Publications

TitleAbstractYear
Filter
PMID(sorted descending)
Filter
nucleotide sequence analysis of marek's disease virus (mdv) serotype 2 homolog of mdv serotype 1 pp38, an antigen associated with transformed cells.marek's disease (md) virus (mdv) serotype 1 (mdv1) pp38, an antigen associated with md-transformed cells, has been identified as an mdv1 serotype-specific antigen by analyses using specific monoclonal antibodies (mabs). in the present study, we determined the region in the mdv serotype 2 (mdv2) genome that has homology with the mdv1 pp38 gene. as a result of sequence analysis, it was determined that an open reading frame (orf) existed in this region. furthermore, northern blot analysis and rever ...19948178479
enhanced expression of the marek's disease virus-specific phosphoproteins after stable transfection of msb-1 cells with the marek's disease virus homologue of icp4.phosphoprotein pp38, coded for by the bamhi-h fragment of the marek's disease herpesvirus (mdv) genome is expressed in tumor cells and tumor cell lines. pp38 is associated with two other phosphoproteins, pp41 and pp24, and can be detected in a small percentage of tumor cells by indirect immunofluorescence assays (iifa). the importance of mdv icp4 for the regulation of pp38 expression was examined in the following msb-1-derived cell lines stably transfected with the selection plasmid pnl1 [mdcc-c ...19948178477
marek's disease virus type 1-specific phosphorylated proteins pp38 and pp24 with common amino acid termini are encoded from the opposite junction regions between the long unique and inverted repeat sequences of viral genome.the nucleotide sequence of the junction region between the long unique (ul) and terminal inverted repeat (trl) sequences of marek's disease (md) virus type 1 (mdv1) dna revealed the presence of a rightward open reading frame of 155 amino acids. the orf inserted into an eukaryotic expression vector transiently expressed an antigen in the cytoplasm of cos7 cells which reacted with the monoclonal antibody m21 against an mdv1-specific phosphorylated protein complex consisting of at least the protein ...19948178465
the glycoprotein b genes of marek's disease virus serotypes 2 and 3: identification and expression by recombinant fowlpox viruses.the nucleotide sequences of the glycoprotein b (gb) genes of marek's disease virus (mdv) serotypes 2 and 3 were determined (gb-2 and gb-3, respectively). the genomic locations of these genes coincide with that of the gb gene of serotype 1 mdv (gb-1). alignment with gb-1 (ross et al., 1989, j. gen. virol. 70, 1789-1804) revealed predicted amino acid identities of 83 and 82% for gb-2 and gb-3, respectively. excluding the predicted n-terminal signal sequences, 8 of 9 potential n-linked glycosylatio ...19948178437
some characteristics of a recent virulent isolate of marek's disease virus. 19948172548
distribution of ia antigen positive cells in chicken embryos infected with oncogenic marek's disease virus (mdv) and md vaccine viruses of serotypes 1, 2 and 3.chick embryos infected at day 13 of embryonic development (ed) with the oncogenic serotype 1 marek's disease virus, isolate b (mdv-b) and three mdv vaccines (cvi988, sb1 and hvt, serotypes 1, 2 and 3, respectively) and uninfected chick embryos were studied for the distribution of ia antigen positive dendritic cells (dc), b cells and mdv antigen positive (ag+) cells in the lymphoid organs and chorioallantoic membrane (cam). the immunofluorescence study was conducted on acetone-fixed organ touch i ...19948160354
efficacy in chickens of a herpesvirus of turkeys recombinant vaccine containing the fusion gene of newcastle disease virus: onset of protection and effect of maternal antibodies.the onset of protection against newcastle disease and the effect of maternal antibodies to newcastle disease virus (ndv) and marek's disease virus (mdv) on vaccine efficacy were determined following vaccination of chickens with a recombinant herpesvirus of turkeys (hvt) vaccine expressing the fusion (f) glycoprotein gene of ndv. onset of protection following intra-abdominal administration of the recombinant hvt/f vaccine at 1 day of age and subsequent ocular challenge with the neurotropic veloge ...19938141730
characterization of marek's disease virus bamhi-a-specific cdna clones obtained from a marek's disease lymphoblastoid cell line.a cdna library was constructed from poly(a)+ rna fractions obtained from a marek's disease (md) lymphoblastoid cell line, mdcc-cu41, in which viral gene expression is very limited. three independent groups (1, 2, and 3) of md virus (mdv)-specific clones were obtained, which were mapped in the inverted repeat region of the bamhi-a fragment of the mdv genome. northern blot analysis showed that probes prepared from these cdna clones hybridized with several transcripts of different sizes in poly(a)+ ...19948122361
nucleotide sequence of the glycoprotein c (gc) homologous gene of marek's disease virus (mdv) serotype 2 and comparison of gc homologous genes among three serotypes of mdv.the sequence analysis of the genomic region of marek's disease virus (mdv) serotype 2 (mdv2) which had homology with the gene encoding mdv serotype 1 (mdv1) homologue of glycoprotein c (gc) of herpes simplex virus revealed that there was a single open reading frame (orf) capable of encoding 479 amino acids. the predicted protein from this orf had strong hydrophobic regions in both the amino and carboxyl termini and several potential n-linked glycosylation sites, as seen in those from the orfs of ...19938117828
assembly pathway of avian infectious laryngotracheitis virus.infectious laryngotracheitis virus (iltv) is the causative agent of a highly contagious upper respiratory tract infection in chickens. at present, iltv vaccines are not satisfactory because of development of a latent carrier status in vaccinated birds. development of recombinant virus vaccines has been hampered by the limited information available on the molecular level and organization of this virus. we isolated 3 assembly intermediates, designated a, b, and c from iltv-infected cells. analysis ...19938116934
interactions between marek's disease virus encoded or induced factors and the rous sarcoma virus long terminal repeat promoter.marek's disease virus transactivates promoters of avian leukemia and sarcoma viruses. in this study, a series of rsv-ltr promoter deletion mutants were used to map sites within the ltr important for mdv-mediated transactivation. mdv-responsive elements within rsv-ltr promoters were localized to a 28-bp segment (nucleotides -109 to -137) which contains a ggtgg pentanucleotide repeat element (pre). nuclear extract proteins from uninfected cells bound to the rsv pre in a sequence-specific manner. e ...19948116231
molecular evolution of herpesviruses: genomic and protein sequence comparisons.phylogenetic reconstruction of herpesvirus evolution is generally founded on amino acid sequence comparisons of specific proteins. these are relevant to the evolution of the specific gene (or set of genes), but the resulting phylogeny may vary depending on the particular sequence chosen for analysis (or comparison). in the first part of this report, we compare 13 herpesvirus genomes by using a new multidimensional methodology based on distance measures and partial orderings of dinucleotide relat ...19948107249
the 132 bp repeats are present in rna transcripts from 1.8 kb gene family of marek disease virus-transformed cells.marek's disease virus (mdv) is an oncogenic, lymphotropic herpesvirus of chickens: loss of its tumourigenic potential is believed to be associated with amplification of the 132 bp repeats from bamhi-d and bamhi-h fragments. we prepared cdna libraries from rpl1 and msb1 cell line and from the latter we identified a clone which spanned the 132 bp repeats within the bamhi-h fragment. by sequencing and northern blot analysis we confirmed the presence of the 132 bp repeats. the analysis by pcr made o ...19938105666
identification and characterization of a marek's disease virus gene homologous to glycoprotein l of herpes simplex virus.we have identified three marek's disease virus (mdv) open reading frames (orfs) within the bamhi d fragment of mdv genome. the predicted polypeptides are homologous to ul1 (glycoprotein l, gl), ul2 (uracil-dna glycosylase), and ul3 (nuclear localizing phosphoprotein) of herpes simplex virus type 1 (hsv-1). comparison of the deduced amino acid sequences of these three orfs with hsv-1 counterparts revealed overall identities of 18, 43, and 49%, respectively. in spite of the low overall amino acid ...19948091671
identification and characterization of marek's disease virus genes homologous to icp27 and glycoprotein k of herpes simplex virus-1.we have identified two marek's disease virus (mdv) genes within the ecori-b fragment of mdv-ga genomic dna. ecori-b is 11.3-kb long and maps within the long unique region of mdv genomes. a 3.2-kb fragment of ecori-b has been sequenced and contains two open reading frames, orf53 and orf54. orf53 (mdv gk), a homolog to hsv-1 glycoprotein k (gk), is 1062 nucleotides long and encodes 354 amino acids (39.5 kda). orf54, designated mdv icp27, based on significant similarity to hsv-1 icp27, is 1419 nucl ...19948091655
identification of latency-associated transcripts that map antisense to the icp4 homolog gene of marek's disease virus.two small rnas (0.9 and 0.75 kb), named marek's disease virus (mdv) small rnas (msrs) and a 10-kb rna, all of which map antisense to the mdv icp4 homolog gene, have been readily detected in mdcc-msb1 mdv-transformed t-lymphoblastoid cells. these rnas were not detectable in reticuloendotheliosis virus-transformed t cells. when mdv was reactivated by treatment of lymphoblastoid cells with 25 micrograms of iododeoxyuridine per ml, the relative levels of the transcripts decreased. these rnas were no ...19948083968
molecular characterization of hawaii virus and other norwalk-like viruses: evidence for genetic polymorphism among human caliciviruses.hawaii virus (hv), from a 1971 family outbreak of gastroenteritis, is serotypically distinct from norwalk virus (nv), recently identified as a human calicivirus by molecular analysis. about 2600 consecutive nucleotides of the hv genome (including those encoding the viral capsid protein) and part of the polymerase region of three other viruses (mdv1, mdv6 and sv7) were sequenced. comparison of the amino acid sequence of the capsid protein of hv with nv and other human caliciviruses (toronto virus ...19948077710
[the isolation of the herpes virus from the white crane and a study of its properties].isolation of a virus agent from sick white cranes in national oka preserve is described. the results of virological and serological studies on specimens from the sick birds permitted a conclusion that the infection in the cranes could be induced by avian herpes virus.19938073746
anti-idiotype antibodies to marek's disease-associated tumour surface antigen in protection against marek's disease.marek's disease-associated tumour surface antigen (matsa) removed by enzymatic (papain) digestion of marek's disease tumour cells was fractionated by gel filtration chromatography. the first peak (f1) was used to raise antibody in rabbits. monoclonal antibody (rph-6) directed against matsa and the anti-f1 igg were used as idiotypic antibodies to raise polyclonal anti-idiotype serum in heterologous hosts; rabbit and goat, respectively. the anti-idiotypes (anti-id) were purified by affinity chroma ...19948042285
integration of multiple chicken retroviruses into multiple chicken herpesviruses: herpesviral gd as a common target of integration.integration of two different avian retroviruses, reticuloendotheliosis virus (rev) and avian leukosis virus (alv), into the genome of two different avian herpesviruses, the herpesvirus of turkeys (hvt) and marek's disease virus (mdv), was investigated. integration events occurred by the fourth and sixth in vitro passage of cells coinfected with rev/hvt and alv/mdv, respectively. in order to further characterize the integration events, integrated proviruses and surrounding herpesviral genetic mat ...19948030268
identification of novel transcripts complementary to the marek's disease virus homologue of the icp4 gene of herpes simplex virus.libraries of cdna were generated from polyadenylated rnas derived from marek's disease virus (mdv)-transformed cell lines by directional cloning of oligo-(dt)-primed cdnas in lambda gt22a. analysis of the libraries for viral sequences showed that a number of cdna clones originated from transcripts mapping in the bamhi a region of the mdv genome. sequencing and fine mapping of these cdnas suggested that the rna transcripts expressed from this region were either in the sense or antisense direction ...19948021600
serotype specificity of b-haplotype influence on the relative efficacy of marek's disease vaccines.b-haplotype genes in the chicken were previously shown to differentially influence vaccine efficacy against challenge with very virulent marek's disease virus according to the type of marek's disease (md) vaccine used. to determine whether md vaccines of the same serotype gave comparable levels of protection against md in chickens of the same haplotype challenged with md virus strain md5, two serotype 1 and two serotype 2 vaccines were compared with one serotype 3 vaccine using chickens of 15-b- ...19948002902
expression of a novel marek's disease virus type 1 (mdv1)-specific protein p40 in insect cells by a baculovirus vector and in chick embryo fibroblasts infected with mdv1.we found that the open reading frame of 1053 nucleotides within the short unique sequence of marek's disease virus (mdv) type 1 (mdv1) expresses a 40 kda protein, using a baculovirus vector in insect cells. mouse antisera against the 40 kda protein reacted with a 40 kda protein in mdv1-infected cells. a cross-reactive polypeptide of 37 kda was also detected in cells infected with herpesvirus of turkey.19947979993
construction of recombinant marek's disease virus type 1 (mdv1) expressing the escherichia coli lacz gene as a possible live vaccine vector: the us10 gene of mdv1 as a stable insertion site.this paper describes the construction of a recombinant marek's disease virus serotype 1 (mdv1) in which the escherichia coli lacz gene was inserted into the open reading frame homologous to the us10 gene of herpes simplex virus 1 (hsv1). the recombinant virus replicated as well in cell culture as the parental mdv1 k-554 strain. chickens immunized with the virus were protected against challenge with virulent mdv1, and produced a high level of antibodies against beta-galactosidase as well as again ...19947975837
characterization of marek's disease virus insertion and deletion mutants that lack us1 (icp22 homolog), us10, and/or us2 and neighboring short-component open reading frames.we report the characterization of marek's disease virus (mdv) strains having mutations in various genes that map to the unique short (us) region of the viral genome. a deletion mutant (ga delta 4.8lac) lacks 4.8 kbp of us region dna, the deleted segment having been replaced by the lacz gene of escherichia coli. this deletion results in the loss of the mdv-encoded us1, us10, and us2 homologs of herpes simplex virus type 1, as well as three putative mdv-specific genes, sorf1, sorf2, and sorf3. two ...19947966617
characterization of proteins encoded by the short unique region of herpesvirus of turkeys by in vitro expression.nine open reading frames mapping in the short unique (us) region of the genome of herpesvirus of turkeys (hvt) were expressed by in vitro transcription and translation. the observed m(r)s of us10, sorf3 and us2 were as predicted from the sequence but there were discrepancies between the observed and predicted m(r)s of us1, protein kinase, gi, gd and ge. these could be accounted for in most cases by post-translational and co-translational processing. analysis of the synthesized products at differ ...19947931161
complex role of gamma-herpesviruses in multiple sclerosis and infectious mononucleosis.various researchers over the past few years have demonstrated higher titers and higher incidence rates of epstein-barr virus (ebv) antibodies in multiple sclerosis (ms) patients compared to controls. these findings were tentatively attributed to immunoregulation abnormalities of ms or perhaps to some other relationship with the ms syndrome yet to be determined. meanwhile, an intensive environmental investigation of the key west cluster just before it ended and for two years afterwards produced t ...19937907407
molecular analysis of the glycoprotein c-negative phenotype of attenuated marek's disease virus.serial passage of oncogenic serotype 1 marek's disease virus (mdv) in cultured avian cells results in attenuation of viral oncogenicity and pathogenicity. coincident with attenuation, expression of mdv glycoprotein c (gc) is significantly reduced. regulation of mdv gc may have important implications for virus-host interactions and have important consequences in the process of viral attenuation. to investigate the mechanism by which mdv gc expression is reduced during attenuation of the very viru ...19947907196
purification of recombinant 38-kda phosphorylated protein of marek's disease virus from insect cells through an affinity column.the 38-kda phosphorylated protein (pp38) of marek's disease virus (mdv) expressed in insect cell line sf9 cells infected with recombinant baculovirus bp38ii was purified through an affinity column made of cnbr-sepharose 4b linked with monoclonal antibody (mab) h19 specific to serotype i mdv. the result of sds-page showed a main band of 38 kda in the lane loaded with the purified pp38, and this band was specifically recognized by mab h19 in western blot. the serum from mice immunized with the pur ...19947893940
[immunological cross-reaction of serotype i marek's disease virus 38kd phosphorylated protein with serotype ii and iii viruses].marek's disease virus (mdv) 38kd phosphorylated protein (pp38), which was identified by monoclonal antibody (mab) h19 specific to pathogenic serotype i of mdv, has been recognized as a transformation-associated antigen specific to serotype i of mdv. the recombinant pp38 was prepared and purified from pp38-expressing recombinant baculovirus infected sf9 cell lysates through a mab h19-affinity column. in indirect fluorescence antibody test, the mouse sera against the purified recombinant pp38 not ...19947871782
characterization of a marek's disease virus mutant containing a lacz insertion in the us6 (gd) homologue gene.we report the construction of a marek's disease virus (mdv) mutant containing the lacz gene of escherichia coli inserted into a homologue of the us6 (glycoprotein d, gd) gene of herpes simplex virus. the mutant was constructed using the high-passage gaatt85 mdv strain as the parent virus, since that strain grows readily in chicken embryo fibroblasts using culture conditions conducive to mutant virus construction. the lacz insertion site was positioned one third of the way into the us6 (gd) open ...19947871761
gene organization in herpesvirus of turkeys: identification of a novel open reading frame in the long unique region and a truncated homologue of pp38 in the internal repeat.the dna sequence of a 4.792-kb fragment comprising 3.176 kb of the long unique region (ul) and 1.605 kb of the internal repeat (irl) flanking ul of herpesvirus of turkeys (hvt) was determined. three potential open reading frames (orfs) and an origin of replication have been identified. orf 1, which maps entirely within ul, has the capacity to code for an 82k protein, 731 amino acids long, which has a counterpart in marek's disease virus (mdv) but not in other herpesviruses. orf 2 has the potenti ...19957871728
expression and purification of recombinant marek's disease virus serotype 1 specific phosphorylated protein pp38 in e. coli.phosphorylated protein pp38 is the only protein that is detected in the marek's disease (md) lymphoma caused by md virus serotype 1 (mdv-1) and lymphoblastoid cell lines. in this study, a recombinant protein coded for by the almost entire open reading frame of the mdv-1 pp38 cdna was produced in e. coli and purified by affinity chromatography. prior to the expression and purification of the protein, cdna containing the entire coding region for pp38 was cloned and its nucleotide sequence was dete ...19947865579
a 14-kda immediate-early phosphoprotein is specifically expressed in cells infected with oncogenic marek's disease virus strains and their attenuated derivatives.previously, we reported two cdnas derived from the marek's disease virus (mdv) long internal repeat region. a 14-kda polypeptide (p14) encoded by two small open reading frames (orfs) from at least two distinct cdnas is expressed in cells lytically infected with both oncogenic and attenuated mdv as well as in cells latently infected and transformed by mdv. in this study, we demonstrate that p14 is serotype 1 specific and highly phosphorylated. given the degree of phosphorylation and lack of homol ...19957831828
the marek's disease virus (mdv) unique short region: alphaherpesvirus-homologous, fowlpox virus-homologous, and mdv-specific genes.despite its previous classification as a gammaherpesvirus, primarily due to its lymphotropism, marek's disease virus (mdv), an oncogenic avian herpesvirus, is phylogenetically more related to the "neurotropic" alphaherpesviruses, characterized by its prototype, herpes simplex virus (hsv) (buckmaster et al., 1988, j. gen. virol. 69, 2033-2042). in this report we present the dna sequence of an 11,286-bp dna segment encompassing the entire 11,160-bp-long us region of the oncogenic avian herpesvirus ...19957831788
mutational analysis of the proteolytic cleavage site of glycoprotein b (gb) of marek's disease virus.the marek's disease virus (mdv) glycoprotein b (gb) precursor, gp100, is proteolytically cleaved into two disulfide-linked subunits, gp60 and gp49. in the gb homologs of most other herpesviruses, a tetrapeptide, arg-xaa-arg-arg, is immediately upstream from the predicted cleavage site. we have investigated the specificity of the proteolytic cleavage in gp100 by introducing mutations within its predicted cleavage site (arg-leu-arg-arg) and expressed these mutants in recombinant fowlpox virus (fpv ...19947821796
the transcripts from the sequences flanking the short component of marek's disease virus during latent infection form a unique family of 3'-coterminal rnas.we have constructed a cdna library using poly(a)+ rna from the stably transformed marek's disease virus cell line mkt-1 and isolated cdnas specific to the short internal repeat region of the bamhi-a fragment of the viral genome. four distinct classes of cdna were identified through sequence analysis of the 5' and 3' termini of each clone isolated, and a representative of each class was chosen for complete sequencing. these cdnas were mapped on the basis of the genomic nucleotide sequence of this ...19957815512
bird viruses in multiple sclerosis: combination of viruses or marek's alone?this is a short report confirming recent articles that birds are very likely involved as vectors of the exogenous causative agent of multiple sclerosis (ms). it also critically reviews the most recent article (macgregor, h. and latiwonk, q., neurol. res., 15 (1993) 391-394.) in which a high percentage of serums from ms patients reacted positively with marek's antigen and it was accidentally discovered that epstein-barr virus antibodies also cross-react positively with marek's antigen. this disco ...19957792060
transactivation activity of meq, a marek's disease herpesvirus bzip protein persistently expressed in latently infected transformed t cells.marek's disease virus (mdv) is an avian herpesvirus that induces a variety of diseases, including t-cell lymphomas, in chickens. in latently infected, transformed lymphoid cells, very few viral transcripts or proteins are detected. we previously described a gene, meq (mdv ecoq), which is persistently expressed in mdv-transformed tumor samples and cell lines. meq codes for a 339-amino-acid protein with a basic-leucine zipper domain near its n terminus and a proline-rich domain near its c terminus ...19957769661
expression of marek's disease virus (mdv) serotype 2 gene which has partial homology with mdv serotype 1 pp38 gene.we constructed the recombinant baculovirus expressing the gene of non-pathogenic marek's disease virus (mdv) serotype 2 (mdv2) which encodes a polypeptide with partial homology to mdv serotype 1 (mdv1) pp38, an antigen associated with transformed cells. the recombinant mdv2 protein was detected as a band of 32 kda in immunoblot analysis with mdv2-infected chicken serum. mouse serum against insect spodoptera frugiperda cells infected with the recombinant baculovirus immunoprecipitated a 38 kda mo ...19957762295
syngeneic lysis of reticuloendotheliosis virus-transformed cell lines transfected with marek's disease virus genes by virus-specific cytotoxic t cells.cell-mediated immune responses against marek's disease virus (mdv) antigens were examined using reticuloendotheliosis virus (rev)-transformed cell lines of two haplotypes (b19b19 and b13b13). these cell lines were stably transfected with cloned fragments of mdv dna resulting in the expression of the mdv-specific phosphoprotein pp38. effector cells were obtained from p2a (b19b19) and s13 (b13b13) chickens at 7 days post inoculation with rev, oncogenic or attenuated serotype 1 mdv (jm-16/o and jm- ...19947725630
differential diagnosis of infectious laryngotracheitis from other avian respiratory diseases by a simplified pcr procedure.a simple polymerase chain reaction (pcr)-based procedure was developed for the detection of avian infectious laryngotracheitis virus (iltv) in chicken trachea, chorio-allantoic membrane (cam), infected hepatoma cells and infectious cell culture supernatant. samples were prepared by dilution in distilled water. after boiling and low speed centrifugation, samples were used for pcr analysis with two primers without special labeling. the pcr analysis for ilt virus could be completed in less than 8 h ...19947714054
use of recombinant pp38 antigen of marek's disease virus to identify serotype 1-specific antibodies in chicken sera by western blotting.a fowlpox recombinant expressing the pp38 antigen of marek's disease virus has been constructed. production of pp38 in chick embryo fibroblasts (cef) infected at a m.o.i. of 1 pfu/cell occurred over a period of 5 days and reached a peak at 72 h after infection. the pp38 antigen could be released from infected cells by freezing and thawing. western blot analysis showed that denatured pp38 antigen reacted with antisera from chickens inoculated with serotype 1 mdv but failed to react with antisera ...19947714041
identification and characterization of a cdna clone derived from the marek's disease tumour cell line rpl1 encoding a homologue of alpha-transinducing factor (vp16) of hsv-1.we have identified and sequenced a 2.3 kb cdna clone rpl(n.s) 6 derived from the marek's disease virus (mdv)-transformed cell line rpl1, which contained open reading frames (orfs) homologous to ul49 (vp22) and ul48 (vp16) of herpes simplex virus. northern blot hybridization identified a 2.5 kb transcript corresponding to this cdna clone in the total rna from msb1 lymphoblastoid cells, but not in rna from the original rpl1 cells, most probably due to the very low level of its transcription. in vi ...19957710361
a study on the function of the glycine residue in the ygdd motif of the rna-dependent rna polymerase beta-subunit from rna coliphage q beta 1.q beta replicases in which the gly residue of the beta-subunit in the motif sequence, ygdd, was replaced with ala, ser, pro, met, or val lost their replicase activity in vivo. in an in vitro mg(2+)-dependent rna-synthesizing system using poly(rc) or mdv-poly(+) rna (a derivative of the naturally occurring small rna that accumulates in the cells during q beta phage infection) as templates, the lysates from the cells expressing such defective replicases exhibited only 2-6% of the enzyme activity o ...19947706217
partial inhibition by turkey herpesvirus of serotype 2 marek's disease virus plaque formation and in vivo infectivity.the increased use of serotype 2 marek's disease virus (mdv) and serotype 3 turkey herpesvirus (hvt) as components of effective bivalent vaccines against marek's disease (md) prompted studies on the possible interactions of these two viruses in vitro and in vivo. the replication of the sb-1 strain of mdv was compared with replication of the fc126/2 strain of hvt in chickens and cell cultures infected with one or both viruses. replication of mdv was reduced in the presence of hvt in both in vitro ...19947702514
cytogenetic studies of cell lines derived from marek's disease virus-induced local lesions.cytogenetic analysis of cell lines derived from marek's disease virus (mdv) induced local lesions was performed to detect the presence of a chromosomal alteration found previously in cell lines derived from mdv-induced visceral tumors. this chromosomal alteration involves an amplified region on the short arm of chromosome 1. trypsin g-binding was performed on 12 local-lesion cell lines having various t-cell receptor phenotypes. eight of 12 cell lines had a diploid female karyotype, and four line ...19947702513
measurement of antibody titer to fowl pox virus by enzyme-linked immunosorbent assay.the usefulness of the measurement of antibody titer to fowl pox virus (fpv) by enzyme-linked immunosorbent assay (elisa) was evaluated in spf chickens with or without inoculation with fpv. the optimum concentration of purified antigen was 10 micrograms/ml of protein. the absorbance at 492 nm was less than 0.10 in the chickens negative to fpv from 1 to 63 days old. by contrast, a higher titer was detected in spf chickens with various fpvs inoculated into the wing web than in non-inoculated chicke ...19947696418
latency and reactivation of marek's disease virus in b lymphocytes transformed by avian leukosis virus.the physical and biological state of the marek's disease virus (mdv) genome in avian leukosis virus (alv)-transformed cells is characterized using cell lines established from alv tumours co-infected with the sb-1 strain of mdv. the mdv genome within the alv-transformed cells was found to be methylated at 5' cpg 3' dinucleotides. less than 2% of the tumour cells expressed mdv antigen and only one virus plaque that was characteristic of an mdv infection was noted when tumour cells were cocultured ...19937691987
characteristics of cvi988/rispens and r2/23, two prototype vaccine strains of serotype 1 marek's disease virus.studies were focused on two attenuated serotype 1 marek's disease (md) vaccine viruses, cvi988/rispens (passage 42) and r2/23 (passage 105). both serotype 1 vaccine viruses provided much higher levels of protection than the prototype md vaccine, turkey herpesvirus (hvt); the best protection was generally provided by cvi988/rispens when compared with other vaccines. the efficacy of neither serotype 1 vaccine was improved by mixture with viruses of other serotypes (synergism). no differences betwe ...19957677647
identification and characterization of a marek's disease virus gene encoding dna polymerase.dna sequence analysis revealed a gene encoding the marek's disease virus (mdv) dna polymerase (pol) within the bamhi-e fragment of the long unique region of the virus genome. identification is based on an extensive amino acid homology between the mdv open reading frame and the dna pol (ul30) of the herpes simplex virus. we describe here a 3540-base-pair fragment of the mdv dna encoding 1180 amino acids with a m(r) of 133,920 daltons as the viral dna pol gene, with the analysis of transcription a ...19957653104
herpesvirus of turkey recombinant viruses expressing infectious bursal disease virus (ibdv) vp2 immunogen induce protection against an ibdv virulent challenge in chickens.two recombinant herpesviruses of turkey (hvt) expressing the vp2 protein of infectious bursal disease virus (ibdv or gumboro disease virus) have been constructed: vhvt001 and vhvt002. the vp2 open reading frame was inserted at the locus of the small subunit of ribonucleotide reductase gene (hsv-1 ul40 homolog) without any exogenous promoter in vhvt001 and at the locus of gl gene (hsv-1 us7 homolog) under the control of the human cytomegalovirus immediate-early promoter in vhvt002. the isolation ...19957645252
sequence characteristics of a gene in infectious laryngotracheitis virus homologous to glycoprotein d of herpes simplex virus.an infectious laryngotracheitis virus (iltv, gallid herpesvirus 1) gene homologous to glycoprotein d of herpes simplex virus (hsv) was identified and characterized by its nucleotide and derived amino acid sequence. the iltv gd gene is located in the unique short region (u(s)) and contains an open reading frame capable of specifying a polypeptide of 380 amino acids, including n- and c- terminal hydrophobic domains consistent with signal and anchor regions respectively, and no potential sites for ...19957612933
influence of the alv6 recombinant avian leukosis virus transgene on production traits and infection with avian tumor viruses in chickens.the biological costs of the alv6 recombinant transgene that in chickens induces dominant resistance to the subgroup a avian leukosis virus (alv), in terms of effects on production traits, were studied. four generations of white leghorn chickens of line tr, segregating for alv6 but free of endogenous viral genes, as well as two generations of crosses between tr and ottawa line wg (wgtr) were tested under a specific-pathogen-free environment. in the birds studied, the transgene appeared unchanged ...19957603962
culture characterization and viral infection of aortic smooth muscle cells from japanese quail susceptible to atherosclerosis.proliferation of aortic smooth muscle cells (smcs), an important feature of atherosclerosis, occurs in the early stage of the disease in japanese quail when fed an atherogenic diet. quail aortic smcs were isolated from a total of 32 quail and cultured in eagle's minimum essential medium supplemented with 10% bovine fetal serum. studies were carried out to characterize the cells in vitro. they grew actively in the early passages, but began to develop cytopathic changes after 3-4 passages and even ...19947601271
marek's disease and new approaches to its control.marek's disease (md) is a lymphoproliferative disorder induced by a herpesvirus. several factors, including those virus-encoded and host-dependent, affect the course of the disease. existing vaccination program is based on the use of attenuated strains of md virus (mdv) serotype 1 and on strains of non-oncogenic serotype 2 (mdv2) and serotype 3 (herpesvirus of turkey-hvt) viruses. failures resulting in disease progress have been reported and indicate need for production of new, more effective va ...19957572471
common antigenic epitopes are present on heat-labile oligomers of mdv glycoprotein b and on hsv glycoprotein b.the antigenic cross-reactivity between the marek's disease virus glycoprotein b (mdv gb) and glycoprotein b (gb) of herpes simplex virus type 1 and 2 (hsv1 and hsv2) was analysed by the immunoblotting method. we studied cell lysates in both denatured and in undenatured form (i.e., unheated) and reacted them with convalescent sera from chickens infected with the rbib mdv strain and with human anti-hsv1 gb. both sera detected the heat-labile mdv gb and the hsv gb oligomers. in addition, monospecif ...19957540344
changes in the nucleosomal structure of the marek's disease virus genome in lymphoblastoid cell line mdcc-msb1 induced by 5-azacytidine.marek's disease virus (mdv) dna in latently infected lymphoblastoid cell lines is considerably methylated. treatment of the mdv-derived lymphoblastoid cell lines mdcc-msb1 (msb1) and mdcc-rp1 (rp1) with 5-azacytidine (5-azc) results in hypomethylation of mdv dna. an increase in mrna from certain portions of mdv dna, including the bamhi-h region, was observed in 5-azc-treated msb1 cells, but not in the agent-treated rp1 cells. after the treatment of cells with 5-azc, a site hypersensitive to dige ...19957538795
enhancement of mrna synthesis from marek's disease virus genome in the lymphoblastoid cell line, mdcc-msb1, by 5-azacytidine.marek's disease virus (mdv) dna in latently infected lymphoblastoid cell lines is considerably methylated. a treatment of the mdv-derived lymphoblastoid cell line, mdcc-msb1 (msb1), with 5-azacytidine (5-azc) resulted in a hypomethylation of mdv dna and an increase in mrna from certain portions of the mdv dna. these results suggest methylation of mdv dna as being one of the factors associated with a repression of transcription of mdv dna in the lymphoblastoid cell line, msb1.19947521217
identification of human telomeric repeat motifs at the genome termini of human herpesvirus 7: structural analysis and heterogeneity.human herpesvirus 6 (hhv-6) and hhv-7 are closely related t-lymphotropic betaherpesviruses which share a common genomic organization and are composed of a single unique component (u) that is bounded by direct repeats (drl and drr). in hhv-6, a sequences have been identified at each end of the dr motifs, resulting in the arrangement adrla-u-adrra. in order to determine whether determine whether hhv-7 contains similar a sequences, we have sequenced the drl-u and u-drr junctions of hhv-7 strain ji, ...19957494318
retention of oncogenicity by a marek's disease virus mutant lacking six unique short region genes.we previously reported the construction of marek's disease virus (mdv) strains having mutations in various genes that map to the unique short (us) region of the viral genome (j.l. cantello, a.s. anderson, a. francesconi, and r.w. morgan, j. virol. 65:1584-1588, 1991; m.s. parcells, a.s. anderson, and r.w. morgan, virus genes 9:5-13, 1994; m.s. parcells, a.s. anderson, and r.w. morgan, j. virol. 68:8239-8253, 1994). these strains were constructed by using a high-passage-level serotype 1 mdv strai ...19957494301
isolation and characterization of marek's disease virus (mdv) cdnas mapping to the bamhi-i2, bamhi-q2, and bamhi-l fragments of the mdv genome from lymphoblastoid cells transformed and persistently infected with mdv.we have isolated and sequenced two cdnas of sizes 2674 and 677 bp from a cdna library derived from mkt-1, a lymphoblastoid cell line transformed and latently infected with marek's disease virus (mdv) using probes corresponding to the right-hand end of the bamhi-i2 fragment of the mdv genome. the larger cdna clone represents an abundant transcript, which extends from the right-hand end of bamhi-i2 to the adjacent bamhi-q2 and bamhi-l fragments of the mdv genome and contains the meq (mdv eco-q) op ...19957491783
virus-neutralization domains on the oligomeric (230 kda) forms of antigen b of herpesvirus of turkeys and marek's disease virus differ in cross-serotypic activity.herpesvirus of turkeys (hvt) is frequently used to protect chickens against marek's disease (md). the hvt and mdv native antigen b complex shares common epitopes. to determine whether these oligomers present virus-neutralizing domains, monospecific antibodies to the hvt and mdv native 230 kda oligomers were produced. the monospecific antibody immunopurified from an anti-hvt avian serum neutralized the in vitro infectivity of the oncogenic isolate mdv-b and the vaccine strains cvi988, sb1 and hvt ...19957483903
endothelial mhc class ii antigen expression and endarteritis associated with marek's disease virus infection in chickens.experimental marek's disease virus (mdv) infection in chickens was used to study the early pathogenesis of virus-induced atherosclerosis. previous investigations using this model have reported the occurrence of atherosclerotic lesions after approximately 7 months postinfection. in this study, a total of 75 susceptible cornell p-line chickens were inoculated intraperitoneally with the cu-2 strain of mdv at 3 days of age and subsequently perfused for histologic examination. at 2, 4, 8, 13, and 20 ...19957483215
isolation and serological differentiation of a herpesvirus from bobwhite quail (colinus virginianus, l. 1758).an infectious agent was isolated from the liver of bobwhite quails (colinus virginianus, l. 1758). the agent was sensitive to chloroform and its multiplication was inhibited by 5-iodine-2-deoxy-uridine. it passed filters with a pore diameter of 220 nm and more but not 100 nm filters. electron microscopic examination revealed numerous nucleocapsids with hollow capsomeres and few enveloped particles in the supernatant fluids of infected cultures. the nucleocapsids were calculated to have 162 capso ...19807447711
selection for virulence and organ-specific metastasis of herpesvirus-transformed lymphoma cells.the marek's disease virus-transformed, non-producer, lymphoma cell line, mdcc-rpi, was selected by sequential transplantation to produce a highly malignant variant, mdcc-ali. this is evidenced gy an 18-fold decrease in ld50. the new cell line has an increased ability to form metastatic lesions in a distribution which mimics the natural disease. further selections for organ-specific metastasis were undertaken with the isolation of two cell lines, mdcc-al2, selected for liver metastasis, and mdcc- ...19807390658
cell-mediated immunity in marek's disease virus-infected chickens genetically selected for high and low concentrations of plasma corticosterone.lines of chickens genetically selected for high (hpc)-and low-plasma corticosterone (lpc) titers were assessed for cell-mediated immunity during marek's disease tumorigenesis. lymphocyte transformation (using phytohemagglutinin and 2,4-dinitrofluorobenzene-bovine serum complex) and mitogen-induced cellular cytotoxicity were evaluated with peripheral blood leukocytes. chickens from the lpc line showed a greater lymphocyte transformation response than those from the hpc line. all tumor-bearing chi ...19807362128
reduced vaccinal protection of turkey herpesvirus against field strains of marek's disease herpesvirus.four isolates of marek's disease herpesvirus (mdv) were obtained from 21-week-old broiler breeders with lesions and mortality from marek's disease (md). they had been properly vaccinated with turkey herpesvirus (hvt). the isolates were designated ala-7, 8, 9, and 10. these 4 mdv strains were compared with the ga isolate of mdv in chickens vaccinated with graded doses of hvt. challenge with the mdv strains was also with graded doses. all 5 isolates of mdv were similar in virulence. however, prote ...19817267529
the in vivo effect of levamisole on phytohaemagglutinin stimulation of lymphocytes in normal and marek's disease virus inoculated chickens. 19817255915
marek's disease as a model for the landry--guillain--barré syndrome: latent viral infection in nonneuronal cells accompanied by specific immune responses to peripheral nerve and myelin.in the chicken, marek's disease virus (mdv) induces a demyelinating peripheral neuropathy that, early in the course of the disease, is histopathologically indistinguishable from that seen in the landry--guillain--barré syndrome in man. a continuing role for a productive infection in the pathogenesis of this disease is unlikely, since neither mdv nor mdv antigens can be characteristically detected in nerves or spinal ganglia examined at necropsy. the authors investigated the possible role of a la ...19817234967
chronological observations of feather pulp lesions in chickens inoculated with marek's disease virus.observations of the feather pulp from chickens inoculated with marek's disease (md) virus revealed diverse lesions similar to those in the peripheral nerves of chickens infected with md. these lesions were categorized as follows: r1-type lesions = from minimal perivascular to diffuse infiltration of small lymphocytes mixed with a few medium lymphocytes or blast cells; r2-type lesion = edema and cellular infiltration consisting of plasma cells and small lymphocytes; and t-type lesion = tumorous p ...19827103893
transplantable marek's disease lymphomas. i. growth characteristics during development in two inbred lines of chickens.lymphomas developed in the pectoral muscle of most chickens inoculated with cells from primary marek's disease virus-induced visceral tumors obtained from chickens of the same inbred line. however, serial passaging of the lymphoma cells in histocompatible hosts generally resulted either in an eventual absence of tumor formation at the inoculation site or in tumor regression. exceptions occurred in two experiments, where tumors grew rapidly and the hosts died early. subsequent passaging of cells ...19827103886
adult t-cell leukemia: antigen in an atl cell line and detection of antibodies to the antigen in human sera.indirect immunofluorescence of certain human sera demonstrated an antigen(s) in the cytoplasm of 1--5% of the cells of a t-cell line, mt-1, from a patient with adult t-cell leukemia (atl), which is endemic in southwestern japan. the antigen was not detected in other human lymphoid cell lines, including six t-cell lines, seven b-cell lines, and four non-t non-b cell lines. the antigen did not show cross antigenicity with that of herpesviruses, including epstein--barr virus, herpes simplex virus, ...19817031654
independence of chicken major histocompatibility antigens and tumor-associated antigen on the surface of herpesvirus-induced lymphoma cells.capping of chicken major histocompatibility (mhc) antigens on normal thymus, spleen, and peripheral blood leukocytes was demonstrated, although mhc antigens appeared to be present on only 15 to 18% of normal thymus cells. mhc antigen capping also occurred on cells from a marek's disease herpesvirus-induced transplantable lymphoma (mdct-nym1). capping of a marek's disease tumor-associated surface antigen (matsa) could be induced on mdct-nym1 lymphoma cells as well as on cells of two marek's disea ...19807000703
natural killer cell activity in chickens: target cell analysis and effect of antithymocyte serum on effector cells.a battery of lymphoid and nonlymphoid cells was examined for susceptibility to lysis by natural killer cells of chickens. several susceptible targets were recognized, and most susceptible among these were cells of line lscc-rp9, derived from a lymphoid tumor induced by rous-associated virus 2. the natural killer reactivity against lscc-rp9 target cells did not appear to be directed against an antigen(s) induced by rous-associated virus 2 because other lymphoid and nonlymphoid cells infected with ...19816971810
surface antigens on marek's disease lymphoblastoid tumor cell lines.a total of 32 marek's disease virus (mdv)-induced cell lines, 1 avian leukosis virus-induced cell line, and 1 reticuloendotheliosis virus (rev)-induced lymphoblastoid cell line were investigated for the presence of fc receptors, surface igm, and ia-like antigen. surface igm and fc receptors could not be demonstrated on any of the cell lines. ia-like antigen was detected on all mdv-induced cell lines and on the 1 rev-induced cell line. ia-like antigen was unrelated to other antigens reported to b ...19826955560
herpesvirus-induced atherosclerosis in chickens.repeated experiments have established that infection with marek's disease herpesvirus (mdv) leads to atherosclerosis in specific pathogen free (spf) normocholesterolemic chickens. neither normocholesterolemic nor hypercholesterolemic uninfected spf chickens develop this disease. the mdv-induced arterial disease is remarkably similar to chronic human atherosclerosis. cholesterol and saturated cholesteryl esters accumulated in cultured arterial smooth muscle cells (smc) infected with mdv. similar ...19836840298
the occurrence of chicken foetal antigen after infection with marek's disease virus in three strains of chicken.an indirect immunofluorescence procedure employing specific antiserum was used to demonstrate chicken foetal antigen (cfa), a membrane antigen typically present on embryonic cells. the expression of cfa by lymphocytes from the peripheral blood, spleen, thymus and bursa was found to decline rapidly after hatching; the bursa, however, contained about 30% cfa-positive cells until at least 120 days of age. after infection of a genetically susceptible strain of chickens (hprs rhode island red) with m ...19836835849
[resistance of different breeds of laying poultry to marek's disease virus].investigated were a total of 447 two-day-old chicks of lines 5-a, ia-73' ll and ls of the leghorn breed divided into 2 groups: controls--99 males and females, and test ones--348 infected at the age of 2 days via intraabdominal injection with 0.4 cm3 heparinized blood each, containing 5000 pfu per dose of the marek's disease virus (ct-1 isolate). both linear and sexual variations were found in the resistance of the birds. most resistant proved to be the 5-a chicks of both sexes, and most suscepti ...19836659344
two sublines of a lymphoblastoid cell line associated with marek's disease virus.from mdcc-msb1, the original marek's disease virus-associated lymphoblastoid cell line, two sublines named mdcc-msb1-33c and mdcc-msb1-41c were differentiated. the mdcc-msb1-33c cell line grew well at 33 degrees, but grew poorly and finally stopped growing at 41 degrees. on the other hand, the mdcc-msb1-41c cell line grew actively at 41 degrees, but at 33 degrees, continuous cultivation was difficult to achieve. mdcc-msb1-33c grew suspended in the liquid medium, as did the original producer mdcc ...19836628902
marek's disease virus-induced transient paralysis: clinical and electrophysiologic findings in susceptible and resistant lines of chickens.results of neurologic examination, eeg, and motor nerve conduction velocity quantitation were analyzed in a line of chickens susceptible to marek's disease virus-induced transient paralysis and compared with findings in a resistant line. both lines were evaluated on the day before virus inoculation (day 1; base line) and on days 12 and 19. the susceptible birds frequently became depressed and paretic on day 11 or 12 and then recovered, and the resistant line rarely was affected clinically. the e ...19836625305
prediction of the occurrence of marek's disease in chickens on the basis of the quantitation of cell-mediated immunity.cell mediated immunity was assayed in chickens on the basis of the dinitrochlorobenzene skin test, t lymphocyte numbers in peripheral blood and the graft-versus-host reaction. it was found that chickens that were to develop clinical marek's disease following exposure to marek's disease virus had significantly lower prechallenge levels of cell mediated immunity than those that were resistant to marek's disease. the graft-versus-host reaction had a smaller coefficient of variation than the other t ...19846609388
presence of adherent cytotoxic cells and non-adherent natural killer cells in progressive and regressive marek's disease tumors.marek's disease virus-induced progressive tumors and marek's disease transplantable local regressive tumors were dispersed by treatment with collagenase and cells were examined in vitro for cytotoxic effector functions against target cells of tumor lines. both types of tumors had adherent and non-adherent cytotoxic cells. the cytotoxicity of adherent cells was detected in an 18-hour but not in a 4-hour 51cr-release assay. the adherent effector cells from progressive tumors were inactivated by pr ...19836606892
[genetic polymorphism of alkaline phosphatase and the resistance to marek's disease virus].experiments were carried out with a total of 222 birds of the 5-a, 6-e, ya-73, ll, and ls lines of the white leghorn breed to find whether or not there existed any correlation between the alkaline phosphatase allels and the resistance to marek's disease. the polymorphism of alkaline phosphatase was evaluated in the blood plasma of birds through horizontal electrophoresis in starch gel after g a hn e [3]. the resistance of the five egg laying lines of birds was found to be associated with the akp ...19836581645
in vitro suppression of t-cell mitogenic response and tumor cell proliferation by spleen macrophages from normal chickens.adherent cells isolated from spleen of normal specific pathogen-free chickens inhibited mitogen-induced blastogenesis of autochthonous, syngeneic, or allogeneic lymphocytes. the adherent cells were also inhibitory to in vitro proliferation of cells of a rapidly dividing tumor line, mdcc-msb-1, derived from a lymphoma induced by marek's disease virus. the effector cell of suppression of both lymphoprolifrative functions appeared to be a macrophage because the suppressive activity of adherent cell ...19806447112
cell-mediated immunity in marek's disease: cytotoxic responses in resistant and susceptible chickens and relation to disease.two experiments were conducted to study the cell-mediated cytotoxicity of peripheral blood leukocytes (pbl) from chickens inoculated with marek's disease virus (mdv) against a marek's disease-derived lymphoblastoid cell line (msb-1) and to associate the cytotoxicity with incidence of disease. in experiment i, moderately susceptible random-bred, specific-pathogen-free chickens were inoculated with mdv (group 1), vaccinated with a herpesvirus of turkeys (hvt) and inoculated with mdv (group 2), vac ...19806445171
extensive homology exists between marek disease herpesvirus and its vaccine virus, herpesvirus of turkeys.marek disease is a lymphomatous disease of chickens caused by infection of a herpesvirus, marek disease virus (mdv). marek disease is the only neoplastic disease for which a successful vaccine has been developed. the vaccine virus, herpesvirus of turkeys (hvt), is non-oncogenic in chickens. despite the strong antigenic relationship between these viruses, previous studies showed that the two viral dnas share little or no homology. using less stringent hybridization conditions and methods that gre ...19846328512
structure of marek's disease virus dna: detailed restriction enzyme map.purified virion dna (120 x 10(6) molecular weight [mw]) of marek's disease virus strain ga was cleaved with bamhi restriction endonuclease, and 27 out of the 29 fragments were cloned into bacterial plasmids. restriction maps for bamhi, bgli, and smai endonucleases were constructed. the genomic structure of marek's disease virus dna was found to be similar to that of herpes simplex virus types 1 and 2. a long unique region (75 x 10(6) mw, located at 10 x 10(6) to 85 x 10(6) mw [10-85] from the le ...19846328029
field trials to test the efficacy of polyvalent marek's disease vaccines in broilers.the efficacies of trivalent (md11/75c + sb-1 + hvt), bivalent (sb-1 + hvt), and turkey herpesvirus (hvt) vaccines against marek's disease (md) were compared in commercial broiler flocks in four trials involving 11 farm locations and 486,300 chickens. in all four trials, chickens receiving polyvalent vaccines had lower leukosis (md) condemnation rates than chickens vaccinated with hvt alone; when data were summarized for each vaccine type in each trial, condemnation rates for the bivalent- or tri ...19846326743
immunization against marek's disease transplantable cell lines.continuous passage of mdcc-rp1, a highly tumorigenic marek's disease (md) lymphoblastoid cell line, in cell culture resulted in a gradual loss in ability of the cell line to cause progressive tumors in susceptible day-old chicks. inoculation of day-old chicks with high-cell-culture-passaged (187th to 417th) nontumorigenic mdcc-rp1 cells gave excellent protection against challenge at 8 days with low-passaged tumorigenic mdcc-rp1 cells but failed to protect against primary tumors caused by inocula ...19846326737
aus in the prevention of marek's disease.aminoureidosulfone (aus) was used as a feed additive to prevent mortality in marek's disease (md)-infected chickens in the laboratory. chicks infected with md virus (5000 plaque-forming units) at 1 day of age were given aus in the feed from 1 day of age until the experiment was terminated. aus, at all concentrations tested, reduced mortality due to marek's disease. chickens receiving aus at the 0.002% level had a 4% mortality rate, those receiving 0.005% had 9% mortality, and those receiving 0.0 ...19846326736
[protecting chickens against marek's disease under laboratory conditions by the administration of marvak, a czechoslovak produced vaccine and vaccine imported from east germany].laboratory trials were conducted to compare the efficiency of two vaccines against marek's disease (md) on the basis of the dynamics of post-vaccination viraemia and by means of a challenge test. two groups of the hx-sl hybrid layers, each containing 40 birds, were vaccinated with the marvak cellular vaccine manufactured in czechoslovakia (100 pfu per chick) or with the insel riems vaccine manufactured in the gdr (1000 pfu per chick). in weekly intervals, half the birds of each group were tested ...19846326372
in vivo and in vitro infections of chicken lymphocytes with marek's disease virus or herpesvirus of turkeys. 19836323800
[early mortality syndrome in chickens following double infection with marek's disease virus and chicken anemia agent]. 19836322482
[vaccinating properties of the kekava 55 strain of attenuated marek's disease virus].two attenuated strains of oncogenic herpes virus, marek's disease virus, were obtained: one by cultivation in chick fibroblast cultures at 37 degrees c, the other at 41 degrees c, i. e. at chicken body temperature. both attenuated strains throughout a large number of passages retain high vaccination efficacy, on the average 76% and 77.3%, respectively. the virus attenuated at 41 degrees c is superior to that attenuated at 37 degrees c in higher reproduction rate in vitro and, possibly, in a grea ...19836322454
identification with monoclonal antibodies of glycoproteins of marek's disease virus and herpesvirus of turkeys related to virus neutralization.by use of monoclonal antibodies cross-reactive with marek's disease virus and herpesvirus of turkeys, three glycoproteins (for marek's disease virus, gp115/110, gp63, and gp50; for herpesvirus of turkeys, gp115, gp62 and gp52) related to virus neutralization were identified. immunization of chickens or rabbits with these glycoproteins purified by affinity chromatography resulted in production of neutralizing antibodies.19846321752
the use of reference preparations in virus content testing of vaccines.a series of virus content tests on newcastle disease, avian infectious bronchitis and marek's disease vaccines was carried out over a period of several years on commercial products together with a standard preparation of each virus. analysis of the results of marek's disease vaccine titrations revealed a good correlation between plaque count and the ratio obtained for the standard vaccine tested in parallel. expression in relation to a reference preparation is therefore of value to vaccine manuf ...19846321508
further characterization of marek's disease virus-infected lymphocytes. ii. in vitro infection.lymphocyte cultures from chicken spleens had been shown to be susceptible to in vitro infection by marek's disease virus (mdv)4 in an earlier report from this laboratory. in that study, virus infection was evidenced by virus isolation and detection of viral internal antigen (via) 2 days post inoculation (dpi), and serial passage was accomplished by adding fresh spleen cells at 2-day intervals. the susceptible cells were identified as bursa-derived lymphocytes (b cells). using a dual fluorescence ...19846321365
further characterization of marek's disease virus-infected lymphocytes. i. in vivo infection.previous reports from this laboratory identified bursa-derived lymphocytes (b cells) and non-b cells as the predominant cell types respectively involved in the early cytolytic and subsequent latent infection of chickens with marek's disease virus (mdv). it was not known whether these differences were qualitative or quantitative or if the method for detection of latent infection (viral antigen production after 48 h of in vitro cultivation) was sensitive enough. to further define the cells involve ...19846321364
genetic relatedness of virulent and avirulent strains of marek's disease virus.comparative studies using southern blot hybridization indicated that the avirulent strains of marek's disease virus (mdv) were probably generated through dna rearrangement that occurred in the limited area(s) of the virulent mdv genome.19846320782
Displaying items 1201 - 1300 of 1987