanisms to generate new viruses. it is well documented that recombinations can occ ...200817922180
host responses are induced in feathers of chickens infected with marek's disease virus.control measures are ineffective in curtailing marek's disease virus (mdv) infection and replication in the feather follicle epithelium (ffe). therefore, vaccinated birds which subsequently become infected with mdv, shed the virulent virus although they remain protected against disease. the present study investigated host responses generated against mdv infection in the feather. we observed that in parallel with an increase in viral genome load and viral replication in the feather, there was a g ...200817949771
the contribution of feathers in the spread of chicken anemia virus.chicken anemia virus (cav) spreads vertically and horizontally, however, the process is mostly still obscure. to further clarify the horizontal cav spread, we examined the contribution of feathers. we demonstrated that cav could be amplified from dna purified from feather shafts of experimentally infected chicks, and the process efficacy was evaluated by comparing the amplification of dna purified from feather shafts and lymphoid organs of cav-experimentally infected chicks. dna from feathers wa ...200818177972
characterization of a newly developed chicken 44k agilent microarray.the development of microarray technology has greatly enhanced our ability to evaluate gene expression. in theory, the expression of all genes in a given organism can be monitored simultaneously. sequencing of the chicken genome has provided the crucial information for the design of a comprehensive chicken transcriptome microarray. a long oligonucleotide microarray has been manually curated and designed by our group and manufactured using agilent inkjet technology. this provides a flexible and po ...200818237426
transcriptional profiling of marek's disease virus genes during cytolytic and latent infection.marek's disease (md), a lymphoproliferative disease of chicken is caused by a highly cell-associated alpha-herpesvirus, marek's disease virus (mdv). mdv replicates in chicken lymphocytes and establishes a latent infection within cd4(+) t cells. the expression analysis of limited viral transcripts have revealed differences in gene expression pattern during cytolytic and latent phases of mdv infection. in this study, we conducted a global gene expression profiling of mdv using oligonucleotide-base ...200818266100
recombinant marek's disease virus (mdv) lacking the meq oncogene confers protection against challenge with a very virulent plus strain of mdv.marek's disease virus (mdv) encodes a basic leucine-zipper protein, meq, that shares homology with the jun/fos family of transcriptional factors. conclusive evidence that meq is an oncogene of mdv came from recent studies of a meq-null virus, rmd5 delta meq. this virus replicated well in vitro, but was non-oncogenic in vivo. further characterization of this virus in vivo indicated that the meq gene is dispensable for cytolytic infection since it replicated well in the lymphoid organs and feather ...200818313812
different signaling pathways expressed by chicken naive cd4(+) t cells, cd4(+) lymphocytes activated with staphylococcal enterotoxin b, and those malignantly transformed by marek's disease virus.proteomics methods, based on liquid chromatography and tandem mass spectrometry, produce large "shotgun" proteomes that are most appropriately compared not at the level of differentially expressed proteins only but at the more comprehensive level of biological networks and pathways. this is now possible with the emergence of functional annotation databases and tools, databases of canonical pathways and molecular interactions and computational text mining tools. here, we used shotgun proteomics, ...200818412384
the ul31 to ul35 gene sequences of duck enteritis virus correspond to their homologs in herpes simplex virus 1.five orfs in the genome of duck enteritis virus (dev) corresponding to ul31, ul32, ul33, ul34, and ul35 genes of herpes simplex virus 1 (hsv-1) were amplified by a modified "targeted gene walking" pcr, cloned, and sequenced. ul33, ul34, and ul35 genes were oriented from the left to the right of genome, while ul31 and ul32 had an opposite orientation. a comparison of deduced amino acid sequences of the dev orfs with their alphaherpesvirus homologs showed well-conserved regions except for the ul34 ...200818459832
association of a marker in the vitamin d receptor gene with marek's disease resistance in poultry.vitamin d is an important immunomodulator that mediates its effect via a nuclear receptor. in this study, we analyzed 3 uncorrelated genetic markers (tag single nucleotide polymorphisms) in the vitamin d receptor gene for association with marek's disease (md) resistance. the database consisted of 400 commercial white leghorn chickens that had been vaccinated with herpes turkey virus and challenged by intraperitoneal injection of the virulent md virus rb1b. viral titers in feather tips were deter ...200818492999
kinetics of marek's disease virus (mdv) infection in broiler chickens 1: effect of varying vaccination to challenge interval on vaccinal protection and load of mdv and herpesvirus of turkey in the spleen and feather dander over time.two experiments in commercial broiler chickens vaccinated with herpesvirus of turkeys (hvt) and challenged with marek's disease virus (mdv) investigated the effects of the vaccination-to-challenge interval (vci) on vaccinal protection against marek's disease, and the kinetics of mdv and hvt load in the spleen and feather dander determined using real-time quantitative polymerase chain reaction. experiment 1 in isolators tested vci of 2, 4 and 7 days, while experiment 2 in floor pens tested vci of ...200818568648
mass spectral data for 64 eluted peptides and structural modeling define peptide binding preferences for class i alleles in two chicken mhc-b haplotypes associated with opposite responses to marek's the chicken, resistance to lymphomas that form following infection with oncogenic strains of marek's herpesvirus is strongly linked to the major histocompatibility complex (mhc)-b complex. mhc-b21 haplotype is associated with lower tumor-related mortality compared to other haplotypes including mhc-b13. the single, dominantly expressed class i gene (bf2) is postulated as responsible for the mhc-b haplotype association. we used mass spectrometry to identify peptides and structural modeling to d ...200818612635
[construction of marek's disease virus serotype 814 strain as an infectious bacterial artificial chromosome].the aim of this study was to construct the complete genome of marek's disease virus serotype 814 strain as an infectious bacterial artificial chromosome (bac). using self-designed selection marker eco-gpt (1.3 kb) and bac vector pbelobac11 (7.5 kb), we constructed the transfer plasmid puab-gpt-bac11. the plasmid puab-gpt-bac11 and mdv total-dna were cotransfected into secondary cefs; we put the virus-containing cells in selection medium for eight rounds and obtained purified recombinant viruses. ...200818616164
functional homologies between avian and human alphaherpesvirus vp22 proteins in cell-to-cell spreading as revealed by a new cis-complementation assay.vp22, encoded by the ul49 gene of marek's disease virus (mdv), is indispensable for virus cell-to-cell spreading. we show herein that mdv ul49 can be functionally replaced with avian and human viral orthologs. replacement of mdv vp22 with that of avian gallid herpesvirus 3 or herpesvirus of turkey, whose residue identity with mdv is close to 60%, resulted in 73 and 131% changes in viral spreading, respectively. in contrast, vp22 replacement with human herpes simplex virus type 1 resulted in 14% ...200818632866
phylogeny of duck enteritis virus: evolutionary relationship in the family understand the evolutionary relationship of duck enteritis virus (dev) in the family herpesviridae and the genome organization of dev.200818645259
host responses in the bursa of fabricius of chickens infected with virulent marek's disease virus.the bursa of fabricius serves as an important tissue in the process of marek's disease virus (mdv) pathogenesis, since b cells of the bursa harbor the cytolytic phase of mdv replication cycle. in the present study, host responses associated with mdv infection in the bursa of fabricius of chickens were investigated. the expression of mdv phosphoprotein (pp)38 antigen, mdv glycoprotein (gb) and mdv viral interleukin (vil)-8 transcripts was at the highest at 4 days post-infection (d.p.i.) and then ...200818675437
vaccination against marek's disease reduces telomerase activity and viral gene transcription in peripheral blood leukocytes from challenged chickens.we investigated whether telomerase activity and viral gene transcription were associated with protection against the rb-1b strain of marek's disease virus (mdv) in chickens vaccinated with rispens cvi988 or the herpes virus of turkey (hvt). telomerase activity in peripheral blood leukocytes (pbls) seemed to be an appropriate marker of lymphoma and levels of viral transcription were correlated with the virulence of mdv strains. vaccinated protected birds had lower levels of telomerase activity an ...200818680776
a functional microrna-155 ortholog encoded by the oncogenic marek's disease virus.kaposi's sarcoma-associated herpesvirus-encoded microrna (mirna) mir-k12-11 was recently shown to be a functional ortholog of mir-155, a mirna that plays a major role in lymphoid malignancies and the modulation of immune responses. here we show that mir-m4, encoded by the highly oncogenic marek's disease virus of chickens, shares common targets with mir-155 and thus is also a functional ortholog of mir-155, the first one identified in an alphaherpesvirus. the observation that two distinct oncoge ...200918945769
homodimerization of marek's disease virus-encoded meq protein is not sufficient for transformation of lymphocytes in chickens.marek's disease virus (mdv), the etiologic agent of marek's disease, is a potent oncogenic herpesvirus. mdv is highly contagious and elicits a rapid onset of malignant t-cell lymphomas in chickens within several weeks after infection. mdv genome codes an oncoprotein, meq, which shares resemblance with the jun/fos family of bzip transcription factors. similar to jun, the leucine zipper region of meq allows the formation of homo- and heterodimers. meq homo- and heterodimers have different dna bind ...200918971275
construction of an infectious marek's disease virus bacterial artificial chromosome and characterization of protection induced in chickens.marek's disease virus (mdv) is a highly oncogenic alphaherpesvirus that induces rapid-onset t-cell lymphoma in poultry. the complete genome of the avirulent vaccine strain mdv-814 was cloned as an infectious bacterial artificial chromosome (bac) using an 8.8-kb fragment containing the self-designed selective marker guanosine phosphoriboxyl transferase. the recombinant virus mdv-814-bac was generated by co-transfection of a bac transfer vector and mdv-814 total dna, and was purified by eight roun ...200919026690
molecular analysis of us10, s3, and us2 in duck enteritis virus.a 4554-bp fragment was amplified from the dev c-kce vaccine strain by single oligonucleotide nested polymerase chain reaction with partially known sequences for the dev us1 and us10 genes. three open reading frames containing the genes encoding us10, s3, and us2 were predicted using the editseq program (dnastar). the s3 and us2 genes have the same transcription orientation but are oriented head-to-head with respect to us10. the promoters and polyadenylation signals were predicted. two poly a seq ...200919130202
effects of transferrins and cytokines on nitric oxide production by an avian lymphoblastoid cell line infected with marek's disease virus.marek's disease virus (mdv), the causative agent of marek's disease (md), is a herpesvirus that infects poultry causing t lymphomas. although vaccination may prevent lymphomas formation, it is not known whether it controls viral replication and spreading in the environment. ovotransferrin (otrf), a member of the transferrin family, is known to exert in vitro antiviral activity in primary cultures of chicken embryo fibroblasts (cef). in addition otrf is produced by cef and by an avian lymphoblast ...200919133294
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