| study of host-pathogen interactions to identify sustainable vaccine strategies to marek's disease. | marek's disease virus is a highly cell-associated, lymphotropic alpha-herpesvirus that causes paralysis and neoplastic disease in chickens. the disease has been contained by vaccination with attenuated viruses and provides the first evidence for a malignant cancer being controlled by an antiviral vaccine. marek's disease pathogenesis is complex, involving cytolytic and latent infection of lymphoid cells and oncogenic transformation of cd4+ t cells in susceptible chickens. innate and adaptive imm ... | 2004 | 15207454 |
| induction of telomerase activity in avian lymphoblastoid cell line transformed by marek's disease virus, mdcc-msb1. | telomerase has been studied extensively in human and murine tumors, but little is known about the role of telomerase in the tumor biology of other vertebrate species such as the chicken. we studied the telomerase activity of the lymphoblastoid cell line derived from lymphomas induced by marek's disease virus (mdcc-msb1) compared with another avian cell line (pa5) and peripheral blood lymphocytes (pbl) using the telomeric repeat amplification protocol (trap) assay. telomerase activity in mdcc-msb ... | 2004 | 15232141 |
| an outbreak of marek's disease in chickens in central ethiopia. | a study was conducted on an outbreak of marek's disease in a commercial poultry farm containing 8500 chickens in central ethiopia. on repeated visits, farm and flock history was collected, sick birds were examined and clinical signs and daily mortality were recorded. a total of 80 (27 sick and 53 dead) birds 12-22 weeks old, were collected, autopsied and examined. the mortality rate was 46% for the first 14 weeks of the outbreak. acute and chronic (classical) forms of the disease, the respective ... | 2004 | 15241973 |
| characterization of four very virulent argentinian strains of marek's disease virus and the influence of one of those isolates on synergism between marek's disease vaccine viruses. | isolates of marek's disease virus (mdv) from vaccinated flocks in argentina were characterized as very virulent (vv) and very virulent plus (vv+) strains. experimental infection with these viruses caused a high incidence of marek's disease in both resistant n-2a line and susceptible p-2a line birds. vaccine viruses from each of the three marek's disease viral serotypes were evaluated alone and in various combinations for protection against challenge with a vvmdv called nulp-1. vaccination of p-2 ... | 2004 | 15276986 |
| 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 ... | 2004 | 15285502 |
| marek's disease virus-encoded meq gene is involved in transformation of lymphocytes but is dispensable for replication. | marek's disease virus (mdv) causes an acute lymphoproliferative disease in chickens, resulting in t cell lymphomas in visceral organs and peripheral nerves. earlier studies have determined that the repeat regions of oncogenic serotype 1 mdv encode a basic leucine zipper protein, meq, which structurally resembles the jun/fos family of transcriptional activators. meq is consistently expressed in mdv-induced tumor cells and has been suggested as the mdv-associated oncogene. to study the function of ... | 2004 | 15289599 |
| 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 ... | 2004 | 15327791 |
| characterization and localization of the unique marek's disease virus type 2 orf873 gene product. | studies on marek's disease virus (mdv)-unique genes are important for understanding the biological nature of the virus. based on complete dna sequence analyses of the mdv genomes, the mdv genomes contain presumably at least five mdv-unique genes, which are commonly conserved among the three mdv serotypes. a recombinant baculovirus that contains the mdv serotype 2 (mdv2)-unique gene, orf873, under the polyhedrin promoter was constructed and designated racorf873. polyclonal and monoclonal antibodi ... | 2004 | 15365234 |
| 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 ... | 2004 | 15380365 |
| analyzing the h19- and t65-epitopes in 38 kd phosphorylated protein of marek's disease viruses and comparing chicken immunological reactions to viruses point-mutated in the epitopes. | dna sequencing analysis in 38 kd phosphorylated protein (pp38) orf of marek's disease viruses (mdv) indicated that all tested 10 virulent strains with different pathotypes had 'a' at base #320 and glutamine at aa#107 while reacted with monoclonal antibody (mab) h19 in indirect fluorescence antibody test (ifa). however, vaccine strain cvi988 had 'g' at base#320 and arginine at aa#107 instead, when it was negative in ifa with mab h19. some strains were also reactive with mab t65 in ifa while there ... | 2004 | 15382680 |
| 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 ... | 2004 | 15529969 |
| 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 ... | 2004 | 15542691 |
| 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 ... | 2005 | 15582699 |
| 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 ... | 2004 | 15592893 |
| 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 ... | 2004 | 15666861 |
| 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 ... | 2004 | 15742626 |
| 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 ... | 2005 | 15757475 |
| the protein encoded by the us3 orthologue of marek's disease virus is required for efficient de-envelopment of perinuclear virions and involved in actin stress fiber breakdown. | marek's disease virus (mdv) encodes a protein exhibiting high amino acid similarity to the us3 protein of herpes simplex virus type 1 and the gene 66 product of varicella-zoster virus. the mdv us3 orthologue was replaced with a kanamycin resistance gene in the infectious bacterial artificial chromosome clone bac20. after transfection of us3-negative bac20 dna (20deltaus3), the resulting recombinant 20deltaus3 virus exhibited markedly reduced growth kinetics. virus titers on chicken embryo cells ... | 2005 | 15767401 |
| the pp38 gene of marek's disease virus (mdv) is necessary for cytolytic infection of b cells and maintenance of the transformed state but not for cytolytic infection of the feather follicle epithelium and horizontal spread of mdv. | marek's disease virus has a unique phosphoprotein, pp38, which is suspected to play an important role in marek's disease pathogenesis. the objective of the present study was to utilize a mutant virus lacking the pp38 gene (rmd5deltapp38) to better characterize the biological function of pp38. this work shows that the pp38 gene is necessary to establish cytolytic infection in b cells but not in feather follicle epithelium, to produce an adequate level of latently infected t cells, and to maintain ... | 2005 | 15767457 |
| pro-inflammatory responses in chicken spleen and brain tissues after infection with very virulent plus marek's disease virus. | in 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 ... | 2005 | 15802959 |
| 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 ... | 2005 | 15811851 |
| isolation of recombinant field strains of marek's disease virus integrated with reticuloendotheliosis virus genome fragments. | two marek's disease virus (mdv) field strains were isolated from chickens with tumors independently from guangdong and guangxi provinces, and it was confirmed that there were no co-infections with reticuloendotheliosis viruses (rev) in chicken embryo fibroblast cells (cef) in indirect fluorescence antibody test (ifa) with rev-specific monoclonal antibodies. by dot blot hybridization and pcr of genomic dna of mdv-infected cef, it was indicated that ltr fragments of rev genome were integrated into ... | 2005 | 15844360 |
| 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 ... | 2005 | 15845359 |
| 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 ... | 2005 | 15857974 |
| 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 ... | 2005 | 15890938 |
| characterization of a very virulent marek's disease virus mutant expressing the pp38 protein from the serotype 1 vaccine strain cvi988/rispens. | marek's disease virus (mdv), a highly cell-associated oncogenic chicken herpesvirus, causes marek's disease in domestic chickens. a unique phosphoprotein of mdv, pp38, has previously been associated with the maintenance of transformation in mdv-induced tumor cell lines. however, recently, the biological properties of a deletion mutant virus (rmd5deltapp38) revealed that pp38 is involved in early cytolytic infection in lymphocytes but not in the induction of tumors. thus, pp38 is important for ea ... | 2005 | 15965611 |
| [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( ... | 2005 | 15989227 |
| the nonessential ul49.5 gene of infectious laryngotracheitis virus encodes an o-glycosylated protein which forms a complex with the non-glycosylated ul10 gene product. | the ul10 and ul49.5 genes of avian infectious laryngotracheitis virus (iltv) encode putative envelope proteins which are conserved in alpha, beta, and gammaherpesvirinae. many of the corresponding gene products have been shown to be glycosylated and to form heterodimeric protein complexes with each other. unlike the homologous gm proteins of other herpesviruses, the ul10 protein of iltv is not detectably glycosylated [fuchs, w., mettenleiter, t.c., 1999. dna sequence of the ul6 to ul20 genes of ... | 2005 | 16022905 |
| development of a one-step strip test for the diagnosis of chicken infectious bursal disease. | a rapid diagnostic strip for chicken infectious bursal disease (ibd) was developed based on membrane chromatography using high-affinity monoclonal antibodies directed to chicken infectious bursal disease virus (ibdv). the diagnostic strip has high specificity for detection of chicken ibdv antigen and recognizes a variety of the virus isolates, including virulent and attenuated strains, with no cross-reactivity to other viruses, such as newcastle disease virus, marek's disease virus, infectious b ... | 2005 | 16094819 |
| a marek's disease virus vil-8 deletion mutant has attenuated virulence and confers protection against challenge with a very virulent plus strain. | marek's disease virus (mdv) is an alpha-herpesvirus that causes rapid development of t-cell lymphomas in chickens. mdv-encoded vil-8 is homologous to the cellular il-8 gene, and its function in mdv pathogenesis has yet to be determined. using overlapping cosmid clone-based technology, we have generated an mdv vil-8 deletion mutant virus, rmd5/delta vil-8. in vivo experiments with this mutant virus demonstrated that deletion of vil-8 results in attenuation of the virus and induction of significan ... | 2005 | 16094823 |
| marek's disease: the continuing struggle between pathogen and host. | | 2004 | 16129335 |
| evolution of marek's disease -- a paradigm for incessant race between the pathogen and the host. | marek's disease (md) is a highly contagious lymphoproliferative disease of poultry caused by the oncogenic herpesvirus designated marek's disease virus (mdv). md has a worldwide distribution and is thought to cause an annual loss over 1 bn us dollars to the poultry industry. originally described as a paralytic disease, today md is mostly manifested as an acute disease with tumours in multiple visceral organs. md is controlled essentially by the widespread use of live vaccines administered either ... | 2005 | 16129338 |
| differential detection of turkey coronavirus, infectious bronchitis virus, and bovine coronavirus by a multiplex polymerase chain reaction. | the objective of the present study was to develop a multiplex polymerase chain reaction (pcr) method for differential detection of turkey coronavirus (tcov), infectious bronchitis coronavirus (ibv), and bovine coronavirus (bcov). primers were designed from conserved or variable regions of nucleocapsid (n) or spike (s) protein gene among tcov, ibv, and bcov and used in the same pcr reaction. reverse transcription followed by the pcr reaction was used to amplify a portion of n or s gene of the cor ... | 2006 | 16137773 |
| 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 ... | 2005 | 16140742 |
| analysis of transcriptional and translational activities of marek's disease (md) virus genes in md central nervous system lesions in chickens. | the expression of marek's disease virus (mdv) gene products and transcripts was observed in tissues obtained from the central nervous system (cns) of chickens experimentally infected with a very virulent strain (md/5) of mdv. many cells antigen-positive for mdv early gene products, but not for late gene products, were detected immunohistochemically in the necrotizing lymphomatous lesions. the positive signals were found only in necrotic or degenerated neoplastic lymphoblasts. abundant transcript ... | 1999 | 16147548 |
| 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 ... | 2005 | 16147570 |
| direct evidence of host genome acquisition by the alphaherpesvirus marek's disease virus. | many herpesviruses including marek's disease virus (mdv), a poultry alphaherpesvirus, carry homologous host genes presumably acquired during viral evolution. we have characterized one recent acquisition by mdv in considerable detail. the virulent mdv strain md11 previously was isolated from a commercial chicken and initially propagated on duck cells. in the process of cloning the entire md11 genome in a bacterial artificial chromosome (bac), we obtained an infectious clone in which the entire te ... | 2006 | 16155725 |
| detection of the meq gene in the t cell subsets from chickens infected with marek's disease virus serotype 1. | the meq gene was thought to be only detected in marek's disease virus serotype 1 (mdv 1) including a very virulent strain, md5, while l-meq, in which a 180-bp sequence is inserted into the meq open reading frame, is found in other strains of mdv 1, such as cvi 988/r6. however, both meq and l-meq were previously detected by pcr in chickens infected with mdv 1, suggesting that mdv 1 may consists of at least two subpopulations, one with meq, the other with l-meq. to further analyze these subpopulat ... | 2005 | 16190317 |
| isolation of marek's disease virus: revisited. | splenocytes from chickens infected with low-passage stocks of marek's disease virus (mdv) rb-1b, a very virulent (vv) strain and vv+ rk-1 were used to compare the efficacy of chick kidney cells (ckc), chicken embryo fibroblasts (cef) and chicken embryo kidney cells (cekc) for virus isolation. ckc were superior to cef and cekc. mdv foci were present at 4 days post infection in ckc but not until 6 days post infection in cef or cekc. virus yield was higher in ckc than in cef or cekc at 6 days post ... | 2005 | 16191687 |
| marek's disease virus meq transforms chicken cells via the v-jun transcriptional cascade: a converging transforming pathway for avian oncoviruses. | marek's disease virus (mdv) is a highly pathogenic and oncogenic herpesvirus of chickens. mdv encodes a basic leucine zipper (bzip) protein, meq (mdv ecoq). the bzip domain of meq shares homology with jun/fos, whereas the transactivation/repressor domain is entirely different. increasing evidence suggests that meq is the oncoprotein of mdv. direct evidence that meq transforms chicken cells and the underlying mechanism, however, remain completely unknown. taking advantage of the df-1 chicken embr ... | 2005 | 16203997 |
| 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 ... | 2005 | 16227220 |
| synthesis of chicken major histocompatibility complex class ii oligomers using a baculovirus expression system. | chicken major histocompatibility complex (mhc) b21 and b19 haplotypes are associated with resistance and susceptibility to marek's disease (md), respectively. t-cell-mediated immune response is crucial in coordinating protection against marek's disease virus (mdv) infection, but it has been difficult to identify and characterize antigen-specific t-cells. mhc class ii tetramers and oligomers have been widely used for characterization of antigen-specific t-cells in the context of infectious and au ... | 2006 | 16236525 |
| absolute quantitation of marek's disease virus and herpesvirus of turkeys in chicken lymphocyte, feather tip and dust samples using real-time pcr. | the further development of taqman quantitative real-time pcr (qpcr) assays for the absolute quantitation of marek's disease virus serotype 1 (mdv1) and herpesvirus of turkeys (hvt) viruses is described and the sensitivity and reproducibility of each assay reported. using plasmid dna copies, the lower limit of detection was determined to be 5 copies for the mdv1 assay and 75 copies for the hvt assay. both assays were found to be highly reproducible for ct values and calculated copy numbers with m ... | 2006 | 16290211 |
| development of a real-time pcr assay using sybr green chemistry for monitoring marek's disease virus genome load in feather tips. | feather follicles of birds infected with marek's disease virus (mdv) serve as the sole source of infectious virus particles. the present study was aimed at developing a sybr green real-time pcr assay to detect and quantify mdv loads in feather tips targeting meq gene of the virus. the assay had a dynamic range of 8 logs, mean inter- and intra-assay coefficient variation (cv) of <5% and minimum detection limit of 15 mdv genome copies when plasmid dna was used as the template. the sensitivity of t ... | 2006 | 16300836 |
| [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 ... | 2005 | 16342758 |
| nuclear localization and dynamic properties of the marek's disease virus oncogene products meq and meq/vil8. | marek's disease virus (mdv) is an avian herpesvirus that causes t-cell lymphomas and immune suppression in susceptible chickens. at least one gene product, mdv eco q-encoded protein (meq), is essential for the oncogenicity of mdv. alternative splicing permits the meq gene to give rise to two major transcripts encoding proteins designated meq and meq/vil8. meq is a basic leucine zipper protein capable of modulating transcription. the meq/vil8 protein retains a modified leucine zipper, along with ... | 2006 | 16414993 |
| 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 ... | 2006 | 16446447 |
| relationship between marek's disease virus load in peripheral blood lymphocytes at various stages of infection and clinical marek's disease in broiler chickens. | vaccination with herpesvirus of turkey (hvt) vaccine provides protection against clinical marek's disease (md) but does not preclude infection with wild-type md virus (mdv). the quantity of mdv detected in circulating lymphocytes during the early period after infection may be a useful predictor of subsequent clinical md later in the life. a study was designed to quantify mdv and hvt copy number in peripheral blood lymphocytes (pbl) using real-time polymerase chain reaction between days 5 and 35 ... | 2006 | 16448942 |
| stability of marek's disease virus 132-bp repeats during serial in vitro passages. | the marek's disease virus (mdv) genome contains 2 sets of 132-bp tandem repeat sequences. an increase in 132-bp repeat units has been associated with attenuation of oncogenicity during in vitro passage. by cloning entire genomes, we demonstrated that the copy number of 132-bp repeats can differ within an individual mdv genome. the stability of the 132-bp repeats during cell passage depended on the initial copy number. when both sets of repeats contained 2 copies, the copy number remained stable, ... | 2006 | 16489507 |
| herpesvirus of turkey reconstituted from bacterial artificial chromosome clones induces protection against marek's disease. | herpesvirus of turkey (hvt) is an alphaherpesvirus that is widely used as a live vaccine against marek's disease because of its antigenic relationship with marek's disease virus (mdv). in spite of a similar genome structure, hvt has several unique genes, the functions of which are not completely understood. as a first step in carrying out detailed analysis of the functions of the hvt genes, a full-length infectious bacterial artificial chromosome (bac) clone of hvt was constructed. dna from two ... | 2006 | 16528024 |
| 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 ... | 2006 | 16541136 |
| 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 ... | 2006 | 16544576 |
| pathogenicity and antigenicity of clones from strains of marek's disease virus and the herpesvirus of turkeys. | virus was extracted by filtration from chicken embryo fibroblast cultures infected with the jm, high passage jm(jmhp), ga, and rpl39 strains of marek's disease virus (mdv) and from the herpesvirus of turkeys (hvt) and purified by cloning. the plaques produced by clones of hvt, jmhp, and other mdv strains differed in morphology from one another. clones of mdv varied greatly in pathogenicity for chickens, but jmhp and hvt were nonpathogenic. two pathogenic clones of jm virus and a clone of jmhp vi ... | 1971 | 16557968 |
| a mass spectrometry-based proteomic approach to study marek's disease virus gene expression. | marek's disease virus (mdv) is an avian herpesvirus that causes a lymphoproliferative disorder in chickens. mdv transitions between a lytic phase in which new viruses are produced and a latent phase in which the virus lays dormant. the mechanism controlling this lytic-to-latent switch remains unclear. to better understand the lytic phase of mdv infection, a mass spectrometry-based strategy was developed to identify viral proteins and to qualitatively examine their abundance in lytically infected ... | 2006 | 16563527 |
| the role of pp38 in regulation of marek's disease virus bi-directional promoter between pp38 and 1.8-kb mrna. | marek's disease virus (mdv) contains a bi-directional promoters located between pp38 gene and 1.8-kb mrna in the long inverted repeat region of the viral genome. the involvement of pp38 gene in up-regulating the activity of these promoters was analyzed by transient expression of chloramphenicol acetyltransferase (cat) reporter gene. two cat reporter plasmids, pp(pp38)-cat and pp(1.8-kb)-cat, were constructed to express cat under the control of the bi-directional promoter in both orientations. th ... | 2006 | 16604452 |
| examination of the effect of a naturally occurring mutation in glycoprotein l on marek's disease virus pathogenesis. | we recently reported a comparison of glycoprotein-encoding genes of different marek's disease virus pathotypes (mdvs). one mutation found predominantly in very virulent (vv)+mdvs was a 12-bp (four-amino acid) deletion in the glycoprotein l (gl)-encoding gene in four of 23 mdv strains examined (three were vv+mdvs and one was a vvmdv). this mutation was noted in the gl of the tk (615k) strain, but not in the rl (615j) strain of mdv. these strains have identical mutations in the meq gene characteri ... | 2006 | 16617990 |
| 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 ... | 2006 | 16650486 |
| 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 ... | 2006 | 16651385 |
| lymphoid organ size varies among inbred lines 6(3) and 7(2) and their thirteen recombinant congenic strains of chickens with the same major histocompatibility complex. | the objective was to evaluate lymphoid organ size in chickens from a series of 13 recombinant congenic strains (rcs) and their highly inbred parental lines (6(3) and 7(2)). the parental line 6(3) was selected for resistance to tumors induced by marek's disease virus and avian leukosis viruses, whereas line 7(2) was selected for susceptibility to these tumors. each rcs on the average contains a random one-eighth of genome from the donor line 7(2). previous studies have shown that lines 6(3) and 7 ... | 2006 | 16673761 |
| absolute quantification using real-time polymerase chain reaction of marek's disease virus serotype 2 in field dust samples, feather tips and spleens. | methods for taqman quantitative real-time pcr (qpcr) assays to detect the three serotypes of marek's disease virus (mdv) are available, and absolute quantification has been developed for mdv serotype 1 and serotype 3. the development of a method for absolute quantification of marek's disease virus serotype 2 (mdv2) is described in this paper. using plasmid dna, the lower detection limit of the mdv2 assay was determined to be 10 copies. three independent assay runs showed highly reproducible ct v ... | 2006 | 16678918 |
| vaccinal control of marek's disease: current challenges, and future strategies to maximize protection. | marek's disease is an economically important lymphoid neoplasm of chickens, caused by oncogenic strains of marek's disease herpesvirus. the disease can be successfully controlled by vaccination with attenuated or non-pathogenic mdv strains. however, vaccine failures do occur as field strains continue to evolve towards pathotypes of greater virulence, and this evolution is likely to be driven by the vaccines themselves. two general strategies can be considered to improve protection by vaccination ... | 2006 | 16682084 |
| 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. | 2006 | 16682501 |
| [comparison of the relative luciferase activity in secondary cef by different heterogenous strong promoters, mdv gb promoter and the composed promoters]. | to improve the protection efficiency of the recombinant marek' s disease viruses (mdv) in chickens with or without maternal antibodies,the work of selecting the optimal promoters for the construction of recombinant mdv was carried out. combined with the efficient genetic manipulation, the composed promoters was constructed by use of the mdv gb core promoter with the regulatory elements from the early immediately promoter and enhancer of hcmv, the promoter and enhancer of sv40 or the partial enha ... | 2006 | 16736599 |
| [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 ... | 2006 | 16755916 |
| suggesting the possible role of turkey herpesvirus or hvt-like as a predisposing factor or causative agent in multiple sclerosis. | wild birds are referred to as 'vectors' of an exogenous causative agent of ms, in particular the marek's disease virus, but this has yet to be confirmed. the epidemiology of ms shows that it occurs worldwide but that there is a high incidence of ms clusters within specific geographical distributions such as in cooler, temperate, zones in a north/south gradient from the equator. furthermore, these regions are well known as preferred zones for wintering/breeding/feeding purposes and for having a h ... | 2006 | 16777352 |
| marek's disease herpesviruses i. production and preliminary characterization of marek's disease herpesvirus a antigen. | a method was developed for the large-scale production of marek's disease herpesvirus a antigen in duck embryo fibroblast roller bottle cultures in quantities sufficient to permit its purification and characterization. maximum yield was obtained in serum-free culture medium harvested daily. the marek's disease herpesvirus a antigen was stable at ph 2.0 and was a glycoprotein based on its sensitivity to trypsin, specific immune co-precipitation of radioactive amino acids and glucosamine, and detec ... | 1975 | 16789152 |
| marek's disease herpesviruses ii. purification and further characterization of marek's disease herpesvirus a antigen. | marek's disease herpesvirus a antigen was purified greater than 200-fold with a 24% recovery by ion exchange column chromatography, isoelectric focusing, and preparative polyacrylamide gel electrophoresis. the antigen had an isoelectric point of 6.68 +/- 0.03 in the presence of 1 m urea and 0.05% brij 35, a nonionic detergent, and approximately 6.5 in the absence of dissociating agents. when analyzed by electrophoresis on analytical polyacrylamide gels, the purified antigen migrated as a single ... | 1975 | 16789153 |
| marek's disease virus-induced transient paralysis is associated with cytokine gene expression in the nervous system. | marek's disease (md)-associated transient paralysis (tp) was experimentally induced in chickens by intraperitoneal inoculation of rb1b strain of marek's disease virus (mdv). between 7 and 11 days post-infection (d.p.i.), neck and limb paralysis was observed in 18% of infected chickens, which was associated with various degrees of edema, vacuolation, perivascular cuffing of mononuclear cells, and glial cell infiltration mainly in the cerebrum, cerebellum, and brain stem. the chickens that were in ... | 2006 | 16817759 |
| expression of marek's disease virus phosphorylated polypeptide pp38 produces splice variants and enhances metabolic activity. | the phosphorylated polypeptide (pp)38 of oncogenic marek's disease (md) herpesvirus (mdv) is expressed during lytic infections in vivo and in vitro, but its functions have not been fully elucidated. the quail cell line qt-35, latently infected with mdv, was used to generate qtp32 in which pp38 is expressed under control of a tetracycline controlled promoter to examine possible functions of pp38. induction of pp38 did not influence late mdv genes expression, but it enhanced mitochondrial dehydrog ... | 2006 | 16876339 |
| marek's disease virus encodes micrornas that map to meq and the latency-associated transcript. | micrornas (mirnas) are a class of small (approximately 22-nucleotide) regulatory molecules that block translation or induce degradation of target mrnas. these have been identified in a wide range of organisms, including viruses. in particular, the oncogenic gammaherpesviruses kaposi's sarcoma herpesvirus and epstein-barr virus encode mirnas that could potentially regulate either viral or host genes. to determine if marek's disease virus (mdv), an oncogenic alphaherpesvirus of chickens, encodes m ... | 2006 | 16912324 |
| multiple alternative splicing to exons ii and iii of viral interleukin-8 (vil-8) in the marek's disease virus genome: the importance of vil-8 exon i. | the marek's disease virus (mdv) eco q (meq) and the interleukin-8 (il-8) mdv homologue (vil-8) genes, and the open reading frames rlorf5a and rlorf4 are encoded within the repeat long (ir(l) and tr(l)) regions of the mdv genome. the recent cloning and characterization of rlorf4 led to the identification of a rlorf4/vil-8 splice variant using 3' rapid amplification of cdna ends (race). further characterization of 3'race products amplified with primers located within the meq, rlorf5a, or rlorf4 ge ... | 2007 | 16927116 |
| oncogenic marek's disease viruses lacking the 132 base pair repeats can still be attenuated by serial in vitro cell culture passages. | marek's disease virus (mdv) can be attenuated by serially passing the virus in cell culture. during cell culture passage, two copies of a 132 bp repeat are expanded to over 30 copies. we deleted the two copies of the 132 bp repeat region in a pathogenic mdv and demonstrated that the virus was still pathogenic. the pattern and frequency of tumors in the parental and mutant virus were the same. early virus replication, and the appearance of persistent neurological disease were also similar between ... | 2007 | 16927124 |
| polymorphisms in the repeat long regions of oncogenic and attenuated pathotypes of marek's disease virus 1. | the nucleotide sequences of the terminal repeat long (tr(l)) and internal repeat long regions (ir(l)) in the genomes of 13 strains of marek's disease virus type 1 (mdv-1) were determined and represent the largest collection of sequencing data from a contiguous region (12.8 kb) in the serotype 1 genomes. the collection of strains used in this study has been well characterized with respect to their virulence and contains members of each pathotype (4 attenuated, 1 mildly virulent, 3 virulent, 2 ver ... | 2007 | 16964553 |
| 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 ... | 2007 | 17028059 |
| 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 ... | 2006 | 17039834 |
| 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 ... | 2006 | 17058503 |
| cytokine gene expression patterns associated with immunization against marek's disease in chickens. | the present study explored the immunological correlates of protection mediated by a live bivalent vaccine consisting of herpesvirus of turkeys (hvt) and sb-1 against infection with the rb1b strain of marek's disease virus (mdv). compared to unvaccinated infected chickens, vaccinated protected birds had lower expression of interleukin (il)-6, il-10 and il-18 genes in spleen. however, there was no difference between these two groups of birds in the expression of interferon (ifn)-gamma, il-4, il-12 ... | 2007 | 17070626 |
| hematology, serum chemistry, and serology of galápagos penguins (spheniscus mendiculus) in the galápagos islands, ecuador. | the galápagos penguin (spheniscus mendiculus) is an endangered species endemic to the galápagos islands, ecuador. in 2003 and 2004, 195 penguins from 13 colonies on the islands of isabela and fernandina in the galápagos archipelago were examined. genetic sexing of 157 penguins revealed 62 females and 95 males. hematology consisted of packed cell volume (n = 134), white blood cell differentials (n = 83), and hemoparasite blood smear evaluation (n = 114). microfilariae were detected in 22% (25/114 ... | 2006 | 17092893 |
| comparison of methods for analysis of selective genotyping survival data. | survival traits and selective genotyping datasets are typically not normally distributed, thus common models used to identify qtl may not be statistically appropriate for their analysis. the objective of the present study was to compare models for identification of qtl associated with survival traits, in particular when combined with selective genotyping. data were simulated to model the survival distribution of a population of chickens challenged with marek disease virus. cox proportional hazar ... | 2006 | 17129564 |
| antiviral properties of combination peptides of hiv-1 rev nls and nes. | nuclear translocation signal has been identified as a mediator of protein shuttling between nuclear and cytoplasm. here we report that the combination of peptides from nuclear localization signal (nls) and nuclear export signal (nes) of hiv-1 rev have an antiviral activity against the herpes virus of turkey and marek's disease virus serotype 1. | 2006 | 17168825 |
| 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 ... | 2006 | 17184215 |
| 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 ... | 2006 | 17201670 |
| health evaluation of free-ranging and captive blue-fronted amazon parrots (amazona aestiva) in the gran chaco, bolivia. | bolivia has a total of 47 species of psittacidae, seven of which have been identified in our study site, the semiarid gran chaco of the isoso. one species, the blue-fronted parrot (amazona aestiva), is frequently captured by local isoseño guaraní indians for exploitation on the national and international market. these birds are often temporarily housed in small villages under unhygienic conditions with poultry and other domestic species. on occasion, these parrots escape back to the wild. additi ... | 2005 | 17312715 |
| involvement of the oncoprotein c-myc in viral telomerase rna gene regulation during marek's disease virus-induced lymphomagenesis. | marek's disease virus (mdv) is an alphaherpesvirus that induces a highly malignant t-lymphoma in chickens. the viral genome encodes two identical copies of a viral telomerase rna subunit (vtr) that exhibits 88% sequence identity to its chicken ortholog chtr. the minimal telomerase ribonucleoprotein complex consists of a protein subunit with reverse transcriptase activity (tert) and an rna subunit (tr). the active complex compensates for the progressive telomere shortening that occurs during mito ... | 2007 | 17314164 |
| 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 ... | 2007 | 17339769 |
| [preparation and immunological characterization of monoclonal antibodies against vp22 carboxyl terminus of marek's disease virus serotype 1]. | to prepare and characterize monoclonal antibodies (mab) against vp22 carboxyl terminus of cvi988/rispens strain of marek's disease virus serotype 1. | 2007 | 17343794 |
| expression of chicken interleukin-2 by turkey herpesvirus increases the immune response against marek's disease virus but fails to increase protection against virulent challenge. | as 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 ... | 2007 | 17364512 |
| 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 ... | 2007 | 17374751 |
| sequential autoprocessing of marek's disease herpesvirus protease differs from that of other herpesviruses. | herpesviruses encode a unique serine protease essential for viral capsid maturation. this protease undergoes autoprocessing at two sites, r and m, at the consensus sequence (v, l, i)(p3)-x(p2)-a(p1)/s(p1') (where x is a polar amino acid). we observed complete autoprocessing at the r and m sites of marek's disease virus (mdv) protease following production of the polyprotein in escherichia coli. site-directed mutagenesis confirmed the predicted sequence of the r and m sites, with the m site sequen ... | 2007 | 17376905 |
| 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 ... | 2007 | 17393086 |
| 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 ... | 2007 | 17459919 |
| ovotransferrin expression and release by chicken cell lines infected with marek's disease virus. | mammals posses both serum transferrin and lactoferrin, whose functions are taken over in birds by ovotransferrin, displaying both iron transport and antibacterial activities. ovotransferrin also exerts antiviral activity towards marek's disease virus, an avian member of the herpes family of viruses. this virus infects lymphoid organs and induces the transcription of ovotransferrin in infected chicken embryo fibroblasts. however, it has not yet been established whether ovotransferrin gene transcr ... | 2007 | 17464355 |
| route of challenge is critical in determining the clinical outcome of infection with a very virulent oncogenic herpesvirus, marek's disease virus. | the majority of experimental studies examining marek's disease virus infection have used parenteral injection of cell-associated virus. the aim of this study was to examine whether the route of entry of virus was critical in determining the outcome of infection. susceptible (l7) and resistant (l6) white leghorn chickens were infected with a very virulent marek's disease virus, rb1b, by either the intra-abdominal or intra-tracheal route. birds infected by the intra-tracheal route had earlier, hig ... | 2007 | 17479368 |
| evaluation of marek's disease field isolates by the "best fit" pathotyping assay. | although determination of the pathotype is central to the study of marek's disease (md) field isolates, methods are not standardized and results from different laboratories may not compare well with the original avian disease and oncology laboratory assay. this study was designed to investigate the validity of the "best fit" pathotyping assay, a simplified method recently described for testing of field isolates of md virus (mdv). twenty serotype 1 mdv strains were isolated from 12 breeder and co ... | 2007 | 17479374 |
| detection of the virulent marek's disease virus genome from feather tips of wild geese in japan and the far east region of russia. | marek's disease (md) virus (mdv) is known to cause malignant lymphomas in chickens. in 2001, we first reported an md case in a white-fronted goose (anser albifrons) in japan. therefore, the prevalence of mdv in the wild geese was surveyed by nested pcr using feather-tip samples in japan and the far east region of russia, breeding habitats of geese migrating to japan. mdv was detected in about 30% of analyzed white-fronted geese. furthermore, by nucleotide sequence analysis, we confirmed that thi ... | 2007 | 17497232 |
| 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 ... | 2007 | 17506972 |
| extended gene map reveals tripartite motif, c-type lectin, and ig superfamily type genes within a subregion of the chicken mhc-b affecting infectious disease. | mhc haplotypes have a remarkable influence on whether tumors form following infection of chickens with oncogenic marek's disease herpesvirus. although resistance to tumor formation has been mapped to a subregion of the chicken mhc-b region, the gene or genes responsible have not been identified. a full gene map of the subregion has been lacking. we have expanded the mhc-b region gene map beyond the 92-kb core previously reported for another haplotype revealing the presence of 46 genes within 242 ... | 2007 | 17513765 |
| prevalence and molecular characterization of meq in feather follicular epithelial cells of korean broiler chickens. | marek's disease (md) is a highly contagious lymphoproliferative disease of chickens. meq is the relevant oncogene and four isoforms, long (l)-meq, meq, short (s)-meq and very short (vs)-meq, have been identified. although md is important in the poultry industry, the prevalence and molecular properties of korean md virus (mdv) among broiler chickens remain unclear. therefore, we characterized meq in pooled feather tips sampled at 3- and 5-week-old chickens from 21 unvaccinated and 22 vaccinated b ... | 2007 | 17516161 |
| sequence determination of variable regions within the genomes of gallid herpesvirus-2 pathotypes. | comparative genomic studies of attenuated and virulent strains of gallid herpesvirus 2 (gahv-2) have identified 6 regions of sequence variability. these regions include the open reading frames (orfs) encoding ul36 and ul49 and regions devoid of large orfs (132-bp repeats, a-like sequences and the junctions flanking the unique short region). our data indicate that the carboxyl terminus of ul36 contains regions of heterogeneity that are unique to cvi988-derived attenuated strains. a deletion of th ... | 2007 | 17557133 |
| phylogeny and recombination history of gallid herpesvirus 2 (marek's disease virus) genomes. | phylogenetic analyses based on concatenated amino acid sequences from orthologous loci from eight genomes of alpha herpesviruses infecting birds provided strong support for the following hypotheses: (1) gallid hv3 is a sister taxon to gallid hv2 but gallid hv1 is not closely related to the other two chicken herpesviruses; (2) meleagrid hv1 is closer to both gallid hv2 and gallid hv3 than is gallid hv1; (3) within gallid hv2, the virulent ga genome forms an outgroup to both the avirulent cvi988 g ... | 2007 | 17566585 |