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[immunogenic quality of foot-and-mouth disease virus].routine analysis of suspensions of foot-and-mouth disease virus and eluates of vaccine by the isopycnic method in analytical ultracentrifuge demonstrates the important heterogeneity of the viral population. this heterogeneity increases during inactivation of the virus by formol. in view of this dispersion of the physical characteristics of viral particles it may be asked (a) whether the immunogenic value is linked to the total quantity of particles which, we know, are very different from each ot ...1976198301
an evalutation of some methods of assay of foot-and-mouth disease antigen for vaccines.the relative merits of various in vitro assay systems for the measurement of the quality and quantity of foot-and-mouth disease virus vaccine antigen will be discussed. the assay systems include : viral infectivity, complement fixing activity, particle counts, radial diffusion titre and single radial haemolysis titre. the predictive value of the tests for the immunogenicity of the final vaccine product will be evaluated against the results of 50% protective dose titres determined in guinea pigs ...1976198302
comparison of laboratory techniques for the evaluation of the antigenic potency of foot-and-mouth disease virus cultures and vaccines. 1976198304
antibody response of tropical range cattle to foot-and-mouth disease virus. i. comparison of three tests. 1976198305
fast modification of foot-and-mouth disease virus by selecting clones in bovines. 1976198313
certain aspects of foot--and--mouth disease. virus production in growing bhk suspended cell cultures.production of fmdv in growing bhk suspended cell cultures offers several technical advantages: no medium change and no sedimentation of cells prior to infection are needed, thus saving time and medium. however, the final product should be as free of serum proteins as possible. for this purpose polyethylene-glycol-(peg)-treated serum can be used for the stimulation of cell growth in combination with precipitation of the virus with peg. with this method virus preparations are obtained in which pra ...1976198314
studies on the susceptibility to foot--and--mouth disease virus of bhk cell cultures derived from various sources.cultures of bhk monolayer and suspension cells obtained from a number of laboratories and a group of cloned sub-lines derived from suspension cells were examined for their susceptibility to three fmd virus strains. it was found that the various cultures were sensitive to the test virus strains to differing degrees. it was shown possible to obtain a clone with high susceptibility to asia 1 iran 1/73 virus from a parent culture which had a low susceptibility to that virus. the implication of these ...1976198315
reproducibility of yields of foot--and--mouth disease virus from bhk monolayer and suspension cells.the production of fmd virus from bhk 21 c13 monolayer and suspension cells was examined under standardized conditions and in different systems. the yields of virus from suspension cells did not significantly exceed the yield from monolayer cells, whereas the monolayer cell was capable of producing virus from some strains of fmd virus which would not grow in suspension cells. when different production systems were examined, the scale of operation did not significantly influence the yield of virus ...1976198316
the airborne dispersal of foot-and-mouth disease virus from vaccinated and recovered pigs, cattle and sheep after exposure to infection.foot-and-mouth disease virus was detected during two periods in the air of looseboxes which housed susceptible, vaccinated or recovered pigs, cattle or sheep exposed to infection. the first was 30 min to 22 h after exposure and occurred in all animals. the second was two to seven days after exposure and occurred with those susceptible and vaccinated animals which developed clinical lesions, and with vaccinated and recovered pigs and sheep, which did not develop clinical lesions. vaccination of a ...1977198862
[relationship between the chemical structure and the biological activity of antibodies against the foot-and-mouth disease virus].investigated was the effect of various amino agents (stained and phthalic anhydride and sulfopicric acid) on the complement-and antigen-fixing activity of igg and igm antibodies isolated from guinea pig sera, the donor animals being hyperimmunzed with type o, strain polyana, of the foot-and-mouth disease virus, at the moderate modification (75-86 per cent acetylation, and 36-40 per cent 'phthalation') of the primary amino groups the foot-and-mouth disease antibodies retained only half of the con ...1977199988
routine titration of foot-and-mouth disease virus suspensions by analytical ultracentrifugation 2nd communication: sedimentation equilibrium method.a routine method for the determination of the virus concentration in fmd virus cultures and vaccines was developed. this method was based on sedimentation equilibrium in the analytical ultraviolet scanning ultracentrifuge. the virus suspension was first clarified. the virions were then sedimented in a preparative ultracentrifuge. the resuspended virions were diluted in a cesium chloride solution and brought to equilibrium in the density gradient generated in the analytical ultracentrifuge. the o ...1977200195
an assessment by competition hybridization of the sequence homology between the rnas of the seven serotypes of fmdv.a comparison has been made of the rnas of the seven serotypes of foot-and-mouth disease virus (fmdv) by competition hybridization. homology among the three european serotypes a, o, c and the asia i serotype was 60 to 70%. similar homologies were found among the three southern african territories serotypes (sat i, sat 2, sat 3), but homology between the two groups was much lower (25 to 40%). homology between the rnas of subtypes within serotypes a and o was greater than 70%. double competition ex ...1977200707
n-terminal amino acid sequences in the major capsid proteins of foot-and-mouth disease virus types a, o, and c.sequences of amino acids at the n-termini of virus proteins vp1, vp2, and vp3 were determined for foot-and-mouth disease virus types a12 strain 119, o1brugge and c3resende. in the polyacrylamide gel electrophoresis system used to purify the proteins, vp3 migrated faster than vp1 or vp2; and in the virion, vp3 could be cleaved by trypsin into vp3a and vp3b. the n-terminal amino acids for each of the virus types were glycine in vp1, aspartic acid in vp2, and threonine in vp3. no divergences in seq ...1975171452
occurrence of cross reactions to foot-and-mouth disease virus in normal swine sera.sera from 101 swine never exposed to foot-and-mouth disease virus were tested by the plaque-reduction neutralization (prn) and radial immunodiffusion techniques for cross-reactions to 5 types of foot-and-mouth disease viruses. depending on the group of sera and the virus used, the percentage of sera cross-reacting at low levels varied from 0 to 50% with the prn technique and 0 to 20% with the radial immunodiffusion technique. 5erum-neutralization tests in mice support the finding of neutralizing ...1977201197
[structure of the protein membrane of the foot-and mouth disease virus]. 1977202058
[post-vaccinal immunity against heterologous subtypes of the foot-and-mouth disease virus]. 1977202059
immune and antibody responses to an isolated capsid protein of foot-and-mouth disease virus.the purified capsid proteins vp1, vp2, and vp3 of foot-and-mouth disease virus type a12 strain 119 emulsified with incomplete freund's adjuvant were studied in swine and guinea pigs. swine inoculated on days 0, 28, and 60 with 100-mug doses of vp3 were protected by day 82 against exposure to infected swine. serums from animals inoculated with vp3 contained viral precipitating and neutralizing antibodies, but such serums recognized fewer viral antigenic determinants than did antiviral serums. cap ...1975171309
enhancement by diethylamineothyl-dextran of the plaque-forming activity of foot-and-mouth disease virus-antibody complexes in pig kidney ib-rs-2 cells.mixtures of foot-and-mouth disease (fmd) virus and homologous antibody, assayed for surviving plaque-forming units (pfu) in pig kidney ib-rs-2 cells, demonstrated an average ten-fold greater recovery of infectivity when diethylaminoethyl-dextran (deae-dextran) was included in the overlay medium. this enhancement, which was not detected in baby hamster kidney bhk21 cells, was due to the ability of the polycation to potentiate attachment of virus-antibody complexes to the ib-rs-2 cells. in some in ...1977202225
removal of acetylethyleneimine from suspensions of inactivated foot-and-mouth disease virus. 1975166252
proteins induced in bhk cells by infection with foot-and-mouth desease virus.although the infection of bhk cells with foot-and-mouth disease virus did not cause a marked inhibition of cellular protein synthesis, the proteins synthesized gradually changed from host-specific to virus-specific. the synthesis of at least thirteen virus-induced proteins was demonstrated by polyacrylamide electrophoretic analysis of the infected cells. only a small proportion of the virus-induced proteins was incorporated into the mature virus particles. the addition of amino acid analogues ca ...1975164515
the use of the haemagglutination-inhibition test for detecting antibodies to type sat 2 foot-and-mouth disease viruses in cattle sera.two strains of type sat 2-foot-and-mouth disease virus which gave high titres of haemagglutinin activity reacted type-specifically in direct haemagglutination-inhibition tests with reference, bovine convalescent antisera. comparisons of the haemagglutination-inhibition and the serum neutralization tests using cattle sera showed that both were equally specific and sensitive for detecting virus antibody.1975163274
cross reactions of normal bovine sera with foot-and-mouth disease virus: incidence, duration, and effect of shipping stress.serum samples were obtained from 30 hereford steers in an area known to be free of foot-and-mouth disease (fmd) viruses as follows: before shipment and 4 times during a 70-day period after shipment; the sera were tested for the presence of cross-reacting antibody to various viruses. percentages of sera containing cross-reacting antibody to fmd virus detected by the plaque-reduction neutralization and the radial immunodiffusion techniques were higher for the fmd viruses asia and sat i5 than for t ...1978206170
comparative biochemical and serological analysis of five isolates of a single serotype of foot-and-mouth disease virus.a comparison has been made of some of the biochemical and serological characteristics of five isolates of foot-and-mouth disease virus (fmdv), serotype a. three of the viruses have been assigned to the same subtype, a22; the other two belong to different subtypes, a5 and a24. rna competition hybridization and two-dimensional electrophoresis of the oligonucleotides produced by ribonuclease t1 showed that the three a22 viruses formed a group which could be distinguished from the a5 and a24 viruses ...197994348
the production of foot-and-mouth disease virus from bhk 21 c 13 cells grown on the surface of deae sephadex a50 beads.methods are described which make possible the production of foot-and-mouth disease (fmd) virus from bhk 21 c13 monolayer cells which have been grown on the surface of serum coated deae sephadex a50 beads. the yield of cells and their susceptibility to infection by fmd virus are equivalent to conventional roux monolayer systems. the potential for the commercial application of the deae sephadex a50 system is discussed in relation to other unit process monolayer systems and in particular to the sys ...1976179635
indirect complement fixation test with foot-and-mouth disease virus antigen concentrated by polyethylene glycol precipitation.to a bhk-21 cell culture fluid infected with the o, a, or asia 1 type of foot-and-mouth disease (fmd) virus was added polyethylene glycol 16000 to a concentration of 10% (w/v). then the fluid was concentrated to one-tenth of the original volume. the resulting concentrated virus antigens showed a complement fixation (cf) titer ranging from 12 to 14. the rate of recovery of cf activity was in a range of 40 approximately 80%. each antigen was applied to the indirect complement fixation (icf) test w ...1978206842
isolation of foot-and-mouth disease virus from yak. 1978207010
growth of foot-and-mouth disease virus in the upper respiratory tract of non-immunized, vaccinated, and recovered cattle after intranasal inoculation.non-immunized, vaccinated, and recovered cattle were inoculated intranasally with various doses of foot-and-mouth disease virus. samples of oesophageal-pharyngeal (op) fluid were taken periodically for up to 7 days after inoculation and virus titres of these samples were plotted as pharyngeal virus growth curves. in non-immunized cattle, the length of the lag period and of the growth period were inversely proportional to the dose of virus given. maximum titres were observed when clinical signs w ...1976180177
effect of zinc and other chemical agents on foot-and-mouth-disease virus replication.chemical agents reported to inhibit the growth of various ribonucleic acid and deoxyribonucleic acid viruses were tested against foot-and-mouth disease virus in cell culture. these included zn(2+), aurintricarboxylic acid, polyribocytidylic acid, polyriboinosinic acid, phosphonoacetic acid, and the viral contact inactivator n-methyl isatin beta-thiosemicarbazone alone and with cuso(4). the most effective agent, zn(2+), inhibited foot-and-mouth disease virus production in primary calf kidney cell ...1978208461
ribonuclease activities associated with purified foot and mouth disease virus.ribonuclease activities internally and externally associated with purified foot-and mouth disease virus were detected. the outer activity was easily removed by cesium chloride or by detergent (sarkosyl). the inner activity is not removable by any procedure used and could be the enzyme responsible for the heterogeneity normally observed in the extracted fmdv-rna. it is not known at present if both activities are related to the same or to different enzymes.1978208488
secretory antibody responses in cattle infected with foot-and-mouth disease virus.antibody responses in serum, saliva, nasal secretions, or esophageal-pharyngeal fluid of foot-and-mouth disease virus-infected steers were examined by single radial immunodiffusion and mouse-neutralization tests. in steers infected with type o foot-and-mouth disease virus, high serum antibody titers were detected within 10 days after infection. antibody was first detected in saliva at 30 days and gradually increased to a plateau at about 90 days. small amounts of antibody continued to be secrete ...1978209706
foot and mouth disease virus. ii. endoribonuclease activity within purified virions. 1978210581
the detection of antibody to virus-infection associated (via) antigen in various species of african wildlife following natural and experimental infection with foot and mouth disease virus.the double immuno-diffusion (did) test has been applied to detect antibody to via antigen in sera from various species of african wild ungulates. in conjunction with the serum neutralisation (sn) test it can be used to decide the degree of risk of movement of animals to other countries free from foot and mouth disease (fmd). the value of the test in assessing the history of infection is limited by its relatively low sensitivity and specificity in respect of virus type.1978210744
[some modern data on the antigenic makeup of the foot-and-mouth disease virus and their practical significance]. 1976183347
[use of ultrasonics in purifying the aphthous foot-and-mouth disease virus]. 1978211705
[radial immunodiffusion reaction in research with the foot-and-mouth disease virus]. 1978211706
[type-specific variations in structural polypeptides of foot-and-mouth disease virus]. 1978211982
[effect of the ph of the medium on the morphology of bp cell cultures and their sensitivity to the foot-and-mouth disease virus]. 197934920
antibody responses to type-specific and "virus-infection-associated" antigens in cattle vaccinated with inactivated polyvalent foot and mouth disease virus in north malawi. 1978212157
the effect of cesium salts on dense poliovirus particles.the buoyant density of dense poliovirus particles has been examined in density gradients other than cesium chloride in order to determine the dependence of this property on the nature of the solvent. in urografin (sodium and methylglucamine amidotrizoate), dense poliovirus particles banded at two densities--1.33 and 1.39 g/cm(3)--whereas in cesium metrizoate they banded only at 1.39 g/cm(3) and in cesium sulfate at 1.38 g/cm(3). the presence of cesium ions gives rise to the occurrence of dense p ...1978213398
preadsorption of boar semen with kaolin: increased efficiency of foot-and-mouth disease virus detection.the boar semen-associated cytotoxic factor(s), but not the antiviral activity, were removed by adsorption with kaolin. although foot-and-mouth disease virus was efficiently removed from medium by kaolin or kieselguhr, the virus was not removed from semen-virus mixtures. because the cytotoxicity induced by boar semen apparently altered the ability of tissue culture cells to support virus replication, preadsorption with kaolin increased the probability of detecting this virus in semen samples.1978213994
isolation of immunizing cyanogen bromide-peptides of foot-and-mouth disease virus. 1978214084
early events in the interaction between foot-and mouth disease virus and primary pig kidney cells.foot-and-mouth disease virus (fmdv) attached to pig kidney cells at 0 degrees c and could only be recovered in a form with a sedimentation coefficient and buoyant density lower than that of the native virus. incubation of the virus-cell complex at 37 degrees c caused disruption of about 80% of the particles into a 12s protein sub-unit that had the same polypeptide composition as that produced by reducing the ph of the virus below ph7. the remaining 20% had the same polypeptide and rna compositio ...1978214518
a re-appraisal of the biochemical map of foot-and-mouth disease virus rna.the proteins induced by infection of bhk 21 cells with foot-and-mouth disease virus have been compared by tryptic peptide analysis. the results indicate that there are three primary products 5'--p88, p52, p100--3'. the polypeptide p56, which we considered previously to be a primary product, is derived from the region of the genome that codes for p100. the results indicate that there are alternative cleavage pathways of p100, the polypeptide coded for by the 3' end of the genome.1978214522
[determination of the amount of the 140s-component of foot-and-mouth disease virus]. 1978214930
excretion of foot-and-mouth disease virus in oesophageal-pharyngeal fluid and milk of cattle after intranasal infection.the virus growth in the pharyngeal area and the virus excretion in milk of susceptible and vaccinated dairy cows after intranasal instillation of foot-and-mouth disease (fmd) virus type o1 were examined. ten vaccinated cows were purchased through a market. of these, nine had delivered their first calf. the cows were inoculated 2-9 months after having received the last dose of vaccine. all vaccinated cows resisted the intranasal challenge. the virus multiplied in the pharyngeal area but, compared ...1978215675
persistence of foot-and-mouth disease virus in butter and butter oil. 197827543
neutralization kinetics studies with type sat2 foot-and-mouth disease virus strains. 1. factors that influence the rate and pattern of neutralization.a study of the kinetics of inactivation of foot-and-mouth disease virus type sat 2 strains revealed that in most cases the rate of neutralization was not rectilinear. deviations from first-order kinetics observed represented biphasic or parabolic and stepwise reactions. the initial rate was rapid and showed no lag phase or shoulder. the effects of deviations from linearity could be minimized by dilution of antiserum to a suitable extent. treatment of virus-antibody mixtures with anti-species glo ...197713123
[formation of immunity in sheep inoculated with varying doses of the foot-and-mouth disease virus 0194]. 1979217141
the n-terminal sequence of three coat proteins of foot-and-mouth disease virus. 1978217392
[early events in the replication of foot and mouth disease virus: subcellular localization of viral rna synthesis]. 1977218264
[micromethod of determining the complement-binding properties of commercial series of the foot-and-mouth disease virus].investigations were carried out to establish the possibility of using a micromethod of the complement-fixation test to determine the complement-fixing properties of productional series of the foot-and-mouth disease virus. it was found that the micromethod referred to is an economically profitable and practically simple one. it is readily applicable requiring no particular apparatuses and equipment, is specific, and can successfully be used instead of the routinely employed cft method. the microm ...1978218334
stability and immunogenicity of empty particles of foot-and-mouth disease virus.three strains of foot-and-mouth disease virus were shown to contain significant amounts of naturally occurring 75s, empty particles as well as the infectious, 140s full particles. one of these strains--a pando (1970)--was studied in detail. the empty particles from this virus strain were shown to have an observed sedimentation coefficient of 67s in 0.04 m phosphate buffer; they were labile in sds, non-infectious and probably rna-free and, on heating, they broke down to 12s subunits as did the 14 ...1979218538
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
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
[radial immunodiffusion study of foot-and-mouth disease virus type a].the radial immunodiffusion(ri), was used to study f. m. d. viruses, type a. it was found that the specific linkage between f. m. d. antigens and antibodies could be demonstrated through ri with the formation of precipitation circles. it was demonstrated that specific reactions were produced when homologus or heterologus antigens and sera of one and the same f. m. d. virus type interacted. the size of the precipitation circles proved inversely proportional to the concentration of antibodies in th ...1978219587
immune response of neonatal swine to inactivated foot-and-mouth disease virus vaccine with oil adjuvant. i. influence of colostral antibody. 1977220635
cross reactions of normal bovine serums with foot-and-mouth disease virus. 1977220636
purification of foot-and-mouth disease virus infection-associated antigen. 1978221935
typing foot-and-mouth disease virus by fluorescent antibody technique.typing of foot-and-mouth disease (fmd) virus was performed by the direct fluorescent antibody (fa) technique. type-specific fa was prepared from the following two sorts of procedures: (1) fa against live virus (fa-live) was prepared from hyperimmune serum taken from guinea pigs having received live fmd virus. then it was adsorbed with concentrated heterotype antigen. (2) fa against inactivated virus (fa-inact) was prepared from antiserum taken from guinea pigs immunized with purified fmd virus i ...1976189221
[various physical and chemical properties of the 73s unit of the foot-and-mouth disease virus].at all 3 studied fmd-viruses typs o2, a5 and c we could show the 73s unit in the analytical ultracentrifuge and in the electron microscope. 73s unit is found in the normal cycle of purification of virus and by density gradient centrifugation separated and purified. in cscl ph 7.6 its density is 1.308 +/- 0,005 g/ml. its sedimentation coefficient has a value of 72.7 +/- 1,5s. in electron microscope it show itself as a empty virus capsid. its diameter is in partial purified preparations with 25 +/ ...1976190967
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
biochemical mapping of the foot-and-mouth disease virus genome.four primary cleavage products, mol. wt. 10(3) x 100, 88, 56 and 52 (p100, p85, p56 and p52 respectively) are present in bhk 2i cells infected with foot-and-mouth disease virus (fmdv). however, no precursor polyprotein equal to the sum of their mol. wt. was detected, even when amino acid analogues and proteolytic enzyme inhibitors were used. three of the primary products were shown to cleave to smaller polypeptides, including the capsid polypeptides of the virus. polypeptide p88, which was shown ...1977195008
[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
[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
[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
[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
evidence for a mouse pathogenicity locus in certain temperature-sensitive mutants of foot-and-mouth disease virus.serial tissue culture passaging of three foot-and-mouth disease temperature-sensitive mutants demonstrated the stability of their temperature sensitivity and mouse avirulence characteristics. recovery of mouse-virulent temperature-sensitive viruses after passage of the mutants in mice suggested that these were not covariant expressions of the same locus, but were under the control of different genes.1977197007
modeling and computer stimulation approach to the mechanism of foot-and-mouth disease virus neutralization assays.block neutralization data since 1949 for the foot-and-mouth disease virus system have been analyzed in terms of a unified mass-action theory for computing the amounts of infectious complexes. proof that infectious complexes contribute considerably to the assays was obtained by demonstrating a reduction in titer after an additional reaction with anti-ig antibody before the assay. in the suckling-mice assay with intraperitoneal inoculation, both the data of others and our own on several types indi ...1977197591
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
[interaction between foot-and-mouth disease virus and the cells of different chronically infected animals]. 1979228472
isolation of foot-and-mouth disease virus messenger rna from membrane-bound polyribosomes and characterization of its 5' and 3' termini. 1979228483
the relation of poly(a) length to specific infectivity of viral rna: a comparison of different types of foot-and-mouth disease virus. 1979228485
effect of oesophageal-pharyngeal secretions from normal cattle on foot-and-mouth disease virus o1. 1977201131
foot and mouth disease virus. i. stability of its ribonucleic acid. 1978202081
dose-response relationships in a microneutralization test for foot-and-mouth disease viruses.two-dimensional quantal microneutralization tests on foot-and-mouth disease viruses, in which neutralizing antibody activity was titrated against a serial range of virus doses, demonstrated a variety of dose-response curves some of which were rectilinear, others clearly curvilinear. moreover, in the case of the non-linear responses obtained with some antisera, the shape of the curve was such that antibody titres recorded with doses of virus ranging from 10(3)-10(5) tcd50 were closely similar. st ...1978202650
cross reaction between bovine enterovirus and south african territories i5 foot-and-mouth disease virus.a bovine enterovirus (e76t) isolated from a 2-year-old bull produced serologic cross reactions to south african territories (sat) i5 foot-and-mouth disease virus when inoculated into guinea pigs and cattle. cross-reacting serum titers to sat i5 virus of 1:320 by the plaque-reduction neutralization test and 1:20 by the radial immunodiffusion test occurred in 2 steers after they were inoculated with the e76t virus. in 1 steer, maximal cross-reacting titers appeared related to a 2nd exposure to the ...1978204230
[study of the a strain of foot-and-mouth disease virus which also occurred in the netherlands]. 1978205008
the challenge of vaccinated pigs with foot-and-mouth disease virus. 1979231356
foot-and-mouth disease virus immunogenic capsid protein vpt: n-terminal sequences and immunogenic peptides obtained by cnbr and tryptic cleavages.the immunogenic capsid protein (vpt), circa 30 kiladaltons (kd), of foot-and-mouth disease virus was examined for (i) its ability to induce neutralizing antibody in guinea pigs after chemical modifications and cnbr or tryptic cleavages and (ii) n-terminal amino sequence homology across three virus types. the immunogenicity of vpt was inactivated by glutaraldehyde treatment, carboxymethylation and maleylation or citraconylation. however, de-citraconylation restored part of the lost activity. clea ...1979231585
enzyme-labelled immunosorbent assay techniques in foot-and-mouth disease virus research.the indirect elisa technique has been developed successfully to measure antibodies to foot-and-mouth disease virus (fmdv) in cattle sera. preliminary studies using a standard serum assay show that reproducible results are obtained. the method should prove useful for the examination of antibody titres in sera from large numbers of cattle or other animals.1978206625
[protective effect in the serum of rabbits inoculated with bhk-21 cells infected with foot-and-mouth disease virus].the present investigation was developed to determine the presence of protecting effects in the serum of rabbits inoculated with bhk 21 cells infected with foot-and-mouth disease virus, subtype c2. the rabbits received 252 mg. of antigens harvested 60, 65, 75, 90, 120 and 210 minutes post infection. these antigens were inactivated with two procedure: formaldehyde 0.015% and beta-propiolactone 0.2% and were inyected with incomplete freund's adjuvant; the last inoculations were given with live anti ...1979231797
[subtypes of foot-and-mouth disease virus type a. genetic markers of clones obtained from 4 strains isolated in argentina between 1961 and 1970].the results obtained studying the genetic markers g, t and rtc of different clones of subtypes of foot-and-mouth disease virus type a are presented in this paper. the subtypes were isolated during outbreaks of foot and mouth disease in argentine. no significative differences among the subtypes were observed with the t marker. for the other markers, the results seem to indicate a gradual change related with the serological variation. because of their sensibility to guanidine hidrochloride, it is ...1979231800
factorial experimental design applied to the immunological study of two foot-and-mouth disease virus subtypes. 2. theoretical study of experimental models.a certain number of theoretical models of immunological relations that 2 foot-and-mouth disease viruses can support, were constructed so as to discuss in each case, the results of the factorial analysis of the data. this method provided a specific answer to each of the questions that were asked in the presence of a test of this kind. the results obtained with several immunological cross-tests comparable to that of the a greece 69-a allier viruses, illustrated most of the theoretical models.1979231920
factorial experimental design applied to the immunological study of two foot-and-mouth disease virus subtypes. 1. a greece 1969 -- a allier example.a double immunological cross-test, carried out with the index k method, is subjected to a statistical analysis by a factorial experiment. the a greece and a allier viruses, which have been taken as an example of the calculations procedure, seem to be in 2 immunologically different subtypes.1979231923
in vitro comparison of foot-and-mouth disease virus subtype variants causing disease in vaccinated cattle.foot-and-mouth disease virus isolates of types o, a and sat 2, from diseased animals in herds routinely vaccinated twice a year were compared antigenically with the vaccine strains in the complement-fixation, neutralization and radial immunodiffusion tests. it was found that strains which had readily infected vaccinated cattle had r values against the vaccine strain in the complementfixation and radial immunodiffusion tests of 30 or less, while strains causing primary outbreaks with little sprea ...1978206626
more precise location of the polycytidylic acid tract in foot and mouth disease virus rna.the polycytidylic acid [poly(c)] tract in foot and mouth disease virus rna has been located about 400 nucleotides from the 5' end of the rna by analysis of the products from the digestion of the rna with rnase h in the presence of oligodeoxyguanylic acid [oligo(dg)]. this treatment produces a small fragment (s) containing the small protein covalently linked to the rna and a large fragment (l) that migrates faster than untreated rna on low-percentage polyacrylamide gels, lacks the poly(c) tract a ...1978207892
[treatment of swine cell line with antibiotics: effect on growth kinetics and susceptibility to foot-and-mouth disease virus and to mycoplasma-like organisms].cell cultures treated with tylosin tartrate and kanamycin sulphate antibiotics were studied in relation to the cell growth rate, the susceptibility to the foot-and-mouth disease virus and to the microorganism eradication. these treatments did not affect the cell growth rate and the cell behavior to the viral infection. on the other hand, the decontamination of the intracytoplasmatic formas of mycoplasma-like organism was not observed.1979233199
[isolation of bovine cell lines and susceptibility to foot-and-mouth disease virus].morphology and chromosomes of cell sublines derived from two new bovine kidney lines are reported. cell susceptibility to the foot-and-mouth disease virus is discussed. one of the sublines showed epithelial-like cells, while the remainder, elonged fibroblastic-like cells. most of them had a diploid number of chromosomes. from these sublines only one was sensible to the foot-and-mouth disease virus.1979233200
[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
microneutralization tests for serological typing and subtyping of foot-and-mouth disease virus strains.a microneutralization test for serotyping of fmd viruses is described. it is based on earlier observations by booth, rweyemamu & pay (1978) that dose-response relationships in quantal microneutralizations often deviated from linearity. the typing test described therefore utilizes undiluted virus preparations. in about 90% of samples a positive typing was obtained in contrast with about 50% for the complement fixation test. the test was also found to be susceptible to minimal quantities of hetero ...1978211160
differentiation between specific and nonspecific reactions of bovine sera and foot and mouth disease virus (fmdv) in immunodiffusion tests.the precipitating and neutralizing activities of normal bovine sera with fmdv were studied and compared. twenty-two out of 79 normal bovine sera gave a positive reaction in micro neutralization tests with fmdv type o, while six did so with type a. in rid tests 32 sera were positive with type o and 28 with type a virus. almost all of the 79 sera gave a positive reaction in the rid with trypsin treated virus of both types. after three to four fold concentration most sera also gave visible reaction ...1978211990
[occurrence of an increased reaction to challenge infection after vaccination with aerosols of inactivated foot-and-mouth disease virus]. 1976961209
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
survival of foot-and-mouth disease virus in cheese.persistence of foot-and-mouth disease virus during the manufacture of cheddar, mozzarella, camembert cheese prepared from milk of cows experimentally infected with the virus was studied. cheese samples were made on a laboratory scale with commercial lactic acid starter cultures and the microbial protease marzyme as a coagulant. milk was heated at different temperatures for different intervals before it was made into cheese. food-and-mouth disease virus survived the acidic conditions of cheddar a ...1976184130
pathogenesis of foot-and-mouth disease: clearance of the virus from the circulation of cattle and goats during experimental viraemia.viraemia is an important aspect of the pathogenesis of infectious diseases, but the mechanisms of entry and removal of virus from the vascular system particularly in natural hosts are poorly understood. the results of this study showed that the clearance of foot and mouth disease virus (fmdv) from the circulation of cattle and goats followed the general rules for the clearance of inert particulate materials and other viruses from the circulation. high doses of infused fmdv were cleared less effi ...1976185289
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