| presence of lesions without virus replication in the thymus of chickens exposed to infectious bursal disease virus. | specific-pathogen-free (spf) chickens were exposed to the im and va isolates of virulent infectious bursal disease virus (ibdv). both viruses induced rapidly progressing lymphoid cell depletion in the bursa. the bursal lesions persisted through the observation period of 16 days. the virus-exposed birds also had histologic lesions in the thymus. thymic lesions peaked at 3-4 days postinoculation (pi) and then subsided. immunofluorescence (if) and antigen-capture enzyme-linked immunosorbent assay ( ... | 1993 | 8257365 |
| rapid and quantitative assay system for measuring anti-infectious bursal disease virus antibody using monoclonal antibody bound to polystyrene latex microspheres. | a monoclonal antibody (mab) to infectious bursal disease virus (ibdv) that has virus-neutralizing activity was bound to polystyrene latex microspheres the microspheres agglutinated with extracts of bursae from chickens infected with ibdv. agglutination was inhibited in a competitive manner by adding serum obtained from ibdv-infected chickens. the level of agglutination-inhibition depended on the serum antibody titer against ibdv. the reaction was visually accomplished within 5 minutes. the titer ... | 1993 | 8257372 |
| antibody detection in matched chicken sera and egg-yolk samples by commercial enzyme-linked immunosorbent assay kits for newcastle disease virus, infectious bronchitis virus, infectious bursal disease virus, and avian reovirus. | elisa kits have been used to detect antibody in egg yolk. the major advantage eggs offer over blood samples is the ability to collect samples without compromising flock biosecurity. a disadvantage to using egg yolk over sera concerns the method of preparing yolk for antibody testing. the technique used in this study involved a simple dilution method with no mixing or extraction. to determine the adequacy of yolk samples to replace serum samples, a serum sample and the first six eggs were obtaine ... | 1993 | 8257378 |
| flow cytometric analysis of the neutralizing immune response against infectious bursal disease virus using reticuloendotheliosis virus-transformed lymphoblastoid cell lines. | infectious bursal disease virus (ibdv) is a lymphotropic virus with cytocidal effect on b lymphocytes of the bursa of fabricius. we investigated the susceptibility of clonal populations of reticuloendotheliosis virus-transformed chicken b lymphocytes of both spleen and bursal origin to ibdv infection. the infected cells were metabolically-labelled and the viral polypeptides were analyzed by immunoprecipitation using monoclonal antibodies (mabs). virus adsorption and the effects of neutralizing c ... | 1993 | 8263113 |
| agar gel precipitin line patterns and pathogenicity of infectious bursal disease viruses. | twenty-nine strains of infectious bursal disease virus could be classified into three groups by the agar gel precipitin line patterns using two representative base antigens of f539 and g691 strains. the precipitin line of the first group (16 strains including f539) did not fuse with that of g691 base antigen and spur was seen. the line of the second group (2 strains) did not fuse with those of both base antigens. the line of the third group (11 strains including g691) did not fuse with that of f ... | 1993 | 8384895 |
| genetic differences in susceptibility of chicken lines to infection with infectious bursal disease virus. | mortality rates in 11 inbred and partially inbred chicken lines inoculated with a very virulent strain (cs89) of infectious bursal disease virus (ibdv) varied considerably, being highest (almost 80%) in a brown leghorn line (brl). bursa of fabricius to body weight ratios were depressed in the survivors in each line, but no differences were observed between lines. however, histological examination of bursae from survivors showed that, although bursal damage occurred in every line, it was most sev ... | 1993 | 8385328 |
| immunomodulating effects of levamisole in chicks immunocompromised by infectious bursal disease virus. | immunomodulating effects of levamisole in experimentally ibd induced immunosuppressed 7-days old white leghorn chicks have been observed. for this, infectious bursal disease (ibd) virus (poona strain) was used. all the chicks were immunised with sheep red blood cells to monitor antibody responses. a group of chicks each from infected (ps-l) and uninfected (pbs-l) groups were given 4 injections of levamisole hydrochloride at the daily dose of 1.5 mg per 100 g body weight starting from the second ... | 1993 | 8385372 |
| chemiluminescent detection of infectious bursal disease virus with a pcr-generated nonradiolabeled probe. | a polymerase chain reaction (pcr)-generated digoxigenin-labeled nonradioactive oligonucleotide probe was developed and utilized in slot-blot hybridization coupled with chemiluminescence for the detection of infectious bursal disease virus (ibdv). the probe was prepared from the rna of the standard challenge strain (stc) of ibdv serotype 1 by reverse transcription followed by 2 pcr amplifications with 2 separate sets of primers. rna of stc viruses prepared from bursae infected with stc viruses wa ... | 1993 | 8389597 |
| infectious bursal disease virus structural proteins expressed in a baculovirus recombinant confer protection in chickens. | plasmids were prepared that contained cdna segments of the large genomic segment a of infectious bursal disease virus (ibdv) strain gls-5. the genes encoding the ibdv structural proteins (vp2, vp3 and vp4) were introduced into the baculovirus transfer vector pbluebaci to obtain a recombinant baculovirus vibd-7. when insect cells were infected with recombinant viruses, the result was synthesis of ibdv precursor proteins which were processed by the viral protease. the recombinant ibdv antigens wer ... | 1993 | 8389805 |
| infectious bursal disease virus structural protein vp2 expressed by a fowlpox virus recombinant confers protection against disease in chickens. | two fowlpox virus recombinants were constructed which expressed the host-protective antigen, vp2, of infectious bursal disease virus (ibdv). recombinant fpv-vp 2.4.3 contained the gene for the vp 2-vp4-vp3 polyprotein under the control of the vaccinia virus late promoter p.l 11 inserted within the thymidine kinase (tk) gene of fpv. in infected chicken embryo skin (ces) cells vp2 and vp3 proteins were correctly processed from the polyprotein precursor molecule. recombinant fpv-vp2 contained only ... | 1993 | 8394069 |
| a rapid quantitative method for detecting infectious bursal disease virus using polystyrene latex microspheres. | a monoclonal antibody (mab) to infectious bursal disease virus (ibdv) was bound to polystyrene latex microspheres. the microspheres agglutinated with extracts of bursae and sera from chickens infected with all strains or isolates of ibdv tested. agglutination appeared within a 10-min reaction time. the assay could detect a 10(3.7) to 10(4.5) mean embryo infective dose (eid50) of the virus in 0.01 ml and the titer of the assay was 10- to 40-times higher than that of the agar gel precipitin test. | 1993 | 8395538 |
| sequence comparisons of a highly virulent infectious bursal disease virus prevalent in japan. | variable cdna regions in the vp2 gene of five highly virulent infectious bursal disease viruses (ibdvs) isolated in japan were amplified by polymerase chain reaction (pcr) and sequenced. the nucleotide sequences of five highly virulent ibdvs were identical. comparisons of the nucleotide and the deduced amino acid sequences with those of other strains of ibdv indicated that japanese highly virulent ibdv is different from all other strains of ibdv that were compared. the number of amino acids that ... | 1993 | 8395796 |
| production and characterization of monoclonal antibodies against variant a infectious bursal disease virus. | monoclonal antibodies (mabs) were produced against a variant subtype of infectious bursal disease virus (ibdv) from delaware variant isolate a (var-a). splenocytes from immunized mice were fused to myeloma cells, and antibody-producing hybridomas were screened by dot-blot enzyme-linked immunosorbent assay (elisa) and indirect immunofluorescence (if) against the homologous isolate. specificity of the mabs was tested against viral isolates representing all six serologic subtypes of ibdv and three ... | 1993 | 8395799 |
| immunohistochemical detection of infectious bursal disease virus in formalin-fixed, paraffin-embedded chicken tissues using monoclonal antibody. | immunoperoxidase and immunofluorescence techniques detected and localized infectious bursal disease virus (ibdv) in formalin-fixed paraffin-embedded sections of the bursa of fabricius of experimentally and naturally infected chickens. the primary antibody was a monoclonal antibody that bound all ibdv serologic subtypes, including the gls isolate. both techniques were valuable in detecting ibdv. the presence and severity of microscopic lesions in the bursa correlated with the location and number ... | 1993 | 8395809 |
| seroprevalence of infectious bursal disease (ibd) in parts of tamil nadu, india. | sera samples of 400 apparently healthy broiler poultry from 23 commercial farms and 120 sera samples from commercial layer poultry [with specific lesions of infectious bursal disease (ibd) in the internal organs] were screened for the presence of ibd serotypes i, ii and the variant strain by the agar gel immuno diffusion (agid) test, employing standard antigens. likewise the bursae, spleen and kidney specimen from 96 layer poultry with lesions suggestive of ibd were screened for the presence of ... | 1993 | 8403839 |
| efficacy of subcutaneous application of live infectious bursal disease vaccine in young chickens with maternally derived antibody. | the infectivity of neutralized ibdv by normal chicken serum (ncs) was detected in day-old and 3-week-old chicken spleen adherent (csa) cells, and that of neutralized ibdv by maternal antibody (mn-ab) was detected in 3-week-old csa cells. moreover, csa cells from day-old chickens had complement receptor (cr), and csa cells from 1-week-old had both cr and fc receptor (fcr). however, the infectivity of neutralized ibdv by mn-ab was confirmed on csa cells which were blocked for fcr on csa cells by h ... | 1995 | 8519892 |
| comparison of neutralizing epitopes among infectious bursal disease viruses using radioimmunoprecipitation. | monoclonal antibodies (mabs) were used to analyze the relatedness of neutralizing epitopes of infectious bursal disease virus (ibdv) strains. the mab b69 neutralized the homologous d78 virus but not the md and del-a variant strains of ibdv. mabs 33e8 and r63 neutralized d78 and variant strains md and del-a. a cdna clone consisting of a 1000-base-pair fragment of the vp2 gene from the del-a ibdv strain was translated using an in vitro system. six peptides were observed following translation, whic ... | 1995 | 8561733 |
| the effect of route of inoculation on protection by killed vaccines in chickens. | the effect of various routes of immunization on protection against challenge by virulent agents was examined in chickens. chickens were immunized intratracheally, intranasally, per os, by crop gavage, and intramuscularly. agents examined were killed haemophilus paragallinarum, mycoplasma gallisepticum, and infectious bursal disease virus. results of immunization by intratracheal administration were equivalent to those produced by parenteral administration. all vaccines effectively induced produc ... | 1995 | 8561734 |
| a highly sensitive, broad-spectrum infectivity assay for infectious bursal disease virus. | in order to develop an infectivity assay for infectious bursal disease virus (ibdv), an enzyme-linked immunosorbent assay (elisa) for detecting ibdv antigens was developed using a rabbit antiserum to ibdv. the elisa detected both serotypes 1 and 2 of ibdv, purified virus proteins at a concentration of about 0.1 ng/well and about 10(4) to 10(5) infectious units/well, and was about 10(3) times more sensitive than an agar gel precipitin test. by using the elisa for detecting ibdv antigens in the cu ... | 1995 | 8561743 |
| restriction fragment profiles of genome segment a of infectious bursal disease virus correlate with serotype and geographical origin of avibirnaviruses. | previous analysis of the two serotypes of infectious bursal disease virus (ibdv) have demonstrated the correlation between antigenicity and similarities of nucleotide and amino acid sequences of the vp2 coding region in genome segment a. restriction fragment profiles of genomic segment a cdna of five ibdv isolates (qc-2 and qt-1 of serotype 1, sk9, and nos. 39 and 52 of serotype 2) were determined in order to establish the genetic relationship of these viruses to other avibirnaviruses. the restr ... | 1996 | 8595603 |
| susceptibility of chicken lymphoid cells to infectious bursal disease virus does not correlate with the presence of specific binding sites. | pathogenic serotype 1 strains of infectious bursal disease virus (ibdv) replicate efficiently in lymphoid cells of the bursa of fabricius of chicken. lymphoid cells in other organs are not susceptible. apathogenic serotype 2 strains do not replicate in lymphoid bursa cells or in other lymphoid cells. chicken embryo fibroblasts (cef), however, efficiently replicate strains of either serotype. binding studies showed that strains of both ibdv serotypes bind to lymphoid cells isolated from the bursa ... | 1996 | 8683211 |
| determination of the 5' and 3' terminal noncoding sequences of the bi-segmented genome of the avibirnavirus infectious bursal disease virus. | terminal sequences of the bi-segmented dsrna genome of 3 different strains of infectious bursal disease virus (ibdv) were analyzed by the rapid amplification of cdna 5' ends (5'race) procedure. both segments are 85% homologous in a 32-nucleotide sequence comprising the 5' end, whereas the 3' end has a conserved pentamer. comparison to published terminal sequences of other ibdv strains revealed high conservation between the two segments but more serotype-specific nucleotide changes (5 on segment ... | 1996 | 8712930 |
| apoptosis in cell cultures induced by infectious bursal disease virus following in vitro infection. | chicken embryo fibroblasts (cefs) and vero cells infected with infectious bursal disease virus (ibdv) exhibited the biochemical feature of apoptosis. agarose gel electrophoresis of dna extracted from ibdv-infected cells revealed the characteristic laddering pattern of dna fragmentation, which was more intense in infected cefs than in vero cells. the appearance of apoptotic nucleosomal dna fragments in ibdv-infected cefs was independent of virus replication and occurred at an early stage followin ... | 1996 | 8713023 |
| determination of optimum formulation of a novel infectious bursal disease virus (ibdv) vaccine constructed by mixing bursal disease antibody with ibdv. | a novel vaccine against infectious bursal disease virus (ibdv) has been developed. the new vaccine was constructed by mixing bursal disease antibody (bda) contained in whole antiserum with live ibdv before lyophilization. to establish various formulations of bda and ibdv, several bda doses between 5 units and 80 units of bda/50 microliters were mixed with 100 eid50/50 microliters of ibdv suspension in expt. 1; in expt. 2, several ibdv doses between 10 eid50/50 microliters and 977 eid50/50 microl ... | 1995 | 8719201 |
| pathogenicity and persistence of salmonella enteritidis and egg contamination in normal and infectious bursal disease virus-infected leghorn chicks. | the pathogenicity and persistence of salmonella enteritidis (se) phage type 8 and resulting egg contamination in normal and infectious bursal disease virus (ibdv)-infected white leghorn chicks were evaluated over 34 weeks and in some birds over a 64-week period. four hundred 1-day-old specific-pathogen-free (spf) straight-run white-leghorn chickens were allotted into four treatment groups: negative control, ibdv-infected, ibdv+se-infected, and se-infected. chicks were infected with ibdv at 1 day ... | 1995 | 8719211 |
| comparison of virus replication efficiency in lymphoid tissues among three infectious bursal disease virus strains. | in order to study replication efficiency of infectious bursal disease virus (ibdv) in lymphoid tissues, both the virus titers and the virus antigen titers in four lymphoid tissues were compared among chickens inoculated with ehime/91 (about 50% mortality), j1 (no mortality), or k (attenuated) ibdv strains during 1-7 days postinoculation (pi). ibdv antigens in tissue homogenates were detected by an enzyme-linked immunosorbent assay. in the bursa of fabricius, higher virus titers were maintained f ... | 1995 | 8719219 |
| coding sequences of both genome segments of a european 'very virulent' infectious bursal disease virus. | the sequences of segment a (encoding the vp2-vp4-vp3 polyprotein and vp5) and segment b (encoding vp1) of a recent, 'very virulent' (vv) european isolate (uk661) of infectious bursal disease virus (ibdv), a birnavirus, have been determined. there are 26 to 36 amino acid substitutions compared to any other type i ibdv within the segment a polyprotein (of these, 15 are unique) and about 50 substitutions within vp1 (of which 16 are unique). there is more variation compared to classical and antigeni ... | 1996 | 8725117 |
| replacement of challenge procedures in the evaluation of poultry vaccines. | vaccination of poultry flocks, especially parent flocks, is often performed with the intention of protecting the progeny via maternal antibodies during the first weeks of life. the efficacy of this vaccination schedule, more precisely described as induction of indirect protection, is normally proven by challenging the chickens. to avoid the challenge, some trials were performed, with the intention of establishing a correlation between antibody titres of vaccinated hens, embryonated eggs, and hat ... | 1996 | 8785945 |
| infectious bursal disease viral rna amplification using rt/pcr from bursa tissue following phenol: chloroform inactivation of the virus. | the preservation of viable infectious agents for future studies could create complicated logistic problems, and at times it is not feasible. methods for preserving the genetic integrity of inactivated agents would not only facilitate these studies but would also make it possible to transport inactivated preparations around the world. in this report, the effect of inactivation on the genetic material of infectious bursal disease virus (ibdv) was studied. tissues from the bursa of fabricius of bir ... | 1996 | 8790899 |
| concomitant ornithobacterium rhinotracheale and newcastle disease infection in broilers in south africa. | ornithobacterium rhinotracheale was first isolated from broilers in south africa in 1991. the importance of o. rhinotracheale infections has been established, with growth suppression, respiratory symptoms, and arthritis commonly seen as complications. dual infection with newcastle disease and o. rhinotracheale in 28-day-old broilers led to more severe respiratory lesions and higher mortality rates than in birds with only newcastle disease. it was concluded that the pathogenicity of newcastle dis ... | 1996 | 8790906 |
| identification of sequence changes responsible for the attenuation of highly virulent infectious bursal disease virus. | the genetic changes responsible for the attenuation of infectious bursal disease virus (ibdv) have not been defined at the molecular level, although passage of the virus in cell culture results in the loss of virulence. to understand the molecular basis of ibdv virulence and attenuation, the ibdv genome segment encoding the precursor polyprotein (nh2-vp2-vp4-vp3-cooh) of a cell culture-adapted okymt strain derived from highly virulent okym was cloned as cdna, and the nucleotide sequence was dete ... | 1996 | 8806555 |
| enzyme-linked immunosorbent assay-based detection of antibodies to antigenic subtypes of infectious bursal disease viruses of chickens. | an enzyme-linked immunosorbent assay (elisa) using a fragment of the infectious bursal disease virus (ibdv) vp2 gene expressed in baculovirus was developed. a 944-bp portion of the vp2 gene from the del-a strain of ibdv was ligated into the pac360 transfer vector and transfected into baculovirus, recombinant baculoviruses were identified by dot blot hybridization. the recombinant baculovirus 9a5 expressed a 57-kda vp2 fusion protein, which was immunoprecipitated. this baculovirus-expressed vp2 w ... | 1996 | 8807213 |
| synthetic transcripts of double-stranded birnavirus genome are infectious. | we have developed a system for generation of infectious bursal disease virus (ibdv), a segmented double-stranded rna virus of the birnaviridae family, with the use of synthetic transcripts derived from cloned cdna. independent full-length cdna clones were constructed that contained the entire coding and noncoding regions of rna segments a and b of two distinguishable ibdv strains of serotype i. segment a encodes all of the structural (vp2, vp4, and vp3) and nonstructural (vp5) proteins, whereas ... | 1996 | 8855321 |
| epitope mapping of capsid proteins vp2 and vp3 of infectious bursal disease virus. | twenty hybridoma cell lines producing monoclonal antibodies (mabs) against serotype 1 infectious bursal disease virus (ibdv) of gbf-1 and the attenuated gbf-1e strains were produced. the mabs recognized major structural proteins vp2 and vp3. mab recognition sites were mapped using recombinant escherichia coli clones which expressed n-terminal and (or) c-terminal truncated virus antigens, and competitive-binding assays. at least 3 conformation-dependent serotype 1 specific virus neutralizing anti ... | 1996 | 8856029 |
| in vitro attenuation of highly virulent infectious bursal disease virus: some characteristics of attenuated strains. | some strains of highly virulent infectious bursal disease virus (hv-ibdv) were adapted through serial passage in embryonated eggs. the embryonated egg-adapted hv-ibdv was successfully adapted to grow in chicken embryo fibroblast (cef) cell cultures showing a cytopathic effect by preparing the cef cells from the virus-infected embryos. the embryonated egg- and cell culture-adapted strains significantly reduced their pathogenicity to, and did not kill any, young chickens in experimental infection. ... | 1996 | 8883777 |
| pathogenicity studies of an arkansas variant infectious bursal disease virus. | a variant infectious bursal disease virus (ibdv), ibdv-s977, was blind passaged in cell culture, plaque purified, and attenuated by serial passage at a high multiplicity of infection (moi) in chick embryo fibroblasts (cef). cell culture passages of virus caused less bursal atrophy and splenomegaly than did the original isolate and retained immunogenicity; however, virus tended to persist for a longer time in the bursa and spleen of birds infected with the highest cef passages. antibody to both l ... | 1996 | 8883779 |
| influence of the host system on the pathogenicity, immunogenicity, and antigenicity of infectious bursal disease virus. | the effect of the host system on the pathogenicity, immunogenicity, and antigenicity of infectious bursal disease virus (ibdv) was investigated. one classic (sal) and one variant strain (in) of ibdv were passaged separately six times in three host systems, namely bgm-70 continuous cell line, primary chicken embryo fibroblast (cef) cells, or embryonating chicken eggs (embryos) or one time in the bursa of fabricius (bf) of specific-pathogen-free (spf) chickens. passage in bgm-70 cells or cef cells ... | 1996 | 8883783 |
| comparison between antigen-capture elisa and conventional methods used for titration of infectious bursal disease virus. | two antigen-capture enzyme-linked immunosorbent assays (polyclonal and monoclonal ac-elisas) were developed and evaluated for titration of infectious bursal disease viruses (ibdvs) propagated in different host systems, namely bgm-70 continuous cell line, primary chicken embryo fibroblast cells, and chicken bursa of fabricius. the polyclonal system was more sensitive (p < 0.05) than the monoclonal system but both were specific as indicated by the negative results obtained with three non-ibdvs. th ... | 1996 | 8883784 |
| pathogenicity, attenuation, and immunogenicity of infectious bursal disease virus. | an investigation was conducted in specific-pathogen-free chickens on the pathogenicity of bursa-derived and tissue culture-attenuated classic (stc) and variant (in) serotype 1 strains of infectious bursal disease virus. the in bursa-derived virus caused bursal inflammation, necrosis, and atrophy earlier than the bursa-derived stc virus. both viruses lost their pathogenicity after four passages in bgm-70 cells. a statistically significant level (p < 0.05) of protection was observed in spf chicken ... | 1996 | 8883785 |
| antigenic characterization of an arkansas isolate of infectious bursal disease virus. | the s977 strain of infectious bursal disease virus (ibdv) was isolated in northwest arkansas in 1977 from the bursae of young broilers with high maternal antibody titers to the moulthrop strain of ibdv (bursavac). the comparison of a plaque-purified isolate of s977 with other ibdv serotype 1 and serotype 2 strains using virus neutralization indicates that s977 is a subtype of serotype 1 vaccine viruses and the md variant strain of ibdv and has no relatedness to the delaware variant a (vara) viru ... | 1996 | 8883789 |
| divergent antibody responses to vaccines and divergent body weights of chicken lines selected for high and low humoral responsiveness to sheep red blood cells. | primary and secondary antibody responses to intramuscularly administered proteins of eschericia coli (f11), newcastle disease virus (ncd), infectious bronchitis virus (ib), and infectious bursal disease virus (ibd), respectively, were measured at weekly intervals in two chicken lines. the latter had been divergently selected for high and low antibody responses to sheep red blood cells (srbc), and in a random-bred control line. an oil-based adjuvant was required to induce primary and secondary an ... | 1996 | 8883795 |
| sequence analysis of the bicistronic drosophila x virus genome segment a and its encoded polypeptides. | drosophila x virus represents the entomobirnavirus genus of the family birnaviridae. segment a of this bisegmented dsrna containing virus was cloned and sequenced. the 3360-bp-long nucleotide sequence revealed the presence of two open reading frames (orfs). a large orf of 3096 nucleotides, which is flanked by a 107-bp 5' and a 157-bp 3'-untranslated region, and a 711-nucleotide-long small orf located within the carboxy half of the large orf but in a different reading frame. the large orf encodes ... | 1996 | 8918922 |
| susceptibility of chicken embryos to highly virulent infectious bursal disease virus. | the susceptibility of chicken embryos to highly virulent infectious bursal disease virus (hvibdv), strains f539 and dv86, was examined with respect to three inoculation routes and compared with the classical type of ibdv, strain g691. death patterns of embryos infected with strains f539 and dv86 of hvibdv were observed constantly and most of the infected embryos died; however, the death pattern associated with the strain g691 of classical ibdv was erratic and not related to the virus titer inocu ... | 1996 | 8959664 |
| insect cell-derived vp2 of infectious bursal disease virus confers protection against the disease in chickens. | infectious bursal disease virus (ibdv) has become a major problem in recent years. conventional vaccines make use of attenuated or inactivated viral strains, but these are gradually losing their effectiveness. we investigated the possibility of using purified vp2, a subunit of ibdv structural protein expressed in insect cells, as a vaccine. the vp2 gene was cloned into pacym1. the cloned gene was expressed in a baculovirus system, giving rise to a high quantity of recombinant vp2 (rvp2) protein. ... | 1996 | 8980802 |
| antigenicity, pathogenicity, and immunogenicity of small and large plaque infectious bursal disease virus clones. | a serotype 1 variant strain of infectious bursal disease virus designated in was passaged 40 times in bgm-70 cell line. a small plaque (sp) clone and a large plaque (lp) clone were then isolated and plaque purified four times. the sp and lp viruses formed circular plaques about 0.5 mm and 6.0 mm in diameter, respectively. both clones lost their pathogenicity for specific-pathogen-free (spf) chickens and did not elicit significant levels of virus-neutralizing antibody titers. however, the sp and ... | 1996 | 8980814 |
| restriction analysis of the md infectious bursal disease virus strain. | the variant md strain of infectious bursal disease virus (ibdv) was examined using restriction fragment length polymorphism (rflp) and the molecular variation was compared with published sequences of both variant and classic ibdv strains. viral rna was transcribed into cdna using reverse transcriptase and then amplified by the polymerase chain reaction (pcr). three separate but overlapping fragments of 1603 bp, 1496 bp, and 1066 bp containing the entire coding region for vp2, vp4, and vp3, respe ... | 1996 | 8980828 |
| three-dimensional structure of infectious bursal disease virus determined by electron cryomicroscopy. | infectious bursal disease virus (ibdv), a member of the birnaviridae group, is a commercially important pathogen of chickens. from electron micrographs of frozen, hydrated, unstained specimens, we have computed a three-dimensional map of ibdv at about 2 nm resolution. the map shows that the structure of the virus is based on a t=13 lattice and that the subunits are predominantly trimer clustered. the subunits close to the fivefold symmetry axes are at a larger radius than those close to the two- ... | 1997 | 8985353 |
| applications in in ovo technology. | by mid-august 1995, 55% of broiler embryos in north america were vaccinated for marek's disease using the inovoject system, with 201 inovoject machines placed with 16 of the top 25 poultry producers, providing the industry with the capacity to inject in excess of 400 million eggs per month or about 5 billion eggs per annum. in ovo administration of a bursal disease antibody-infectious bursal disease virus (bda-ibdv) complexed vaccine to specific-pathogen-free (spf) embryos was safer and more pot ... | 1997 | 9037703 |
| history of infectious bursal disease in the u.s.a.--the first two decades. | infectious bursal disease (ibd) emerged in 1957 as a clinical entity responsible for acute morbidity and mortality in broilers on the delmarva peninsula. the condition spread rapidly and was recognized throughout the u.s. broiler and commercial egg production areas by 1965. early attempts to isolate the etiologic agent were impeded by a lack of specific-pathogen-free (spf) eggs and by deficiencies in viral and serologic techniques. by 1967, the highly infectious nature of the agent was recognize ... | 1997 | 9087316 |
| sequence comparisons of the variable vp2 region of eight infectious bursal disease virus isolates. | the vp2 gene is part of the genomic segment a of infectious bursal disease virus (ibdv). it has been identified as the major host-protective antigen of ibdv and is known to contain conformationally dependent protective epitopes. a 643-base pair segment covering the hypervariable region of this gene from three recent serologic variant ibdv isolates from the southeastern united states, two variants from the delmarva peninsula, and three serologic standard viruses were amplified and sequenced using ... | 1997 | 9087318 |
| molecular identification of infectious bursal disease virus strains. | twenty-two infectious bursal disease virus (ibdv) strains were examined using the reverse transcriptase/polymerase chain reaction-restriction endonuclease (rt/pcr-re) assay. a 394-bp fragment of the vp2 gene was amplified and tested for six different restriction enzyme sites. although the ecorii enzyme was used in previous rt/pcr-re assays, results obtained using the isoschizomer bstni were more consistent because its activity does not rely on multiple restriction sites. ten different rt/pcr-re ... | 1997 | 9087325 |
| further development and use of a molecular serotype identification test for infectious bronchitis virus. | previously, we developed a rapid serotype identification test for infectious bronchitis virus (ibv) that utilizes the reverse transcriptase-polymerase chain reaction (rt-pcr) and restriction fragment length polymorphism analysis. the rt-pcr is used to amplify the s1 gene from rna extracted from the virus grown in eggs. restriction enzyme digestion and electrophoresis of that pcr product is used to determine the serotype of the virus. the purpose of this study was threefold. first, using a modifi ... | 1997 | 9087326 |
| detection of infectious bursal disease viruses in commercially reared chickens using the reverse transcriptase/polymerase chain reaction-restriction endonuclease assay. | bursa samples from the united states, mexico, and puerto rico were tested for the presence of infectious bursal disease virus (ibdv) using the reverse transcriptase/polymerase chain reaction-restriction endonuclease (rt/pcr-re) assay. this assay amplifies a 394-bp fragment of the ibdv vp2 gene. a total of 151 samples were tested. each was from a different physical location or farm. forty-eight of the samples were determined to contain ibdv using rt/pcr. the re profiles on 44 of these positive sa ... | 1997 | 9087330 |
| plasma alpha 1-acid glycoprotein in chickens infected with infectious bursal disease virus. | the concentration and affinity to concanavalin a (cona) of plasma alpha 1-acid glycoprotein (agp) and agp levels in extracts of liver tissues were investigated in specific-pathogen-free chickens infected with the highly virulent hps-2 strain or virulent reference gbf-1 strain of infectious bursal disease virus. the plasma agp value in uninfected control 3- to 7-wk-old chickens was 161.8 +/- 25.8 micrograms/ml (mean +/- sd), and cona-unreactive and cona-reactive agp comprised 47% and 63% of total ... | 1997 | 9087333 |
| infectious bursal disease virus: a review of molecular basis for variations in antigenicity and virulence. | | 1997 | 9114957 |
| modified activity of a vp2-located neutralizing epitope on various vaccine, pathogenic and hypervirulent strains of infectious bursal disease virus. | nine monoclonal antibodies (mabs) to a vaccine strain of infectious bursal disease virus (ibdv) of intermediate virulence were characterized in western-blot, radioimmunoprecipitation, elisa additivity, and neutralization assays. at least two distinct serotype 1-specific conformation-dependent overlapping neutralizing antigenic domains were shown to be present on ibdv-vp2, and were respectively probed by mabs 3 and 4, and by mabs 6 and 7. ten serotype 1 vaccine or pathogenic ibdv strains were tes ... | 1997 | 9125042 |
| the characterization of infectious bursal disease virus strains/isolates from field outbreaks in india. | three infectious bursal disease virus (ibdv) isolates were adapted to culture in chick embryo fibroblast cells in which they produced a cytopathic effect. the isolates were identified as ibdv by virus neutralization tests using a standard hyperimmune serum against infectious bursal disease, physicochemical properties and their pathogenicity in chick embryos and chicks. the ibdv s394 strain was antigenically different from ibdv s194/ibdv s494 as well as from the ibdv intermediate georgia strain, ... | 1997 | 9151413 |
| poultry virus infection in antarctic penguins. | | 1997 | 9153386 |
| the culture of chicken embryo fibroblast cells on microcarriers to produce infectious bursal disease virus. | the cultures of chicken embryo fibroblast (cef) cells in flasks, spinner bottles, and bioreactors were studied. the growth and metabolism characteristics of cef cells and the feasibility of the cef cell culture in bioreactor were investigated. the plating process of the cef cells on gt-2 microcarriers in spinner bottles was studied, and a plating kinetic model was presented. the culture of cef cells in 1.5 l celligen bioreactor to produce infectious bursal disease virus (ibdv) had met success. w ... | 1997 | 9170258 |
| morphological evidence of apoptosis in chickens infected with infectious bursal disease virus. | two-week-old specific pathogen-free chickens were infected with the infectious bursal disease virus by the ocular route. immediately, and at 4 and 8 days after infection, groups of three chickens were killed and tissue samples were collected. under electron microscopical examination, typical apoptotic cells were seen in the bursa of fabricius (bf) and in the spleen. tissue sections stained with haematoxylin and eosin were subjected to image analysis to quantify cellular depletion in the follicle ... | 1997 | 9179749 |
| vp5 of infectious bursal disease virus is not essential for viral replication in cell culture. | infectious bursal disease virus (ibdv), a member of the birnaviridae family, encodes in its bisegmented double-stranded rna genome four structural virion proteins, vp1, vp2, vp3, and vp4, as well as a nonstructural protein, vp5. recently, the establishment of an infectious crna system for ibdv has been described (e. mundt and v. n. vakharia, proc. natl. acad. sci. usa 93:11131-11136, 1996). here, we report the isolation of a vp5- ibdv mutant constructed by site-directed mutagenesis of the methio ... | 1997 | 9188642 |
| proliferation and apoptosis in infection with infectious bursal disease virus: a flow cytometric study. | programmed cell death, or apoptosis, is involved in the normal physiology of many immunocompetent organs, including lymphocytes of the bursa of fabricius in chickens. involvement of apoptosis has also been described in some viral diseases such as aids. the purpose of this work was to study the potential role of apoptosis in the pathogenesis of gumboro disease in the bursa of fabricius. our results show that 1-3 days after infection of young chickens with infectious bursal disease virus, the numb ... | 1997 | 9201393 |
| coagglutination test for rapid detection of infectious bursal disease virus antigen. | | 1997 | 9203312 |
| use of an experimental chicks model for paratuberculosis enteritis (johne's disease). | developments in the diagnosis and treatment of paratuberculosis is constrained by the lack of an experimental animal model. to investigate this problem conventional chicks immunodepressed by a cyclophosphamide injection and concurrent inoculation of infectious bursal disease virus (ibdv) were infected with mycobacterium paratuberculosis and kept for 4 months. the immunodepressed chicks eliminated mycobacteria with their faces from the first month until the third month and developed typical intes ... | 1997 | 9208444 |
| identification and comparison of point mutations associated in classic and variant infectious bursal disease viruses. | restriction enzymes (re) were used to identify point mutations in the nucleotide sequences of the infectious bursal disease virus (ibdv) strains del-e, del-a, stc, in, bursine 2, and bio-burs. the point mutations at amino acid sites 222, 254 and 323 were identified using res bstni, styi and mboi, respectively. the nucleotide sequences of stc, in, bursine 2 and bio-burs were determined at each of these sites. nucleotide sequence analysis using this data and previously reported data for del-e and ... | 1997 | 9213387 |
| quantitative competitive polymerase chain reaction for detection and quantification of infectious bursal disease virus cdna and rna. | a polymerase chain reaction (pcr)-based method to measure complementary dna (cdna) and rna levels of infectious bursal disease virus (ibdv) was developed. quantification was achieved by quantitative competitive pcr (qc-pcr) amplification. a competitor, a deletion mutant of the wild type ibdv cdna, was 10-fold serially diluted and co-amplified with ibdv cdna after being reversely transcribed from the viral rna. after agarose gel electrophoresis, staining, and densitometric scanning, the bands on ... | 1997 | 9220388 |
| evidence that virion-associated vp1 of avibirnaviruses contains viral rna sequences. | the vp1 encoded by genomic segment b of birnaviruses is generally known to exist as a genome-linked protein (vpg) and as a "free" polypeptide of 90 kda in virus particles. the guanylylation activity associated with infectious bursal disease virus (ibdv) was demonstrated by incubating purified virus in presence of [alpha 32p] gtp; optimum activity in the 90 kda form of vp1 was seen in low salt concentration in the presence of 4 mm magnesium ions over a wide range of incubation temperatures. the i ... | 1997 | 9229010 |
| myeloperoxidase activity in chicken heterophils and adherent cells. | chicken heterophils are known to lack myeloperoxidase (mpo) activity. in this paper, evidence is presented to show that chicken heterophils and adherent cells contain a dna sequence that is homologous to segment 10 of the human mpo gene; histochemical staining and microplate assay also show that heterophils and adherent cells contain mpo activity. | 1997 | 9261969 |
| viral diseases of the immune system and strategies to control infectious bursal disease by vaccination. | viral infections which are immunosuppressive can affect the economics of poultry production, often as a result of the chicken's increased susceptibility to secondary infections and sub-optimal response to vaccinations. the mechanism of this immunosuppression has been studied in detail for certain chicken viruses. the replicating virus can have both direct and indirect effects on the cells of the immune system. the special role of the bursa of fabricius, as a lympho-epithelial organ, will be ment ... | 1997 | 9276986 |
| passive protection of specific pathogen free chicks against infectious bursal disease by in-ovo injection of semi-purified egg-yolk antiviral immunoglobulins. | in order to develop an experimental model for passive immunity in spf chickens, active neutralizing immunoglobulins (ig) directed against infectious bursal disease virus (ibdv) were extracted from the yolk of eggs laid by conventional layers immunized against ibdv. concentrated ig extracts were inoculated via the intra-vitellin route into 7-day-old embryonated spf hen eggs. although detrimental to hatchability, ig inoculation resulted in hatching two series of spf chicks with passive immunity ag ... | 1997 | 9283288 |
| the major antigenic protein of infectious bursal disease virus, vp2, is an apoptotic inducer. | infectious bursal disease virus (ibdv) is the causative agent of an economically important poultry disease. vaccinia virus recombinants expressing the ibdv mature structural capsid proteins vp2 and vp3 were generated by using vectors for inducible gene expression. characterization of these recombinant viruses demonstrated that expression of vp2 leads to induction of apoptosis in a variety of mammalian cell lines. transfection of cell cultures with a expression vector containing the vp2 coding re ... | 1997 | 9311897 |
| effects of beta-carotene and canthaxanthin on aflatoxicosis in broilers. | in 2 x 3 factorial experiments, 240 broiler chicks were fed diets containing 0, 0.01, and 0.02% beta-carotene or canthaxanthin with or without 5 ppm aflatoxin to determine the effects of these two carotenoids on the health and well-being of broilers subjected to aflatoxin poisoning. neither beta-carotene nor canthaxanthin was effective at overcoming the growth-depressing effects of aflatoxin. relative liver weights were significantly higher in broilers receiving dietary aflatoxin in the presence ... | 1997 | 9316107 |
| a second form of infectious bursal disease virus-associated tubule contains vp4. | preparations of density gradient-purified infectious bursal disease virus (ibdv) were found to contain full and empty icosahedral virions, type i tubules with a diameter of about 60 nm, and type ii tubules 24 to 26 nm in diameter. by immunoelectron microscopy we demonstrate that virions and both types of tubular structures specifically react with anti-ibdv serum. in infected cells intracytoplasmic and intranuclear type ii tubules reacted exclusively with an anti-vp4 monoclonal antibody, as did t ... | 1997 | 9343252 |
| systemic and local antibody responses to infectious bronchitis virus in chickens inoculated with infectious bursal disease virus and control chickens. | serum and local (respiratory) antibody responses to infectious bronchitis virus (ibv) were studied in 5-wk-old white leghorn-type control chickens and chickens inoculated with infectious bursal disease virus (ibdv) at 1 day of age. of the chickens inoculated with ibv alone, 93% had detectable levels of ibv antibodies in the sera and 87% had detectable antibodies in the respiratory lavage fluids. compared to this group, only 73% and 65% of ibdv-ibv inoculated chickens had serum and respiratory an ... | 1997 | 9356695 |
| expression of md infectious bursal disease viral proteins in baculovirus. | genomic segment a of the variant infectious bursal disease virus (ibdv) strain md was amplified by reverse transcriptase/polymerase chain reaction and further characterized by baculovirus expression. three different baculovirus clones were constructed containing the genes encoding vp2, vp2/vp4, and the complete polyprotein cloned into the baculovirus transfer vector pvl1392. baculovirus recombinants were identified by dot blot hybridization and were plaque purified three times. baculovirus expre ... | 1997 | 9356708 |
| restriction fragment length polymorphisms in the vp2 gene of infectious bursal disease viruses. | infectious bursal disease viruses (ibdvs) were examined for restriction fragment length polymorphisms in a fraction of the vp2 gene with the use of the reverse transcriptase/polymerase chain reaction-restriction fragment length polymorphism (rt/pcr-rflp) assay. the restriction enzymes bstni and mbol were used to obtain rflp results. a third enzyme, styi, was tested, but its utility for differentiation of ibdv strains was limited. thirteen vaccine viruses and five ibdv strains that were previousl ... | 1997 | 9356709 |
| appearance of t cells in the bursa of fabricius and cecal tonsils during the acute phase of infectious bursal disease virus infection in chickens. | groups of 3-wk-old specific-pathogen-free chickens were inoculated intraocularly with two virulent and one vaccine strain of infectious bursal disease virus (ibdv). during the acute phase of infection, the bursa of fabricius and cecal tonsil were examined by immunohistochemistry for ibdv antigen and t cell. with all three viruses examined, the infection resulted in the appearance of viral antigen in the bursa accompanied by the presence of cd3+ cells. the cd3+ cells were predominantly tcr2+ and ... | 1997 | 9356710 |
| antigenic and s-1 genomic characterization of the delaware variant serotype of infectious bronchitis virus. | a previously unrecognized infectious bronchitis virus (ibv) serotype, referred to hereafter as the delaware variant (de var), was isolated from commercial broiler chickens during a severe, widespread respiratory disease epornitic in the delmarva peninsula region of the united states in january-march 1992. the de var serotype was found to be antigenically unrelated by virus-neutralization (vn) test to nine reference ibv serotypes from north america. additional vn tests indicated that the de var i ... | 1997 | 9356713 |
| cytotoxic activity of cells recovered from the respiratory tracts of chickens inoculated with infectious bronchitis virus. | previously uninoculated control chickens and chickens exposed to infectious bursal disease virus (ibdv) at 1 day of age were intranasally exposed to the m41 strain of infectious bronchitis virus (ibv) at 5 wk of age. between 7 and 13 days after inoculation with ibv, cells were collected from the respiratory tracts of both groups of chickens and assayed for in vitro cytotoxic activity against a lymphoblastoid lscc-rp9 target cell line using a 4-hr 51chromium-release assay (cra). compared to thymo ... | 1997 | 9356717 |
| limited antigenic variation among recent infectious bursal disease virus isolates from france. | seven neutralizing monoclonal antibodies (mabs) to infectious bursal disease virus (ibdv) were used in an antigen-capture elisa for the antigenic characterization of 58 ibdv isolates obtained in france since 1989. fifty-six isolates exhibited an antigenic profile which was different from reference strain faragher 52/70, and similar to french very virulent ibdv strain 89,163 (no binding of two mabs). two strains (3.4%), isolated in 1991 and 1994, showed additional antigenic modifications resultin ... | 1997 | 9413517 |
| efficacy of a novel infectious bursal disease virus immune complex vaccine in broiler chickens. | two experiments were conducted to test the efficacy of a novel infectious bursal disease virus (ibdv) vaccine in broiler chickens with maternal ibdv immunity. the ibdv vaccine was formulated by mixing ibdv strain 2512 with bursal disease antibodies (bda) to produce the ibdv-bda complex vaccine. in expt. i, 1-day-old cobb x cobb broiler chickens were vaccinated subcutaneously with either ibdv-bda or commercial live intermediate ibdv vaccine (vaccine a) or were left unvaccinated. in expt. 2, the v ... | 1997 | 9454922 |
| in-situ apoptosis in chickens infected with infectious bursal disease virus. | groups of specific pathogen-free chickens aged 3 weeks were inoculated with one of three strains of infectious bursal disease virus (ibdv), namely: (1) a classical virulent strain, im-ibdv; (2) an antigenic variant-e strain, ve-ibdv; and (3) an attenuated vaccine strain, b2-ibdv. the bursa of fabricius and thymus were examined 1 to 5 days after inoculation for histopathological lesions, ibdv antigen, and in-situ apoptosis. infection of chickens with im-, ve-, or b2-ibdv resulted in the appearanc ... | 1998 | 9500235 |
| generation of a mutant infectious bursal disease virus that does not cause bursal lesions. | a reverse genetics system for birnavirus, based on synthetic transcripts of the infectious bursal disease virus (ibdv) genome, was recently developed (e. mundt and v. n. vakharia, proc. natl. acad. sci. usa 93:11131-11136, 1996). to study the function of the 17-kda nonstructural (ns) protein in viral growth and pathogenesis, we constructed a cdna clone of ibdv segment a in which the first and only initiation codon (atg) of ns protein was mutated to a stop codon (tag). transfection of vero cells ... | 1998 | 9525581 |
| antigenic and immunogenic properties of baculovirus-expressed infectious bursal disease viral proteins. | genomic segment a of the variant md infectious bursal disease virus (ibdv) was amplified by reverse transcriptase/polymerase chain reaction, cloned, and expressed in the baculovirus expression system. three different baculovirus recombinants expressing the genes encoding vp2, vp2/vp4, and the complete polyprotein (vp2/vp4/vp3) were prepared. the three antigens were used in separate enzyme-linked immunosorbent assays, and each detected antibodies against the variant ibdv strains md, del-a, del-e, ... | 1998 | 9533084 |
| [gumboro vaccination]. | | 1998 | 9537067 |
| national surveillance of poultry diseases in lebanon. | from 1992 to mid-1996, a national survey of poultry diseases in lebanon was conducted. this surveillance included meat breeder, layer breeder, commercial layer and chicken broiler flocks. the history, signs, lesions and laboratory tests of poultry were used in the diagnosis of prevalent poultry diseases. culture techniques were used to screen for bacterial diseases; serological techniques and, to a lesser extent, culture techniques were used to diagnose viral diseases; and both serological and c ... | 1997 | 9567302 |
| penguin mystery. | | 1998 | 9578772 |
| expression of orf a1 of infectious bursal disease virus results in the formation of virus-like particles. | a recombinant vaccinia virus inducibly expressing orf a1 of infectious bursal disease virus (ibdv) has been constructed and characterized. cells infected with this recombinant virus express the ibdv polyprotein, which is proteolytically processed to give mature vp2, vp3, and vp4 polypeptides. an electron microscopy study revealed that the cytoplasm of cells infected with the recombinant virus contains abundant ibdv-like particles (vlp). these vlp form close-packed paracrystalline arrays that are ... | 1998 | 9603319 |
| research notes: elispot assay for detection of antibody secreting cells to infectious bursal disease virus in chickens. | the elispot assay was used to enumerate antibody secreting cells (asc) in spleens of chickens infected with infectious bursal disease virus (ibdv). in the first experiment, chickens were orally challenged with ibdv. spleens were collected 14 d later and used for elispot assay. the assay detected 16 to 28 igg asc per 10(6) splenocytes and 3 to 6 igm asc per 10(6) splenocytes. in the second experiment, chickens were vaccinated against ibdv and orally challenged with ibdv 14 d after vaccination. sp ... | 1998 | 9603352 |
| enhanced expression of cytokine genes in spleen macrophages during acute infection with infectious bursal disease virus in chickens. | we examined the effects of infectious bursal disease virus (ibdv) on splenic t cells and macrophages. in acute ibdv infection, splenocytes responded poorly to con a stimulation. however, when t cells were isolated from whole spleen cells, purified t cells responded normally to con a. this result indicated that functional t cells were present in the spleen but mitogen-induced proliferation of t cells was being suppressed by other cells. previous studies indicated that soluble factors from suppres ... | 1998 | 9613445 |
| preliminary report of a controlled trial of mth-68/b virus vaccine treatment in acute b and c hepatitis: a phase ii study. | eighty four patients with viral hepatitis attributed to infection with hepatitis b virus (hbv) (n = 43) or hepatitis c virus (hcv) (n = 41) were included in this study employing the mth-68/b vaccine, an attenuated variant of bursal disease virus. twenty of the 43 patients in the hbv group, and 22 of the 41 hcv patients were treated with mth-68/b. the remaining patients received conventional therapy. significantly more patients progressed into active chronic hepatitis on conventional therapy (13% ... | 1998 | 9615801 |
| identification and characterization of rna-binding activities of avian reovirus non-structural protein sigmans. | cytoplasmic extracts prepared from avian reovirus (arv) strain s1133-infected chicken embryo fibroblasts were examined for the presence of rna-binding proteins in order to identify and characterize arv rna-binding proteins. analysis of binding activity to poly(a)-sepharose indicated that infected cells contained significant amounts of a protein that co-migrated with arv protein sigmans present in total virus-infected cell extracts. determination of the n-terminal amino acid sequence of several p ... | 1998 | 9634083 |
| genetic resistance to avian viruses. | viral infections of poultry can be catastrophic in terms of both welfare and economics, and although vaccines have been very successful in combating these diseases, new forms of viruses have evolved which present increasing difficulties for vaccine control. differences in genetic susceptibility are known to exist for many of the major viral pathogens of poultry. consequently, an increase in the level of genetic resistance provides a possible means of enhancing protection of flocks. this is parti ... | 1998 | 9638814 |
| [comparative analysis of the vp2 variable region of the gene from infectious bursal disease virus isolates]. | variable cdna regions in the vp2 gene of 24 isolates of infectious bursal disease virus (ibdv) isolated in russia in 1993-1996 were amplified by the "nested" pcr and sequenced. the primary structure analysis of the vp2 gene variable region revealed 2 major groups of ibdv isolates. the first group consisted of the isolates with the structure identical or closely related to the highly virulent european strains cs89, 74/89a, 661, jy86, and dv86, the second group included the isolates with a high le ... | 1998 | 9511141 |
| sequence and phylogenetic analyses of highly virulent infectious bursal disease virus. | the nucleotide sequences of the genome segments a and b encoding the precursor polyprotein (nh2-vp2-vp4-vp3-cooh) and vp1 were determined for a highly virulent strain of infectious bursal disease virus (ibdv). the precursor polyprotein and vp1 coding regions of highly virulent okym strain consisted of 3039 nucleotides (1012 deduced amino acids) and 2640 nucleotides (879 deduced amino acids), respectively. comparison of the deduced amino acid sequences of the highly virulent ibdv (hv-ibdv) with o ... | 1997 | 9267454 |
| genetic heterogeneity in the vp2 gene of infectious bursal disease viruses detected in commercially reared chickens. | the genetic heterogeneity of infectious bursal disease virus (ibdv) vaccine strains was compared with ibdv detected in bursa tissue of commercially reared chickens. the vaccine strains tested represented classic viruses from the united states, south africa, england, and france plus variant viruses from the united states. bursa tissue samples used for the detection of ibdv from commercially reared chickens were from the united states. genetic heterogeneity was examined using restriction fragment ... | 1998 | 9645324 |
| immunorheophoresis for the diagnosis of infectious bursal disease. | the immunorheophoresis (ir) technique was used for the detection of infectious bursal disease antigen from bursae collected from field cases and experimentally infected chickens. when these results were compared with that of the agar gel immunodiffusion (agid) test, they showed excellent agreement as determined by kappa value. however, the time taken for the appearance of the precipitin lines was reduced from 14-24 hr in the agid test to 3-5 hr in the ir technique. | 1998 | 9645332 |
| infectious bursal disease virus changes the potassium current properties of chicken embryo fibroblasts. | infectious bursal disease virus (ibdv) is the causative agent of an economically significant poultry disease. ibdv infection leads to apoptosis in chicken embryos and cell cultures. since changes in cellular ion fluxes during apoptosis have been reported, we investigated the membrane ion currents of chicken embryo fibroblasts (cefs) inoculated with the cu-1 strain of ibdv using the patch-clamp recording technique. incubation of cefs with ibdv led to marked changes in their k+ outward current pro ... | 1998 | 9657954 |
| a novel technique for in-vivo assay of viral regulatory regions in genomes of animal rna viruses. | a novel in-vivo assay system for mapping and analyzing regulatory signals which promote transcription and expression of viral rna genomes is described. the system was developed using infectious bursal disease virus (ibdv), a double-stranded rna virus and vero cells which are permissive for ibdv, as a model. the model system consisted of engineered modifications of an enhancer-less pgl3-promoter vector such that deleted lengths of the 5' noncoding region of genome segment a of ibdv were positione ... | 1998 | 9672132 |
| infectious bursal disease virus polyprotein processing does not involve cellular proteases. | the larger genome segment, segment a, of infectious bursal disease virus (ibdv) encodes vp2, vp3 and vp4 as a precursor polyprotein. the viral protease, vp4, is responsible for self-processing of the polyprotein, however, there are additional secondary precursor products such as vpx whose further processing has not been defined. expression of ibdv cdnas in vitro with rabbit reticulocyte lysates in a coupled transcription-translation system and in the sindbis virus expression system (with bhk-21 ... | 1997 | 9672603 |