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routine titration of foot and mouth disease virus suspensions by analytical ultracentrifugation. 1: sedimentation method.infectivity and complement fixation (cf) tests are commonly used for the routine titration of foot and mouth disease (fmd) virus suspensions. only recently were techniques published for the routine determination of the virus concentration by the physical properties of the virions (fayet et al., 1971; barteling et al., 1974). these techniques are based on the separation of the virions from the culture fluid by sedimentation through a sucrose gradient, in a preparative ultracentrifuge. the ultrav ...1976185978
[role of antibodies in the antigenic variability of the foot-and-mouth disease virus]. 1976186935
inhibitors of foot-and-mouth disease virus. temperature-dependence of the effect of guanidine on virus growth.in suspended secondary calf kidney cells infected with foot-and-mouth disease virus (fmdv) the temperature range for optimal virus growth is shifted down by 3 to 5 degrees c in the presence of 1--2 mm guanidine. for some virus strains this shift is so effective that at infraoptimal temperatures virus yield in guanidine-treated cells exceeds that of the corresponding control by more than one log10. on the contrary, at supraoptimal temperatures inhibition of virus growth by the drug is strongly en ...1976187151
a foot-and-mouth disease vaccine for swine.an inactivated vaccine containing purified foot-and-mouth disease virus type o1, strain brugge, emulsified with incomplete freund's adjuvant was studied in swine. the antigen mass ranged from 0.02 to 416 mug in 0.25 ml of vaccine. at 90 days postinoculation (dpi) 33 to 100% of the swine which had been inoculated with 0.72% mug or larger amounts of antigen were protected against challenge. there was little protection at 182 dpi although the neutralizing titers obtained with 2.9, 34.6 and 416 mug ...1976187292
the location of the ploy(c) tract in the rna of foot-and-mouth disease virus.fragments of foot-and-mouth disease virus rna of decreasing size, containing the 3' poly(a) sequence have been prepared by alkali treatment and sucrose gradient centrifugation followed by oligo(dt)-cellulose affinity chromatography. polyacrylamide gel electrophoresis of the ribonuclease t1 resistant oligonucleotides from these polyadenylated fragments has enabled us to locate the position of some of the longer oligonucleotides on the rna. in particular the poly c tract has been shown to be near ...1976187724
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
[foot-and-mouth disease in ethiopia. serologic and immunologic study of type a foot-and-mouth disease virus]. 1976189363
[cultivation of the foot-and-mouth disease virus in various vnk-21 cell sublines]. 1976189481
[use of indirect complement fixation test for studying foot and mouth disease virus].the indirect complement-fixation test was used in experiments for the subtype differentiation, and with the agar gel diffusion and the serum neutralization test was studied the immunity in cattle that had already recovered from foot-and-mouth disease or were immunized against the disease. it was found that the indirect complement-fixation test is instrumental in the demonstration of the antigenic differences between the foot-and-mouth viruses. comparative experiments have shown that the indirect ...1976189484
[attempts to adapt bnk cells to cultivation in suspension and study of the antigenic properties of foot-and-mouth diseases viruses obtained from them].experiments were carried out to cultivate the foot-and-mouth disease virus under laboratory conditions in a suspension of the bhk-21 cell line. results showed that the number of cells cultivated in a susfor 48 to 72 hours of incubation reaches up to 2.2 x 10(6). it was also found that certain conditions should be observed for the successful cultivation of the cells in suspension, such as aeration, ph, and respective temperature. it was demonstrated that foot-and-mouth diseases viruses obtained f ...1976189487
[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
subtyping of foot-and-mouth disease virus. 1976198283
[serological study of several strains of foot-and-mouth disease virus type "o" isolated in europe between 1971 and 1975: application of the biomathematical system of classification].nine strains of foot-and-mouth disease virus type "o" received in our laboratories since 1971 have been studied serologically by osler's quantitative method of complement fixation (50% hemolysis). the results, submitted to the biomathematical system of bidimensional classification, allow to conclude that at present in europe there are two groups of foot-and-mouth disease strains of type "o"; one has reference to our vaccinal strain "o lausanne 1965" and the other to "o romania 1972" strain, whic ...1976198285
examination of differences between foot-and-mouth disease virus strains using a radioimmunoassay techinque.a radioimmunoassay (ria) technique was used to compare different samples of type sat 2 foot-and-mouth disease (fmd) viruses. the reaction involved the measurement of the competition of heterologous virus with homologous virus for previously titrated homologous antiserum. the results showed that differences occurred between the viruses examined. viruses could be grouped according to their ability to compete with the homologous virus, and statistically significant differences between virus 'groups ...1976198286
[classification of strains of foot-and-mouth disease virus according to the relationship-dominance model for a better understanding of the concept of serologic and immunologic subtype].the homologous and heterologous serological titers of a specific serum can be integrated in a bidimensional system which characterizes the criteria of relationship and dominace. this bidimensional classification specifies more precisely the serological properties of each strain compared with the others (taxonomic purpose) and allows eventual guidance in the choice of vaccinal strains (epizootiologic and prophylactic purposes).1976198287
serological differentiation of foot-and-mouth disease virus strains in relation to selection of suitable vaccine viruses. 1976198288
antibody response of tropical range cattle to foot-and-mouth disease virus. ii. evaluation of response to o-1, a-27, and a-18 subtypes. 1976198289
new media and their advantages in the production of suspended cells and foot--and--mouth disease virus.the problems related to the use of serum in cell culture are reviewed. the possibility of substituting the serum with peptones has already been shown. different peptones have been tested: one of the best is a peptone obtained from meat and casein pepsin pancreatically digested. bhk 21/13 cells were cultivated in serum-free media for 35 passages. the 0.81 cultures without automatic ph control had a cycle length of 3 days; starting with concentrations of 0.4 x 10(6) cells/ml, concentrations higher ...1976198293
[routine physico-chemical testing of concentrated virulent and inactivated foot-and-mouth disease virus antigens].the ponderal quantity of 140 s antigens and their peptide distribution are controlled in concentrated virulent and inactivated preparations proir to their being transformed into vaccines. a certain variability in the amount of 140 s particles and in the titer of peptide sensitive to trypsin (vp1) has been demonstrated in the virulent preparations. after treatment by inactivating agents (glycidaldehyde, binary ethyleneimine and formaldehyde) two types of alteration of the viral capsid are shown : ...1976198300
[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
[study of foot-and-mouth disease virus inhibitors in cell cultures and experimental animals].studied was the inhibiting action of some synthetic agents conditionally denoted no. 3 (benzamidazol), no. 76, and no. 78 (imidazolins) on the reproduction of the foot-and-mouth disease virus in cell cultures, newborn mice and guinea pigs. it was irrefutably demonstrated that all three agents produce an inhibiting effect on the virus. this effect was enhanced by the combined use of these inhibitors. it was found that best effect on the virus' replication produced the combination of agent no. 3 a ...1976193238
[study of the immunity in swine vaccinated with type c anti-foot-and-mouth disease vaccine].experiments were carried out to adapt a cell culture strain of the foot-and-mouth disease virus, type c, to the organism of susceptible pigs. it was established that 4 to 5 passages are needed to adapt the virus, all treated animals showing the symptoms of the disease from the 24 hour following infection which assumed a generalized course. in determining the index of protection (p) of a given f.m.d. vaccine through challenging immunized pigs its value proves to be 4.5. it is stressed that this i ...1976193242
use of cell cultures with persistent virus infections to test the efficacy of antiviral compounds.bhk-21 cells persistently infected with either vaccinia or foot and mouth disease virus were used to study the efficacy of antiviral compounds. the results of the persistent infection cell culture (picc) test were compared with those obtained by the plaque reduction (pr) test. the comparison showed that: (1) the picc test is more informative than the pr test; (2) stimulative as well as inhibitory activities of compounds are detectable, and (3) since the picc test can be carried on for several we ...1976182439
susceptibility of the indian squirrel to foot-and-mouth disease virus. 1976183340
[some modern data on the antigenic makeup of the foot-and-mouth disease virus and their practical significance]. 1976183347
[electrophoretic studies of foot-and-mouth disease virus subtypes a1-a5 from various sources using carrier-free zone electrophoresis in a glucose density gradient]. 1976183418
[local interferon production in cattle after intranasal infection with avirulent ibr/ipv virus and its effect on a subsequent infection with foot-and-mouth disease virus]. 1976183421
[structure of foot-and-mouth disease virus]. 1976183422
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
localisation on foot-and-mouth disease virus (fmdv) of an antigenic deficiency induced by passage in bhk cells.passage of fmdv in bhk suspended cells was confirmed to induce an antigenic deficiency on the virion. by immunodiffusion experiments with complete virus, with trypsin-treated virus and with 12s virus fraction it was shown that the induced antigenic deficiency is located on the trypsin-removable part of the virion. these results were confirmed by absorption experiments.1976184763
effect of heat on foot-and-mouth disease virus (fmdv) in the components of milk from fmdv-infected cows.foot-and-mouth disease virus (fmdv) survived in skim milk, cream and the pelleted cellular debris components of milk obtained from fmdv-infected cows after pasteurization at 72 degrees c for 0-25 min. virus was recovered from whole milk of infected cows after that milk was heated at 72 degrees c. for 5 min. and from the skim milk component after it was heated at the same temperature for 2 min. evaporation of the whole milk samples after they were heated at 72 degrees c. for 3 min. did not inacti ...1976185284
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
experimental placental transfer of foot-and-mouth disease virus in mice.an attenuated type o foot-and-mouth disease (fmd) virus which was virulent for infant, but not for pregnant, mice proved to be superior to a virulent type c fmd virus in the development of a model system for the study of placental transfer of fmd in mice. when mice were inoculated at day 8 or 12 of gestation with type o fmd virus, the virus was detectable in the maternal pancreas for 3 days and in the placenta for 6 days. viral levels in the fetus and the amniotic fluid were inconsistent and wer ...1976179452
the production of foot-and-mouth disease virus from bhk 21 c 13 cells grown on the surface of glass spheres.in view of the advantages which are associated with the use of the bhk monolayer cell for the production of foot-and-mouth disease (fmd) virus, a unit system using glass spheres was developed to grow bhk monolayer cells and to test the susceptibility of such cells to fmd virus. the yield of cells and their susceptibility compares favorably with green bhk monolayer cells which have been grown in roux bottles.1976179634
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
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
cell-free translation of foot-and-mouth disease virus rna into identifiable non-capsid and capsid proteins.foot-and-mouth disease virus (a member of the picornavirus group) rna could be translated effectively in an s-30 extract from ehrlich ascites tumour cells. this translation was inhibited by aurintricarboxylic acid, cycloheximide, puromycin and rnase. cell-free products of translation were identified by disc gel electrophoresis and immunoprecipitation with specific antisera. gel electrophoresis of the products without prior immunoprecipitation suggested the synthesis of some of the non-capsid pro ...197661250
[antigenic structures of the foot-and-mouth disease virus]. 197667699
further studies of the physical and metabolic properties of foot-and-mouth disease virus temperature-sensitive mutants.three temperature-sensitive (ts) mutants of foot-and-mouth disease virus were classified as ribonucleic acid negative and as belonging to the same complementation group when measured by virus yields and 3h uridine incorporation in paired, mixed infections at the nonpermissive temperature (38.5c). mutant ts-22, the only mutant able to produce plaques at 38.5 c, was more sensitive to acid than were the parental wild-type or other mutant viruses. diethylaminoethyl-dextran did not enhance the plaque ...19765377
cultivation of foot and mouth disease virus in bovine leukocyte cultures for use in the complement fixation test.bovine leukocyte cultures achieved good growth after 72 hours of cultivation. foot-and mouth disease (fmd) virus type 0 multiplied in such cultures to a titre of 10(6) tcid50/0.1 ml. the cell culture-grown virus was found to be suitable for the complement fixation test (cft) after purification and concentration with calcium phosphate.19769808
physico-chemical properties of swine vesicular disease virus.titration of svdv on primary pig kidney cell cultures revealed a plating efficiency of less than or equal to 0,9 x 10(-3). concentration and purification of the svd-virus propagated on pig kidney cell cultures were done by chloroform treatment, adsorption, differential- and density gradient centrifugation. the following physical parameters were found: svdv is an isometrical rna-virus having a diameter of 25,1 +/- 1,0 nm. it is resistent to the action of chloroform, ether and ph. the virus has a ...197610872
effect of methyl glyoxal on infectivity and antigenicity of foot-and-mouth disease virus.the inactivating effect of methyl glyoxal on foot-and-mouth disease (fmd) virus was studied. the rate of inactivation depended upon the drug concentration, incubation temperature and ph of the medium. rna recovered from the inactivated virus was not infectious. the complement-fixing activity of the virus was not reduced by methyl glyoxal treatment. the antigenicity of inactivated virus preparations determined by levels of virus neutralizing antibody in the blood sera of immunized white rats and ...197611665
[several criteria of evaluation of foot-and-mouth disease virus reproduced in cell cultures in suspension].the study of the plaques produced by viruses asia and o1 reveals different properties which may depend on the virus or on the cell or its method of culture. antigenic differences and subsequent immunological differences correspond to differences in plaques. on the other hand, the cell line in suspension evolves both in its morphology and its receptivity during the passages. all these variations imply the observations of quantitative and qualitative criteria of evaluation in order to prepare vacc ...197671255
[resistance of vaccinated animals to heterologous subtypes of the foot-and-mouth disease virus]. 1976176768
foot-and-mouth disease virus rna. presence of 3'-terminal polyriboadenylic acid and absence of amino acid binding ability. 1976176778
a comparison of molecular weights of foot-and-mouth disease virus rna fragments determined from lengths and s-rates.a comparison was made of the calculated mol. wt. of rna fragments from foot-and-mouth disease virus (fmdv) types a12 strain 119, c3 resende and o1 brugge. the mol. wt. were calculated by two methods: from the measurements of strand lengths in the electron micrographs and from the observed sedimentation rates (s-rates). rna extracted from virus by dialysis against water usually had three to four prominent strands of different lengths. mol. wt. calculated from s-rates (and converted to strand leng ...1976177721
characterization of the minor polypeptides in the foot-and-mouth disease particle.in addition to the four major polypeptides vp1 and vp4, foot-and-mouth disease virus particles contain two minor polypeptides, mol. wt. 40 x 10(3) (p40) and 52 x 10(3) (p52). extensive purification procedures failed to remove these minor polypeptides from the virus particles. polypeptide p40 co-electrophoresed in sds-polyacrylamide gels with vp0, the probable precursor of vp2 and vp4 and was inaccessible to iodination in situ. the second minor polypeptide, p52, co-electrophoresed with the virus ...1976177728
further observations of foot and mouth disease virus type s.a.t 1 infection of cattle in tanzania. 197616300346
[types and subtypes of foot-and-mouth disease virus and their practical significance]. 197776365
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
neutralization kinetics studies with type sat 2 foot-and-mouth disease virus strains.a comparison of homologous and heterologous rates of neutralization demonstrated that antigenic relationships of foot-and-mouth disease virus strains could be differentiated quantitatively by the kinetics of neutralization method described previously (rwysed this way gave r values which were similar to those obtained with other neutralization test methods but which were generally smaller than those obtained with complement fixation test results. it was demonstrated that there were wide differenc ...197768071
induction of neutralizing antibodies and immunity in vaccinated guinea pigs by cyanogen bromide-peptides of vp3 of foot-and-mouth disease virus.the specificity of guinea pig antisera against large cyanogen bromide-cleaved peptides of the virus capsid protein vp3 of foot-and-mouth disease virus type o1, strain kaufbeuren has been characterized by double immunodiffusion, virus neutralization and protection tests. antibodies to purified 146s particles and the cleavage peptides of vp3 showed an incomplete cross-section against vp3 peptide antigen when reacted in immunodiffusion tests, indicating that new antigenic determinants are exhibited ...197765445
demonstration of trypsin-sensitive antigenic determinants common to the intact virus particle and the 12s subunit of the uga 6/70 strain of foot-and-mouth disease virus type sat 2. 197767182
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
[cultivation of the foot-and-mouth disease virus on a monolayer of inoculable cells piglet kidney grown in vitro]. 1977195389
[comparison of the immunogenic potencies of purified inactivated foot-and-mouth disease virus particles with variable amounts of vp1 protein (author's transl)]. 1977195512
determination of the time to harvest foot-and-mouth disease virus cultures by measurements of the supernatant concentration of lactic dehydrogenase. 1977195645
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
protein covalently linked to foot-and-mouth disease virus rna. 1977197422
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
[basic moments in the interactions between the foot-and-mouth disease virus and cells in cell cultures]. 1977197687
[early events in the replication of foot and mouth disease virus: subcellular localization of viral rna synthesis]. 1977218264
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
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
effect of oesophageal-pharyngeal secretions from normal cattle on foot-and-mouth disease virus o1. 1977201131
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
in vivo interference in vesicular stomatitis virus infection.inactivated defective interfering and complete particles of vesicular stomatitis virus given intracerebrally to adult mice protect them against challenge with homologous virus whether this is given at the same time or several days later. two separate protective processes appear to be involved. the first, which comes into operation immediately after inoculation, is also effective against heterologous strains of vesicular stomatitis virus, rabies (another rhabdovirus), and a neurotropic strain of ...1977191397
immunogenic and cell attachment sites of fmdv: further evidence for their location in a single capsid polypeptide.chymotrypsin cleaves only one of the four major polypeptides of foot-and-mouth disease virus (fmdv serotype o) in situ. this polypeptide (vp1, mol. wt. 29 x 10(3) was first cleaved into fragments of mol. wt. 20 and 9 x 10(3) and further cleavage could be prevented by the addition of a large excess of bovine serum albumin. the infectivity of the virus particles at this stage was the same as that of the intact virus although the rate of attachment to bhk 21 cells was slower and the immunogenic act ...1977192841
[epidemiologic significance of permanent foot-and-mouth disease virus excretors]. 1977188407
interferon inducers and foot-and-mouth disease vaccines: influence of two synthetic polynucleotides on antibody response and immunity in guinea pigs and swine.polyriboadenylic-polybouridylic acid enhanced the immunological response of guinea pigs to aqueous foot-and-mouth disease virus vaccine. polyriboninosinic-polyribocytidylic acid enhanced the early antibody production of swine to oil emulsified foot-and-mouth disease virus vaccine. polyriboninosinic-polyribocytidylic acid alone did not stimulate resistance to foot-and-mouth disease in swine.1977188530
antirival activity of n-phenyl-n'-arylthiourea derivatives against some rhinoviruses.the effect of 12 derivatives of n-phenyl-n'-aryl- or alkylthiourea, inhibitors of human enteroviruses and foot-and-mouth disease virus, on reproduction of some rhinoviruses (h-17, b-632) in hela bristol cells was studied. as screening methods both the multicylce growth test in roller tube cultures and two variants of plaque inhibition tests were employed. the compounds selected were tested in one-step growth cycle set-up. we established that n-phenyl-n'-4-hydroxyphenylthiourea (v-24) and n-pheny ...1977188604
biochemical analysis of a virulent and an avirulent strain of foot-and-mouth disease virus.a comparison has been made of some of the serological and physicochemical properties of a virulent and an avirulent strain of foot-and-mouth disease virus, serotype sat1. the avirulent strain (sat1-82) was derived from the virulent strain (sat1-7) by serial passage in bhk 21 cells. the viruses were indistinguishable in cross-neutralization tests. in immunodiffusion tests a clear spur line was obtained with the sat1-82 antiserum but not with sat1-7 antiserum. the major polypeptides of the two vir ...1977188983
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
[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
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
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
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
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
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