Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| identification and sequence analysis of the homologues of the herpes simplex virus type 1 glycoprotein h in marek's disease virus and the herpesvirus of turkeys. | the glycoprotein h (gh) genes of two avian herpesviruses, marek's disease virus and the herpesvirus of turkeys, have been cloned and sequenced and the coding regions found to be of 2439 and 2424 nucleotides respectively. the predicted primary polypeptide products of these open reading frames are 813 and 808 amino acids and correspond to mrs of 90,800 and 91,100. both amino acid sequences exhibit characteristic glycoprotein features such as hydrophobic signal and anchor sequences and potential si ... | 1993 | 8389802 |
| development of pcr method specific for marek's disease virus. | a rapid polymerase chain reaction (pcr) assay specific for marek's disease virus (mdv) was developed. this assay was able to detect mdv in inoculated chick kidney cells at dilutions of 10(-5). negative pcr results were obtained using uninoculated chick cells, marek's disease vaccine (sb), herpesvirus of turkeys (hvt) and fowl laryngotracheitis vaccine (lt). bursae, feathers and kidneys from mdv infected chickens were positive in the pcr assay. the same tissues from normal chickens were negative. ... | 1993 | 8391640 |
| selection of marek's disease virus recombinants expressing the escherichia coli gpt gene. | we developed a positive selection method for recovering marek's disease virus (mdv) recombinants. the escherichia coli xanthine-guanine phosphoribosyltransferase gene (gpt), under the control of the major immediate-early promoter from cytomegalovirus, was inserted into the inverted repeats flanking the unique long (ul) region of a non-pathogenic serotype 2 mdv strain 281mi/1. in a second demonstration of the usefulness of the positive selection system, the gpt gene was inserted into the inverted ... | 1993 | 8393240 |
| the complete sequence and gene organization of the short unique region of herpesvirus of turkeys. | the dna sequence of the whole of the short unique region (u(s)) and that of part of the short terminal repeat (trs) of herpesvirus of turkeys (hvt) were determined. hvt u(s) is 8.6 kbp long and contains eight potential open reading frames (orfs). seven of these have counterparts in the u(s) of herpes simplex virus type 1 (hsv-1). the homologous proteins include us1, us2, us10, protein kinase (us3) and the glycoproteins gd, gi and ge. in addition, hvt contains one orf which has a counterpart in t ... | 1993 | 8409940 |
| molecular evolution of infectious laryngotracheitis virus (iltv; gallid herpesvirus 1): an ancient example of the alphaherpesviridae? | an analysis of two essential genes of infectious laryngotracheitis virus (iltv), glycoprotein d (gd) and the immediate early gene, herpes simplex virus homologue icp27, was performed with the equivalent gene homologues from several alphaherpesviruses. amino acid (aa) sequence analysis revealed that these iltv genes shared limited homology to other alphaherpesvirus equivalents and were distinct from the two other avian herpesviruses, marek's disease virus (mdv) and herpesvirus of turkeys (hvt). s ... | 1995 | 8545960 |
| a comparative study of histological conditions suitable for both immunofluorescence and in situ hybridization in the detection of herpesvirus and its antigens in chicken tissues. | our objective was to identify an optimal single set of conditions for use in both indirect immunofluorescence assays (ifa) and in situ hybridization (ish) to detect viral proteins and nucleic acids in avian lymphoid and neural tissues. various fixatives were evaluated for use with ifa to detect turkey herpesvirus (hvt) glycoprotein b (gb) and ish to identify hvt mrna in chicken tissues. a precipitating fixative (acetone) was compared to crosslinking fixatives [buffered glutaraldehyde-picric acid ... | 1996 | 8648086 |
| effect of serotype 2 and 3 marek's disease vaccines on the development of avian leukosis virus-induced pre-neoplastic bursal follicles. | the effect of serotype 2 and 3 marek's disease virus (mdv) vaccines on the development of pre-neoplastic bursal lesions induced by two strains of subgroup a avian leukosis virus (alv) was studied. chickens of line 15i5 x 7(1) susceptible to alv-induced lymphoma were inoculated at hatch with rous-associated virus-1 (rav-1) or strain rpl-40 of subgroup a alv. all chickens, except for negative controls, were also inoculated at hatch with strain 301b/1 of serotype 2 mdv or strain fc126 of turkey her ... | 1995 | 8719208 |
| protective efficacy of a recombinant herpesvirus of turkeys as an in ovo vaccine against newcastle and marek's diseases in specific-pathogen-free chickens. | we investigated the potential of a herpesvirus of turkey (hvt)-based recombinant virus (rhvt) as an in ovo vaccine to protect specific-pathogen-free chickens against newcastle disease (nd) and marek's disease (md). the rhvt, designed to express fusion (f) and hemagglutinin-neuraminidase (hn) glycoproteins of the lentogenic hitchner b1 strain of nd virus (ndv), as well as glycoproteins a and b of the ga strain of serotype 1 md virus (mdv) was efficacious in protecting chickens against nd and md. ... | 1996 | 8782342 |
| protection and synergism by recombinant fowl pox vaccines expressing genes from marek's disease virus. | recombinant fowl poxviruses (rfpv) were constructed to express genes from serotype 1 marek's disease virus (mdv) coding for glycoproteins b (gb1), c (gc), and d (gd) and tegument proteins ul47 and ul48, as well as genes from serotypes 2 and 3 mdv coding for glycoprotein b (gb2 and gb3). these rfpvs, alone and in various combinations, including combinations of fowl poxvirus (fpv)/gbs with turkey herpesvirus (hvt), were evaluated for ability to protect maternal antibody-positive (ab+) and -negativ ... | 1996 | 8790888 |
| genetic susceptibility to marek's disease virus of local chickens in taiwan. | marek's disease is a contagious disease in chickens caused by marek's disease virus (mdv) infection. invasion of very virulent mdv (vvmdv) was considered to be a major cause of vaccine break, resulting in a large economic loss in the poultry industry. two strains of the vvmdv (strains ltb-1 and lts-1) have been reported in taiwan, causing early mortality and formation of lymphoid tumors in broilers and layers. in this study, we report the susceptibility of local chickens in taiwan to inoculation ... | 1996 | 8883787 |
| influence of chicken genotype on protection against marek's disease by a herpesvirus of turkeys recombinant expressing the glycoprotein b (gb) of marek's disease virus. | two inbred lines of white leghorn chickens which differ in b-haplotype were immunized at 2 days of age with a thymidine kinase negative (tk-ve) herpesvirus of turkeys (hvt) recombinant expressing the glycoprotein b (gb) gene of marek's disease virus (mdv) and were challenged 6 days later with 1000 p.f.u. of the highly virulent rb1b strain of mdv. mock-vaccinated chickens and chickens immunized with a spontaneous tk-ve hvt mutant served as controls. genetically resistant b21 chickens were protect ... | 1996 | 8920698 |
| identification of a potential marek's disease virus serotype 2 glycoprotein d gene with homology to herpes simplex virus glycoprotein d. | the gene of marek's disease virus (mdv) serotype 2 (mdv2) homologous to glycoprotein d (gd) of herpes simplex virus (hsv) was identified and characterized by its nucleotide and predicted amino acid sequences. the mdv2 gd homologous gene contains an open reading frame capable of specifying a polypeptide of 385 amino acids, which include n- and c-terminal hydrophobic domains consistent with signal and anchor regions, respectively, and two potential n-linked glycosylation sites, one of which was lo ... | 1996 | 8973534 |
| onset of protective immunity in chicks after vaccination with a recombinant herpesvirus of turkeys vaccine expressing newcastle disease virus fusion and hemagglutinin-neuraminidase antigens. | the onset of protective immunity from lethal newcastle disease virus (ndv) challenge of chicks was determined after vaccination with a recombinant herpes virus of turkeys (hvt) expressing the fusion and hemagglutinin-neuraminidase proteins of ndv. one-day-old specific-pathogen-free chicks devoid of maternal antibodies to ndv were vaccinated with 130 to 3300 plaque forming units of hvt (depending on the trial) and then challenged at 4, 7, 10, and 14 days postvaccination (dpv) with a neurotropic v ... | 1996 | 8980804 |
| antigen-specific lymphoproliferative responses to tetanus toxoid: a means for the evaluation of marek's disease virus-induced immunosuppression in chickens. | antigen-specific lymphoproliferative responses were examined in chickens following immunization with tetanus toxoid (ttx). the immune competence of chickens was assessed by mitogen assay utilizing phytohemagglutinin (pha)-stimulation and ttx-specific antigen proliferation assay (ttx-apa). immune spleen cells but not peripheral blood leucocytes demonstrated specific proliferation following stimulation in vitro in a ttx-apa. in this study, we examined firstly the effects of marek's disease (md)-as ... | 1996 | 9032901 |
| increased virulence of marek's disease virus field isolates. | the continuation of an apparent evolutionary trend of marek's disease virus (mdv) towards greater virulence may explain recent increased losses from marek's disease (md) in vaccinated flocks. to address this question, the virulence of 31 isolates of serotype 1 mdv obtained from layer or broiler flocks between 1987 and 1995 were characterized. each isolate was cultured in duck embryo fibroblasts for four to six passages, and ascertained to be free from contamination with avian retroviruses, chick ... | 1997 | 9087332 |
| efficacy of inovoject egg injection system for delivering marek's disease vaccine under hatchery conditions. | the ability of the inovoject egg injection system to effectively deliver the appropriate titer of herpesvirus of turkeys (hvt) vaccine during normal hatchery operation was evaluated. the inovoject machines configured for the jamesway and chickmaster commercial hatchers both maintained the integrity of the hvt vaccine without an appreciable loss in titer from the diluted vaccine to the egg. | 1997 | 9201414 |
| identification and dna sequence analysis of the marek's disease virus serotype 2 genes homologous to the thymidine kinase and ul24 genes of herpes simplex virus type 1. | the thymidine kinase (tk) gene has been used as a safe and convenient locus for expression of heterologous proteins in some alphaherpesviruses including herpesvirus of turkeys (hvt) antigenically related to marek's disease virus (mdv) serotypes 1 (mdv1) and 2 (mdv2). in mdv2 strain hprs 24 genome, genes equivalent to the tk and ul24 homologues of herpes simplex virus type 1 were identified and sequenced. the mdv2 ul24 gene overlaps the 5' end of the tk gene in a head-to-head orientation. the pre ... | 1997 | 9208458 |
| recombinant fowlpox virus vaccines against australian virulent marek's disease virus: gene sequence analysis and comparison of vaccine efficacy in specific pathogen free and production chickens. | we have cloned and sequenced the glycoprotein genes gb, gc and gd of the australian virulent marek's disease virus (mdv) isolate woodlands no. 1. the glycoprotein gb and gc sequences were identical to the homologs of other virulent mdv type 1 strains, and the glycoprotein gd sequence contained only one unique amino acid substitution. recombinant fowlpox viruses (rfpvs) expressing the mdv glycoprotein genes were constructed and their efficacy as vaccines was evaluated in specific pathogen free (s ... | 1997 | 9255932 |
| herpesvirus of turkeys homologue of hsv vp16 is structurally related to varicella zoster virus trans-inducing protein encoded by orf 10. | expression of the immediate-early genes of alpha-herpesviruses is stimulated by a family of trans-inducing factors represented by vp16 of hsv-1 and orf10 gene product of vzv. we have identified and determined the nucleotide sequence of the ul48 gene encoding the herpesvirus of turkeys (hvt) homologue of hsv vp16. the gene maps to the bamhi-j fragment and appears to be expressed in a form of bicistronic transcript together with ul49. the deduced amino acid sequence of the protein encoded by hvt u ... | 1997 | 9354269 |
| a simple immunoperoxidase plaque assay to detect and quantitate marek's disease virus plaques. | we report an immunoperoxidase-based staining technique that can be used to rapidly and accurately detect and quantitate marek's disease virus (mdv) plaques. monolayer cultures were fixed and incubated with a monoclonal antibody specific for mdv. after washing, a second antibody of horseradish peroxidase-conjugated goat anti-mouse igg was applied, incubated for 1 hr, and washed with phosphate-buffered saline. after the cultures were incubated with diaminobenzidine, cocl2, and h2o2, the plaques ap ... | 1997 | 9356696 |
| serological characteristics of a membrane glycoprotein gp82 of marek's disease virus. | marek's disease virus (mdv) is a cell-associated herpesvirus of gallinaceous fowl. glycoproteins of herpesviruses have been reported to be important in stimulating humoral and cell-mediated immune responses against viral infection. at least eight glycoproteins of mdv have been identified, and glycoprotein b (gb) has been reported to produce protective immunity. in addition to glycoproteins, other cell membrane proteins may also be important for engendering immunity. in an attempt to determine wh ... | 1997 | 9454915 |
| pathogenesis of marek's disease (md) and possible mechanisms of immunity induced by md vaccine. | marek's disease (md) is a lymphoproliferative disease of chicken, which is characterized by malignant t cell-lymphoma formation. this disease can be effectively prevented by vaccination with attenuated md virus (mdv), apathogenic mdv or herpesvirus of turkey. md vaccines are ones of a few vaccines which can prevent virus-induced tumor among mammalian and avian species. to determine the roles of t cell subsets in the protection mechanism, chickens vaccinated with an attenuated mdv (cvi988) were d ... | 1998 | 9492353 |
| latent turkey herpesvirus infection in lymphoid, nervous, and feather tissues of chickens. | in earlier studies, we found that a late gene product, glycoprotein b (gb) was highly expressed in lymphoid tissues of chickens inoculated with turkey herpesvirus (hvt). the objectives of the present study were twofold. first, we wanted to expand on our previous research and determine if gb expression declines or disappears during later time periods of hvt infection. second, we wanted to correlate gb expression with presence of hvt, i.e. if gb expression is absent, can hvt still be detected? fif ... | 1998 | 9645320 |
| the genetic organization and transcriptional analysis of the short unique region in the genome of nononcogenic marek's disease virus serotype 2. | studies on the marek's disease virus (mdv) serotype 2 (mdv2) genome may be important for understanding the naturally nononcogenic nature of the virus. to determine the complete dna sequence of mdv2 unique short (us) region, genomic bamhi fragments f, m1 and r were sequenced. the mdv2 us region is 12109 bp long and contains 12 potential open reading frames (orfs) likely to encode for proteins. seven of them exhibit homologies to herpes simplex virus type 1 (hsv-1) us1 (icp22), us2, us3 (protein k ... | 1998 | 9879770 |
| response of embryonic chicken lymphocytes to in ovo exposure to lymphotropic viruses. | to examine effects of virus exposure on embryonic lymphoid organ structure, apoptosis, and lymphoid cell subpopulations. | 1999 | 10451200 |
| atherosclerosis induced by infection with marek's disease herpesvirus in chickens. | this research was suggested after crystals that we observed in herpesvirus-infected cell cultures were identified as cholesterol. other reports and the development of defined reagents led us to select the use of marek's disease herpesvirus (mdv) infection of chickens to demonstrate a potential role of herpesviruses in the pathogenesis of atherosclerosis. available for our use were a clone-purified strain of mdv of known virulence, genetically selected, specific pathogen-free chickens, and approp ... | 1999 | 10539849 |
| an acute form of transient paralysis induced by highly virulent strains of marek's disease virus. | a novel syndrome was observed after inoculation of 3-wk-old chickens with highly virulent marek's disease virus (mdv) strains. this syndrome was characterized by the acute onset of neurologic signs including flaccid paralysis of neck and limbs 9-10 days postinoculation, typically resulting in death 1-3 days after the onset of clinical signs. most affected birds died, and spontaneous recovery was rare. few if any gross tissue changes were found. histologic brain lesions included acute vasculitis ... | 1999 | 10611987 |
| effect of native chicken interferon on mdv replication. | marek's disease virus (mdv) is an oncogenic alphaherpesvirus. its specific phosphorylated protein, pp38 has been implicated in mdv oncogenesis. in order to check whether the known anti-viral or anti-proliferative actions of interferon (ifn) are of importance in marek's disease (md), chicken embryo fibroblasts (cefs) were infected with attenuated serotype-1 mdv strain cvi988, or with herpesvirus of turkeys (hvt). different concentrations of native chicken ifn were added to the cell cultures, prio ... | 1999 | 10696431 |
| evidence for marek's disease in turkeys in germany: detection of mdv-1 using the polymerase chain reaction. | since 1994 tumorous lesions have been monitored in turkeys on three farms in germany. on one of these farms, chickens also had tumorous lesions. affected turkeys were retarded in growth, apathic, pale and almost unable to move. the older the animals got, the more indistinct the clinical signs became. mortality started at an age of 5 weeks and reached between 20% and 60% by the end of the fattening period of about 20 weeks. the aetiological differential diagnosis includes reticuloendotheliosis (r ... | 1999 | 10696435 |
| tissue-specific restriction of latent turkey hvt transcription. | using in situ hybridization, latent turkey herpesvirus (hvt) transcription was examined in lymphoid and/or nonlymphoid tissues. blood samples were taken for virus isolation from chickens at 7 and 240 days post infection (pi) representing time points for productive and latent turkey herpesvirus infections, respectively. spleen, thymus, sciatic and brachial nerves from infected chickens were analyzed for latent hvt transcription and hvt glycoprotein b (gb) expression at 240 days pi. using indirect ... | 1999 | 10696436 |
| non-essential loci in the bamhi-i and -f fragments of the hvt fc126 genome. | the sequence of bamhi-i fragment of the herpesvirus of turkeys (hvt) fc126 strain dna was analyzed for the presence of potential open reading frames (orfs). four complete (orfs 2 to 5) and 2 partial orfs (orfs 1 and 6) were detected. orfs 2 and 3 were homologous to the hsv-1 ul55 and the ehv-1 gene 3, respectively. the orf 6 was already partially sequenced by smith et al. (virology 207, 205-216, 1995), and was homologous to a marek's disease virus (mdv) orf located in a similar position (orf 21; ... | 1999 | 10696442 |
| vaccination of broilers with hvt expressing an eimeria acervulina antigen improves performance after challenge with eimeria. | the sequence encoding part of the 100 kda refractile body protein (ea1a) from eimeria acervulina was cloned into the us10 locus of herpesvirus of turkeys (hvt) downstream of ltr promoter. expression of the fusion protein was shown in vitro. recombinant hvt showed a delayed and slightly reduced level of viremia compared to the parent strain in spf chickens as well as in broilers. effect on the performance of broilers vaccinated with recombinant or parent hvt was measured by challenge at day 24 wi ... | 1999 | 10696444 |
| efficacy of a combination vaccine containing mdv cvi 988 strain and hvt against challenge with very virulent mdv. | with the emergence of very virulent marek's disease virus (mdv) strains, vaccines based on herpesvirus of turkeys (hvt) appear to be not powerful enough to confer full protection, whereas in chicken flocks vaccinated with mdv cvi 988 strain protective immunity sometimes is generated not early enough for full protection. for this reason combination vaccines containing hvt as well as cvi 988 have been developed. in this paper the beneficial effect of combining both types of virus strains in one va ... | 1999 | 10696445 |
| a recombinant fowlpox virus vaccine expressing glycoprotein b gene from cvi988/rispens strain of mdv: protection studies in different chickens. | recombinant fowlpox virus (rfpv) was constructed to express glycoprotein b (gb) gene from cvi988/rispens strain of marek's disease virus (mdv). the rfpv-gb/r alone and in combination with herpesvirus of turkey (hvt) preparations were evaluated for their protective efficacy against challenge with very virulent mdv strains md5 and rb1b in different chickens. the rfpv-gb/r alone induced protection comparable to that by hvt vaccines in both ab- spf chickens and ab+ production chickens. significant p ... | 1999 | 10696446 |
| inhibitory effects of nitric oxide and gamma interferon on in vitro and in vivo replication of marek's disease virus. | the replication of marek's disease herpesvirus (mdv) and herpesvirus of turkeys (hvt) in chicken embryo fibroblast (cef) cultures was inhibited by the addition of s-nitroso-n-acetylpenicillamine, a nitric oxide (no)-generating compound, in a dose-dependent manner. treatment of cef culture, prepared from 11-day-old embryos, with recombinant chicken gamma interferon (rchifn-gamma) and lipopolysaccharide (lps) resulted in production of no which was suppressed by the addition of n(g)-monomethyl l-ar ... | 2000 | 10729136 |
| nucleotide sequence of the gene encoding the major capsid protein of herpesvirus of turkeys. | the gene encoding the major capsid protein (mcp) vp5 of herpesvirus of turkeys (hvt) was identified and sequenced. it has a single open reading frame of 4236 nucleotides encoding 1412 aa protein. the gene is flanked by vp23 and ul20 sequences and is localized in the unique long region (ul) within the bamhi-b fragment. comparison of amino acid homology has shown its clear position among the alpha-herpesviruses rather than beta- or gamma-herpesviruses. the vp5 is expressed from polycistronic mrna ... | 2000 | 10872871 |
| the genome of a very virulent marek's disease virus. | here we present the first complete genomic sequence, with analysis, of a very virulent strain of marek's disease virus serotype 1 (mdv1), md5. the genome is 177,874 bp and is predicted to encode 103 proteins. mdv1 is colinear with the prototypic alphaherpesvirus herpes simplex virus type 1 (hsv-1) within the unique long (ul) region, and it is most similar at the amino acid level to mdv2, herpesvirus of turkeys (hvt), and nonavian herpesviruses equine herpesviruses 1 and 4. mdv1 encodes 55 hsv-1 ... | 2000 | 10933706 |
| transactivation of latent marek's disease herpesvirus genes in qt35, a quail fibroblast cell line, by herpesvirus of turkeys. | the qt35 cell line was established from a methylcholanthrene-induced tumor in japanese quail (coturnix coturnix japonica) (c. moscovici, m. g. moscovici, h. jimenez, m. m. lai, m. j. hayman, and p. k. vogt, cell 11:95-103, 1977). two independently maintained sublines of qt35 were found to be positive for marek's disease virus (mdv)-like genes by southern blotting and pcr assays. sequence analysis of fragments of the icp4, icp22, icp27, vp16, meq, pp14, pp38, open reading frame (orf) l1, and glyc ... | 2000 | 11024146 |
| the genome of turkey herpesvirus. | here we present the first complete genomic sequence of marek's disease virus serotype 3 (mdv3), also known as turkey herpesvirus (hvt). the 159,160-bp genome encodes an estimated 99 putative proteins and resembles alphaherpesviruses in genomic organization and gene content. hvt is very similar to mdv1 and mdv2 within the unique long (ul) and unique short (us) genomic regions, where homologous genes share a high degree of colinearity and their proteins share a high level of amino acid identity. w ... | 2001 | 11134310 |
| adaptation of marek's disease virus to the vero continuous cell line. | marek's disease virus (mdv) is a highly infectious, cell-associated oncogenic herpesvirus. production of md vaccines has been limited to primary chicken and duck embryo fibroblast (cef and def) cultures. these have a limited life span and cannot be readily stored in liquid nitrogen. moreover, the need to prepare cef and def cells on a regular basis from 10 to 11 day-old embryos derived from a flock that must be tested continuously for the presence of avian pathogens adds to the cost of vaccine p ... | 2001 | 11230930 |
| herpesvirus connection in the expression of autoimmune vitiligo in smyth line chickens. | the smyth line (sl) chicken is an animal model for human vitiligo, a common acquired depigmentary disorder affecting about 1-2% of people worldwide. the vitiligo-like depigmentation in sl chickens typically develops when the birds are between 6 and 14 weeks of age and may affect 70-95% of hatch mates. the development of sl vitiligo is considered to depend on two interacting components, namely an inherent melanocyte defect and an autoimmune reaction to melanocytes. recently, a role for an environ ... | 2001 | 11277493 |
| the genome of herpesvirus of turkeys: comparative analysis with marek's disease viruses. | the complete coding sequence of the herpesvirus of turkeys (hvt) unique long (u(l)) region along with the internal repeat regions has been determined. this allows completion of the hvt nucleotide sequence by linkage to the sequence of the unique short (u(s)) region. the genome is approximately 160 kbp and shows extensive similarity in organization to the genomes of marek's disease virus serotypes 1 and 2 (mdv-1, mdv-2) and other alphaherpesviruses. the hvt genome contains 75 orfs, with three orf ... | 2001 | 11297687 |
| no effect of turkey herpesvirus infections on the outcome of avian pneumovirus infections in turkeys. | to determine whether turkey herpesvirus (hvt) impairs the aspecific and specific defense against an avian pneumovirus (apv) infection, specific-pathogen-free turkeys were inoculated at 7 days of age with hvt and 1, 5, or 7 wk later with apv. clinical signs, apv replication, and development of antibodies against apv were evaluated. no differences were found between the birds that received both hvt and apv and those that received only apv. | 2001 | 11417838 |
| early posthatch protection against marek's disease in chickens vaccinated in ovo with a cvi988 serotype 1 vaccine. | cvi988, a serotype 1 marek's disease virus (mdv), was used as an in ovo vaccine in specific-pathogen-free chickens to determine if this virus induces early posthatch protection against marek's disease as has been shown previously for turkey herpesvirus. mdv cvi988 was injected at embryonation day (ed) 17 (group 1) or at hatch (group 2). a third group (group 3) was left unvaccinated. at 1, 2, 3, 4, 5, and 7 days of age, chickens from each group were sampled and examined as follows: a) single-cell ... | 2001 | 11569737 |
| complete, long-lasting protection against lethal infectious bursal disease virus challenge by a single vaccination with an avian herpesvirus vector expressing vp2 antigens. | marek's disease herpesvirus is a vaccine vector of great promise for chickens; however, complete protection against foreign infectious diseases has not been achieved. in this study, two herpesvirus of turkey recombinants (rhvts) expressing large amounts of infectious bursal disease virus (ibdv) vp2 antigen under the control of a human cytomegalovirus (cmv) promoter or cmv/beta-actin chimera promoter (pec promoter) (rhvt-cmvvp2 and rhvt-pecvp2) were constructed. rhvt-pecvp2, which expressed the v ... | 2002 | 11991992 |
| 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 ... | 2002 | 12047084 |
| effect of in ovo vaccine delivery route on herpesvirus of turkeys/sb-1 efficacy and viremia. | a study was designed to ascertain the influence of in ovo site of inoculation and embryonic fluid type on the development of marek's disease (md) vaccine viremia and efficacy against md challenge. the experiments were divided into in vitro and in vivo phases. in the in vitro phase, herpesvirus of turkeys/sb-1 vaccine was combined with basal medium eagle (bme) medium (control), amniotic fluid, or allantoic fluid and subsequently titrated on secondary chick embryo fibroblast cultures. there were n ... | 2002 | 12061635 |
| marek's disease in turkeys. i. a seven-year survey of commercial flocks and experimental infection using two field isolates. | marek's disease virus (mdv) causes immunosuppression and tumors in chickens, but the turkey is an unusual host for the virus, and tumors caused by mdv in turkeys are unique. we describe the prevalence of turkey tumors in israel between 1993 and 2000, their molecular diagnosis by polymerase chain reaction (pcr), and the natural distribution of herpesvirus of turkeys (hvt). most clinical cases with tumors in commercial turkeys were diagnosed as mdv. the reproduction of marek's disease (md) in turk ... | 2002 | 12061640 |
| recent increase of marek's disease in korea related to the virulence increase of the virus. | the incidence of marek's disease (md), an important neoplastic disease of chickens, suddenly increased in 1997 in korea. most md cases of this country were detected in chickens over 20 wk of age. five md viruses were isolated from field flocks in which severe md losses had occurred, and one of the viruses was studied to compare its pathotype with the prototype jm strain. the isolate komd-ic induced severe depression not only in body weight but also in relative bursal weight, and the depression b ... | 2002 | 12243513 |
| field trial in commercial broilers with a multivalent in ovo vaccine comprising a mixture of live viral vaccines against marek's disease, infectious bursal disease, newcastle disease, and fowl pox. | a multivalent in ovo vaccine (miv) was tested for safety and efficacy in a commercial broiler complex. the miv comprised five replicating live viruses including serotypes 1, 2, and 3 of marek's disease virus (mdv), an intermediate infectious bursal disease virus (ibdv) and a recombinant fowl poxvirus (fpv) vector vaccine containing hn and f genes of newcastle disease virus (ndv). the performance of miv-vaccinated broilers was compared with that of hatchmates that received turkey herpesvirus (hvt ... | 2002 | 12243525 |
| 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 ... | 2002 | 12427339 |
| antiviral and antitumoral effects of recombinant chicken myelomonocytic growth factor in virally induced lymphoma. | chicken myelomonocytic growth factor (cmgf) is a 27-kda glycoprotein that stimulates the growth and activation of cells from the monocyte/macrophage lineage. recombinant cmgf was produced in a prokaryotic (escherichia coli) expression system and purified via a c-terminal his-tag. treatment of 2-week-old histocompatible b(13)/b(13) chickens highly susceptible to marek's disease (md) with rcmgf (two daily injections of 50 microg rcmgf per chicken) enhanced background and lps-inducible systemic no ... | 2002 | 12433057 |
| immunological tolerance in chickens hatching from eggs injected with cell-associated herpesvirus of turkey (hvt). | cell-associated herpesvirus of turkeys (hvt) was inoculated in ovo at various stages of incubation. chickens hatching from these eggs were tested for anti-hvt antibodies by several serologic procedures including enzyme-linked immunosorbent assay, indirect immunofluorescence assays, and western blot. viremic chickens that remained free of detectable antibodies were considered tolerant to hvt. chickens exposed to hvt at embryonation day 14 or earlier had 6-33% incidence of tolerance. tolerant chic ... | 2003 | 12631525 |
| melanocyte-specific cell mediated immune response in vitiliginous smyth line chickens. | smyth line chickens (sl) are an animal model to study human autoimmune vitiligo. vitiligo in sl chickens is characterized by a post-hatch loss of feather melanocytes (mc) resulting in feather depigmentation. the etiopathology of this disease remains unclear, however, a hypothesis that cell-mediated immunity (cmi) plays an important role in the destruction of melanocytes has been proposed based on previous studies. to support this hypothesis, the delayed wattle response (dwr) to mc lysates was ex ... | 2003 | 12935784 |
| protection and synergism by recombinant fowl pox vaccines expressing multiple genes from marek's disease virus. | recombinant fowl poxviruses (rfpvs) were constructed to express genes from serotype 1 marek's disease virus (mdv) coding for glycoproteins b, e, i, h, and ul32 (gb1, ge, gi, gh, and ul32). an additional rfpv was constructed to contain four mdv genes (gb1, ge, gi, and ul32). these rfpvs were evaluated for their ability to protect maternal antibody-positive chickens against challenge with highly virulent mdv isolates. the protection induced by a single rfpv/gb1 (42%) confirmed our previous finding ... | 2003 | 14562881 |
| characterization of vnr-13, the first alphaherpesvirus gene of the bcl-2 family. | the bcl-2 family, including antiapoptotic and proapoptotic members, plays key regulating roles in programmed cell death. we report the characterization of a new member of the bcl-2 family, encoded by herpesvirus of turkeys (hvt). the product of this gene shares 80% homology with nr-13, an apoptosis inhibitor, which is overexpressed in avian cells transformed by the v-src oncogene. this new gene, that we propose to call vnr-13, is the first member of the bcl-2 family to be isolated among alpha-he ... | 2003 | 14644608 |
| herpesvirus of turkeys: microarray analysis of host gene responses to infection. | herpesvirus of turkeys (hvt) provides an economically important live vaccine for prevention of marek's disease (md) of chickens. md, characterized by both immunosuppression and t-cell lymphoma, is caused by another herpesvirus termed marek's disease virus (mdv). microarrays were used to investigate the response of chicken embryonic fibroblasts (cef) to infection with hvt. genes responding to hvt infection include several induced by interferon along with others modulating signal transduction, tra ... | 2004 | 14972539 |
| detection and localization of avian alphaherpesviruses in embryonic tissues following in ovo exposure. | we investigated whether chicken embryonic tissues are susceptible to infection with virulent marek's disease virus (mdv). groups of embryonic day (ed) 17 chicken embryos and 1-day-old chicks were compared for tissue sites of viral persistence of mdv and herpesvirus of turkeys (hvt) in lungs, thymuses, bursae of fabricius and spleens. mdv dna was detectable in the lungs and thymuses of embryos at 3 days post-inoculation (dpi) by in situ hybridization, while hvt dna was only present in embryonic l ... | 2004 | 15019243 |
| the efficacy of recombinant fowlpox vaccine protection against marek's disease: its dependence on chicken line and b haplotype. | earlier studies have shown that the b haplotype has a significant influence on the protective efficacy of vaccines against marek's disease (md) and that the level of protection varies dependent on the serotype of md virus (mdv) used in the vaccine. to determine if the protective glycoprotein gene gb is a basis for this association, we compared recombinant fowlpox virus (rfpv) containing a single gb gene from three serotypes of mdv. the rfpv were used to vaccinate 15.b congenic lines. nonvaccinat ... | 2004 | 15077806 |
| field evaluations of safety and efficacy of an australian marek's disease vaccine. | to demonstrate the safety and efficacy of the marek's disease virus-1 vaccine (strain bh 16) from field studies in comparison with the cvi 988 rispens vaccine currently available in australia. | 2003 | 15080446 |
| marek's disease vaccination, with turkey herpesvirus, and enrofloxacin modulate the activities of hepatic microsomal enzymes in broiler chickens. | chickens were vaccinated against marek's disease intramuscularly at one day of age. enrofloxacin was given ad libitum in the drinking water at concentrations of 50, 100 and 250 mg/l from 8 days to 13 days of age when the animals were killed and the activities of cytochrome p-450 enzymes in the liver were measured. vaccinated non-treated chickens served as a positive control. a negative control group was neither vaccinated nor treated. vaccination decreased the activity of aniline hydroxylase and ... | 2004 | 15168752 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| use of a vectored vaccine against infectious bursal disease of chickens in the face of high-titred maternally derived antibody. | interference by maternally derived antibody (mda) is a major problem for the vaccination of young chickens against infectious bursal disease (ibd). the choice of the timing of vaccination and of the type (degree of attenuation) of modified-live vaccine (mlv) to use is often difficult. an ibd vectored vaccine (vhvt13), in which turkey herpesvirus (hvt) is used as the vector, was recently developed. this vaccine is administered once at the hatchery, either in ovo or by the subcutaneous route, to 1 ... | 2007 | 17560594 |
| 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 ... | 2003 | 17585455 |
| 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 ... | 2007 | 17622613 |
| effects of vaccine dose, virus challenge dose and interval from vaccination to challenge on protection of broiler chickens against marek's disease virus challenge. | to examine the effects of varying the doses of turkey herpesvirus (hvt) vaccine and marek's disease virus (mdv) challenge at two intervals after vaccination on the protection of chickens against challenge with mdv. | 2007 | 17760936 |
| a recombinant turkey herpesvirus expressing chicken interleukin-2 increases the protection provided by in ovo vaccination with infectious bursal disease and infectious bronchitis virus. | in ovo vaccination remains an attractive option for the mass application of vaccines to poultry, ensuring a uniform application of vaccine in a cost-effective manner. however, the number of vaccines that can be delivered safely by this method is limited. several infectious bursal disease virus (ibdv) vaccines can be given in ovo though most are delivered post-hatch and there are no currently licensed embryo-safe infectious bronchitis virus (ibv) vaccines. reduction in the dose of vaccines given ... | 2007 | 17996994 |
| characterization of lorf11, a unique gene common to the three marek's disease virus serotypes. | the unique open reading frame 11 (lorf11) of marek's disease virus (mdv) is present in all three serotypes of mdv and is located in the unique long region of the mdv genome. in the serotype 1 md5 genome, lorf11 comprises 2711 nucleotides and encodes a predicted protein of 903 amino acids. in order to study the biological function of lorf11 we deleted it from the mdv cosmid a6 by using the reca-assisted restriction endonuclease cleavage method. the recombinant cosmid, a6deltalorf11, was transfect ... | 2007 | 18251393 |
| determination of optimal conditions for thawing and diluting cell-bound cvi 988 marek's disease vaccine and stability of the diluted vaccine. | the cell-associated vaccine strain cvi 988, which is the active component of several commercial marek's disease vaccines, normally is frozen and stored in liquid nitrogen. in order to ascertain good efficacy of the vaccine, it is crucial that the right procedures are followed for thawing and diluting of the virus. in the study presented here, ampoules containing the frozen product were taken from storage in liquid nitrogen and were thawed in a water bath at 27 c, which is similar to a lukewarm b ... | 2007 | 18251410 |
| antibody response of chickens to serotype 1, 2, or 3 marek's disease vaccines based on elisa with infected cells as antigen. | an enzyme-linked immunosorbent assay (elisa) was applied to evaluate the antibody response of commercial white leghorn chickens to vaccination against marek's disease (md) at hatch (day 0) with serotype-1 (rispens), -2 (sb-1), or -3 (turkey herpesvirus, hvt) vaccine virus and to challenge on day 21 with md virus. antigens for the test were whole chicken embryo fibroblast cells infected with rispens, sb-1, or hvt. the chickens were progeny of stock that had been vaccinated with hvt, and on day 21 ... | 2007 | 18251413 |
| expression of cytokine genes following pre- and post-hatch immunization of chickens with herpesvirus of turkeys. | induction of immune response as characterised by expression of cytokine genes in the spleen following immunization of pre- and post-hatch chickens with herpesvirus of turkeys (hvt) vaccine was studied. the pattern of expression of ifn-gamma and il-10 genes in pre-hatch immunized chickens was different from that observed in post-hatch hvt immunized chickens. this expression pattern of cytokine genes was associated with significantly higher hvt transcripts in pre-hatch immunized chickens than in p ... | 2008 | 18406020 |
| comparison of the genomes of 15 avian herpes-virus isolates by restriction endonuclease analysis. | differentiation of herpesvirus isolates has been performed mostly on the basis of biological properties and serology. in this study, 15 herpesvirus isolates from different species of birds were compared by restriction endonuclease analysis of genomic dna. all herpesviruses were isolated in europe or are used as vaccine viruses there. the isolates could be differentiated into seven groups based on restriction patterns. the largest group contains isolates from passeriform and psittacine birds and ... | 1997 | 18483909 |
| 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 ... | 2008 | 18568648 |
| inhibition of marek's disease virus replication by retroviral vector-based rna interference. | rna interference (rnai) is a promising antiviral methodology. we recently demonstrated that retroviral vectors expressing short-hairpin rnas (shrna-mirs) in the context of a modified endogenous micro-rna (mirna) can be effective in reducing replication of other retroviruses in chicken cells. in this study, similar rnai vectors are shown to inhibit replication of the avian herpesvirus, marek's disease virus (mdv, also known as gallid herpesvirus type 2), and its close relative, herpesvirus of tur ... | 2008 | 18570965 |
| molecular cloning and sequence analysis of the duck enteritis virus ul5 gene. | duck enteritis virus (dev) is a herpesvirus that causes an acute, contagious, and fatal disease. in the present article, the dev ul5 gene was cloned and sequenced from a vaccine virus. according to the consensus sequence of herpesvirus ul5 and ul3 gene degenerate oligonucleotide primers were designed and were used in the polymerase chain reaction (pcr) to amplify dna products with 4577 bp in size. dna sequence analysis revealed a 2568 bp open reading frame (orf) encoding a 855 amino acid polypep ... | 2008 | 18582977 |
| 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% ... | 2008 | 18632866 |
| enhancement of reticuloendotheliosis virus-induced bursal lymphomas by serotype 2 marek's disease virus. | the effect of serotype 2 and 3 marek's disease virus (mdv) vaccines on the pathogenesis of reticuloendotheliosis virus (rev)-induced bursal and non-bursal lymphomas was examined in chickens of rprl lines 15i(5) x 7(1) and 6(3) x 0, respectively. at hatch, chickens were vaccinated with strain 301b/1 of serotype 2 mdv or strain fc126 of turkey herpesvirus (hvt), a serotype 3 mdv and inoculated with spleen necrosis virus (snv), a non-defective strain of rev. in another experiment, bursas from 14-we ... | 1996 | 18645839 |
| load of challenge marek's disease virus dna in blood as a criterion for early diagnosis of marek's disease tumors. | outbreaks of marek's disease (md) in vaccinated flocks still occur sporadically and lead to economic losses. unfortunately, adequate methods to predict md outbreaks are lacking. in the present study, we have evaluated whether high load of challenge md virus (mdv) dna in peripheral blood could aid in the early diagnosis of md and in monitoring efficacy of vaccines against md. one experiment was conducted to simulate field conditions by combining various vaccines (turkey herpesvirus [hvt] and hvt ... | 2008 | 18646447 |
| effects of age at infection with serotype 2 marek's disease virus on enhancement of avian leukosis virus-induced lymphomas. | inoculation of susceptible, 15i5 x 7i chickens with serotype 2 marek's disease virus (mdv) at various ages had no influence on the development of avian leukosis virus (alv)-induced viraemia or antibody in chickens infected with alv and turkey herpesvirus (hvt) at hatch. however, the incidence of alv-induced lymphoma (ll) was significantly higher in chickens infected with alv and hvt at hatch and inoculated with serotype 2 mdv up to 6 weeks of age than in chickens receiving serotype 2 mdv at 8 to ... | 1993 | 18671041 |
| further characterisation of a variant type of turkey herpesvirus which releases large quantities of cell-free viruses into culture medium. | a variant type of turkey herpesvirus (hvt/vt) which releases large quantities of cell-free virus into its culture medium was compared with the prototype of the fc 126 strain of hvt (hvt/wt) as to the biological and serological characteristics. the lack of replication-defective hvt/vt in chickens was considered to be due to the inability of the virus to infect and replicate in lymphocytes and not to temperature-sensitive defects at 41 degrees c. no obvious antigenic differences were found between ... | 1989 | 18679841 |
| replication of marek's disease virus in chicken feather tips containing vaccinal turkey herpesvirus dna. | the presence of herpesvirus of turkeys (hvt) dna in the feather tips of chickens vaccinated with hvt was assessed by dot blot hybridisation with a probe specific for hvt and lacking homology to mdv dna. only small amounts of hvt dna were detected in the feather tips of chickens that were vaccinated or left in contact with hvt vaccinated chickens. however when chickens were challenged with virulent mdv, hvt dna was detected in the feather tips of vaccinated chickens and the largest amount was det ... | 1991 | 18679997 |
| marek's disease virus isolates with unusual tropism and virulence for ocular tissues: clinical findings, challenge studies and pathological features. | outbreaks of marek's disease (md) were diagnosed in two flocks from the same company. clinical signs, mainly blindness (>90%), but also depression, mild paralysis, and 11 to 12% mortality by 20 weeks of age were observed. md virus, serotype 1 was isolated. the isolates were designated nc-1 (flock 1) and nc-2 (flock 2). challenge experiments were conducted with these isolates and with two reference md virus strains (jm/102w and md5) in unvaccinated, turkey herpesvirus- (hvt) vaccinated and bivale ... | 1991 | 18680042 |
| efficacy and safety of cell associated vaccines against marek's disease virus grown in a continuous cell line from chickens. | the marek's disease virus (mdv) vaccine strains cvi 988 and herpes virus of turkeys (hvt) strain fc126, usually are grown in primary chicken embryo fibroblasts (cef). we found that the strains could be grown also in the so-called jbj-1 cell line to titres in the same range as when chicken embryo fibroblasts were used. the jbj-1 cell line is a fibroblast-like continuous chicken cell line, which can be grown in flat bottom tissue culture flasks, roller bottles and on micro carriers. we investigate ... | 2008 | 18706949 |
| [reconstituting turkey herpesvirus with bacterial artificial chromosome clones]. | herpesvirus of turkey (hvt) is an alpherpesvirus and widely used as a live vaccine against marek's disease (md) because of its antigenic relationship with marek's disease virus (mdv). | 2008 | 18720848 |
| cellular and cytokine responses in feathers of chickens vaccinated against marek's disease. | in marek's disease virus infection, feather follicle epithelium (ffe) constitutes the site of formation of infectious virus particles and virus shedding. the objective of this study was to characterize cellular and cytokine responses as indicators of cell-mediated immune response in ffe and associated feather pulp following immunization against marek's disease. analysis of feather tips collected between 4 and 28 days post-immunization (d.p.i.) from chickens vaccinated post-hatch with either cvi9 ... | 2008 | 18722673 |
| enhancement of natural killer cell activity by marek's disease vaccines. | vaccination against marek's disease with herpesvirus of turkeys (hvt) has been reported to cause increased natural killer (nk) cell activity as detected in vitro against lscc-rp9 target cells. the effect of vaccination with sb-1 (a nononcogenic chicken herpesvirus), hvt and the hvt/sb-1 combination on nk cell activation was compared in marek's disease susceptible (p-2) and resistant (n-2) chickens. birds were vaccinated at 7 days of age and nk cell activity was measured between 3 and 42 days aft ... | 1987 | 18766591 |
| isolation of chicken anaemia agent and marek's disease virus from chickens vaccinated with turkey herpesvirus and lesions induced in chicks by inoculating both agents. | a disease that was characterised by high mortality, necrotic lesions, severe thymic and bursal atrophy, as well as marek's disease (md) lesions, occurred in two young layer chicken flocks vaccinated with turkey herpesvirus (hvt) at hatching. an agent similar to the chicken anaemia agent, designated caa82-2, and a virulent md virus strain, designated md82-2, were isolated from the kidneys of affected chickens. dual inoculation of young chicks with both agents resulted in early mortality associate ... | 1987 | 18766615 |
| embryo vaccination of chickens with turkey herpesvirus: characteristics of the target cell of early viral replication in embryonic lung. | inoculation of turkey herpesvirus (hvt) into chicken eggs at the 17th day of embryonation resulted in recovery of high titres of the virus from the lung of the embryo. infection of the lung was not characterised by extensive virus-induced cell lysis because in situ viral internal antigen (via) of hvt was not detected. examination of single cell suspensions of lungs from embryos at peak viral activity revealed that the target cells of virus infection were adherent and lacked surface antigens dete ... | 1987 | 18766646 |
| depression of vaccinal immunity to marek's disease by infection with chicken anaemia agent. | chicken anaemia agent (caa) depressed protective vaccinal immunity against marek's disease (md) when vaccinated chicks were inoculated with caa at 1 to 14 days of age. in chicks inoculated with caa alone, a typical caa infection as manifested by early mortality, decrease in haematocrit value, severe lymphoid depletion in the lymphoid organs, and aplasia of the bone marrow occurred only when one-day-old chicks were inoculated. when both turkey herpesvirus (hvt) and caa were inoculated, a typical ... | 1988 | 18766691 |