Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| poultry vaccines: an analysis of the animal trials required for vaccine testing and the way to reduce or refine these tests. | the testing of vaccines for use in chickens requires a large number of animal trials. especially for poultry vaccines, quality testing of each batch consists of testing for extraneous agents in chickens for all products and potency tests for inactivated products. for the licensing of a vaccine a number of safety and efficacy tests is necessary. the safety testing covers dose and overdose studies, and the influence on reproductive performances and immunological functions. for live vaccines some a ... | 1999 | 10566779 |
| storage of viruses on filter paper for genetic analysis. | the purpose of this study was to develop a method to store viruses on filter paper without the need for special conditions for future use of the genetic material. two non-enveloped viruses were used as models. infectious bursal disease virus (ibdv), a double-stranded rna virus that infects chickens, belongs to the birnaviridae family. hemorrhagic enteritis virus (hev), with double-stranded dna, belongs to the adenoviridae family. three different solutions were found suitable for loading the viru ... | 1999 | 10598079 |
| efficient rescue of infectious bursal disease virus from cloned cdna: evidence for involvement of the 3'-terminal sequence in genome replication. | to study the mechanism of replication of infectious bursal disease virus (ibdv), and to determine factors on the ibdv rna which are involved in viral replication, we used cloned full-length cdna of both the a- and b-segments to generate infectious ibdv. infectious ibdv was rescued from plasmids that contained full-length ibdv cdna behind a t7 promoter, by transfecting these plasmids into cells which were infected with a recombinant fowlpox virus that expressed t7 rna polymerase. by using the cdn ... | 1999 | 10600604 |
| persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency. | chicken anaemia virus (cav) infectivity and the effect of highly virulent infectious bursal disease virus (hv ibdv) infection on cav's infectivity were examined in chickens inoculated with cav or inoculated dually with cav and hv ibdv. five chickens inoculated dually with hv ibdv at 35 days old and then with cav at 40 days old exhibited no clinical signs of disease, but showed atrophic bursae of fabricius when necropsied 4 weeks later. upon examining the chickens at 7 days postinoculation (dpi) ... | 1999 | 10607503 |
| european-like pathogenic infectious bursal disease viruses in brazil. | 1999 | 10501589 | |
| enhancing yield of infectious bursal disease virus structural proteins in baculovirus expression systems: focus on media, protease inhibitors, and dissolved oxygen. | structural proteins of the poultry pathogen, infectious bursal disease virus (ibdv), were expressed in the baculovirus/insect cell expression system. to date, several reports have indicated that animal virus structural proteins are expressed only at low yield in this system. in this article, several factors were examined to enhance yield. these include medium, dissolved oxygen level, and the addition (in vivo and in vitro) of protease inhibitors. specifically, two media were compared, and sf-900 ... | 1999 | 10585191 |
| adaptation of very virulent infectious bursal disease virus to chicken embryonic fibroblasts by site-directed mutagenesis of residues 279 and 284 of viral coat protein vp2. | the full-length rna genomes of a chicken embryonic fibroblast (cef)-nonpermissive, very virulent infectious bursal disease virus (ibdv) (strain hk46) were amplified into cdnas by reverse transcription-pcr. the full-length cdnas were sequenced and subcloned into a eukaryotic expression vector, from which point mutations were introduced into the vp2 region by site-directed mutagenesis. the wild-type and mutated plasmids were transfected directly into cefs to examine their ability to generate cef-p ... | 1999 | 10074133 |
| failure of viral protein 3 of infectious bursal disease virus produced in prokaryotic and eukaryotic expression systems to protect chickens against the disease. | in recent years, infectious bursal disease virus (ibdv) has become a serious economic problem as a result of the emergence of new and very virulent strains. most of the antibodies produced against ibdv are for the structural proteins viral protein (vp) 2 (vp2) and vp3. the purpose of this study was to test the potential of recombinant vp3 to induce protective antibodies. the gene for vp3 was isolated from a virulent strain of the virus and cloned into prokaryotic (escherichia coli) and eukaryoti ... | 1999 | 10216754 |
| viral protein 1 sequence analysis of three infectious bursal disease virus strains: a very virulent virus, its attenuated form, and an attenuated vaccine. | comparisons between sequences of very virulent, virulent, and attenuated strains of the infectious bursal disease virus (ibdv) may indicate sites on the genome co-inciding with virulence. in an attempt to detect if such sites exist on the coding region of segment b, viral protein 1 (vp1) (encoded for by segment b) of a very virulent israeli virus, il3; its attenuated strain, il4; and the attenuated winterfield vaccine 2512 were cloned and sequenced. a comparison was made among them and with six ... | 1999 | 10216760 |
| chimeric infectious bursal disease virus-like particles expressed in insect cells and purified by immobilized metal affinity chromatography. | chimeric virus-like particles (vlps) of infectious bursal disease virus (ibdv) were produced by coinfecting spodoptera frugiperda (sf-9) insect cells with two recombinant baculoviruses, vibd-7 and vedlh-22. vibd-7 encodes vp2, vp3, and vp4 of the ibdv structural proteins. vedlh-22 encodes vp2 with five histidine residues at the carboxy-terminus (vp2h). coinfection produced hybrid vlps composed of vp2, vp2h, and vp3. the additional histidine residues on vp2h enabled the efficient purification of ... | 1999 | 10397829 |
| lysis of myelocytes in chickens infected with infectious bursal disease virus. | in specific-pathogen-free chickens infected with the highly virulent hps-2 strain or virulent reference gbf-1 strain of infectious bursal disease virus (ibdv), pathologic changes of the bone marrow were investigated. on histologic examination, bone marrow lesions were prominent in the hps-2 group but only mild in the gbf-1 group. the bone marrow of the hps-2 group showed severe lysis and depletion of heterophil myelocytes with pyknotic nuclear alteration 2-3 days after inoculation. on examinatio ... | 1999 | 10098643 |
| correlation of enzyme-linked immunosorbent assay titers with protection against infectious bursal disease virus. | we examined the utility of baculovirus-expressed infectious bursal disease virus (ibdv) proteins to act as antigens in the enzyme-linked immunosorbent assay (elisa). the three ibdv protein antigens tested included 1) a truncated vp2, 2) whole vp2, and 3) the polyprotein products vp2, vp3, and vp4. serum samples from 2-wk-old commercially reared broilers were collected and tested in the three elisas. serum samples were obtained from 34 different commercial broiler flocks. an average of 14 serum s ... | 1999 | 10396631 |
| proteolytic processing in infectious bursal disease virus: identification of the polyprotein cleavage sites by site-directed mutagenesis. | the infectious bursal disease virus (ibdv), a member of the birnaviridae family, is the causative agent of an immune depressive disease that affects domesticated and wild avian species. the expression strategy of ibdv includes the synthesis of a 110-kda polyprotein containing the capsid precursor polypeptides. the polyprotein is autocatalitically processed rendering three polypeptides: nh2-vpx-vp4-vp3-cooh. we have carried out a systematic analysis, using a series of plasmids encoding polyprotei ... | 1999 | 10489352 |
| recovery of antibody-producing ability and lymphocyte repopulation of bursal follicles in chickens exposed to infectious bursal disease virus. | we studied the long-term effect of infectious bursal disease virus (ibdv) in chickens. specifically, the restoration of virus-induced bursal lesions and the duration of humoral immunodeficiency were examined. one-week-old specific-pathogen-free chickens were intraocularly inoculated with an intermediate vaccine strain (ibdv-vac) or a virulent strain (im-ibdv). at intervals postinoculation (pi), chickens were examined for histopathologic lesions. at 1, 3, 5, 10, or 15 wk pi, the chickens were inj ... | 1999 | 10494408 |
| experimental inoculation of avian polyomavirus in chemically and virally immunosuppressed chickens. | the purpose of this series of experiments was to determine the effect of various types of immunosuppressive treatments (cyclophosphamide, infectious bursal disease virus [ibdv], chicken anemia virus [cav], and combination infection with ibdv and cav) on susceptibility of chickens to challenge with avian polyomavirus. in the first experiment, chickens were chemically bursectomized with intraperitoneal injections of cyclophosphamide; in the second study, chickens were orally inoculated with ibdv; ... | 1999 | 10494416 |
| differentiation of infectious bursal disease virus strains by restriction analysis of rt-pcr-amplified vp2 gene sequences. | the techniques of reverse transcription-polymerase chain reaction (rt-pcr) and restriction analysis were used to differentiate highly virulent indian field isolates of infectious bursal disease virus (ibdv) from vaccine strains. primers were designed to amplify the variable region of vp2 gene coding for major virus neutralizing epitopes. the 552 bp pcr products generated from four vaccine strains and five field isolates were digested with restriction enzymes drai, hhai, mvai, stui, styi, and taq ... | 1999 | 10749370 |
| evaluation of serological, histological and immunocytochemical methods for the detection of infectious bursal disease virus infection in broiler flocks in new zealand. | to study and compare three diagnostic methods for the detection of infectious bursal disease virus (ibdv) infection. | 1999 | 16032098 |
| development of an experimental model of bacterial chondronecrosis with osteomyelitis in broilers following exposure to staphylococcus aureus by aerosol, and inoculation with chicken anaemia and infectious bursal disease viruses. | a series of experiments was designed in an attempt to reproduce bacterial chondronecrosis with osteomyelitis in broiler chickens using a natural route of infection. birds in isolators were exposed to a suspension of staphylococcus aureus by aerosol or exposed to s. aureus and subsequently inoculated with chicken anaemia virus (cav) alone, or with cav and infectious bursal disease virus (ibdv). subsequently, s. aureus was recovered and bacterial chondronecrosis with osteomyelitis was diagnosed, b ... | 1999 | 16147547 |
| high immunogenicity of the pressure-inactivated virus. | effects of high hydrostatic pressure on the activity of infectious bursal disease virus (ibdv) was described. the infectivity of ibdv decreased with the increasing of pressure and pressurizing time and may be completely lost, indicated by the tests with chicken embryo fibrablast cell and young chicken as models. how-ever, pressure-inactivated ibdv still remained high immunogenicity and might induce high levels of protecting serum antibody. fluorescence spectroscopy showed obvious differences bet ... | 1999 | 12136191 |
| development of a ssrna internal control reagent for an infectious bursal disease virus reverse transcription/polymerase chain reaction-restriction fragment length polymorphism diagnostic assay. | infectious bursal disease virus (ibdv), family birnaviradae, is the etiologic agent of a commercially important, globally distributed, contagious, immunosuppressive disease of young chickens. a restriction enzyme-compatible ssrna internal control was developed for an ibdv reverse transcription/polymerase chain reaction-restriction fragment length polymorphism (rt/pcr-rflp) diagnostic assay. an 841-bp bacteriophage-lambda dna fragment was directionally ligated to 3' and 5' oligonucleotide linkers ... | 1999 | 12968731 |
| bursal lymphocyte proliferation in the presence of phorbol myristate acetate: effect of ibdv strains on the proliferation response. | phorbol myristate acetate (pma) was shown to be highly mitogenic for bursal lymphocytes (optimal concentration 2 μg/ml). groups of 1-day-old chickens were inoculated with infectious bursal disease virus (ibdv, vaccine or virulent strains). seven days after infection bursae were removed and the proliferation response of the bursal lymphocytes to pma was determined. a significant reduction in the proliferation response was observed in the ibdv-inoculated birds. the results confirm that pma is mito ... | 1999 | 26915386 |
| infected and apoptotic cells in the ibdv-infected bursa of fabricius, studied by double-labelling techniques. | infections of young chickens with infectious bursal disease virus (ibdv) result in depletion of lymphoid cells of the bursa of fabricius (bf) due to necrosis and apoptotic processes. interactions between ibdv and lymphoid cells were investigated by labelling paraffin-embedded tissue sections of infected bf with combinations of either immunohistochemistry (ihc), in situ hybridization (ish) or in situ tunel reaction (ist). with regard to specificity and sensitivity, results of ish were comparable ... | 1999 | 26915384 |
| [production of avian infectious bursitis virus by in vivo dna genomic transcription]. | generation of infectious particles of infectious bursal disease virus (ibdv) has been essentially performed by transfecting susceptible cells with in vitro synthesized crnas of genomic segments a and b. in the present study, we have explored the possibility to proceed directly in vivo without taking into account the extra-genomic vector-derived sequences. for this purpose, cdnas of segments a and b were subcloned into an eucaryotic expression vector under the control of the immediate early cmv p ... | 2000 | 14658230 |
| cloning and expression of the vp2 gene of an infectious bursal disease virus. | a serotype i infectious bursal disease virus (ibdv) strain hz96 was isolated in hangzhou, china, in 1996 and attenuated by adaptation to chicken embryo fibroblast cells. the vp2 gene of strain hz96 was amplified by reverse transcription-polymerase chain reaction, cloned, and sequenced. compared with the vp2 sequences of other ibdv strains, hz96 is most related to two attenuated strains, cu-1 and pbg98, and two attenuated chinese strains, harbin and cj801bkf. hz96 shares nucleotide sequence homol ... | 2000 | 10737658 |
| development of probes for differentiation of infectious bursal disease virus strains of various virulence by dot-blot hybridization. | two different radio-labeled nucleic acid probes, prepared from reverse transcription-polymerase chain reaction (rt-pcr) amplified variable region of vp2 and vp1 gene sequences of a highly virulent infectious bursal disease virus (ibdv), were tested for their ability to detect field isolates of ibdv directly in clinical bursal tissue specimens and vaccine strains of ibdv in tissue cultures. the vp2 gene probe was able to detect both field isolates and vaccine strains of ibdv under high as well as ... | 2000 | 11252670 |
| pathological and immunological study of an in ovo complex vaccine against infectious bursal disease. | the appearance of very virulent strains of infectious bursal disease (ibd) virus at the end of the 1980s made it necessary to develop more effective immunization procedures. to facilitate this, the immunogenicity and the immunosuppressive effect of a mild (g-87), an intermediate (libd) and an intermediate-plus (ibdv 2512) ibdv strain were tested after the in ovo inoculation of 18-day-old spf and broiler chicken embryos. it was established that no noteworthy difference existed between the immuniz ... | 2000 | 11402661 |
| immunostimulatory effects of the muramyl dipeptide analogue lk415 in chickens immunized with a vaccine strain of infectious bursal disease virus. | the effects of muramyl dipeptide (mdp) synthetic analogue lk415 on the immune response of chickens immunized with a live vaccine against infectious bursal disease (ibd) were studied in two independent trials, using levamisole hydrochloride as comparative immunostimulant. groups of five-week-old commercial chickens (isa brown) were immunized orally with 10 doses of the vaccine strain of ibdv (winterfield strain). the chickens were then given four injections of the mdp analogue lk415 in a dosage o ... | 2000 | 11402707 |
| ascorbic acid supplementation improved antibody response to infectious bursal disease vaccination in chickens. | the purpose of the present study was to determine if supplementation of ascorbic acid (aa) to the diet would have a beneficial effect on infectious bursal disease (ibd) vaccination of chickens for protection against infectious bursal disease virus (ibdv) infection. two hundred forty specific pathogen-free (spf) chickens were divided into eight experimental groups. a 2 x 2 x 2 factorial arrangement in a completely randomized design was used; aa supplementation at 1,000 ppm in the diet, vaccinatio ... | 2000 | 10824956 |
| protection from ibdv-induced bursal damage by a recombinant fowlpox vaccine, fpibd1, is dependent on the titre of challenge virus and chicken genotype. | expression of the vp2 capsid protein of infectious bursal disease virus (ibdv) in an vaccine strain of fowlpox has produced an experimental recombinant vaccine, fpibd1. successful vaccination with fpibd1 was dependent on the titre of challenge virus for high titres of challenge virus were able to overcome protection induced by fpibd1 whereas challenge with a low titre of virus did not. the genotype of chicken also has an important effect on the outcome of challenge possibly as a result of the ma ... | 2000 | 10869768 |
| heat lability of five strains of infectious bursal disease virus. | an extensive world trade environment has created a need for many nations to protect their food animal industries against the importation of pathogenic microorganisms. we initiated studies to determine how cooking conditions would affect the viability of different infectious bursal disease virus (ibdv) strains. five different viral strains were tested. the strains included two serotype 1 variant viruses, del-a and md; two serotype 1 classic viruses, stc and d78; and a serotype 2 virus, oh. a 100- ... | 2000 | 10875765 |
| infectious bursal disease live vaccines: changes in the virus population during serial passage in chickens and chicken embryo fibroblast cells. | two attenuated infectious bursal disease virus strains used as commercial live vaccine were passaged five successive times in specific-pathogen-free chickens and chicken embryo fibroblast (cef) cells. both attenuated strains increased in virulence during the passage in susceptible chickens as evidenced by the decrease in bursa/body weight ratios. a direct nucleotide sequence analysis of the vp2 hypervariable domain amplified by the reverse transcription-polymerase chain reaction revealed that th ... | 2000 | 10879907 |
| antigenic properties and diagnostic potential of baculovirus-expressed infectious bursal disease virus proteins vpx and vp3. | the routine technique for detecting antibodies specific to infectious bursal disease virus (ibdv) is a serological evaluation by enzyme-linked immunosorbent assay (elisa) with preparations of whole virions as the antigens. to avoid using complete virus in the standard technique, we have developed two new antigens through the expression of the vpx and vp3 genes in insect cells. vpx and especially vp3 were expressed at high levels in insect cells and simple to purify. the immunogenicity of both pr ... | 2000 | 10882666 |
| rescue of very virulent and mosaic infectious bursal disease virus from cloned cdna: vp2 is not the sole determinant of the very virulent phenotype. | many recent outbreaks of infectious bursal disease in commercial chicken flocks worldwide are due to the spread of very virulent strains of infectious bursal disease virus (vvibdv). the molecular determinants for the enhanced virulence of vvibdv compared to classical ibdv are unknown. the lack of a reverse genetics system to rescue vvibdv from its cloned cdna hampers the identification and study of these determinants. in this report we describe, for the first time, the rescue of vvibdv from its ... | 2000 | 10888607 |
| infectious bursal disease (gumboro disease). | infectious bursal disease (ibd) (gumboro disease) has been described throughout the world, and the socio-economic significance of the disease is considerable world-wide. various forms of the disease have been described, but typing remains unclear, since antigenic and pathotypic criteria are used indiscriminately, and the true incidence of different types is difficult to determine. moreover, the infection, when not fatal, leads to a degree of immunosuppression which is often difficult to measure. ... | 2000 | 10935278 |
| characteristics of bursal t lymphocytes induced by infectious bursal disease virus. | infectious bursal disease virus (ibdv) is an avian lymphotropic virus that causes immunosuppression. when specific-pathogen-free chickens were exposed to a pathogenic strain of ibdv (im), the virus rapidly destroyed b cells in the bursa of fabricius. extensive viral replication was accompanied by an infiltration of t cells in the bursa. we studied the characteristics of intrabursal t lymphocytes in ibdv-infected chickens and examined whether t cells were involved in virus clearance. flow cytomet ... | 2000 | 10982331 |
| significance of infectious bursal disease serology in an integrated quality control program under european epidemiologic conditions. | in this study performed between 1993 and 1997, infectious bursal disease virus (ibdv) antibody titers and performance data were recorded in a vertically integrated monitoring scheme in order to make a follow-up from day-old parents down to the broilers at slaughter. all measured data were used two by two in a simple correlation study to calculate the degree to which they were linearly correlated. it appeared that high and/or uniform antibody titers in the parents were correlated with increased d ... | 2000 | 11007008 |
| sequence of precursor polyprotein gene (segment a) of infectious bursal disease viruses isolated in korea. | the coding regions of segment a of two recent korean very virulent (vv) infectious bursal disease virus (ibdv) isolates (kk1 and ksh) and one atypical ibdv isolate (k310) were amplified by reverse transcriptase-polymerase chain reaction, sequenced, and compared with published sequences for ibdv. the overall amino acid sequence similarity of the kk1 and ksh strains compared with foreign vvibdv strains was between 97.43% and 98.02%. the kk1 and ksh strains, like vvibdv strains, share unique amino ... | 2000 | 11007021 |
| vp5, the nonstructural polypeptide of infectious bursal disease virus, accumulates within the host plasma membrane and induces cell lysis. | infectious bursal disease virus (ibdv) encodes a 17-kda nonstructural polypeptide known as vp5. this polypeptide is not essential for virus replication in vitro but it plays an important role in in vivo dissemination and pathogenesis. we have characterized the expression of vp5 in three eukaryotic systems: (i) ibdv-infected chicken embryo fibroblasts; (ii) bsc-1 cells infected with a recombinant vaccinia virus vector; and (iii) cos-1 cells transiently transfected with a plasmid vector. immunoflu ... | 2000 | 11080482 |
| different architectures in the assembly of infectious bursal disease virus capsid proteins expressed in insect cells. | infectious bursal disease virus (ibdv) capsid is formed by the processing of a large polyprotein and subsequent assembly of vpx/vp2 and vp3. to learn more about the processing of the polyprotein and factors affecting the correct assembly of the viral capsid in vitro, different constructs were made using two baculovirus transfer vectors, pfastbac and pacym1. surprisingly, the expression of the capsid proteins gave rise to different types of particles in each system, as observed by electron micros ... | 2000 | 11118356 |
| [proliferation of attenuated infections bursal disease virus(ibdv) on vero cell on large scale]. | vero cell was selected as productive carrier in production of attenuated ibdv. the optimal conditions in culturing ibdv in agitating bottle were figured out. after proliferation, supernatant was harvested in batch process under the condition of five-liter-agitated fermenter. the result shows it was successful to culture ibdv by this methodology. | 2000 | 11191776 |
| serological monitoring on layer farms with specific pathogen-free chickens. | to monitor the existence of avian pathogens in laying chicken flocks, specific pathogen-free (spf) chickens were introduced into two layer farms and reared with laying hens for 12 months. spf chickens were bled several times after their introduction and examined for their sero-conversion to avian pathogens. as a result, antibodies to eight or ten kinds of pathogens were detected in spf chickens on each farm. antibodies to infectious bronchitis virus (ibv), avian nephritis virus, mycoplasma galli ... | 2000 | 11193353 |
| dual-viral vector approach induced strong and long-lasting protective immunity against very virulent infectious bursal disease virus. | to induce strong protective immunity against very virulent infectious bursal disease virus (vvibdv) in chickens, two viral vector systems, marek's disease and fowlpox viruses expressing the vvibdv host-protective antigen vp2 (rmdv, rfpv), were used. most of chickens vaccinated with the rfpv or rmdv alone, or vaccinated simultaneously with both at their hatch (rmdv-rfpv(1d)), were protected against developing clinical signs and mortality; however, only zero to 14% of the chickens were protected a ... | 2000 | 10753704 |
| ibdv-induced bursal t lymphocytes inhibit mitogenic response of normal splenocytes. | we examined the suppressive activity of bursal t cells induced by infectious bursal disease virus (ibdv) in inbred (15x7) and outbred commercial specific-pathogen-free (spf) chickens. the suppressive activity was measured by the ability of bursal and splenic t cells from ibdv-infected chickens to inhibit mitogenic responses of normal splenocytes. the bursacytes but not the splenocytes of ibdv-infected chickens inhibited the mitogenic responses of normal splenocytes. the mitogenic inhibition by t ... | 2000 | 10760389 |
| infectious bursal disease virus structural protein vp2 expressed by a baculovirus recombinant in bombyx mori. | vp2 cdna gene of the infectious bursal disease virus hz96 strain, encoding a major host-protective antigen, was cloned into baculovirus transfer vector pbacpak8, resulting in a recombinant transfer vector pbacpak-vp2. the vector pbacpak-vp2 and linearized dna of modified baculovirus bm-bacpak6 were co-transfected into the cultured bombyx mori (bm) n cells, in which homologous recombination occurred. then, baculovirus recombinants were screened out. the bm cells and bm larvae were infected with t ... | 2000 | 12075455 |
| effect of ascorbic acid supplementation on the immune response of chickens vaccinated and challenged with infectious bursal disease virus. | one-day-old chickens were divided into two groups and reared under similar conditions. one group was fed a diet supplemented with 1000ppm ascorbic acid and the other group was fed an identical diet, but not supplemented with ascorbic acid. both groups were vaccinated against infectious bursal disease (ibd) at 7 days of age and challenged orally with 4x10(5) of 50% embryo-lethal-dose ibdv 14 days later. the number of anti-ibdv antibody secreting cells, production of interleukin-2 (il-2) by spleno ... | 2000 | 10760396 |
| characterization of avian reovirus non structural protein sigmans synthesized in escherichia coli. | the coding region of avian reovirus s1133 genomic segment s4, encoding the non structural protein sigmans, was inserted into expression vector pet28a and the protein was expressed in escherichia coli bl21(de3) as a fusion protein containing a c-terminal peptide with six tandem histidines (his-tag). the expressed protein (esigmans) consistent with the expected molecular size of the avian reovirus protein sigmans synthesized in infected cells was readily purified by his-bind resin. the esigmans wa ... | 2000 | 10773313 |
| measuring infectious bursal disease virus rna in blood by multiplex real-time quantitative rt-pcr. | a quantitative reverse transcription polymerase chain reaction (rt-pcr) protocol for assessing infectious bursal disease virus (ibdv) rna levels in blood was developed using the abi prism 7700 sequence detection system coupled with taqman chemistry. to control for variations in sampling and processing between samples 28s rrna was co-amplified in a multiplex reaction and used to quantify total rna. relative quantification and standardisation was achieved using a log10 dilution series of rna extra ... | 2000 | 10716338 |
| immunoadjuvant activities of e. coli- and plasmid-expressed recombinant chicken ifn-alpha/beta, ifn-gamma and il-1beta in 1-day- and 3-week-old chickens. | in the present study we assessed the capacity of recombinant e. coli- or plasmid-expressed chicken interferons (ifn) and chicken il-1beta, to exert immunostimulatory activities for humoral immune responses, in day-old and adult chickens. we observed that both recombinant e. coli-expressed chicken ifn-alpha/beta and ifn-gamma facilitated the induction of a primary and also a secondary antibody response, using tetanus toxoid (tt) as a bacterial model antigen, in immunologically mature 3-week-old c ... | 2000 | 10715530 |
| immunocytochemical techniques to investigate the pathogenesis of infectious micro-organisms and the concurrent immune response of the host. | for poultry as well as for mammalian species used for scientific research, many immunocytochemical techniques have been developed to investigate in detail the interaction between infectious micro-organisms and the nonspecific and specific immune systems of the host. in this review three techniques have been described with all technical details necessary to perform them correctly: (1) single immunocytochemical staining to detect the infectious micro-organisms in situ at their site of infection, ( ... | 2000 | 10717284 |
| infectious bursal disease virus of chickens: pathogenesis and immunosuppression. | infectious bursal disease virus (ibdv) is an important immunosuppressive virus of chickens. the virus is ubiquitous and, under natural conditions, chickens acquire infection by the oral route. igm+ cells serve as targets for the virus. the most extensive virus replication takes place in the bursa of fabricius. the acute phase of the disease lasts for about 7-10 days. within this phase, bursal follicles are depleted of b cells and the bursa becomes atrophic. abundant viral antigen can be detected ... | 2000 | 10717289 |
| role of ser-652 and lys-692 in the protease activity of infectious bursal disease virus vp4 and identification of its substrate cleavage sites. | the polyprotein of infectious bursal disease virus (ibdv), an avian birnavirus, is processed by the viral protease, vp4. previous data obtained on the vp4 of infectious pancreatic necrosis virus (ipnv), a fish birnavirus, and comparative sequence analysis between ibdv and ipnv suggest that vp4 is an unusual eukaryotic serine protease that shares properties with prokaryotic leader peptidases and other bacterial peptidases. ibdv vp4 is predicted to utilize a serine-lysine catalytic dyad. replaceme ... | 2000 | 10725424 |
| chimeras in noncoding regions between serotypes i and ii of segment a of infectious bursal disease virus are viable and show pathogenic phenotype in chickens. | two serotypes, i and ii, have been identified for infectious bursal disease virus (ibdv), a member of the family birnaviridae: here, the generation by reverse genetics of ibdv chimeras in segment a of the bisegmented genome is reported. the 5- and 3'-noncoding regions (ncrs) of a serotype ii strain were exchanged with the ncrs of a full-length cdna clone of segment a of a serotype i strain. isolated chimeric viruses were characterized in cell culture and susceptible chickens. the results show th ... | 2000 | 10644853 |
| isolation and characterization of an antigenically distinct 68-kd protein from nonviral intracytoplasmic inclusions in boa constrictors chronically infected with the inclusion body disease virus (ibdv: retroviridae). | the relationship between a retroviral infection and the development of nonviral intracytoplasmic inclusion bodies was studied in a boa constrictor model. twelve juvenile age- and size-matched inclusion body disease (ibd)-negative boas were randomly divided into three groups. each group was inoculated intraperitoneally with 1 ml of an ibd virus (ibdv)-infected liver homogenate or 1 ml of normal boa liver homogenate (sham-inoculated control) or was left untreated. all boas were monitored for devel ... | 2000 | 11055868 |
| active residues and viral substrate cleavage sites of the protease of the birnavirus infectious pancreatic necrosis virus. | the polyprotein of infectious pancreatic necrosis virus (ipnv), a birnavirus, is processed by the viral protease vp4 (also named ns) to generate three polypeptides: pvp2, vp4, and vp3. site-directed mutagenesis at 42 positions of the ipnv vp4 protein was performed to determine the active site and the important residues for the protease activity. two residues (serine 633 and lysine 674) were critical for cleavage activity at both the pvp2-vp4 and the vp4-vp3 junctions. wild-type activity at the p ... | 2000 | 10666235 |
| antigen quantification as in vitro alternative for potency testing of inactivated viral poultry vaccines. | routine batch control of licensed inactivated viral vaccines for poultry usually includes a potency assay as a measure of vaccine efficacy. potency assays often consist of vaccination-challenge experiments in the target species or in laboratory animals. instead of measuring the protection of vaccinated animals against virulent pathogens, the serological response after vaccination can be quantified for some vaccines. in vitro antigen quantification assays would be attractive alternatives for the ... | 2000 | 11087135 |
| synthesis in escherichia coli of avian reovirus core protein varsigmaa and its dsrna-binding activity. | the genome segment s2 of p6ian reovirus (arv) s1133 was cloned and sequenced. the entire s2 nucleotide sequence is 1325 bp long with one long open reading frame that encodes a protein of 415 amino acids, corresponding to varsigmaa, a major core protein of arv. s2 possesses a pentanucleotide, tcatc, at the 3'-terminus of its plus strand, common to other known genome segments of arv and to 10 genome segments of mammalian reovirus. amino acid sequence analysis revealed that varsigmaa contains a car ... | 2000 | 10612658 |
| antigenic and sequence heterogeneity of infectious bursal disease virus strains isolated in australia. | six recently isolated field strains of infectious bursal disease virus (ibdv) were compared to vaccine strains at the antigenic and genetic level to ascertain the level of heterogeneity among australian ibdv strains. five strains, 01/94, 02/95, 03/95, 04/95 and 08/95, isolated at four locations in the state of victoria, were antigenic variants. they failed to react with monoclonal antibodies directed against two different epitopes on the vp2 protein which were present in vaccine strains and one ... | 2000 | 10893155 |
| rocket immunoelectrophoresis in the diagnosis of infectious bursal disease. | the rocket immunoelectrophoresis (rie) test was used for the qualitative detection and quantitative estimation of infectious bursal disease virus (ibdv) specific antigen in experimentally infected chickens and samples collected from suspected outbreaks. the ibdv specific antigen was detected in the bursae of experimentally inoculated chickens up to 5 days post infection (pi) by the agar gel precipitation (agp) test and 7 days pi by the rie test. the rie detected ibdv specific antigen in a signif ... | 2000 | 10907288 |
| evaluation of a filter paper blood sampling technique for quantitative assessment of antibodies to infectious bursal disease virus. | 2000 | 10907289 | |
| generation of full-length cdna of the two genomic dsrna segments of infectious bursal disease virus. | to determine the complete nucleotide sequence of infectious bursal disease virus (ibdv) isolates, an efficient method was developed to generate full-length cdna of both the genomic a- and b-segments. reverse transcription was carried out at the highest possible temperature (50 degrees c) for the reverse transcriptase enzyme, and the single stranded cdna was subsequently amplified by using an optimized pcr. the double stranded, full-length cdna was efficiently cloned into a high copy number plasm ... | 2000 | 10644086 |
| effects of hydrostatic pressure on the structure and biological activity of infectious bursal disease virus. | the effects of high hydrostatic pressure on the structure and biological activity of infectious bursal disease virus (ibdv), a commercially important pathogen of chickens, were investigated. ibdv was completely dissociated into subunits at a pressure of 240 mpa and 0 degrees c revealed by the change in intrinsic fluorescence spectrum and light scattering. the dissociation of ibdv showed abnormal concentration dependence as observed for some other viruses. electron microscopy study showed that mo ... | 2000 | 10880972 |
| the vp2 variable region of african and german isolates of infectious bursal disease virus: comparison with very virulent, "classical" virulent, and attenuated tissue culture-adapted strains. | 11 african and two german ibdv strains isolated in the mid '80s from field outbreaks in vaccinated and unvaccinated chicken flocks displayed features of very virulent (vv) ibdv strains. the sequence data of the vp2 variable region and phylogenetic analysis confirm that these strains can be grouped within vv ibdv strains which appeared at the same time on the three continents africa, asia, and europe. strain cu-1wt, responsible for severe ibd outbreaks in germany 13 years earlier, showed some rel ... | 2000 | 10664410 |
| self-assembly of the infectious bursal disease virus capsid protein, rvp2, expressed in insect cells and purification of immunogenic chimeric rvp2h particles by immobilized metal-ion affinity chromatography. | a gene encoding a structural protein (vp2) of a local strain (p3009) of infectious bursal disease virus (ibdv) was cloned and expressed using the baculovirus expression system to develop a subunit vaccine against ibdv infection in taiwan. the expressed rvp2 proteins formed particles of approximately 20-30 nm in diameter. those particles were partially purified employing sucrose density gradient ultracentrifugation, and the purified particles were recognized by a monoclonal antibody against the v ... | 2000 | 10581441 |
| tissue print hybridisation and reverse transcriptase pcr in the detection of infectious bursal disease viruses in bursal tissues. | the genome segments of infectious bursal disease viruses (ibdv) in the bursa of fabricius from experimently infected chickens or field samples were detected by tissue print hybridization (tph) with subsequent reverse transcriptase (rt)- polymerase chain reaction (pcr). bursae were imprinted onto nylon membrane and then hybridized with a cloned digoxigenin (dig)-labeled cdna probe. tissue prints on nylon membrane were readily distinguished from control prints by color development and differences ... | 2000 | 10684766 |
| interactions in vivo between the proteins of infectious bursal disease virus: capsid protein vp3 interacts with the rna-dependent rna polymerase, vp1. | little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (ibdv). by using the yeast two-hybrid system, which allows the detection of protein-protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the lexa dna-binding domain and the b42 transactivation domain. a heterologous interaction between vp1 and vp3, and homologous interactions of pvp2, vp3, vp5 and possibly vp1, were found by co-express ... | 2000 | 10640560 |
| in situ hybridization, immunohistochemistry, and in situ reverse transcription-polymerase chain reaction for detection of infectious bursal disease virus. | development of molecular techniques for the detection of infectious bursal disease virus (ibcv) is an important area of research. an in situ hybridization (ish) test was developed with a 491-bp cdna fragment derived from the vp2 gene of ibdv. the fragment was amplified and simultaneously labeled with incorporation of digoxigenin-11-dutp in a nested polymerase chain reaction (pcr) assay. the resulting digoxigenin-labeled 491-bp nested pcr product was used as probe for ish to detect and localize i ... | 2000 | 10737657 |
| antibody titers to infectious bursal disease virus in broiler chicks after vaccination at one day of age with infectious bursal disease virus and marek's disease virus. | the effect of day-of-age vaccination with infectious bursal disease virus (ibdv) alone or in combination with marek's disease virus (mdv) in broiler chicks was investigated. one-day-old commercial broiler progeny obtained from ibdv-immunized breeder flocks were vaccinated subcutaneously according to the manufacturer's directions with live-attenuated commercially available vaccines as follows: ibdv alone, mdv alone, ibdv + mdv, and unvaccinated control. ibdv was not detected after vaccination by ... | 2000 | 11195642 |
| serologic survey of slaughter-age ostriches (struthio camelus) for antibodies to selected avian pathogens. | serum samples from 163 slaughter-age ostriches (struthio camelus) in ohio and indiana were tested for antibodies to avian influenza virus (aiv), newcastle disease virus (ndv), paramyxovirus (pmv) 2, pmv3, pmv7, infectious bursal disease virus (ibdv), bordetella avium, mycoplasma synoviae, mycoplasma gallisepticum, ornithobacterium rhinotracheale, salmonella pullorum, salmonella gallinarum, and salmonella typhimurium. one ostrich had antibodies to aiv h5n9, 57% of the ostriches had antibodies to ... | 2000 | 11195659 |
| immune responses to intermediate strain ibd vaccine at different levels of maternal antibody in broiler chickens. | 2000 | 11147275 | |
| a non-canonical lon proteinase lacking the atpase domain employs the ser-lys catalytic dyad to exercise broad control over the life cycle of a double-stranded rna virus. | we have identified a region related to the protease domain of bacterial and organelle atp-dependent lon proteases in virus protein 4 (vp4) of infectious bursal disease virus strain p2 (ibdvp2), a two-segmented double-stranded rna virus. unlike canonical lons, ibdvp2 vp4 possesses a proteinase activity though it lacks an atpase domain. ser652 and lys692 of ibdvp2 vp4 are conserved across the lon/vp4 family and are essential for catalysis. lys692 has the properties of a general base, increasing th ... | 2000 | 10619850 |
| performance of an rt-nested pcr elisa for detection of newcastle disease virus. | a sensitive and specific rt-nested pcr coupled with an elisa detection system for detecting newcastle disease virus is described. two nested pairs of primer which were highly specific to all the three different pathotypes of ndv were designed from the consensus fusion gene sequence. no cross-reactions with other avian infectious agents such as infectious bronchitis virus, infectious bursal disease virus, influenza virus, and fowl pox virus were observed. based on agarose electrophoresis detectio ... | 2000 | 10713378 |
| replication of classical infectious bursal disease virus in the chicken embryo related cell line. | infectious bursal disease (ibd) is an acute, highly contagious viral disease. the diagnosis of ibd depends on time-consuming and costly procedures, like virus isolation on chick embryos and histopathological examination. a double antibody sandwich enzyme-linked immunosorbent assay (das-elisa), immunoperoxidase and reverse transcription polymerase chain reaction (rt-pcr) were applied in this study to detect classical ibd virus (ibdv) after three blind passages of the lukert strain on chicken embr ... | 2000 | 19184807 |
| bacterial chondronecrosis with osteomyelitis ('femoral head necrosis') of broiler chickens: a review. | bacterial chondronecrosis with osteomyelitis (bco) in chickens was first reported in 1972 and is now recognized as an important cause of lameness in broiler chickens. recent systematic studies of causes of lameness in birds reared in northern ireland have shown that it was the most common cause of lameness, being present in 17.3% of lame birds. furthermore, it was also detected in birds presented as ''found dead''. overall losses in male birds due to bco were estimated to be 0.75% of all birds p ... | 2000 | 19184841 |
| bacterial chondronecrosis with osteomyelitis ('femoral head necrosis') of broiler chickens: a review. | bacterial chondronecrosis with osteomyelitis (bco) in chickens was first reported in 1972 and is now recognized as an important cause of lameness in broiler chickens. recent systematic studies of causes of lameness in birds reared in northern ireland have shown that it was the most common cause of lameness, being present in 17.3% of lame birds. furthermore, it was also detected in birds presented as ''found dead''. overall losses in male birds due to bco were estimated to be 0.75% of all birds p ... | 2000 | 19184815 |
| transfer of antibodies elicited by baculovirus-derived vp2 of a very virulent bursal disease virus strain to progeny of commercial breeder chickens. | a baculovirus-derived recombinant vp2 (rvp2) subunit vaccine elicited anti-infectious bursal disease virus (ibdv) antibodies in commercial flocks. the induced antibody levels were similar to those evoked against ibdv by a commercial vaccine. the levels remained higher than that of the negative controls for at least four and a half months in commercial chickens. the antibodies were also transferred to their offspring and were detected in the blood of the progeny for at least 20 days after hatchin ... | 2000 | 19184783 |
| efficacy of inactivated infectious bursal disease (ibd) vaccines: comparison of serology with protection of progeny chickens against ibd virus strains of varying virulence. | the efficacy of inactivated infectious bursal disease vaccines was determined by measuring both the antibody response of vaccinated chickens and clinical protection of progeny chicks from vaccinated dams. similar virus neutralizing (vn) antibody titres were obtained in 4-week-old chickens and mature hens after vaccination with one vaccine dose. vn titres below 10 log 2 increased considerably between the fourth and seventh week after vaccination in 4-week-old chickens as well as in mature chicken ... | 2001 | 19184920 |
| pathogenicity of sspi-positive infectious bursal disease virus and molecular characterization of the vp2 hypervariable region. | the pathogenicity of four isolates of infectious bursal disease virus (ibdv) that have restriction fragment length polymorphism patterns of very virulent ibdv (vvibdv), based on the presence of sspi and taqi sites in the vp2 hypervariable region, was studied in specific pathogen free chickens. chickens inoculated with isolates 92/04, 94/b551 and 97/61 developed severe clinical signs with a high mortality ranging from 70 to 80%, whereas the 94/273 isolate caused 10% mortality. regardless of the i ... | 2001 | 19184922 |
| amino acid changes in the variable region of vp2 in three infectious bursal disease viruses with different virulence, originating from a common ancestor. | an infectious bursal disease virus (ibdv), hyd(c), from an outbreak was isolated and plaque-purified in bgm-70 cells. from the moderately virulent plaque-purified virus, two ibdvs with relatively high and low virulence were obtained by passaging the virus in specific pathogen free chickens and bgm-70 cells 10 and seven times, respectively. comparison of amino acid sequences of the vp2 variable region of these viruses revealed that three amino acids at positions 279, 284 and 300 (asp, thr and glu ... | 2001 | 19184961 |
| t-cell suppression by cyclosporin-a enhances infectious bursal disease virus infection in experimentally infected chickens. | in this study, the role of t lymphocytes was investigated in chickens experimentally infected with infectious bursal disease virus (ibdv). chickens were treated with cyclosporin-a (cs-a), a selective t-cell suppressant drug, by the intramuscular route, starting 3 days before virus infection and every third day thereafter,and infectious bursal disease pathogenesis was compared in such t-cell suppressed and intact chickens using a vaccine strain; namely, georgia and a field isolate of ibdv. treatm ... | 2001 | 19184916 |
| innovation and discovery: the application of nucleic acid-based technology to avian virus detection and characterization. | polymerase chain reaction (pcr)-based approaches to the detection, differentiation and characterization of avian pathogens continue to be developed and refined. the pcrs, or reverse transcriptase-pcrs, may be general, designed to detect all or most variants of a pathogen, or to be serotype, genotype or pathotype specific. progress is being made with respect to making nucleic acid approaches more suitable for use in diagnostic laboratories. robotic workstations are now available for extraction of ... | 2001 | 19184952 |
| rapid identification of "very virulent" strains of infectious bursal disease virus by reverse transcription-polymerase chain reaction combined with restriction enzyme analysis. | a reverse transcription-polymerase chain reaction (rt-pcr) combined with restriction enzyme analysis (rea) was developed for differentiation of classical virulent (cv) and very virulent (vv) strains of infectious bursal disease virus (ibdv). the vp2 gene was used for primer annealing to amplify the hypervariable region. an amplification product was obtained with serotype 1 and serotype 2 strains of ibdv.the restriction enzymes saci and bspmi were used to identify and to differentiate the serotyp ... | 2001 | 19184874 |
| [workshop: immunosuppression in chickens]. | 2001 | 11194506 | |
| immune responses to marek's disease virus infection. | 2001 | 11217429 | |
| safety and efficacy of in ovo administration of infectious bursal disease viral vaccines. | in ovo vaccination against marek's disease virus and infectious bursal disease virus (ibdv) in commercial broilers in the united states is common. little information exists as to the safety and efficacy of intermediate ibdv vaccines given in ovo. experiments were initiated to determine the safety and efficacy of three commercially available live intermediate ibdv vaccines by in ovo route. commonly used vaccines were given at 18 days of embryonation to specific-pathogen-free (spf) broiler embryos ... | 2001 | 11332475 |
| isolation of monoclonal antibodies that inhibit the binding of infectious bursal disease virus to lscc-bk3 cells. | three hybridoma cell lines producing monoclonal antibodies (mabs) against lscc-bk3 cells which are susceptible to infectious bursal disease virus (ibdv) infection were produced and characterized. the mabs, designated t7, q11 and q13, inhibited the attachment of ibdv to lscc-bk3 cells. furthermore, these mabs bound to lscc-bk3 but not to nonpermissive cells in flow cytometry. mab t7 detected a 110-kda membrane protein of lscc-bk3 cells, whereas q11 and q13 reacted with membrane proteins of molecu ... | 2001 | 11258465 |
| detection of cell membrane proteins that interact with virulent infectious bursal disease virus. | to detect the molecules that interact with infectious bursal disease virus (ibdv), the chicken b lymphoblastoid cell line, lscc-bk3, which is permissive for virulent ibdv infection was investigated. the sodium dodecyl sulfate-solubilized plasma membrane fraction from the cells was subjected to a virus overlay protein binding assay. the ibdv specifically bound to proteins in lscc-bk3 plasma membranes with molecular weights of 70, 82 and 110 kda. this is the first report to demonstrate cellular mo ... | 2001 | 11258466 |
| recombinant semliki forest virus vector exhibits potential for avian virus vaccine development. | the semliki forest virus (sfv) expression system was evaluated as a basis for avian vaccine development. initial studies indicated that 1-day-old specific pathogen-free (spf) chicks were susceptible to infection with an infectious strain of sfv, producing sfv-specific antibodies but no clinical disease. one-day-old spf chicks immunised intramuscularly with recombinant replication-defective sfv (rsfv) particles expressing the escherichia coli (e. coli) lacz reporter gene developed high titres of ... | 2001 | 11312006 |
| vp5 and the n terminus of vp2 are not responsible for the different pathotype of serotype i and ii infectious bursal disease virus. | two serotypes have been identified in infectious bursal disease virus (ibdv), a member of the family birnaviridae: a reverse genetics system was used for generation of chimeras in genome segment a of the two serotypes, in which the complete viral vp5 gene and 3' noncoding region (ncr), or parts thereof, were exchanged. the engineered viruses were characterized in vitro and in vivo in comparison to serotype i and ii ibdv. our results show that ibdv chimeras exhibit a different phenotype in cell c ... | 2001 | 11125169 |
| molecular and antigenic characterization of bangladeshi isolates of infectious bursal disease virus demonstrate their similarities with recent european, asian and african very virulent strains. | three isolates of infectious bursal disease virus (ibdv), obtained from chickens in bangladesh in 1999 and designated as bd 1/99, bd 2/99 and bd 3/99, were characterized. in an antigen capture enzyme-linked immunosorbent assay using a panel of vp2-specific neutralizing monoclonal antibodies (mab), all three isolates showed a mab-binding profile similar to that of very virulent ibdv (vvibdv) strains. in contrast to the classical virulent strains, they did not react with mab 3 and mab 4. molecular ... | 2001 | 11393817 |
| efficacy and safety of an infectious bursal disease virus intermediate vaccine in ovo. | the study was divided into two experiments. in the first experiment, the efficacy of in ovo intermediate vaccine against infectious bursal disease virus (ibdv) was determined by challenge at 21 days of age with virulent ibdv in specific-pathogen-free (spf) and commercial chickens. this vaccine was able to induce active immunity and to protect spf chickens to challenge; protection was not complete in commercial chickens, as testified by bursal lesions, bursal index after challenge, and vaccine im ... | 2001 | 11785875 |
| virus enhancement following infection with antibody-coated infectious bursal disease virus (ibdv) in chickens. | a novel concept of vaccination, employing virus-antibody complex has been reported for the control of infectious bursal disease in chickens. a comparison of virus replication, serum neutralizing antibody response and pathogenicity in chickens inoculated with the antibody coated virus, prepared by mixing virus and antibody in different ratios (1:1, 1:0.1, 1: 0.01) and virus alone without antibody, has been made. antibody coated virus (when mixed in certain crucial ratios) replicated to a higher m ... | 2001 | 12018533 |
| effect of moi ratio on the composition and yield of chimeric infectious bursal disease virus-like particles by baculovirus co-infection: deterministic predictions and experimental results. | virus-like particles (vlps) are empty particles consisting of virus capsid proteins that closely resemble native virus but are devoid of the native viral nucleic acids and therefore have attracted significant attention as noninfectious vaccines. a recombinant baculovirus, vibd-7, which encodes the structural proteins (vp2, vp3, and vp4) of infectious bursal disease virus (ibdv), produces native ibd vlps in infected spodoptera frugiperda insect cells. another baculovirus, vedlh-22, encodes vp2 th ... | 2001 | 11536133 |
| dna-mediated vaccination against infectious bursal disease in chickens. | the objective of the present study was to investigate the feasibility of a dna vaccine to protect chickens against infectious bursal disease virus (ibdv) infection. a plasmid dna carrying vp2, vp4, and vp3 genes of the standard challenge (stc) strain of ibdv was constructed and designated as pcr3.1-vp243-stc. one-day-old chickens were intramuscularly injected with the plasmid pcr3.1-vp243-stc once (group d1), twice (group d2), or three times (group d3) at weekly intervals. chickens at 3 weeks ol ... | 2001 | 11672894 |
| molecular characteristics of full-length genomic segment a of three infectious bursal disease viruses in china: two attenuated strains and one virulent field strain. | the full-length cdna of genomic segment a of three infectious bursal disease viruses, two attenuated strains (hz2 and jd1) and one virulent field strain (zj2000), was amplified in a single step by reverse transcription-polymerase chain reaction, cloned into pgem-t easy vector, and sequenced. the full length of cloned segment a contains 3259 nucleotides, which includes two partially overlapping open reading fragments (orfs) orf1 and orf2, flanked by 5' and 3' noncoding regions. these strains shar ... | 2001 | 11785891 |
| amplification and cloning by long rt-pcr of full-length genome of larger segment of chicken infectious bursal disease virus. | to develop the genetic rescue techniques for infectious bursal disease virus (ibdv), birnaviridae family, the full-length cdna of the larger segment of the chicken ibdv was amplified and cloned by long rt-pcr. a comparison of four purification and extraction methods of rna from ibdv infected chicken embryoid fibroblasts (cef) showed that the ultracentrifugation followed by proteinase kdigestion extracted dsrna more effectively. then reverse transcription was carried out at 50 degrees using super ... | 2001 | 12050800 |
| detection of infectious bursal disease vaccine viruses in lymphoid tissues after in ovo vaccination of specific-pathogen-free embryos. | control of infectious bursal disease virus (ibdv) by vaccination is important for poultry production worldwide. two vaccines, an ibdv immune complex (icx) vaccine and an ibdv-2512 vaccine, were administered at 100 mean embryo infectious dose to specific-pathogen-free 18-day-old broiler embryos in ovo. at 3, 6, 9, 15, and 21 days post in ovo vaccination (piov), bursa, spleen, and thymus tissues were collected and analyzed for virus protein by antigen capture chemiluminescent enzyme-linked immunos ... | 2001 | 11785894 |
| amino acid comparison of infectious bursal disease viruses placed in the same or different molecular groups by rt/pcr-rflp. | infectious bursal disease virus (ibdv) strains have been identified and placed into molecular groups by a reverse transcriptase (rt)/polymerase chain reaction (pcr)-restriction fragment length polymorphism (rflp) assay. the predicted amino acid sequences corresponding to the region of the genome examined by rflp were determined and compared for 14 ibdv strains from different molecular groups and 11 ibdv strains that were identified in molecular group 6. among the viruses within molecular group 6 ... | 2001 | 11417812 |
| [enhanced immunogenicity of plasmid encoding polyprotein gene of infectious bursal disease virus by co-administration of chicken interleukin 2 (il-2)]. | chicken interleukin 2 (il-2) is one of important nonmammalian cytokines isolated recently. the influencing of il-2 on immunogenicity of dna vaccine was examined using infectious bursal disease virus as a model. the il-2 cdna of xiaoshan chicken and the polyprotein gene of ibdv-zj2000 were amplified by rt-pcr, cloned, sequenced and inserted into the control of cmv promoter and enhancer of pci vector. 14-day-old chickens were vaccinated intramuscularly with dna vaccine, two weeks later, they were ... | 2001 | 11910759 |
| immune response and resistance to infectious bursal disease virus of chicken lines selected for high or low antibody response to escherichia coli. | two experimental broiler lines were developed by divergent selection for high (hh) and low (ll) antibody response to escherichia coli. antibody response of these lines to immunization with a commercial vaccine (whole inactivated virus, wiv) against infectious bursal disease virus (ibdv) or with proteins vp2 and vp3 of that virus, and their resistance to challenge with a virulent ibdv, were tested. the study was performed with 213 male and female chicks from the tenth generation of the hh and ll ... | 2001 | 11469649 |
| proliferation of lung macrophages in acute fatal viral infections in chickens. | marked proliferation of macrophages engulfing yellow pigments and fragmented erythrocytes were seen in the air capillaries and blood capillaries of the lungs of chickens affected with acute fatal viral hydropericardium syndrome, highly pathogenic infectious bursal disease, and highly pathogenic avian influenza. proliferation of lung macrophages was associated with systemic proliferation of macrophages. acute destruction of erythrocytes in these infections may have induced systemic hyperplasia of ... | 2001 | 11785886 |