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[the population structure of the african swine fever virus based on the quantitative hemadsorption trait].subpopulation composition of 8 asfv isolates and variants differing in virulence was evaluated comparatively by their haemadsorption capacity. the "quantitative haemadsorption marker" was shown to be useful for characterization of the strains, virus population phenotypic heterogeneity and structure. the marker expression was found to correlate with virulence: attenuated variants had low haemadsorption and more subpopulation components with that shift, and vice versa.19911796589
glomerular pathology in surviving pigs experimentally infected with african swine fever virus.twelve miniature pigs were inoculated with an attenuated african swine fever virus to study glomerular involvement in surviving pigs. in acute phase, kidneys were severely affected and displayed a glomerular capillary thrombosis with fibrin deposition in vascular lumen, detected by immunofluorescence. fibrin-positive deposits were progressively cleared between one to three months after infection in surviving pigs. the histological picture in kidneys of surviving pigs, up to one post-infection ye ...19911806048
rapid detection of hog cholera virus in tissues by the polymerase chain reaction.a rapid method for the detection of hog cholera virus (hcv) in infected tissues, using polymerase chain reaction (pcr) was developed. total rna isolated from hcv-infected tissues was reverse transcribed with amv reverse transcriptase and the resulting complementary dna was amplified by taq dna polymerase in the presence of two hcv-specific primers. the amplified dna fragment was detected by agarose gel electrophoresis. the sensitivity of this method was at 10(4) tcid50 of hcv. the sensitivity in ...19911816255
vaccinia virus-mediated expression of african swine fever virus genes.bacteriophage lambda and plasmid clones containing african swine fever virus (asfv) dna inserts, which together covered more than 90% of the genome of a malawi asfv isolate (lil 20/1), were transfected into vaccinia virus (vv)-infected cells. expression of asfv-encoded proteins was assayed at late times after vv infection by immunoprecipitation of [35s]methionine-labeled proteins with hyperimmune serum from asfv-infected pigs, separation of immunoprecipitated proteins by denaturing polyacrylamid ...19911826575
live attenuated pseudorabies virus expressing envelope glycoprotein e1 of hog cholera virus protects swine against both pseudorabies and hog cholera.to investigate whether live attenuated pseudorabies virus (prv) can be used as a vaccine vector, prv recombinants that expressed envelope glycoprotein e1 of hog cholera virus (hcv) were generated. pigs inoculated with these recombinants developed high levels of neutralizing antibodies against prv and hcv and were protected against both pseudorabies and hog cholera (classical swine fever).19911850051
isolation and molecular characterization of the swinepox virus thymidine kinase gene.swinepox virus (spv), the only member of the suipoxvirus genus, shows little antigenic relatedness or dna homology to members of the other poxvirus genera. a spv thymidine kinase (tk) gene was detected and mapped to the left end of the hindiii g fragment using degenerate oligonucleotide probes. cloning and sequencing of a 1.8-kb hindiii-bamhi fragment containing the spv tk gene revealed an open reading frame (orf) of 181 amino acids yielding a predicted polypeptide of mr 20.6 kda with significan ...19911853562
hog cholera virus: molecular composition of virions from a pestivirus.virions from hog cholera virus (hcv), a member of the genus pestivirus, were analyzed by using specific antibodies. the nucleocapsid protein was found to be a 14-kda molecule (hcv p14). an equivalent protein could also be demonstrated for virions from another pestivirus, bovine viral diarrhea virus. the hcv envelope is composed of three glycoproteins, hcv gp44/48, gp33, and gp55. all three exist in the form of disulfide-linked dimers in virus-infected cells and in virions; hcv gp44/48 and gp55 e ...19911870198
the sequences of the ribonucleotide reductase genes from african swine fever virus show considerable homology with those of the orthopoxvirus, vaccinia virus.two african swine fever virus (asfv) recombinant plasmids containing large inserts of dna have been sequenced at random, and translations of the dna sequence have been compared to libraries of vaccinia virus protein sequences. among other genes identified by their extensive homology with vaccinia virus genes were the large and small subunits of ribonucleotide reductase. a 5.5-kb fragment from the malawi (lil20/1) strain of asfv was identified as containing the genes for both these subunits. the ...19911871976
detection of african swine fever virus by a biotinylated dna probe: assay on cell cultures and field samples.african swine fever virus was detected in various samples using a molecular hybridization technique. a fragment located in a constant area of the viral genome was biotin-labelled. this probe, when present at a concentration of 100 ng/ml of the hybridization solution, could detect 10 pg of target dna immobilized on nitrocellulose with cellular dna and rna. the virus was evidenced after being passaged on monkey kidney cells, either 8 h post-inoculation (pi) if the multiplicity of infection (moi) w ...19911897870
protection tests in pigs vaccinated with the lapinized chinese strain of hog cholera virus (hcv) previously adapted in a minipig kidney (mpk) cell line, to challenge infection with virulent hcv.pigs which had been vaccinated with the lapinized chinese strain of hog cholera virus previously adapted in a minipig cell line cultures (mpk-lc-hcv), resultet to be protected when they were subjected to challenge infection with virulent hog cholera virus (hcv) 6 or 11 months later. the challenge virus was never isolated from any of the vaccinated pigs. the mpk-lc-hcv vaccine induced a significant rise of the antibody titer to the hcv in pigs kept under field conditions.19911921741
rapid isolation of monoclonal hybridoma cultures by a 'fusion-cloning' method: the requirement for aminopterin.hybridomas were generated by fusing the balb/c sp2/0 myeloma-like cell line with either: (i) splenocytes from balb/c mice immunized with foot-and-mouth disease virus (fmdv), rinderpest virus (rpv), peste des petits ruminants virus (pprv), african swine fever virus (asfv) or pig thymocytes; or (ii) lymph node cells from cattle immunized with fmdv. if the fusion mixtures were plated in cloning medium of methyl cellulose and hat medium, small hybridoma colonies developed which rarely survived. fusi ...19911954000
hog cholera: an update of present knowledge. 19911959010
african swine fever virus fatty acid acylated proteins.labeling experiments with [3h]palmitic and [3h]myristic acids of african swine fever virus-infected vero cells have shown that 11 proteins induced during infection are covalently bound to myristic acid and that palmitic acid was not attached to viral proteins. the time course of synthesis of the myristylated polypeptides and the requirements of viral dna replication indicated that the myristylated proteins, with the exception of a 13-kda protein, belong to the late class of viral proteins. the m ...19911962463
expression and characterization of the thymidine kinase gene of african swine fever virus.the thymidine kinase (tk) gene of african swine fever virus (asfv) was located within the viral genome by using two degenerate oligonucleotide probes derived from sequences of the vaccinia virus and cellular tk genes. the tk gene was mapped within a 0.72-kbp bglii-xhoi fragment (0.242 to 0.246 map units) derived from a 23.9-kbp sali-b fragment of the asfv genome. identification of this region as the asfv tk gene was confirmed by expression of tk in escherichia coli and by the synthesis of active ...19911987368
structural proteins of hog cholera virus expressed by vaccinia virus: further characterization and induction of protective immunity.a cdna fragment covering the genomic region that encodes the structural proteins of hog cholera virus (hcv) was inserted into the tk gene of vaccinia virus. expression studies with vaccinia virus/hcv recombinants led to identification of hcv-specific proteins. the putative hcv core protein p23 was demonstrated for the first time by using an antiserum against a bacterial fusion protein. the glycoproteins expressed by vaccinia virus/hcv recombinant migrated on sodium dodecyl sulfate-gels identical ...19911987372
protein p22 of african swine fever virus: an early structural protein that is incorporated into the membrane of infected cells.the open reading frame k'177, located at the left end of the african swine fever virus genome, codes for an early induced structural protein of 22,000 da (p22), which is released from the viral particle by the nonionic detergent n-octyl-beta-d-glucopyranoside under conditions that solubilize external viral structural proteins. the predicted amino acid sequence of the protein contains a hydrophobic region at its n-terminus with characteristics of a signal peptide and, at early times after virus i ...19911994575
fc receptors do not mediate african swine fever virus replication in macrophages.titration experiments in swine macrophages have shown that african swine fever virus infectivity was not enhanced in the presence of antiviral antibodies. the early viral protein synthesis and the viral dna replication in swine macrophages infected with virus-antibody complexes were inhibited in the presence of high doses of uv-inactivated virus, which saturated specific virus receptors, but not when fc receptors were saturated with antibodies. these results indicate that african swine fever vir ...19912014648
african swine fever virus attachment protein.treatment of african swine fever virus particles with nonionic detergents released proteins p35, p17, p14, and p12 from the virion. of these proteins, only p12 bound to virus-sensitive vero cells but not to virus-resistant l or ibrs2 cells. the binding of p12 was abolished by whole african swine fever virus and not by similar concentrations of subviral particles that lacked the external proteins. a monoclonal antibody (24bb7) specific for p12 precipitated a protein that, when analyzed by sodium ...19912016759
the primary structure of the thymidine kinase gene of fish lymphocystis disease virus.the dna nucleotide sequence of the thymidine kinase (tk) gene of fish lymphocystis disease virus (fldv) which has been localized between the coordinates 0.678 to 0.688 of the viral genome was determined. the analysis of the dna nucleotide sequence located between the recognition sites of hindiii (0.669 map unit; nucleotide position 1) and acci (nucleotide position 2032) revealed the presence of an open reading frame of 954 bp on the lower strand of this region between nucleotide positions 1868 ( ...19912024501
role of b and t lymphocytes in the specific immunosuppression induced by a protein released by porcine monocytes infected with african swine fever virus.some immunobiological aspects of host responses to an immunosuppressive protein (p36) released by porcine monocytes upon infection with african swine fever virus were analysed in a murine system. treatment of normal, adult c57bl/6 mice with p36 (i) significantly delayed allogenic skin graft rejection; (ii) suppressed the specific plaque-forming cell response to immunization with heterologous erythrocytes; but (iii) induced marked increases in the numbers of 'background' splenic ig-secreting plaq ...19912025617
in vivo study of hemadsorption in african swine fever virus infected cells. 19912063520
molecular characterization of hog cholera virus.an efficient tissue culture system was established which allowed to obtain substantial quantities of hog cholera virus (hcv) from the cell free tissue culture supernatant. after preparation of viral rna and cdna synthesis, the complete hcv genome was cloned and sequenced. comparison with published bvdv sequences revealed a surprisingly high homology between hcv and bvdv at both the nucleotide and the amino acid level. in addition host cellular sequences were identified in bvdv genomes. the genom ...19919210921
bvd monoclonal antibodies: relationship between viral protein specificity and viral strain specificity.seventeen monoclonal antibodies raised against bovine viral diarrhoea virus were divided into three groups on the basis of radioimmunoprecipitation results. seven monoclonal antibodies precipitated a polypeptide of 80kd and defined four domains, all of which showed considerable conservation amongst the 180 pestivirus strains and isolates examined. nine monoclonal antibodies, including six with virus neutralizing activity, precipitated a 53kd polypeptide and all appeared to be directed towards a ...19919210925
cdna probes for the detection of pestiviruses.probes were prepared from genomic rna of hog cholera virus (hcv) after synthesis of cdna and cloning. six probes were selected according to their place on the viral genome determined by sequencing and comparison with bvdv sequence. these probes were hybridized with two strains of hcv (alfort and nord), two strains of bovine viral diarrhea (bvdv) (nadl, new york) and four strains of border disease (bd) (lyon 1, lyon 2, aveyron, iemvt). this panel of six probes seem to be able to differentiate pes ...19919210941
differentiation of pestiviruses by a hog cholera virus-specific genetic probe.a hog cholera virus (hcv)-specific genetic probe has been generated after cloning of the genomic viral rna. this probe distinguished between hcv and the closely related bovine viral diarrhoea virus (bvdv). furthermore, it detected a broad spectrum of hcv strains and isolates which differ in their phenotype such as virulence.19919210943
polymerase chain reaction amplification of segments of pestivirus genomes.reverse transcription followed by polymerase chain reaction (pcr) amplification of a region of the viral genome at the 3' end of the glycoprotein(s) gene was employed with the aim of determining its applicability as a diagnostic tool for pestiviruses. candidate primers were designed, from homologous segments detected by comparison between the sequences of strains nadl, osloss and alfort. a segment of 634 base pairs on the glycoprotein gene was targeted for amplification. segments of five pestivi ...19919210946
pathogenesis of classical swine fever: b-lymphocyte deficiency caused by hog cholera virus.hog cholera, also known as classical or european swine fever, is caused by hog cholera virus, a member of the genus pestivirus. it is shown here that the end stage of lethal infection in the natural host is associated with a dramatic depletion preferentially of b lymphocytes in the circulatory system as well as in lymphoid tissues. already at the onset of disease, viral replication in lymphoid tissues demarcates the germinal centers, and the viral genome remains localized to that site as the dis ...19921731095
mapping and molecular characterization of a functional thymidine kinase from amsacta moorei entomopoxvirus.a thymidine kinase (tk) gene from the entomopoxvirus of amsacta moorei (amepv) has been identified, mapped, cloned, and sequenced. the amepv tk was shown to be biologically functional as cloning of the gene into a tk-derivative of the orthopoxvirus vaccinia creates a tk+ virus. the gene has been localized to a 1.5-kb ecori-q dna fragment which maps to the far left end of the viral genome. sequence analysis reveals an open reading frame (orf) of 182 amino acids potentially encoding a polypeptide ...19921733099
rapid and biologically safe diagnosis of african swine fever virus infection by using polymerase chain reaction.in order to circumvent the need for infectious virus for the diagnosis of african swine fever (asf), we established the polymerase chain reaction (pcr) technique for the detection of asf virus (asfv) dna. a 740-bp fragment that originated from the conserved region of the viral genome was partially sequenced. from this sequence, four pcr primers and one oligonucleotide probe were designed and synthesized. a specific 640-bp pcr product was amplified by using oligonucleotides 1 and 5 as primers and ...19921734041
[12 years control of hog cholera in the eec]. 19921736411
induction of ribonucleotide reductase activity in cells infected with african swine fever virus.infection of vero cells with african swine fever virus (asfv) resulted in a marked increase in ribonucleotide reductase activity. the induction of ribonucleotide reductase was detected early after infection and was proportional to the multiplicity of infection. inhibition of viral dna replication did not affect the induction of the enzyme. several characteristics could distinguish the virus-induced from the normal cell enzyme. asfv-induced ribonucleotide reductase was inhibited by magnesium, was ...19921736545
interferon-gamma production by african swine fever virus-specific lymphocytes.peripheral blood mononuclear cells (pbmc) from inbred pigs that were immunized with autologous macrophages infected with the african swine fever (asf) virus ba71v, a nonvirulent virus isolate, proliferated and produced interleukin-2 in response to homologous and heterologous isolates of the asf virus. they produced, however, interferon (ifn) only when challenged in vitro with homologous or attenuated isolates of the asf virus, but not with heterologous or virulent isolates. the ifn was ph 2 labi ...19921738818
a preliminary map of epitopes on envelope glycoprotein e1 of hcv strain brescia.monoclonal antibodies (mabs) directed against envelope glycoprotein e1 (gp51-54) of hog cholera virus (hcv) strain brescia have been shown to recognize four different antigenic domains a, b, c and d. epitopes of within domain a have mainly been found conserved among hcv strains, whereas epitopes within domains b, c and d are not conserved. we used transiently expressed hybrid e1 genes of hcv strains brescia and "c" to map the non-conserved epitopes on e1. epitopes in domains b and c are located ...19921282755
genes homologous to ubiquitin-conjugating proteins and eukaryotic transcription factor sii in african swine fever virus.the nucleotide sequence of the 6004-bp ecori i fragment of african swine fever virus dna has been determined. translation of the sequence revealed eight closely spaced open reading frames (orfs), three of them reading rightward and five leftward. northern blot hybridization analysis indicated that orfs i73r and i78r were transcribed early in infection, whereas orfs i177l, i196l, and i329l were expressed at late times. transcripts for orfs i215l, i226r, and i243l were detected at low levels in ea ...19921309282
heterogeneous expression of the non-structural protein p80/p125 in cells infected with different pestiviruses.in order to analyse the expression of the non-structural (ns) protein p80/p125 in cells infected with different pestiviruses at the protein level, radioimmunoprecipitations with the pestivirus-specific monoclonal antibody (mab) bvd/c16 were performed. cell lysates infected with cytopathic (cp) and non-cytopathic (ncp) bovine viral diarrhoea (bvd) virus strains and isolates, and with hog cholera (hc) virus strains were analysed. from cpbvd virus-infected cells, the mab precipitated one or more pr ...19921309861
a ubiquitin conjugating enzyme encoded by african swine fever virus.the post-translational modification of proteins by covalent attachment of ubiquitin occurs in all eukaryotes by a multi-step process. a family of e2 or ubiquitin conjugating (ubc) enzymes catalyse one step of this process and these have been implicated in several diverse regulatory functions. we report here the sequence of a gene encoded by african swine fever virus (asfv) which has high homology with ubc enzymes. this asfv encoded enzyme has ubc activity when expressed in escherichia coli since ...19921310934
the pestiviruses. 19921315479
a gene homologous to topoisomerase ii in african swine fever virus.a putative topoisomerase ii gene of african swine fever virus was mapped using a degenerate oligonucleotide probe derived from a region highly conserved in type ii topoisomerases. the gene is located within ecori fragments p and h of the african swine fever virus genome. sequencing of this region has revealed a long open reading frame, designated p1192r, encoding a protein of 1192 amino acids, with a predicted molecular weight of 135,543. open reading frame p1192r is transcribed late after infec ...19921316688
evolution of thymidine and thymidylate kinases: the possibility of independent capture of tk genes by different groups of viruses.phylogenetic analysis of viral and cellular thymidine and thymidylate kinases was performed using computer-assisted methods. multiple alignments and tentative phylogenetic trees were generated for the two families of these enzymes, which include a) thymidine kinases (tk) of mammals, poxviruses, african swine fever virus, e. coli, and bacteriophage t4; and b) thymidylate kinases (thyk) of yeast and poxviruses and distantly related herpesvirus proteins with both enzymatic activities. analysis of t ...19921317076
identification of an african swine fever virus gene with similarity to a myeloid differentiation primary response gene and a neurovirulence-associated gene of herpes simplex virus.here we describe an open reading frame (lmw23-nl) in the african swine fever virus genome that possesses striking similarity to a murine myeloid differentiation primary response gene (myd116) and the neurovirulence-associated gene (icp34.5) of herpes simplex virus. in all three proteins, a centrally located acidic region precedes a highly conserved, hydrophilic 56-amino-acid domain located at the carboxy terminus. lmw23-nl predicts a highly basic protein of 184 amino acids with an estimated mole ...19921323711
protection of piglets born from ruminant pestivirus experimentally infected sows, and their contacts, to the challenge with hog cholera virus.two groups, a and b, of two specific pathogen-free pregnant sows were experimentally infected between the 25th and 29th days post-breeding with two strains of ruminant pestivirus: nadl cytopathic bovine viral diarrhoea virus for group a and aveyron non-cytopathic border disease virus french strain for group b. two other pregnant sows (group c) were kept uninoculated as control. when 7 weeks old, 8 piglets of group c were put in contact with 4 piglets of group a (group d), and 8 other piglets of ...19921324630
the hog cholera virus.hog cholera virus (hcv) is a spherical enveloped particle of about 40-60 nm dia. the viral genome is a single strand rna of about 12,000 bases with positive polarity. one single large open reading frame codes for presumably four structural, i.e. three glycoproteins and a core protein, and about three to five nonstructural proteins. the functional role is not yet fully clear for all viral proteins. hcv belongs to the pestivirus group and it is closely related to bovine viral diarrhoea and border ...19921325334
hog cholera diagnostic techniques.clinical signs and lesions can sometimes provide the basis for a presumptive diagnosis of hog cholera (hc). however, an accurate diagnosis requires laboratory testing. the usual procedure for the detection of viral antigen is the examination of cryostat sections stained with fluorescein-conjugated hc antiserum. a more definitive technique is isolation of the virus in pk-15 cell cultures and identification of the viral antigen in cells using an hc fluorescent antibody conjugate. as bovine viral d ...19921325335
african swine fever virus encodes a gene with extensive homology to type ii dna topoisomerases.nucleotide sequencing of a virulent african swine fever virus (asfv) isolate (malawi lil20/1) identified an open reading frame of 1191 amino acid residues encoding a protein of 134.9 kda. this gene mapped to the sali i and j restriction endonuclease fragments of the asfv genome. the predicted polypeptide was found to share 21.1% identity over a 1077 amino acid region with the human type ii dna topoisomerase. the sequence is compared to other type ii dna topoisomerases and the possible roles in a ...19921335084
thermal and ph stability of pestiviruses.three strains/isolates of hog cholera virus (hcv) and two strains/isolates each of cytopathogenic (cp) and non-cytopathogenic (ncp) biotype of bovine virus diarrhoea virus (bvdv) were each exposed to ph 3, 3.5 and 4 at 4 degrees c, 21 degrees c and 37 degrees c in a number of combinations. infectivity titration and half-life determinations following correlation and regression analysis showed a significant temperature-dependent shortening of half-lives within the ph range investigated. at ph 3, m ...19921335310
analysis of t lymphocyte subsets proliferating in response to infective and uv-inactivated african swine fever viruses.the proliferative response to infective and uv-inactivated african swine fever virus was analyzed in cells from pigs surviving an experimental infection with attenuated virus. all the pigs showed strong dose-dependent proliferative responses to both infective and uv-inactivated virus. this response was also observed when nitrocellulose-bound solubilized virus proteins were used in the assay. heterologous isolates also induced proliferation, however it was significantly lower than that induced by ...19921362304
flow cytometric analysis of african swine fever virus-induced plasma membrane proteins and their humoral immune response in infected pigs.african swine fever (asf) virus-induced plasma membrane proteins may contribute to the protective immune response against the disease since they can be involved in the antibody-mediated lysis of infected cells. in this study we describe the regulation of asf virus-induced plasma membrane protein expression and its antibody induction in pigs after viral infection by flow cytometric analysis. more than 80% of infected cells contained viral antigens on the surface membranes at 6 hr postinfection (h ...19921376539
characterization and pathogenicity for pigs of a hog cholera virus strain isolated from wild boars.one hog cholera virus strain isolated from an outbreak of the disease in a wild boar breeding herd in brittany (france) in 1990 has been characterized with a panel of monoclonal antibodies to hog cholera virus and ruminant pestiviruses: the strain was found to be indistinguishable from that of other domestic pig isolates. the pathogenicity of the strain to domestic pigs was evaluated by infecting intranasally, intramuscularly and by contact 17 specific pathogen-free 6-week- and 12-week-old pigs. ...19921387299
african swine fever virus infection in the iberian soft tick, ornithodoros (pavlovskyella) marocanus (acari: argasidae).one thousand six hundred ornithodoros (pavlovskyella) marocanus velu larvae were fed on a pig infected with african swine fever virus (titer: 10(7.4) had50/ml), and 1,600 larvae were fed on an uninfected pig. ticks in each group were compared for mortality rates, mean time to death for ticks that died, mean time from feeding to either molting or eclosion, percentage of ticks that eclosed or molted, and the number of blood meals per nymph or instar. cumulative virus-induced mortality for all imma ...19921404269
transcriptional analysis of multigene family 110 of african swine fever virus.a transcriptional analysis of the 3.2-kb region of the african swine fever virus genome containing the five members of the multigene family 110 is presented. the mrnas corresponding to the genes studied have short leader sequences with no intervening aug codons before the translational start site, and their 3' ends map within a conserved sequence motif formed by a stretch of seven or more consecutive thymidylate residues. the possible role of this sequence as a signal for the 3'-end formation of ...19921404609
african swine fever virus-induced dna polymerase is resistant to aphidicolin.african swine fever virus (asfv) induces the synthesis of a virus-specific dna polymerase, which is inhibited by phosphonoacetic acid and cytosine arabinoside. in contrast to all other alpha-like dna polymerases of dna viruses, asfv-specific dna polymerase is resistant to aphidicolin. concentrations of the drug as high as 160 microm had no effect on virus production or plaquing efficiency. the resistance of asfv dna polymerase to aphidicolin was confirmed by analyzing the effect of the drug on v ...19921413523
distribution of asfv antigens in pig tissues experimentally infected with two different spanish virus isolates.lymph nodes, spleen, liver, lung and kidney obtained from pigs experimentally infected with two african swine fever virus (asfv) isolates of differing virulence were fixed by perfusion with glutaraldehyde and embedded in paraffin. an immunoperoxidase technique using a polyclonal anti-asfv serum was performed on tissue sections in order to detect asfv antigen. the distribution of asfv antigen in such infected organs is shown and the differences between both infections compared and discussed. mono ...19921414093
localization of african swine fever viral antigen, swine igm, igg and c1q in lung and liver tissues of experimentally infected pigs.an immunohistological study was carried out on lungs and livers of pigs experimentally infected with two different african swine fever virus (asfv) isolates. asfv antigen, swine immunoglobulins (igm and igg) and (clq) complement were demonstrated in both organs at different stages of infection. the asfv antigen was mainly found in mononuclear phagocytic system (mps) cells. immunoglobulins and complement were observed in plasma, infected and non-infected phagocytic cells and cell debris. these fi ...19921430349
molecular characterisation of a dna ligase gene of the extremely thermophilic archaeon desulfurolobus ambivalens shows close phylogenetic relationship to eukaryotic ligases.a 3382 bp fragment containing a gene for a dna ligase from the extremely thermophilic, acidophilic, and facultatively anaerobic archaeon (archaebacterium) desulfurolobus ambivalens was cloned and sequenced. the deduced amino acid sequence (600 amino acids, 67619 molecular weight) showed 30-34% sequence identity with the atp-dependent eucaryal (eukaryotic) dna ligases of schizosaccharomyces pombe, saccharomyces cerevisiae, the human dna ligase i, and with the vaccinia dna ligase. distant similari ...19921437556
[polypeptides p14 and p31 of the african swine fever virus--early proteins located on the membrane of the infected cell].african swine fever virus polypeptides p14 and p31 are synthesized in the presence of phosphonacetic acid which inhibits viral dna replication, and therefore they are early viral proteins. these polypeptides were found to be localized on plasma membranes by immunofluorescence with monospecific antisera and monoclonal antibodies and by selective solubilization of infected cells. the p14-specific antibodies mediate complement-dependent cytolysis and antibody-dependent cytotoxicity of the cells inf ...19921441444
[immune reactions to the african swine fever virus].host immune reactions to african swine fever virus variants differing in their virulence were studied comparatively. their obvious variabilities in antibody induction to some polypeptides active in antibody-dependent cell cytotoxicity and cytotoxic t-lymphocytes were demonstrated. t-helpers of immune pig splenocytes were found to recognize the cells infected with avirulent but not virulent virus variants. the described differences were not connected with the changes in sla-1 antigen expression i ...19921441445
a comparison of the pathogenicity of two strains of hog cholera virus. 1. clinical and pathological studies.the virulence of a strain of hog cholera virus isolated during an outbreak of mild disease in pigs in new south wales in 1960/61 (the nsw strain) was compared over 11 days with that of a virulent strain by inoculating 8 pigs with each virus and comparing the ensuing clinical signs and pathology. both viruses caused persistent pyrexia and leukopenia, the nsw strain 4 to 5 days and the virulent strain 3 days, after inoculation. few other clinical signs were observed in the pigs inoculated with the ...19921445070
a comparison of the pathogenicity of two strains of hog cholera virus. 2. virological studies.quantitative and qualitative differences were demonstrated in the amount of virus in a range of tissues from pigs infected with either the weybridge or new south wales (nsw) strains of hog cholera (hc) virus. the titre of the weybridge strain in samples, as assessed by either virus titration in cell culture or by the density of specific fluorescing cells in tissue sections, was higher than that for the nsw strain. this correlated with the greater severity of the clinico-pathological syndrome ind ...19921445071
evaluation of the complex trapping blocking-elisa in a serological survey during the belgian classical swine fever epizootic in 1990. 19921455586
african swine fever virus infection in the soft tick, ornithodoros (alectorobius) puertoricensis (acari: argasidae).in total, 1,186 second instar ornithodoros (alectorobius) puertoricensis fox second instars were fed on a pig when it had a viremia of 10(5.2) hemadsorption units (had50/ml) and 420 second-instar o. puertoricensis were fed on an uninfected pig. subsequent blood meals for ticks in both groups were from uninfected pigs. the effects of african swine fever virus (asfv) infection on o. puertoricensis populations were evaluated for the following parameters: mortality; mean time to death; percentage mo ...19921460641
survival of hog cholera virus (hcv) in sausage meat products (italian salami).survival of hog cholera virus (hcv) was determined in several sausage meat products (italian salami) prepared with meats from experimentally infected hogs slaughtered at the peak of disease. meats were processed following the technology applied by the main factories of the typical italian production. the survival of hcv was assessed through inoculation in both pk 15 cell monolayers and fully susceptible piglets. in all types of sausages examined hcv was detected up to 75 days of curing by piglet ...19921476864
approaches to the identification of non-essential genes of african swine fever virus.it is poorly understood why vaccines could not be developed for the control and prevention of african swine fever (asf) virus infection. the aim of our study was to identify genes non-essential for asf virus replication because there were indications that certain viral gene products, which apparently are non-essential for viral replication, conferred protection from death due to asf. a cosmid library representing the genome of asf virus strain france 64 was established and characterized. then, i ...19921481351
analyses of the primary in vitro responsiveness of non-immune porcine peripheral blood mononuclear cells with reference to immunization by african swine fever virus antigen and treatment with leucine methyl ester.peripheral blood mononuclear cells (pbmc) from non-immune pigs were immunized in vitro using african swine fever (asf) virus antigen with concomitant mitogenic stimulations known to have varying effects on b and t lymphocyte activity. none of these conditions, including those previously reported as being successful for the in vitro immunization of non-immune porcine pbmc with asf virus antigen, supported the induction of specific antibody. due to the reports on in vitro immunization of human pbm ...19921487303
experimental transmission of african swine fever virus by the soft tick ornithodoros (pavlovskyella) marocanus (acari: ixodoidea: argasidae).a total of 1,600 ornithodoros (pavlovskyella) marcocanus larvae were fed on a pig with a viremia of 10(7.4) had50/ml of african swine fever virus (asfv). infected larvae were sampled daily for 15 d, and nymphs were sampled at least once per instar until they became adults. initial titers of 10(4.48) had50 per larva declined to 10(4.04) within 2 d. larval titers reached a maximum of 10(6.0) had50 per larva 10 d after the infective blood meal. nymphs of each instar were fed on a susceptible pig an ...19921495075
detection of african swine fever viral antigens in paraffin-embedded tissues by use of immunohistologic methods and polyclonal antibodies.tissues obtained from pigs inoculated with african swine fever virus (asfv), fixed by vascular perfusion using glutaraldehyde, and embedded in paraffin or araldite were used for an immunohistologic electron microscopic study. to detect asfv antigens, 4 methods were used on paraffin sections with or without pretreatment of the tissues. use of biotinylated anti-asfv antiserum combined with avidin-biotin complex and peroxidase proved to be the most suitable method, and antigen was detected in tissu ...19921510327
a sensitive dot immunobinding assay for serodiagnosis of african swine fever virus with application in field conditions.the present work describes a simple dot immunobinding assay (dia) for african swine fever virus (asfv) antibody detection that can be used under field conditions. the assay uses nitrocellulose strips dotted with a cytoplasmic soluble antigen (cs-p) of asfv. the nitrocellulose strips are adhered to a plastic handle. the test serum samples react with the cs-p, and antibodies are detected using a protein a-peroxidase conjugate. both incubations are carried out at 20 c. the efficacy of the dia as a ...19921515486
a review on classical swine fever infections in pigs: epizootiology, clinical disease and pathology.a review is given on classical swine fever (csf) including epizootiology, clinical disease and pathology. under the item of epizootiology the history of csf is briefly summarized. ways of transmission are described with special reference to csf in wild boars. the chapter about clinical disease includes the description of different courses of csf such as peracute, acute, subacute form and chronic disease with reference to the course of transplacental infection and fate of the progeny associated w ...19921516362
a tissue culture vaccine with lapinized chinese (lc) strain of hog cholera virus (hcv).the lapinized chinese (lc) strain of hog cholera virus (hcv), was adapted to grow in a cell line from minipig kidney (mpk) where it reached a titer, as determined by immunofluorescence, significantly higher than in rabbits. inasmuch as the immune serum to hcv neutralized the culture-adapted virus, it was concluded that its antigenicity did not undergo any change after adaptation to mpk cells. the mpk-lc adapted virus (mpk-lc-hcv) showed also a higher immunogenic activity in rabbits, in compariso ...19921516363
expression in vivo and in vitro of the major structural protein (vp73) of african swine fever virus.the vp73 protein was produced by in vitro transcription and translation from the xho i-bam hi fragment located between the cla i-n and cla i-h fragments of the viral genome. this dna fragment encodes a late mrna of about 2.6 kb detected in infected ms monkey and bhk hamster cells. the transcript was initiated at a site within two bases upstream of the translation initiation codon. the in vitro synthesized polypeptide shows the same molecular weight as the in vivo synthesized polypeptide, suggest ...19921550491
modulation of splenic macrophages, and swine leukocyte antigen (sla) and viral antigen expression following african swine fever virus (asfv) inoculation.expression of viral and major histocompatibility complex (mhc) antigens and localization of t cells and macrophages was studied in frozen tissue sections of spleens taken from normal pigs or from pigs inoculated with highly virulent lisbon 60 (l60), or with moderately virulent dominican republic 1978 (dr-ii), african swine fever virus (asfv) isolates. splenic sections from l60 inoculated pigs exhibited a large decrease in macrophage staining, whereas dr-ii infected animals appeared more intensel ...19921550493
african swine fever virus: generation of subpopulations with altered immunogenicity and virulence following passage in cell cultures.virus subpopulations with variable virulence, immunogenicity, and infectivity to pigs were readily generated by passaging tengani isolate of african swine fever virus, either biologically cloned or uncloned, in vero cell cultures. avirulent virus populations which account for more than 99% of virus in an uncloned preparation of the 27th passage are laboratory artefacts, perhaps do not exist in nature. furthermore, attenuation of virulence did not occur uniformly in all subpopulations newly gener ...19921558888
[light and electron microscopic findings in the intestine of spontaneous and experimentally-produced african swine fever].light and electron microscopical studies were carried out after experimental induced and spontaneous infection with african swine fever virus. the experimental infection was performed in 18 pigs divided into two groups consisting of 9 animals. the pigs of group i were inoculated with virulent isolate e 70, those of group ii with attenuated isolate e 75. two infected pigs of group i and one control animal were killed on days 3, 5 or 7 p.i., two pigs of group ii and one control animal were killed ...19921559460
genetic manipulation of african swine fever virus: construction of recombinant viruses expressing the beta-galactosidase gene.homologous recombination is shown to be specifically induced in vero cells by infection with african swine fever (asf) virus. the frequency of recombination induced by asf virus infection between cotransfecting plasmids is comparable to that found after infection with the prototype poxvirus, vaccinia virus. the induction of recombination is accompanied by replication of the plasmid templates in the asf virus-infected cells. an asf virus insertion/expression plasmid vector containing the escheric ...19921566585
[is feeding of green silage in areas with hog cholera in wild boar a danger for domestic swine herds? experimental study].in an experimental study we tested the survival of hog cholera virus (hcv) contained in pieces of muscular tissue and organs from experimentally infected swine after incubation in silage. in big (diameter greater than 20 cm) muscular pieces hcv survived even in excellent mineral acid silage (ph 3.8-4.0) after a storage of 5 months. on the other hand in smaller parts (musculature tissue, organs less than 20 cm diameter) we never found virulent hcv after 3 months of incubation. independent of the ...19921575668
a second envelope glycoprotein mediates neutralization of a pestivirus, hog cholera virus.several monoclonal antibodies (mabs) raised against hog cholera virus (hcv) reacted with the hcv structural glycoprotein gp44/48 and neutralized the virus. the presence of hcv gp44/48 on the viral surface was directly demonstrated by immunogold electron microscopy. eight anti-hcv gp44/48 mabs were tested by immunoperoxidase assay against a panel of pestivirus strains. each mab showed a distinct pattern of reactivity with hcv strains. it is suggested that the mabs are well suited for epidemiologi ...19921583727
amino acid sequence and structural properties of protein p12, an african swine fever virus attachment protein.the gene encoding the african swine fever virus protein p12, which is involved in virus attachment to the host cell, has been mapped and sequenced in the genome of the vero-adapted virus strain ba71v. the determination of the n-terminal amino acid sequence and the hybridization of oligonucleotide probes derived from this sequence to cloned restriction fragments allowed the mapping of the gene in fragment ecori-o, located in the central region of the viral genome. the dna sequence of an ecori-xba ...19921583732
comparison of the sequence of the gene encoding african swine fever virus attachment protein p12 from field virus isolates and viruses passaged in tissue culture.comparison of the amino acid sequence of the african swine fever virus attachment protein p12 from different field virus isolates, deduced from the nucleotide sequence of the gene, revealed a high degree of conservation. no mutations were found after adaptation to vero cells, and a polypeptide with similar characteristics was present in an ibrs2-adapted virus. the sequence of the 5' flanking region was conserved among the isolates, whereas sequences downstream of the gene were highly variable in ...19921583733
role of the host cell nucleus in the replication of african swine fever virus dna.an examination by autoradiography of african swine fever virus-infected alveolar macrophages pulse labeled with [3h]thymidine showed that, at early times of viral dna replication, the grains were localized exclusively in the nucleus in 20% of the cells, while in 45% the label was found in the cytoplasm. in the remaining 35%, newly synthesized dna was detected in both the nucleus and the cytoplasm. at later times, the percentage of cells with grains in the nucleus decreased considerably. pulse-ch ...19921585638
characterization of p30, a highly antigenic membrane and secreted protein of african swine fever virus.we have identified and characterized a 30-kda phosphoprotein (p30) of african swine fever virus (asfv) that is synthesized, membrane localized, and released into the culture medium at early times after infection. sequence analysis of the p30 open reading frame predicts a highly antigenic protein with putative phosphorylation, glycosylation, and membrane attachment sites.19921604821
cell culture propagation modifies the african swine fever virus replication phenotype in macrophages and generates viral subpopulations differing in protein p54.we have detected 86 african swine fever (asf) virus-induced proteins in infected pig macrophages by two-dimensional electrophoresis. no differences among protein patterns of wild-type viruses could be observed by this methodology. however, during cell culture adaptation and propagation we have characterized changes in the molecular weight of the asf virus specified protein p54, which show direct correlation with both size and number of viral subpopulation variants generated during cell culture p ...19921604931
morphogenesis of african swine fever virus in monkey kidney cells after reversible inhibition of replication by cycloheximide.the late cytoplasmic phases of african swine fever virus (asfv) morphogenesis in monkey kidney cells have been studied by transmission electron microscopy, focusing attention on the synthesis of viral envelopes. morphogenesis was studied after reversible cycloheximide blockage of monkey kidney cells infected with asfv. asfv appears to synthesize its external and internal envelopes within the cellular cytoplasm, at the same time as the capsid is formed, with intracellular and extracellular virion ...19921605742
an african swine fever virus gene with homology to dna ligases.sequence analysis of the sali g region of the genome of a virulent isolate of asfv (malawi lil 20/1) has revealed an open reading frame with the potential to encode a 48 kilodalton (kd) polypeptide which has significant homology with eukaryotic and prokaryotic dna ligases. this asfv encoded gene also contains the putative active site region of dna ligases including the lysine residue which is necessary for enzyme-adenylate adduct formation, but lacks the c-terminal basic region conserved in othe ...19921614852
swine leukocyte antigen and macrophage marker expression on both african swine fever virus-infected and non-infected primary porcine macrophage cultures.swine leukocyte antigens (sla) and a macrophage specific marker were monitored on porcine macrophages cultured with or without macrophage colony stimulatory factor (m-csf) and on cells infected with african swine fever virus (asfv). sla expression was maximal either in the total cell extract or on the cell surface at 3-4 days of culture; after 4 days these values began to decrease. fluorescence analyses of immunostained macrophages cultured with or without m-csf indicated a major upward shift in ...19921632065
gel retardation analysis of ribonucleotide reductase gene expression in african swine fever virus. 19921633957
a sequence comparison of the vp72 gene of african swine fever virus. 19921633960
localization of the african swine fever virus attachment protein p12 in the virus particle by immunoelectron microscopy.the african swine fever virus attachment protein p12 was localized in the virion by immunoelectron microscopy. purified virus particles were incubated, before or after different treatments, with p12-specific monoclonal antibody 24bb7 and labeled with protein a-colloidal gold. untreated virus particles showed labeling only in lateral protrusions that followed the external virus envelope. mild treatment of african swine fever virions with the nonionic detergent octyl-glucoside or with ethanol onto ...19937679861
reverse interference method for measurement of hog cholera virus (hcv) and anti-hcv antibody.a new procedure was developed for the assay of the hog cholera virus (hcv) and anti-hcv antibody. initially, the suppression effect of hcv on interferon (ifn) by hcv production was confirmed. swine kidney cell cultures preinfected with hcv produced no ifn, even following the addition of ifn inducers. however the sensitivity of the cell to ifn was not influenced by the infection with this virus. based on these results, a new method, named reverse interference method, was established. in this meth ...19937685639
characterization of structural and non-structural proteins of hog cholera virus by means of monoclonal antibodies.a panel of 15 monoclonal antibodies, produced against the hog cholera virus, were characterized by radioimmunoprecipitation assays. using this panel, we were able to identify 4 sets of monoclonal antibodies precipitating each a different viral protein with relative molecular weight of 40, 46, 120 kda, respectively, and a protein complex containing 15, 16, 27, and 55 kda polypeptides which were further characterized. one monoclonal antibody recognized an antigenic determinant at the c-terminal cl ...19937688508
virulent african swine fever virus isolates are neutralized by swine immune serum and by monoclonal antibodies recognizing a 72-kda viral protein.convalescent swine serum to african swine fever virus (asfv) isolate e75 neutralized the infectivity of virulent asfv isolates e75, e70, lisbon 60, malawi lil 20/1 and a low passage tissue culture adapted variant of e75, e75cv/v3, by 86-97% in vero and macrophage cell cultures. a monoclonal antibody, mab-135d4, recognizing an asfv protein of 72 kda also exhibited strong neutralizing activity with these viruses. unexpectedly, both e75 immune sera and mab-135d4 failed to neutralize high passage ti ...19937690502
epitope mapping of envelope glycoprotein e1 of hog cholera virus strain brescia.four antigenic domains (a, b, c and d) on envelope glycoprotein e1 (gp51-54) of hog cholera virus strain brescia have been specified by using 13 monoclonal antibodies (mabs) that recognize non-conserved and conserved epitopes. it was shown that the non-conserved epitopes map to the n-terminal half of e1 by analysis of chimeric e1 proteins of strains brescia and c. conserved epitopes, however, could not be mapped using this approach. here we describe mapping of both conserved and non-conserved ep ...19937691986
[clinical and anatomo-pathological differences in 2 strains of african swine fever virus in angola].african swine fever (asf) is prevalent in angola. it is caused by several strains of viruses, among which silva-porto and huambo 85. a clinical and anatomo-pathological comparative test carried out on the natural and experimental disease showed different and significant characteristics in the behaviour of these two strains. silva-porto generates clinical signs characterized by an haemorrhagic generalized diathesis more marked on the skin, organs and viscera. in addition, the anatomo-pathological ...19938073167
the dna polymerase-encoding gene of african swine fever virus: sequence and transcriptional analysis.the putative dna polymerase-encoding gene of african swine fever virus has been sequenced. the gene, designated g1207r, is located in the central region of the viral genome, and encodes a protein of 1207 amino acids (aa) with a predicted m(r) of 139,835. the gene is transcribed at both early and late stages of infection into a 4.1-kb rna. transcription is initiated at tsp, 8 nucleotides (nt) upstream from the start codon. open reading frame (orf) g1207r contains four direct repeats in tandem clo ...19938293992
[lipids from the african swine fever virus].the lipids of highly purified african swine fever virus (asfv) propagated in porcine bone marrow cells were observed to contain 25.6% phospholipids, 9.7% monoglycerides, 14.1% cholesterol, 17.8% free fatty acids, 14.4% diglycerides, 13.6% triglycerides, and 6.7% cholesterol ethers. diethyl ether extracts mono-, di-, triglycerides, free fatty acids, 50% of cholesterol and cholesterol ethers, and 25% of phospholipids from the virus. analysis of the 14c-sodiumacetate incorporation into viral, cellu ...19938302309
cloning and nucleotide sequence determination of the major envelope glycoprotein (gp55) gene of hog cholera virus (weybridge).a 1.7 kb cdna fragment corresponding to the coding region of the major envelope glycoprotein (gp55) of pestivirus hog cholera (weybridge) was obtained using the polymerase chain reaction (pcr), and then cloned into puc 8. the deduced amino acid sequence of gp55 showed a strong homology to that of hcv strains brescia (94%) and alfort (90%), and to a lesser extent to the closely related gp53 of bovine viral diarrhoea virus strain, nadl (65%). eighteen cysteine residues were identified in the seque ...19938317145
production and characterization of monoclonal antibodies against hog cholera virus (alfort 187 strain). 19938328912
african swine fever virus encodes a serine protein kinase which is packaged into virions.nucleotide sequencing of the sali j region of the virulent malawi (lil20/1) strain of african swine fever virus (asfv) identified an open reading frame (orf), designated j9l, with extensive similarity to the family of protein kinases. this orf encodes a 35.1-kda protein of 299 amino acids which shares 24.6% amino acid identity with the human pim-1 proto-oncogene and 21.0% identity with the vaccinia virus b1r-encoded protein kinase. the asfv orf contains the motifs characteristic of serine-threon ...19938331722
an african swine fever virus gene with a similarity to eukaryotic rna polymerase subunit 6. 19938332503
polyprotein processing in african swine fever virus: a novel gene expression strategy for a dna virus.this report shows that african swine fever virus (asfv)--a large dna-containing virus--synthesizes a polyprotein to produce several of its structural proteins. by immunoprecipitation analysis, we have found that asfv polyprotein is a 220 kda myristoylated polypeptide (pp220) which, after proteolytic processing, gives rise to four major structural proteins: p150, p37, p34 and p14. processing of the asfv polyprotein takes place at the consensus sequence gly-gly-x and occurs through an ordered casc ...19938335009
the skin, tongue, and brain as favorable organs for hog cholera diagnosis by immunofluorescence.hog cholera virus antigens were found densely distributed in skin and tongue of pigs experimentally infected with hog cholera virus. the finding described here warrants the usage of ear biopsies for hog cholera diagnosis on a herd basis.19938347086
glycoprotein e1 of hog cholera virus expressed in insect cells protects swine from hog cholera.the processing and protective capacity of e1, an envelope glycoprotein of hog cholera virus (hcv), were investigated after expression of different versions of the protein in insect cells by using a baculovirus vector. recombinant virus bace1[+] expressed e1, including its c-terminal transmembrane region (tmr), and generated a protein which was similar in size (51 to 54 kda) to the size of e1 expressed in swine kidney cells infected with hcv. the protein was not secreted from the insect cells, an ...19938350404
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