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development of a methodology for the production of foot- and- mouth disease virus from bhk21 c13 monolayer cells grown in a 100 l (20 m2) glass sphere propagator. 1979223915
cell culture on beads used for the industrial production of foot-and-mouth disease virus.the microcarrier culture technique has been applied to a pig kidney cell line. microcarriers consisted of deae sephadex a 50 beads washed and containing carboxymethyl cellulose. sifted beads gave better results than unclassified material. cells for inoculum were prepared in roux flasks. the two types of fermentors which were used (operating capacity 100 l and 150 l) gave similar results. the growth of the cells can easily be followed by microscopic observation and cell count. the yields of cells ...1979223917
the use of frozen bhk21 c13 cells to control the biological parameters for cell and foot-and-mouth disease virus growth.in order to control the four primary variables (cells, serum, medium and physical conditions) in a cell or virus growth system it is important to have a reliable and constant positive control with which to compare any variable of the system components. the use of aliquots of a frozen cell population (stored at -136 degrees c) for this purpose is the subject of this paper. using such cells, tests have been established for the control of sera, media, cell susceptibility and the quality of serum tr ...1979223922
some aspects of fmdv-production in growing cells and a closed system for concentration of fmdv by polyethylene glycol.different commercially available peptone preparations, all derived by enzymatic digestion of meat, were tested for their ability to replace the individual amino acids and polyethylene glycol (peg)-treated serum in bhk suspended cell culture growth medium. cell growth was not impaired if the individual amino acids were replaced by 3 g/l of peptone in combination with 3 g/l lah and 5% peg-treated bovine serum. the concentration of the latter could be reduced to 1% by gradually lowering the concent ...1979223924
immunity to foot-and-mouth disease virus in guinea pigs: clinical and immune responses.clinical and immune responses were determined for guinea pigs infected with different doses of foot-and-mouth disease virus (fmdv) type a12, strain 119, administered by different routes. vesicles developed on the tongue or heel pad 1 day after these areas were intradermally inoculated with fmdv. however, vesicles did not develop on the feet and tongue until 3 to 4 days after the intradermal inoculation of fmdv in the flank skin or after intracardiac or subcutaneous inoculation. infected guinea p ...1979223986
antibody response against foot and mouth disease virus (fmdv). part i: responses measured in sera of vaccinated steers with complete virus, trypsin treated virus, 12 s virus subunits and heterologous virus. 1979225907
[foot-and-mouth disease in buffaloes (bubalus bubalis, linnaeus, 1758): search of antiantigen antibodies and isolation of the virus].the immune response to virus-infection-associated (via) antigen was studied in 379 indian buffalos (bubalus bubalis). these animals were vaccinated three times a year with commercial acetylethyleneimine (aei)--inactivated foot-and-mouth disease vaccines under field conditions. two months after the last vaccination, antibody against virus-infection-associated (via) antigen was found in 23 per cent. foot-and-mouth disease virus -- (fmdv) type c "waldmann" was isolated from oesophageal/pharyngeal f ...1979233417
[early events in the replication of foot and mouth disease virus: subcellular localization of viral rna synthesis]. 1977218264
the immune response against foot-and-mouth disease virus: influence of the t lymphocyte growth factors il-1 and il-2 on the murine humoral response in vivo.recombinant and pure "natural" il-1 and il-2 were compared with the muramyl dipeptide (mdp) component of freund's adjuvant for their capacity to enhance the humoral immune response against foot-and-mouth disease (fmd) virus antigen. using a dose of this antigen which alone did not give a detectable immune response, anti-fmd virus antibody was measured at 14 and 28 days post-vaccination. although il-1 could enhance the response against the virus antigen, in particular when administered 24 h befor ...19921312510
vpg gene amplification correlates with infective particle formation in foot-and-mouth disease virus.in order to analyze the function of vpg amplification in aphthoviruses, we have undertaken the first mutational analysis of the repetitive vpg-coding region using an improved foot-and-mouth disease virus (fmdv) cdna clone from which infective viral rna was synthesized. a set of vpg mutants was constructed by site-directed mutagenesis which includes different vpg deletion mutations, a vpg insertion mutation, and amino acid residue replacement mutations that interfere with binding of the vpg prote ...19921312630
detection of fmdv rna amplified by the polymerase chain reaction (pcr).molecular detection of foot-and-mouth disease virus (fmdv) using the polymerase chain reaction (pcr) is a rapid and accurate method. in this study we present pcr for the detection of fmdv rna in infected bhk cells. using pcr and two primers selected from the rna polymerase gene, a conserved sequence in all types and subtypes of fmdv, we were able to detect fmdv rna present in rna extracted from the fmdv-infected cells. rna from uninfected bhk cells gave negative results. another set of primers s ...19921313822
foot-and-mouth disease virus typing by complement fixation and enzyme-linked immunosorbent assay using monovalent and polyvalent antisera.an indirect "sandwich" enzyme-linked immunosorbent assay (elisa) using polyvalent and monovalent antisera was compared with the 50% complement fixation (cf50) test for the detection of foot-and-mouth disease (fmd) o, a, and c virus types. elisa was more sensitive than cf50 tests when polyvalent antisera were used for detecting the 3 types of virus in epithelial samples, whereas elisa using monovalent antisera was the least sensitive technique. the elisa performed with polyvalent antisera was 9 t ...19921325192
temperature-sensitive mutants of foot-and-mouth disease virus: the isolation of mutants and observations on their properties and genetic recombination.a number of temperature-sensitive mutants were isolated from two strains of foot-and-mouth disease virus (fmdv). various properties of the mutants were examined including comparative growth curves at permissive and restrictive temperatures, cut-off temperatures, thermal lability and ph sensitivity. recombination was observed between various pairs of mutants of fmdv strain pacheco. it occurred early in the growth cycle and the proportion of recombinants remained constant thereafter. maximum recom ...1975237977
[occurrence of an increased reaction to challenge infection after vaccination with aerosols of inactivated foot-and-mouth disease virus]. 1976961209
[serologic study of 2 strains of foot-and-mouth virus, cultured in cell line ib-rs-2, clone 26-3].the antigenic characteristics of the two fmdv plaque size variants asq-pg and asq-pp were studied by serum neutralization kinetics. the results evidentiated that the antiserum asq-pg and asq-pp neutralized both variants at the same extent. the plaque population of these variants after passage in laboratory animals was compared in ib-rs-2 cells.1978224836
[effect of hormones on the susceptibility of the swine cell line ib-rs-2 to foot-and-mouth disease virus].the actions of hydrocortisone and insulin on the multiplication of foot-and-mouth disease virus were studied. the data obtained showed that the infectivity and the synthesis of the virus nucleic acid as evaluated through the plaque assay method and the kinetics of uridine-3h incorporation were increased or decreased by hydrocortisone (2 x 10(-6) m). the induction of both effects seems to be related to the carbohydrate metabolism: when the maintenance medium contained glucose or glucose plus calf ...1978224839
a pathogenesis study of foot-and-mouth disease in cattle, using in situ hybridization.eight calves were exposed in an aerosol chamber to nebulized foot-and-mouth disease virus. two control animals were exposed in a similar manner to cell culture media only. animals were euthanized at intervals and various tissues examined by in situ hybridization using a biotinylated rna probe corresponding to a portion of the viral gene coding for the polymerase enzyme. by this technique large amounts of viral nucleic acid were found in coronary band, interdigital cleft and tongue as early as si ...19921330277
[isolation of foot-and mouth disease virus in swine with other diseases].the authors took a survey of foot-and-mouth disease samples of myocardium and tonsil from swine which was died without clinicals signs of foot-and-mouth disease, with isolation of virus, type o, a and c. it was observed and accentuated relation between the incidence of hog cholera, pneumonia and atipic foot-and-mouth disease, especially from suckling pigs.1978224841
a mechanism involved in the plaque enhancement effect of sodium thiosulfate for foot-and-mouth disease viruses.a mechanism involved in the plaque enhancement effect of foot-and-mouth disease viruses (fmdv) by the addition of sodium thiosulfate (hypo) in the agar overlay medium (aom) previously reported was studied. it was experimentally proved that the diffusion of virus particles through agar overlay medium was enhanced when this salt was incorporated. accordingly, the enlarged plaque formation was assumed to be caused by the enhanced diffusion of viral progenies produced in infectious centers during pl ...19921331716
foot-and-mouth disease: detection of antibodies in cattle sera by blocking elisa.a blocking elisa was developed for the detection of antibodies to foot-and-mouth disease virus sat1, sat2 and sat3 and for the quantification of antibodies on a single dilution of serum. the avidin-biotin system was used. the test was compared with the liquid-phase elisa executed at the world reference laboratory for foot-and-mouth disease. it was found to have favourable logistics and combined high specificity with high sensitivity. the quantitative test using a single dilution of serum was res ...19921333673
[effects of polyionic compounds in the plaque formation of different strains of foot-and-mouth disease virus (fmdv) in the swine cell line ib-rs-2].the effects of dithylaminoethyl (deae)-dextran (dd) and dextran-sulfate (ds) were studied in some strains of the foot-and-mouth disease virus (fmdv). the strains asq-pg, cr and o, large plaque variants in ib-rs-2 cells, when dd or ds were added to the agar overlay, the plaques were inhibited. however, the strains asq-pp and ci, that are small plaque variants in ib-rs-2 cells, when to the agar overlay was added dd the plaques were greatly enhanced while when was added ds the plaques were inhibite ...1978224842
[swine cell sublines with different ploidies. iii. susceptibility to foot-and-mouth disease virus].ib-rs-10-ii subline with tetraploid level cells was more susceptible to the infection by the foot-and-mouth disease virus (fmdv) asq-pg strain than ib-rs-10-i subline with diploid level cells, when number and size of plaques and cytopathogenic effect of the virus were used as criteria. besides, the virus yield in one-cycle of infection was almost the double in ib-rs-10-ii than ib-rs-10-i cell subline and the near-tetraploid cells were more susceptible to be infected by the virus than the near-di ...1978224843
foot and mouth disease virus. ii. endoribonuclease activity within purified virions. 1978210581
relationship between virus neutralization and serum protection bioassays for igg and igm antibodies to foot-and-mouth disease virus.the time interval between administering the serum and the virus was found to influence the results of the in vivo mouse protection test for foot-and-mouth disease antibodies. in particular, for both igg and igm antibodies to strain a12 virus, the mouse protection index increased from zero to a maximum at about 6 h and remained high for at least five days. variations in the antiserum concentration, on a log scale, had a proportional effect on the mouse protection index, if between 1 and 3. the co ...1979219135
[influence of a hypertonic medium on cell susceptibility to foot-and-mouth disease virus].the influence of hypertonic medium on the relationship between two cell clones of ib-rs-2 swine line and the foot-and-mouth disease virus was studied. although the number of infected cells was increased by the cell treatment with the hypertonic medium, before or during the time of virus adsorption and penetration onto the cells, showed by the plaque number, the viral replication was partially inhibited as showed by the plaque size as by the viral yield in one-cycle of infection. on the other han ...1978224844
detection and quantification of foot and mouth disease virus by enzyme labelled immunosorbent assay techniques.enzyme labelled immunosorbent assays (elisa) have been developed to detect and quantify foot and mouth disease (fmd) virus using flexible plastic microtitre plates. the methods were successful for the specific detection of fmd virus and were 50 to 100 times more sensitive than the complement fixation test. the application of the elisa techniques to fmd virus typing and subtyping, and to the assay of antigen concentration during manufacture of vaccines is discussed.1979219137
[the electrophysiological properties of the structural polypeptides of the foot-and-mouth-disease virus].the methodological approaches of isolation of preparations of fmdv structural polypeptides to analyse them by the electrophoresis and electro-focussing methods are presented. the value of isoelectric points of protein coat of fmdv structural polypeptides and corresponding them values of electric potential are determined. the similarity and differences of fmdv serotypes, characterized by the value of relative surface, falling on separate polypeptides, are determined for the virion structure on th ...19921338893
morphogenesis of foot-and-mouth disease virus. i. role of procapsids as virion precursors.the role of procapsids during foot-and-mouth disease virus multiplication was studied on infected bhk-21 cells. purified virus and procapsids were obtained by treating the infected cytoplasmic extracts with rnase and edta. the synthesis of virus, procapsids, and total particles was determined in pulse-chase experiments. a precursor-product relationship between procapsids and virions was obtained. the results show that the rate of synthesis of total particles (virus + procapsids) was linear from ...1979225534
theoretical study about the variability of the genome of foot-and-mouth disease viruses.1. the possibilities of change in amino acids of a protein are discussed in terms of a point mutation. 2. whereas met and trp are forced to change due to a point mutation, other amino acids (ala, arg, gly, leu, pro and val) have a probability of 1/3 to survive in the sequence. 3. on basis of these considerations, the genome from 5 strains (csp, c3ind, o1k, a10 and a12) of the foot-and-mouth disease virus was studied. 4. a hypothetical genealogic tree for these strains is suggested, where csp and ...19921310291
identification and characterization of foot-and-mouth disease virus o1 burgwedel/1987 as an intertypic recombinant.the foot-and-mouth disease virus field isolate burgwedel/1987 subtype o1 was found to differ genetically from the antigenically related strain o1 kaufbeuren within the region encoding the non-structural proteins. this genetic difference was indicated by the rnase mismatch cleavage method and confirmed by nucleotide sequencing. an alignment of sequences encoding proteinase 3c of the burgwedel isolate and several other virus strains identified this isolate as an intertypic recombinant; the parent ...19921312120
isolation and characterization of trypsin-resistant o1 variants of foot-and-mouth disease virus.strains of foot-and-mouth disease virus of types o1 and a10 were isolated which showed no significant loss of infectivity upon trypsinization. these 'trypsin-resistant' (tr) viruses were obtained by serial passage in bhk cells of virus that was trypsin-treated before inoculation of the cells. three o1 isolates were cloned and studied further. cell attachment of those tr o1 variants (otr1) was not reduced by trypsinization, unlike that of parent virus. the polypeptide compositions of tr viruses a ...1979225425
comparison between in vitro neutralization titres and in vivo protection against homologous and heterologous challenge induced by vaccines prepared from two serologically distinct variants of foot-and-mouth disease virus, serotype a22.guinea-pigs were challenged with homologous or heterologous strains of foot-and-mouth disease virus (fmdv) following vaccination with baby hamster kidney (bhk) monolayer cell-adapted or bhk suspension cell-adapted strains of fmdv serotype a22 iraq 24/64. the protection afforded by these vaccines was analysed as a function of antigen dose and the in vitro serum virus neutralization titres achieved. the results show that the level of neutralizing antibody induced that afforded 50% protection was s ...19921312129
sequence and location of the poly c tract in aphtho- and cardiovirus rna.the poly c tract in the rna of the aphtho- and cardio viruses has been examined in several isolates of foot-and-mouth disease virus (fmdv) and encephalomyocarditis (emc) virus. the length of the tract is variable, containing 100 to 170 bases in the fmdv isolates and 80 to 250 bases in the emc virus isolates. each poly c tract contains c. 10% a and u residues, located at the 5' end, i.e. most of the tract is a continuous run of c residues. the position of the tract on the genome was the same in e ...1979223128
a study on the immune response of sheep to foot and mouth disease virus vaccine type 'o' prepared with different inactivants and adjuvants.foot and mouth disease virus (fmdv) type 'o' was inactivated either with formaldehyde or binaryethyleneimine (bei). vaccines were prepared with inactivated virus incorporating aluminum hydroxide gel or mineral oil as an adjuvant. the antibody response in sheep was monitored by serum neutralization and elisa test for a period of six months. significant difference in antibody response was not observed between vaccines inactivated with formaldehyde or bei. on the other hand significant difference i ...19921364024
molecular cloning and expression of the vp1 gene of foot-and-mouth disease virus c1 in e. coli: effect on bacterial cell viability.the vp1 gene of foot-and-mouth disease virus (serotype c1) has been cloned in escherichia coli clts cells, under the control of the bacteriophage lambda pl promoter. the expressed vp1 protein was complete and non-fused, and its molecular weight was indistinguishable from that of the vp1 obtained from virions. cells harbouring the recombinant vectors exhibited symptoms of plasmid instability and toxicity and died in a few weeks even when never exposed to inducing conditions. a new plasmid clone i ...19911369359
nucleotide sequence of the cdna and the derived amino acid sequence for the major antigenic protein of foot and mouth disease virus, type asia 1 63/72.a 0.9 kb cdna for the foot and mouth disease virus (fmdv) type asia 1 63/72, cloned in the plasmid pur222 by dc/dg tailing method, was expressed into a protein which was immunogenic in guinea pigs and cattle. the protein purified to homogeneity was found to be basic and of 38 kda. a sequence of 879 nucleotides of the inserted cdna was obtained. the nucleotide sequence was 65% gc-rich and was homologous to the gene for vpi of fmdv types a5, oik and c3 to the extent of 35-40%. from the nucleotide ...19921317347
dependence of the adenovirus tripartite leader on the p220 subunit of eukaryotic initiation factor 4f during in vitro translation. effect of p220 cleavage by foot-and-mouth-disease-virus l-protease on in vitro translation.the adenovirus tripartite leader (tpt) 5' untranslated region (5'utr) allows translation in poliovirus-infected cells, in which the p220 subunit of eukaryotic initiation factor 4f is degraded. this p220-independent translation was investigated by measuring in vitro translation in a reticulocyte lysate of a reporter gene, chloramphenicol acetyltransferase, coupled to the tpt 5'utr. the p220 subunit was degraded by translation of a foot-and-mouth-disease l-protease construct. surprisingly, the tpt ...19921321714
a comparative study on the immune response of sheep to foot and mouth disease virus vaccine type asia-1 prepared with different inactivants and adjuvants.foot and mouth disease virus type asia-1 was inactivated either with formaldehyde or binaryethylenimine (bei). inactivated vaccines were prepared incorporating aluminium hydroxide gel or mineral oil as an adjuvant. the antibody response to the adult sheep was studied by elisa and sn test for a period of 6 months. there was no difference in the antibody response between vaccines inactivated with formaldehyde or bei. whereas significant difference in the antibody response was observed between gel ...19921314158
cross-reactive and serotype-specific antibodies against foot-and-mouth disease virus generated by different regions of the same synthetic peptide.synthetic peptides based on the vp1 proteins of two serotypes of foot-and-mouth disease virus (fmdv) and having the general formula c-c-(200-213)-p-p-s-(141-158)-p-c-g induce heterologous as well as homologous protection against challenge. substitution of the sequence consisting of residues 200 to 213 (200-213 sequence) with a second copy of the homologous 141-158 sequence (i.e., homodimers) resulted in failure of either serotype peptide to protect heterologously. the antiviral and antipeptide t ...19921372368
modification of foot-and-mouth disease virus o1 caseros after serial passages in the presence of antiviral polyclonal sera.foot-and-mouth disease virus (fmdv) shows a remarkable antigenic variability and, like other rna viruses, presents a high rate of mutation. it has been proposed that selection exerted by antibodies of the host could play a major role in the rapid evolution of fmdv. the present work reports the selection of fmdv antibody-resistant (nr) populations after serial passages of a cloned fmdv o1 caseros strain on secondary monolayers of bovine kidney cells in the presence of subneutralizing antiviral po ...19921374806
evolution of the capsid protein genes of foot-and-mouth disease virus: antigenic variation without accumulation of amino acid substitutions over six decades.the genetic diversification of foot-and-mouth disease virus (fmdv) of serotype c over a 6-decade period was studied by comparing nucleotide sequences of the capsid protein-coding regions of viruses isolated in europe, south america, and the philippines. phylogenetic trees were derived for vp1 and p1 (vp1, vp2, vp3, and vp4) rnas by using the least-squares method. confidence intervals of the derived phylogeny (significance levels of nodes and standard deviations of branch lengths) were placed by ...19921316467
the application of biotechnology to the control of foot-and-mouth disease virus.biotechnology, which less than 10 years ago was heralded as an alternative to epidemiology in providing the answers to the control of foot-and-mouth disease (fmd), has not fulfilled its initial promise. instead it is now complementing epidemiology by providing extremely sensitive and specific tools for identifying and characterizing strains of fmd virus in diagnostic material. considerable advances in our understanding of the evolution of the virus in different field situations has been made pos ...19921330200
maturation of functional antibody affinity in animals immunised with synthetic foot-and-mouth disease virus.a good correlation exists between specific neutralising antibody titre and protection against challenge with foot-and-mouth disease virus (fmdv) in infected or virus-vaccinated cattle, but not in the case of animals immunised with synthetic fmdv peptides. therefore, mechanisms other than simple neutralisation are likely to be important in vivo. antibody affinity may influence the protective capacity of sera from immunised animals and experiments were carried out to measure the functional affinit ...19921316628
does the vp1 gene of foot-and-mouth disease virus behave as a molecular clock?we have carried out a phylogenetic study of the evolution of the vp1 gene sequence from different serological types and subtypes of foot-and-mouth disease virus (fmdv). the maximum-likelihood method developed by hasegawa and co-workers (hasegawa et al. 1985) for the estimation of evolutionary parameters and branching dates has been used to decide between alternative models of evolution: constant versus variable rates. the results obtained indicate that a constant rate model, i.e., a molecular cl ...19921325567
heterotypic lymphoproliferative response in pigs vaccinated with foot-and-mouth disease virus. involvement of isolated capsid proteins.the in vitro viral lymphoproliferative response of pigs vaccinated against foot-and-mouth disease virus (fmdv) has been characterized. peripheral blood mononuclear cells from immunized animals up to 1 year post-immunization (p.i.) showed a time-dependent fmdv-specific response, as assayed by virus-specific cellular blastogenesis. the optimum viral concentration decreased with time (around 20 weeks p.i.), and the response was faster and weaker. lymphoproliferation appeared to be mainly due to cd4 ...19921328475
antiviral effects of a thiol protease inhibitor on foot-and-mouth disease virus.the thiol protease inhibitor e-64 specifically blocks autocatalytic activity of the leader protease of foot-and-mouth disease virus (fmdv) and interferes with cleavage of the structural protein precursor in an in vitro translation assay programmed with virion rna. experiments with fmdv-infected cells and e-64 or a membrane-permeable analog, e-64d, have confirmed these results and demonstrated interference in virus assembly, causing a reduction in virus yield. in addition, there is a lag in the a ...19921331517
expression in yeast of amino-terminal peptide fusions to hepatitis b core antigen and their immunological properties.hepatitis b core protein (hbcag) is a potent antigen that gives both a t-cell-dependent and a t-cell-independent antibody response. it has been shown that a foreign epitope can be fused to the amino terminus of hbcag without affecting particle integrity, and that the resulting chimaeric cores retain the immunogenicity of the foreign epitope. here we describe the efficient expression in yeast of two different chimaeric cores, carrying epitopes of foot and mouth disease virus (fmdv) or human chori ...19901369994
foot-and-mouth disease virus populations are quasispecies. 19921318185
comparison of the immune response elicited by infectious and inactivated foot-and-mouth disease virus in mice.the immune response to foot-and-mouth disease virus (fmdv) elicited by infection or immunization with inactivated virus in adult mice was examined. a model of adoptive transfer of immunocompetent cells was used for this purpose. the results presented here indicate that both short- and long-term secondary immune responses elicited by high doses of inactivated virus are indistinguishable, at the humoral or cellular level, from that observed after infection. the responses to inactivated or infectio ...19911649903
primer design for specific diagnosis by pcr of highly variable rna viruses: typing of foot-and-mouth disease virus.a pcr assay for the specific detection and identification of viral sequences that correlate with established serotypes of foot-and-mouth disease virus (fmdv) has been developed. a new analysis based on homology profiles among reported sequences was used for primer design. rna replicase (3d) gene regions that showed high homology among fmdvs, and low homology to other picornaviruses, were used for pcr amplification. specific and highly sensitive detection was achieved for rna of fmdv types c, a, ...19921318612
conformational study of a nine residue fragment of the antigenic loop of foot-and-mouth disease virus.the nine-residue peptide ac-tasargdla-nhme was selected as model peptide in order to understand the conformational features of the antigenic loop of foot-and-mouth disease virus (fmdv). a throughout exploration of the conformational space has been carried out by means of molecular dynamics (md) and energy minimization. the calculations have been carried out using the amber force field. solvent effects have been included by an effective dielectric constant of epsilon = 4r. the lowest energy confo ...19921329841
genetic relationships between southern african sat-2 isolates of foot-and-mouth-disease virus.sequencing of part of the 1d gene of foot-and-mouth disease virus was used to determine the relationships between sat-2 viruses isolated from outbreaks which occurred in cattle in zimbabwe and namibia and in impala in south africa between 1979 and 1989. the results demonstrated that the outbreaks in different countries were unrelated. surprisingly close relationships were shown between all sat-2 viruses isolated from cattle in zimbabwe since 1983 but the two major epizootics which occurred in 19 ...19921334842
immunological evaluation of the multiple antigen peptide (map) system using the major immunogenic site of foot-and-mouth disease virus.the multiple antigenic peptide (map) system for presenting epitopes to the immune system has been studied with an immunogenic foot-and-mouth disease virus (fmdv) peptide comprising amino acids 141-160 of protein vp1. neutralizing antibody responses known to protect guinea-pigs against challenge infection were obtained with a single inoculation of 0.8-4 micrograms of peptide, presented as an octamer or a tetramer, whereas 20 micrograms of a dimer were required to evoke a similar level of antibody ...19911652552
extensive antigenic diversification of foot-and-mouth disease virus by amino acid substitutions outside the major antigenic site.the antigenic sites a and c (the g-h loop and the c terminus, respectively) in vp1 of foot-and-mouth disease virus (fmdv) have been considered the immunodominant regions of the virus involved in the induction of protection. other antigenic sites have been described but their involvement in protection has not been established. here we report that two closely related but serologically different fmdvs (the field isolate c3 argentina/84 and the vaccine strain c3 resende br/55) have identical a and c ...19921335031
a comparison of type o foot and mouth disease virus field isolates from northern thailand.a survey of type o foot and mouth disease (fmd) virus isolates from northern thailand was undertaken to determine the relationship between field viruses and the vaccine in use, and to gauge the range of antigenic variation among field viruses. isolates were collected from the two most recent epizootics, 1986-1987 and 1989-1990, and assessed using a two-dimensional neutralisation test to determine their relationship to fmd type o1 bangkok 1960 (o bkk/60) reference (vaccine challenge) virus. the c ...19921335305
modifications of the 5' untranslated region of foot-and-mouth disease virus after prolonged persistence in cell culture.the nucleotide sequence of the 5'-untranslated region (5'utr) of the genome of foot-and-mouth disease virus (fmdv) r100, rescued after 100 passages of persistently infected bhk-21 cells, has been compared with that of the parental fmdv c-s8c1. the nucleotide sequence divergence between the two viruses in heteropolymeric regions is 1%. the few mutations located at the 5'-most terminal region (s fragment) and at the internal ribosome entry site (ires) do not appear to affect significantly the tigh ...19921335672
[comparison of various methods for the measurement of the humoral immune response in mice vaccinated with aphthous fever virus].kinetics of the humoral immune primary response and seven-day secondary response of adult cf1 mice to fmdv o1 campos adjuvanted in aluminium hydroxide-saponin (ahs) or in oil emulsion (oe) were evaluated by means of elisa and passive hemagglutination (ph). analysis of the response to ahs vaccine showed that elisa measured maximal titres of primary response at 23 days post-vaccination (dpv), and at day 17 of secondary response, while ph detected maximal titres for primary as well as secondary res ...19921338879
comparison of the 5' and 3' untranslated genomic regions of virulent and attenuated foot-and-mouth disease viruses (strains o1 campos and c3 resende).the complete 5' and 3' non-coding regions of two attenuated south american foot-and-mouth disease virus (fmdv) vaccine strains, o1c-o/e and c3r-o/e, and their corresponding virulent parental strains, o1 campos and c3 resende, have been cloned from polymerase chain reaction-amplified primary cdna. differences observed in the derived nucleotide sequences between attenuated and virulent viruses seem not to affect regulatory signal structures, supporting the theory that genetic variations, primarily ...19911658210
maintenance of foot and mouth disease viruses in buffalo (syncerus caffer sparrman, 1779) in southern africa.using age-related infection rates derived from serological data in available deterministic and specially developed stochastic simulation models, it has been possible to establish that the basic reproductive rates for south african territory (sat) type foot and mouth disease virus in buffalo (syncerus caffer) are high. the models predict that there is a periodicity of infection within herds and possibly the population as a whole. thus, buffalo herds are likely to be more infectious at some times ...19921339066
dual initiation sites of protein synthesis on foot-and-mouth disease virus rna are selected following internal entry and scanning of ribosomes in vivo.the initiation of protein synthesis on foot-and-mouth disease virus rna occurs at two sites separated by 84 nucleotides. immediately upstream from the first of these sites is the internal ribosome entry site (ires), which directs the translation of this rna to be cap-independent. the utilization of these two initiation sites has been examined using artificial fusion genes in vivo under a variety of conditions. additional in-frame aug codons have been introduced between these two authentic start ...19921339342
proliferative lymphocyte responses to foot-and-mouth disease virus and three fmdv peptides after vaccination or immunization with these peptides in cattle.we studied proliferative responses of bovine t lymphocytes to foot-and-mouth disease virus (fmdv) serotypes a, o and c as well as to three peptides including the two major b-cell epitopes of fmdv (vp1[141-156] and vp1[200-213]). peripheral blood mononuclear cells (pbmc) from cattle previously vaccinated with monovalent vaccine responded to both homotypic and heterotypic virus strains. of 14 fmdv-specific bovine t-cell clones, which were prepared from pbmc of an animal vaccinated with the trivale ...19921349300
maximizing the expression of a recombinant gene in escherichia coli by manipulation of induction time using lactose as inducer.the use of isopropyl-beta-d-thiogalactoside (iptg) for induction of the lac-promoter in small-scale cultivations is well established. however, for large-scale microbiological processes the cost of this inducer is a severe limitation. here is described a method by which lactose is used as inducer of the lac promoter with the same efficiency as that of iptg. it was found that after growth on glucose the time of the addition of lactose is important for the quality of induction. the resulting yield ...19921369364
foot-and-mouth disease virus o1lombardy is biochemically related to o2 isolates.the capsid protein vp1-encoding rna regions of the foot-and-mouth disease virus isolates o1lombardy/1946 and o2brescia/1947 were sequenced and found to be closely related to each other and to o2normandy/1949, despite some sequence differences. the o1lombardy sequence was expected to be more closely related to those of the subtype o1 isolates of 1965 and later (e.g., o1kaufbeuren/1966), but this was not the case. the serological subtyping of both the lombardy and the kaufbeuren isolate as o1 stra ...19911663294
fitness alteration of foot-and-mouth disease virus mutants: measurement of adaptability of viral quasispecies.we document the rapid alteration of fitness of two foot-and-mouth disease virus (fmdv) mutants resistant to a neutralizing monoclonal antibody. both mutants showed a selective disadvantage in bhk-21 cells when passaged in competition with their parental fmdv. upon repeated replication of the mutants alone, they acquired a selective advantage over the parental fmdv and fixed additional genomic substitutions without reversion of the monoclonal antibody-resistant phenotype. thus, variants that were ...19911645804
foot-and-mouth disease virus c3 resende subtype analysed by means of competition ria using neutralizing monoclonal antibodies.foot-and-mouth disease virus (fmdv) was analysed using 30 monoclonal antibodies (mabs) obtained from balb/c mice immunized with fmdv c3 resende (c3r) subtype 7 and 14 days before fusion no. 15 and 16 respectively. fourteen mabs were neutralizing and by means of competition radioimmuno assay it was possible to classify them into four groups. the first group consisted of mabs specific for three sequential and three conformational epitopes. the second group consisted of mabs specific for two confor ...19921379398
non-additive effects of multiple amino acid substitutions on antigen-antibody recognition.synthetic peptides have been used to mimic the main antigenic site of foot-and-mouth disease virus (fmdv) of serotype c and of several variant isolates. this region includes multiple continuous b cell epitopes. the effect of single amino acid replacements, individually or in combination, on antigen specificity has been evaluated using monoclonal antibodies. quantitative enzyme immunodot assays have shown that both additive and non-additive effects of multiple replacements occur in continuous b c ...19921376255
antigenic stability of foot-and-mouth disease virus variants on serial passage in cell culture.two neutralizing monoclonal antibody (mab)-resistant variants selected from an isolate of foot-and-mouth disease virus (fmdv) type a5 were repeatedly passaged in cell culture and monitored for susceptibility to neutralization by the selecting mab. a variant isolated with a mab to a conformational epitope (1-og2) lost resistance in 20 passages, while a variant isolated with a mab to a linear epitope (1-ha6) persisted for 30 passages. in both cases, the virus population emerging after passage was ...19911645803
crystallization and preliminary x-ray analysis of three serotypes of foot-and-mouth disease virus.foot-and-mouth disease viruses from serotypes o, a and c have been crystallized. the particular strains studied include o1k, a10(61), a22 iraq 24/64, a24 cruzeiro and c-s8c1. in addition, crystals have been grown of g67, a monoclonal antibody neutralization escape mutant derived from o1k, and of virus r100, recovered after the establishment of a persistent infection in baby hamster kidney cells with c-s8c1. empty particles, capsids which lack the rna genome, have also been crystallized for subty ...19921335517
the n-terminal amino acid sequence is essential for foot-and-mouth disease virus replicase activity.1. foot-and-mouth disease virus replicase was expressed by fusing its cdna to the ompa signal peptide coding sequence present in the pin-iii ompa series vectors. 2. two constructions were developed to express either a full-length or truncated enzyme lacking the 20 amino acids at the n-terminal end. bacterial extracts expressing the recombinant proteins were submitted to sds-page and the presence of the replicase was revealed by immunoblotting. the truncated form exhibited a higher mobility and t ...19921342596
characterization and immune response of a protein produced by a cdna clone of foot and mouth disease virus, type asia 1 63/72.a 0.9 kb double stranded cdna of foot and mouth disease virus (fmdv) type asia 1, 63/72 was cloned in an expression vector, pur222. a protein of 38 kd was produced by the clone which reacted with the antibodies raised against the virus. a 20 kd protein which may be derived from the 38 kd protein contained the antigenic epitopes of the protein vp1 of the virus. injection of 10-20 micrograms of the partially purified 38 and 20 kd proteins or a lysate of cells containing 240 micrograms of the prote ...19921378734
in vitro activities of a recombinant foot-and-mouth disease virus replicase expressed in escherichia coli.1. the replicase gene of foot-and-mouth disease virus (fmdv) was expressed in escherichia coli under the control of a tac promoter. the recombinant enzyme was purified by inclusion body precipitation, elution, and poly(u) sepharose chromatography. 2. the enzyme exhibits poly(a)-dependent oligo(u)-primed poly(u) polymerase activity. the specific activity of the purified replicase is 1.3 x 10(5). the recombinant replicase synthesizes rna using fmdv rna as template, as well as heterologous rnas, su ...19921342607
changes in mononuclear peripheral blood cells in cattle with foot-and-mouth disease.the percentages and absolute numbers of mononuclear peripheral blood cells (mnc) were studied in vaccinated (vac) and non-vaccinated (control) cattle, challenged with foot-and-mouth disease virus (fmdv). all vac cattle but none of the controls resisted challenge. cell populations were studied immediately before and one week after challenge, by direct and indirect immunofluorescence, using polyclonal and monoclonal antibodies against different bovine markers. total b-lymphocytes, as assessed with ...19921347666
rgd-containing peptides of vp1 of foot-and-mouth disease virus (fmdv) prevent virus infection in vitro.rgd-containing peptides from the immunodominant region of vp1 between amino acids 135-160 from foot-and-mouth disease virus (fmdv) type o1 kaufbeuren (o1k) prevented virus adsorption to piglet kidney (pk) cells. the highly conserved amino acid rgd sequence (arg.-gly.-asp.) was a prerequisite of this effect. to prevent infection with 100-200 tcid50 in 10(6) pk cells, 20-250 micrograms of each peptide should have been added.19911683122
a preliminary study of the pathogenesis of foot-and-mouth disease virus using in situ hybridization.five adult guinea pigs were inoculated intraepithelially in the right hindfoot pad with foot-and-mouth disease virus. animals were euthanatized with carbon dioxide at 4, 10, 24, 48, and 72 hours post-inoculation. generalized disease developed in the guinea pigs, as evidenced by depression and inappetance by 24 hours post-inoculation and by the formation of vesicles in the noninoculated hindfoot pad by 48 hours post-inoculation. by in situ hybridization, using a 500 base pair biotinylated rna pro ...19911650051
generation of a subtype-specific neutralization epitope in foot-and-mouth disease virus of a different subtype.an epitope involved in neutralization of foot-and-mouth disease virus (fmdv) of subtype c3 was generated by a single amino acid replacement in vp1 of fmdv of subtype c1. the replacement [ser (139)----ile, in the immunodominant site a] was consistently found in those fmdv c1 santa pau-sp/70 mutants resistant to neutralization by monoclonal antibody (mab) sd6 (specific for most c1 viruses) that acquired the capacity to be neutralized by mab 7ab5 (specific for c3 viruses).19921370534
a single amino acid substitution affects multiple overlapping epitopes in the major antigenic site of foot-and-mouth disease virus of serotype c.neutralizing monoclonal antibodies (nmabs) elicited against foot-and-mouth disease virus (fmdv) of serotype c were assayed with field isolates and variant fmdvs using several immunoassays. of a total of 36 nmabs tested, 23 recognized capsid protein vp1 and distinguished at least 13 virion conformation-independent epitopes involved in neutralization of fmdv c. eleven epitopes of fmdv c-s8c1 have been located in segments 138-156 or 192-209 of vp1 by quantifying the reactivity of nmabs with synthet ...19901690261
studies on antigenic variability of c strains of foot-and-mouth disease virus by means of synthetic peptides and monoclonal antibodies.peptides representing the sequence of the immunodominant loop of foot-and-mouth disease virus strain c-s8 (ytasargdlahltttharhlp, residues 136-156 of vp1) and of several variant viruses have been prepared by solid phase methods. in addition, five peptides with single-residue replacements at leu147 (ile, nle, val, ala, gly) have been synthesized. tosyl and dinitrophenyl protections for histidine have been compared, the latter being found to give better synthetic products. the peptides have been t ...19921378821
modulation of t-cell reactivity to synthetic peptide analogues of foot-and-mouth disease virus in sheep by amino acid substitutions.the ability of synthetic peptide analogues of foot-and-mouth disease virus vp1 capsid protein to induce t-cell proliferation in vitro following immunization of sheep with the uncoupled peptides was assessed. elevated t-cell responses were obtained to a 21-residue peptide containing vp1 residues 141-158, and a 40-residue peptide containing residues 200-213 and 141-158 linked via a diproline-serine spacer. in contrast, no significant t-cell response was obtained with a 19-residue peptide containin ...19921375405
antigenic relationships of foot-and-mouth disease virus serotype asia-1 isolates demonstrated by monoclonal antibodies.a panel (26) of monoclonal antibodies (mabs) was elicited against three distinct isolates of foot-and-mouth disease virus (fmdv) serotype asia-1. each mab was characterized according to the location of its epitope: class i, restricted to the intact virion (140s); class ii, restricted to 140s and the virion protein subunit (12sps); class iii, available on 140s, 12sps and virus protein 1; class iv, restricted to 12sps. in addition, the mabs were further categorized by isotype, neutralization of vi ...19921375792
putative papain-related thiol proteases of positive-strand rna viruses. identification of rubi- and aphthovirus proteases and delineation of a novel conserved domain associated with proteases of rubi-, alpha- and coronaviruses.a computer-assisted comparative analysis of the amino acid sequences of (putative) thiol proteases encoded by the genomes of several diverse groups of positive-stranded rna viruses and distantly related to the family of cellular papain-like proteases is presented. a high level of similarity was detected between the leader protease of foot-and-mouth-disease virus and the protease of murine hepatitis coronavirus which cleaves the n-terminal p28 protein from the polyprotein. statistically significa ...19911652473
[protection from foot-and-mouth disease virus in naturally-susceptible animals by a linear polymer of a synthetic peptide].linear polymer of a peptide corresponding to the fragment 142-155 of the foot-and-mouth disease virus a22(550) protein (vp1) was synthesized. whereas the monomeric peptide was only slightly immunogenic, the polymer induced virus-neutralizing antibodies in rabbits and protected 100% guinea pigs. sheep vaccinated once and cattle vaccinated twice were stable against infection with the homologous virulent foot-and-mouth disease virus.19911665331
analysis of immune responses in the sheep to synthetic peptides of foot-and-mouth disease virus using ovine polyclonal and monoclonal antibodies.a 40-residue peptide incorporating residues 200-213 and 141-158 of foot-and-mouth disease virus vp1 capsid protein strain o1 kaufbeuren was injected uncoupled into sheep, and the immune responses analysed. direct-binding and inhibition experiments showed that the polyclonal antibody response was directed mainly against epitopes unique to the 40-residue peptide but absent from the constituent peptides containing residues 200-213 or 141-158, respectively. further confirmation of the presence of un ...19901690176
correlations between the conformations elucidated by cd spectroscopy and the antigenic properties of four peptides of the foot-and-mouth disease virus.the conformational features of four related antigenic peptides (a, b, c and usa) from the foot-and-mouth disease virus (fmdv) (vp1; 141-160 of serotype a, subtype 12), assessed by cd, were found to correlate with the serological properties of these peptides. the cd spectra of the four peptides, obtained under cryogenic and solvent titration conditions, were consistent with three conformational components (a left-handed extended helix, an alpha-helix and a 3(10) helix) for peptides a and c and fo ...19911651235
outer membrane phoe protein of escherichia coli as a carrier for foreign antigenic determinants: immunogenicity of epitopes of foot-and-mouth disease virus.outer membrane protein phoe of escherichia coli was used for the expression of antigenic determinants of foot-and-mouth disease virus. five hybrid phoe proteins were constructed containing different combinations of two antigenic determinants of vp1 protein of the virus. the hybrid proteins were expressed in two e. coli strains and the proteins were correctly assembled into the outer membrane. the inserted epitopes were exposed at the surface of the cell and were antigenic in this phoe-associated ...19901690490
genetic and phenotypic variability during replication of foot-and-mouth disease virus in swine.a plaque-purified preparation of foot-and-mouth disease virus (fmdv) of serotype c1 (c-s8c1-1), grown in cell culture, was used to infect nonimmunized pigs. no variant genomes were detected in the average populations of 50 viruses isolated from infected animals by direct rna sequencing of the carboxy-terminal half of the vp1 gene. however, a mutant with altered phenotypic properties was present in low proportion in an infected animal. the frequency of mutants resistant to neutralization by sd6 m ...19901700543
antibodies elicited by a biosynthetic peptide related to a major immunogenic area of fmdv a12.foot-and-mouth disease virus (fmdv) capsid contains 60 copies each of four structural proteins, virus proteins 1-4. virus protein 1 (vp1) plays an important immunogenic role, being the only vp that is immunogenic as an isolated protein. even peptides representing a partial amino acid (aa) sequence of vp1 can induce protective immunity in experimental hosts. a 32 aa residue, in a tandem repeat configuration (32dimer), of sero/subtype a-12 lp ab vp1 (aa 132-168) was highly immunogenic for its homo ...19901694429
[primary structure of the gene for protein vp1 from foot-and-mouth disease virus serotype o1 isolated in the ussr].the nucleotides sequence has been determined for the viral rna and some of its cdnas coding for the major antigenic protein of the epidemic stomatitis o1-194 and o1-1618 vp1 viruses. the expressed microheterogeneity has been registered for the population of the strain o1-194.19901694961
synthetic peptides as potential vaccines against foot-and-mouth disease.advances made in our knowledge of the structure of foot-and-mouth disease virus have enabled us to identify a fragment, consisting of 20 amino acids, of one of the four proteins of the particle, which elicits neutralizing antibodies in experimental animals and in cattle and pigs. the fragment has been synthesised chemically by merrifield's solid phase method and biochemically as part of different fusion proteins. the level of the immune response to the peptide, which depends critically on the wa ...19901697533
an overview of the inactivation of fmdv and the implications when residual virus is present in vaccines.most foot-and-mouth disease (fmd) vaccines are prepared by inactivating the virus with acetylethyleneimine or binary ethyleneimine. however, formaldehyde is still used by some manufacturers despite the well-documented evidence that inactivation with this reagent is not a linear or first-order reaction. recent german work provides clear evidence that almost all the outbreaks in western europe in recent years have been caused by viruses closely related to strains which were isolated more than 20 y ...19911665462
detection of t1-oligonucleotides of the foot-and-mouth disease virus rna [correction of dna] by silver staining.viral (v) rna was isolated from purified foot-and-mouth disease virus (fmdv) by phenol-chloroform-isoamylalcohol treatment, digested by rnase t1 and separated by one-dimensional polyacrylamide gel electrophoresis (page). the oligonucleotides were detected by silver staining. about 45 micrograms of vrna corresponding to about 100 ml of infectious bhk-21 cell culture fluid yielded a pattern of nearly 20 bands sufficient to differentiate between the fmd viruses.19901698016
evaluation of a trapping elisa for the differentiation of foot-and-mouth disease virus strains using monoclonal antibodies.a trapping enzyme-linked immunosorbent assay (elisa) has been evaluated for the differentiation of foot-and-mouth disease virus (fmdv) strains using a panel of seven anti-serotype o monoclonal antibodies (mabs). the variation of results within and between tests performed on the same day and on different days was examined using three strains of fmdv. criteria for establishing antigenic differences between the strains as defined by the individual mabs are proposed based on the variability measured ...19911665700
rapid and sensitive detection of foot-and-mouth disease virus in tissues by enzymatic rna amplification of the polymerase gene.direct detection of foot-and-mouth disease (fmd) virus from infected bovine and porcine tissue was investigated using a modified polymerase chain reaction (pcr) technique. a high degree of conservation was found in the genomic region coding for the viral rna polymerase among the seven fmd viral (fmdv) serotypes. an oligomeric primer pair and probe were constructed from consensus sequence data within this area. first strand cdna was synthesized using random hexamers and moloney mulv reverse trans ...19911666635
two mechanisms of antigenic diversification of foot-and-mouth disease virus.the amino acid replacements that underlay the diversification of the main antigenic site a (vp1 residues 138 to 150) of foot-and-mouth disease virus (fmdv) of serotype c have been identified. sixteen new vp1 sequences of isolates from 1926 until 1989 belonging to subtypes c1, c2, c3, c4, c5, and unclassified are reported. the reactivities in enzyme-linked immunoelectrotransfer blot assays of capsid protein vp1 with a panel of neutralizing monoclonal antibodies that recognize sites a or c (the vp ...19911653494
fixation of mutations at the vp1 gene of foot-and-mouth disease virus. can quasispecies define a transient molecular clock?the number of nucleotide (nt) substitutions found in the vp1 gene (encoding viral capsid protein) between any two of 16 closely related isolates of foot-and-mouth disease virus (fmdv) has been quantified as a function of the time interval between isolations [villaverde et al., j. mol. biol. 204 (1988) 771-776]. one of them (isolate c-s12) includes some replacements found in isolates that preceded it and other replacements found in later isolates. the study has revealed alternating periods of rap ...19911653754
the capsid protein-encoding sequence of foot-and-mouth disease virus o2brescia.nucleotide sequences encoding the four capsid proteins of foot-and-mouth disease virus subtype o2brescia/1947 have been determined. these and the deduced amino acid sequences were compared with those of a subtype o1 virus strain. the nucleotide sequences differed at 259 positions, causing only 35 amino acid changes. vp4 and vp2 differed by 2.4 and 1.8%, whereas vp1, known as major viral antigen, and vp3 differed by 8% and 5.5%, respectively. the differences occur mainly in protein domains not in ...19911656918
the detection of antibodies against foot-and-mouth disease virus (fmdv) in filter paper eluates from pig sera or whole blood by elisa.the use of pig blood samples dried on paper discs for the detection of antibodies against fmdv by the liquid phase blocking elisa has been evaluated. the average volume of whole heparinised blood required to fully saturate 6.0 mm discs was 7.65 microliters (range 7.2 to 8.1; variation = 0.24, p = 0.05). when 200 clinically healthy animals were assessed by virus neutralisation (vn) titres up to 1/22 were recorded against types o, a and c, 97% being 1/11 or less. using elisa, results were more ske ...19911666636
cleavage of foot-and-mouth disease virus polyprotein is mediated by residues located within a 19 amino acid sequence.the 2a region of the foot-and-mouth disease virus (fmdv) polyprotein is only 16 amino acids in length. during synthesis of the fmdv polyprotein a primary proteolytic processing event occurs between the 2a and 2b regions of the polyprotein. the activity responsible for this cleavage is not known but it is thought that either an unidentified virus-encoded proteinase may be responsible, or that 2a acts as a substrate for a host cell proteinase. a series of recombinant fmdv polyproteins has been con ...19911658199
interaction of a cellular 57-kilodalton protein with the internal translation initiation site of foot-and-mouth disease virus.a cellular 57-kda protein (p57) that binds specifically to the internal translation initiation site in the 5' untranslated region of foot-and-mouth disease virus rna was detected in cell extracts of different mammalian species by uv cross-linking. the protein binds to two distinct sites of the translation control region which have as the only common sequence a uuuc motif. the first binding site consists of a conserved hairpin structure, whereas the second binding site contains an essential pyrim ...19911658355
expression, processing, and assembly of foot-and-mouth disease virus capsid structures in heterologous systems: induction of a neutralizing antibody response in guinea pigs.plasmids containing the foot-and-mouth disease virus structural protein precursor (p1) and 3c protease genes or the p1 gene alone were expressed in escherichia coli. a recombinant baculovirus containing the p1 gene was also generated and expressed in spodoptera frugiperda cells. expression of the p1 and 3c genes in e. coli resulted in efficient synthesis and processing of the structural protein precursor and assembly into 70s empty capsids. this material reacted with neutralizing monoclonal anti ...19911658362
[detection of neutralizing antibodies in calves after single vaccination against foot-and-mouth disease virus type asia 1 in the field].on june 20th 1984 appeared the first fmd-type asia 1 outbreak in greece. around the outbreak all susceptible animals were vaccinated with asia 1 vaccine produced by iffa mereiux. three weeks after this first vaccination blood samples have been collected and examined for neutralizing antibodies. from 101 examined calves 37 were younger than 6 months, 63 between 6-11 months and one was 12 months old. the titer of the first group was less than 1.2 in 14 and greater than 1.8 in 8 calves. by the seco ...19911659374
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