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
[role of antibodies in the antigenic variability of the foot-and-mouth disease virus]. 1976186935
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
[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
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
[cultivation of the foot-and-mouth disease virus on a monolayer of inoculable cells piglet kidney grown in vitro]. 1977195389
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
[comparison of the immunogenic potencies of purified inactivated foot-and-mouth disease virus particles with variable amounts of vp1 protein (author's transl)]. 1977195512
[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
determination of the time to harvest foot-and-mouth disease virus cultures by measurements of the supernatant concentration of lactic dehydrogenase. 1977195645
[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
[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
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
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
fast modification of foot-and-mouth disease virus by selecting clones in bovines. 1976198313
[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
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
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
[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
subtyping of foot-and-mouth disease virus. 1976198283
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
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
protein covalently linked to foot-and-mouth disease virus rna. 1977197422
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
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
[basic moments in the interactions between the foot-and-mouth disease virus and cells in cell cultures]. 1977197687
[use of ultrasonics in purifying the aphthous foot-and-mouth disease virus]. 1978211705
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
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
[radial immunodiffusion reaction in research with the foot-and-mouth disease virus]. 1978211706
effect of oesophageal-pharyngeal secretions from normal cattle on foot-and-mouth disease virus o1. 1977201131
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
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
foot and mouth disease virus. i. stability of its ribonucleic acid. 1978202081
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
[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
[type-specific variations in structural polypeptides of foot-and-mouth disease virus]. 1978211982
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
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
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
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 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
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
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
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
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
indirect complement fixation test with foot-and-mouth disease virus antigen concentrated by polyethylene glycol 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
[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
[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
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
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
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
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
foot and mouth disease virus. ii. endoribonuclease activity within purified virions. 1978210581
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
isolation of foot-and-mouth disease virus from yak. 1978207010
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
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
[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
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
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
immune response to virus-infection-associated (via) antigen in cattle repeatedly vaccinated with foot-and-mouth disease virus inactivated by formalin or acetylethyleneimine.the results of experiments to investigate antibody to 'virus infection associated' (via) antigen in cattle repeatedly vaccinated with formalin- or acetylethyleneimine- (aei) inactivated foot-and-mouth disease (fmd) vaccines under laboratory conditions are reported. results are also presented from some vaccinated animals subsequently exposed to fmd infection. antibody against via was not detected before and after the first vaccination with formalin or aei-inactivated vaccine but did develop in al ...1979216744
the n-terminal sequence of three coat proteins of foot-and-mouth disease virus. 1978217392
inactivated-concentrated virus antigen for indirect complement fixation test of foot-and-mouth the culture fluids of bhk-21 cells infected with each of types o, a, and asia 1 of foot-and-mouth disease virus was added acetylethyleneimine to 0.05% (v/v). the mixtures were incubated at 37 degrees c for 24 hours. to them were then added polyethylene glycol 6000 to 10% (w/v), and the mixtures concentrated to one-tenth of the initial volume. the resulting inactivated-concentrated virus antigens showed a complement fixation (cf) titer ranging from 12 to 24. the recovery rate of cf activity wa ...1978216926
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
[formation of immunity in sheep inoculated with varying doses of the foot-and-mouth disease virus 0194]. 1979217141
[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
[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
[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
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 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
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
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
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
[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
[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
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
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
the specific detection of foot-and-mouth disease virus whole particle antigen (140s) by enzyme labelled immunosorbent assay.a solid-phase micro-enzyme-labelled immunosorbent assay (elisa) using guinea pig antiserum against purified (140s) inactivated foot-and-mouth disease (fmd) virus has been used in a sandwich technique to specifically measure 140s virus in the presence of 12s material.1979222837
[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
a blastogenic test for foot-and-mouth disease.a blastogenic test to detect peripheral blood leukocytes specifically sensitized to foot-and-mouth disease virus antigen is described. the test is carried out in microtitre plates and optimum conditions were found by titration. these employed 7.5 x 10(5) cells/well and 20 complement fixing units of antigen. peak [3h]thymidine incorporation was found to take place at 2-3 days.1979229161
application of the enzyme linked immunosorbent assay to the detection and identification of foot-and-mouth disease indirect enzyme linked immunosorbent assay (elisa) was applied to the detection and identification of foot-and-mouth disease (fmd) virus types. the test proved successful for the specific detection of virus from infected tissue culture, and from epithelial tissues from bovines suspected of having fmd. the elisa compared favourably with the complement fixation (cf) test, being more sensitive and unaffected by anticomplementary factors.1979229162
[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
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
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
immune response of neonatal swine to inactivated foot-and-mouth disease virus vaccine with oil adjuvant. i. influence of colostral antibody. 1977220635
[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
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
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