Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| the use of arms pcr and rflp analysis in identifying genetic profiles of virulent, attenuated or vaccine strains of tgev and prcv. | the use of arms (amplification refractory mutation system) pcr coupled with rflp (restriction fragment length polymorphism) analysis has been used to identify a unique genetic marker on the ambico oral vaccine strain. this method was also used to characterize the genetic profiles of a number of other tgev strains. this procedure takes advantage of the nucleotide differences between the ambico strain, and the miller and purdue strains. within the s gene there are three nucleotide differences betw ... | 1995 | 8830487 |
| coronaviruses in polarized epithelial cells. | coronaviruses have a marked tropism for epithelial cells. in this paper the interactions of the porcine transmissible gastroenteritis virus (tgev) and mouse hepatitis virus (mhv-a59) with epithelial cells are compared. porcine (llc-pk1) and murine (mtal) epithelial cells were grown on permeable supports. by inoculation from the apical or basolateral side both tgev and mhv-a59 were found to enter the polarized cells only through the apical membrane. the release of newly synthesized tgev from llc- ... | 1995 | 8830469 |
| transmissible gastroenteritis coronavirus, but not the related porcine respiratory coronavirus, has a sialic acid (n-glycolylneuraminic acid) binding activity. | the hemagglutinating activity of transmissible gastroenteritis virus (tgev), an enteric porcine coronavirus, was analyzed and found to be dependent on the presence of alpha-2,3-linked sialic acid on the erythrocyte surface. n-glycolylneuraminic acid was recognized more efficiently by tgev than was n-acetylneuraminic acid. for an efficient hemagglutination reaction the virions had to be treated with sialidase. this result suggests that the sialic acid binding site is blocked by virus-associated c ... | 1996 | 8764078 |
| use of nonradioactive cdna probes to differentiate porcine respiratory coronavirus and transmissible gastroenteritis virus isolates. | 1996 | 8744748 | |
| immunohistochemistry of transmissible gastroenteritis virus antigens in fixed paraffin-embedded tissues. | an immunohistochemistry technique was developed using fixed tissues to study the presence and location of transmissible gastroenteritis virus (tgev) antigens in situ. experimentally infected gnotobiotic and conventional pigs as well as pigs with natural tgev infection were examined. the staining technique was based on detection of the major structural protein of tgev, the nucleocapsid, by using a pool of 3 monoclonal antibodies. formalin and periodate-lysine-paraformaldehyde (plp)-fixed intestin ... | 1996 | 8744736 |
| isolation of porcine respiratory coronavirus from pigs affected with porcine reproductive and respiratory syndrome. | four cytopathogenic viruses were isolated in cpk cells derived from porcine kidneys from tonsils and lungs of 3 of 15 pigs affected with porcine reproductive and respiratory syndrome virus. physicochemically and morphologically, the isolates were similar to a coronavirus. the isolates were not distinguished from transmissible gastroenteritis virus (tgev) by a neutralization test using polyclonal antibodies, but differentiated from tgev by monoclonal antibodies capable of discriminating between t ... | 1996 | 8741277 |
| a continuous epitope from transmissible gastroenteritis virus s protein fused to e. coli heat-labile toxin b subunit expressed by attenuated salmonella induces serum and secretory immunity. | antigenic site d from the spike protein of transmissible gastroenteritis virus (tgev), which is a continuous epitope critical in neutralization, has been expressed as a fusion protein with e. coli heat-labile toxin b subunit (lt-b) in attenuated s. typhimurium. synthetic peptides containing the sequence of site d induced tgev neutralizing antibodies when inoculated subcutaneously in both rabbits and swine. a synthetic oligonucleotide encoding residues 373-398 of tgev s protein, including antigen ... | 1996 | 8725098 |
| contribution of passive immunity to porcine respiratory coronavirus to protection against transmissible gastroenteritis virus challenge exposure in suckling pigs. | to determine the ability of porcine respiratory coronavirus (prcv) infections to induce passive immunity in suckling pigs to transmissible gastroenteritis virus (tgev) challenge exposure. design and animals: 4 tgev seronegative sows and their litters (group a) served as controls, whereas 2 other groups (b and c) of sows (also tgev seronegative) were oronasally inoculated with live prcv during 1 or 2 subsequent pregnancies, respectively. | 1996 | 8723879 |
| [identification and characterization of new and unknown coronaviruses using rt-pcr and degenerate primers]. | a modified method of the reverse transcription followed by polymerase chain reaction (rt-pcr) was developed in order to examine the genome of a recently discovered virus, the porcine epidemic diarrhoea virus (pedv), which resembled morphologically the coronaviruses. the published sequences of the genomes of various coronaviruses were compared. on the level of the amino acid sequence, conserved regions, common to all coronaviruses, were found in the gene encoding the nonstructural protein 1b as w ... | 1996 | 8720732 |
| characterization of transmissible gastroenteritis coronavirus s protein expression products in avirulent s. typhimurium delta cya delta crp: persistence, stability and immune response in swine. | the spike protein from transmissible gastroenteritis virus (tgev) was expressed in attenuated s. typhimurium delta cya delta crp delta asd chi 3987. three partially overlapping fragments of tgev s gene, encoding the amino-terminal, intermediate, and carboxy-terminal end of the protein, as well as the full length gene were inserted into the asd+ plasmid pya292 to generate recombinant plasmids pyats-1, pyats-2, pyats-3, and pyats-4, respectively, which were transformed into s. typhimurium chi 3987 ... | 1996 | 8701580 |
| elimination of transmissible gastroenteritis virus from a pig farm by culling and serological surveillance. | the first and only outbreak of transmissible gastroenteritis in pigs in ireland occurred in 1984 in a 650-sow unit which was one of three such units owned by one enterprise which supplied pigs to a 12,000 head fattening unit in the same ownership. the depopulation of the clinically infected unit and extensive serological monitoring of pigs in the other units and in pig farms throughout the country has proved successful in the elimination of transmissible gastroenteritis infections from pigs in i ... | 1996 | 8686150 |
| classical transmissible gastroenteritis returns. | 1996 | 8677610 | |
| the transmissible gastroenteritis coronavirus contains a spherical core shell consisting of m and n proteins. | coronaviruses are enveloped rna viruses involved in a variety of pathologies that affect animals and humans. existing structural models of these viruses propose a helical nucleocapsid under the virion envelope as the unique internal structure. in the present work, we have analyzed the structure of the transmissible gastroenteritis coronavirus. the definition of its organization supports a new structural model for coronaviruses, since a spherical, probably icosahedral, internal core has been char ... | 1996 | 8676505 |
| tropism of human adenovirus type 5-based vectors in swine and their ability to protect against transmissible gastroenteritis coronavirus. | the infection of epithelia] swine testicle and intestinal porcine epithelial (ipec-1) cell lines by adenovirus type 5 (ad5) has been studied in vitro by using an ad5-luciferase recombinant containing the firefly luciferase gene as a reporter. porcine cell lines supported ad5 replication, showing virus titers, kinetics of virus production, and luciferase expression levels similar to those obtained in human 293 cells, which constitutively express the 5'-end 11% of the ad5 genome. the tropism of ad ... | 1996 | 8648712 |
| induction of protective immunity against transmissible gastroenteritis virus after exposure of neonatal pigs to porcine respiratory coronavirus. | to test the ability of porcine respiratory coronavirus (prcv) to induce protective immunity to antigenically related transmissible gastroenteritis virus (tgev) in neonatal pigs. | 1996 | 8633800 |
| tandem placement of a coronavirus promoter results in enhanced mrna synthesis from the downstream-most initiation site. | insertion of the 17-nucleotide promoter region for the bovine coronavirus n gene as part of a 27-nucleotide cassette into the open reading frame of a cloned synthetic defective-interfering (di) rna resulted in synthesis of subdi rna transcripts from the replicating di rna genome. duplicating and triplicating the promoter sequence in tandem caused a progressive increase in the efficiency of subgenomic mrna synthesis despite a concurrent decrease in the rate of di rna accumulation that was not spe ... | 1996 | 8610468 |
| molecular characterization of transmissible gastroenteritis coronavirus defective interfering genomes: packaging and heterogeneity. | three transmissible gastroenteritis virus (tgev) defective rnas were selected by serial undiluted passage of the pur46 strain in st cells. these rnas of 22, 10.6, and 9.7 kb (di-a, di-b, and di-c, respectively) were detected at passage 30, remained stable upon further passage in cell culture, and significantly interfered with helper mrna synthesis. rna analysis from purified virions showed that the three defective rnas were efficiently packaged. virions of different densities containing either f ... | 1996 | 8610441 |
| cloning, sequencing and expression of the s protein gene from two geographically distinct strains of canine coronavirus. | the gene encoding the spike (s) protein from two geographically distinct strains (american and british) of canine coronavirus (ccv) was cloned and sequenced. the nucleotide sequence revealed open reading frames of 1443 or 1453 amino acids, respectively. structural features include an n-terminal hydrophobic signal sequence, a hydrophilic cysteine-rich cluster near the c-terminus, two heptad repeats and 29 or 33 potential n-glycosylation sites. pairwise comparisons of s amino acid sequences from t ... | 1995 | 8607285 |
| immunohistological demonstration of feline infectious peritonitis virus antigen in paraffin-embedded tissues using feline ascites or murine monoclonal antibodies. | feline infectious peritonitis (fip) virus antigen was demonstrated after methanol, ethanol or formalin fixation in paraffin-embedded tissues by means of monoclonal and polyclonal antibodies. the monoclonal antibody was induced by immunization with transmissible gastroenteritis virus. polyclonal antibodies were obtained by purification on protein a-sepharose of ascites fluid from a cat with fip. almost all cats diagnosed as suffering from fip by postmortem and histological examination exhibited f ... | 1995 | 8588340 |
| cloning and sequencing of a 8.4-kb region from the 3'-end of a taiwanese virulent isolate of the coronavirus transmissible gastroenteritis virus. | the nucleotide sequence (8396 nucleotides) was determined, from the 3'-end of the putative polymerase gene to the poly(a) tail, for a taiwanese virulent isolate, tfi, of transmissible gastroenteritis virus (tgev). the tfi nucleotide sequence had very high identity to the british virulent field isolate fs772/70 (98.3%), the attenuated purdue 115 (96.7%) and from the s gene to orf-4 gene region, to the low passaged virulent miller (98.3%) strains of tgev. comparison of the tfi s protein sequence w ... | 1995 | 8546012 |
| cellular immune responses of pigs after primary inoculation with porcine respiratory coronavirus or transmissible gastroenteritis virus and challenge with transmissible gastroenteritis virus. | the contribution of cell-mediated immunity to protective immunity against virulent transmissible gastroenteritis virus (tgev) infection conferred by primary porcine respiratory coronavirus (prcv) or tgev exposure was assessed in pigs that were challenged with tgev 24 days after a primary oronasal inoculation with prcv or tgev when 11 days old. prcv exposure induced partial protection against tgev challenge in suckling pigs based upon a decreased number of diarrhea cases (42% vs. 90% in age-match ... | 1995 | 8533315 |
| transmissible gastroenteritis coronavirus: the development and applications of the fixed-cell immunoperoxidase technique. | since the first demonstration in 1971 that solid-phase enzyme-linked immunosorbent assays (elisas) could be used for the quantitative determination of antigens and antibodies, this method has been widely applied in serodiagnosis of parasitic and infectious diseases. in addition to the classic elisa variants using antigen or antibody to coat the plastic plates, there has recently been growing interest in the application of fixed-cell elisa to research and diagnostic work on viral diseases. the au ... | 1993 | 8400392 |
| inhibition of appearance of ph-dependent virus-cell fusion by neutralizing monoclonal antibodies to transmissible gastroenteritis virus. | five mabs, which showed neutralizing (nt) activity and recognized s (previously designated e2) glycoprotein of tge virus to-163, inhibited cell fusion by tge virus in ib-rs-2 cells. other s-specific mabs with no nt activity did not inhibit the cell fusion. the results indicate that a neutralization epitope is same or very close to a fusion active site. the kinetics of membrane fusion following a reduction in ph were also investigated. the cell fusion appeared between 2 and 6 hr after the bindin ... | 1993 | 8399749 |
| sequence determination of the nucleocapsid protein gene of the porcine epidemic diarrhoea virus confirms that this virus is a coronavirus related to human coronavirus 229e and porcine transmissible gastroenteritis virus. | the nucleotide sequence of 1.7 kbp cdna, comprising the region nearest the 3' end of the genome of the porcine epidemic diarrhoea virus (pedv), has been independently determined for two european isolates of pedv. almost identical results were obtained for the two isolates, which were derived from cases of pedv infection in belgium and britain in 1977 and 1987, respectively. the sequences contained a 1323 nucleotide (nt) open reading frame (orf), which showed moderate identity to the nucleocapsid ... | 1993 | 8397280 |
| binding of porcine transmissible gastroenteritis virus by enterocytes from newborn and weaned piglets. | enterocytes were harvested by chelation in a series of seven fractions from the tips of the villi to the crypts of the jejunum of newborn or weaned piglets. binding of the low cell culture passaged miller-6 strain of transmissible gastroenteritis virus (tgev) to villous enterocytes from newborn piglets was at a high level, similar to that observed to cultured swine testis (st) cells. binding of the virus to cryptal enterocytes from newborn piglets or to villous or cryptal enterocytes from weaned ... | 1993 | 8395743 |
| a spike protein-dependent cellular factor other than the viral receptor is required for mouse hepatitis virus entry. | previous studies have shown that some mouse strains are resistant to mouse hepatitis virus (mhv) infection despite the presence of functional viral receptors (k. yokomori and m. m. c. lai, j. virol. 66, 6931-6938, 1992). to determine the molecular requirement for mhv infection, several cell lines derived from both susceptible and resistant mouse strains were tested for their ability to support infection by two different mhv strains, jhm and a59. most of the cell lines tested, including ones from ... | 1993 | 8395126 |
| porcine respiratory coronavirus: molecular features and virus-host interactions. | since 1984, a previously unrecognized respiratory coronavirus, causing a mostly unapparent infection, has rapidly and massively spread within the swine population in europe, and few years later, a virus with similar characteristics has been identified in the usa. the agent, designated prcv, appears to be derived from the porcine enteric coronavirus tgev. the aim of the present article is to review comprehensively the state of the knowledge about this new virus and its infection. the review inclu ... | 1993 | 8393722 |
| experience with a planned exposure program for the control of enzootic transmissible gastroenteritis in swine. | oral inoculation of pregnant sows and gilts with a homogenate of pig intestines containing live, virulent transmissible gastroenteritis (tge) virus was associated with significant (p < 0.01) reduction of mortality in nursery pigs in a herd affected with enzootic tge. the mortality of weaned pigs from april through june 1981, when sows were not vaccinated or inoculated, was 9.3%. mortality of weanling pigs from july through december 1981 was 5.7% (p < 0.01), and stayed consistently between 2.6 an ... | 1993 | 8391524 |
| comparative study of different immunoserological techniques for the detection of antibodies against transmissible gastroenteritis (tge) coronavirus. | in order to carry out a sero-epidemiological survey of transmissible gastroenteritis (tge) infection in a high-density pig-breeding area the murcia region, spain), the sensitivity and the specificity of 5 different techniques were compared. twenty-four sera from non-infected and infected pigs were analyzed by the following tests: in vitro neutralization, indirect elisa with concentrated virus, indirect elisa with purified virus, immunocapture elisa and velcia (virus-enzyme linked cell immunoassa ... | 1993 | 8391366 |
| enrichment of coronavirus-induced interferon-producing blood leukocytes increases the interferon yield per cell: a study with pig leukocytes. | porcine peripheral blood mononuclear cells, which secrete ifn alpha in response to a coronavirus, transmissible gastroenteritis virus, were detected by a filter immunoplaque assay (elispot). ifn alpha-producing cells (ipc), which are present at a low frequency in the blood, could be enriched up to 100-fold by sequential depletion of plastic-adherent cells and cell fractionation on metrizamide density gradients. ipc were present in the non-adherent low-density cell subpopulation. cell selection e ... | 1993 | 8390709 |
| a sero-epizootiological study of porcine respiratory coronavirus in belgian swine. | a porcine respiratory coronavirus (prcv), antigenically closely related to transmissible gastroenteritis virus (tgev), appeared in the european swine population in 1984. the present serological study was performed to obtain insight into the epizootiology of prcv and of tgev. prcv-induced neutralizing antibodies were found in 90.6 per cent of the 160 sera collected from sows at slaughter, demonstrating the enzootic appearance of prcv in the belgian swine population. a serological study of fatteni ... | 1993 | 8388592 |
| isotype-specific antibody-secreting cells to transmissible gastroenteritis virus and porcine respiratory coronavirus in gut- and bronchus-associated lymphoid tissues of suckling pigs. | antibody-secreting cells (asc) were enumerated in gut- and bronchus-associated lymphoid tissues of pigs exposed to three antigenically related coronaviruses: virulent transmissible gastroenteritis virus (tgev), attenuated tgev, and porcine respiratory coronavirus (prcv). exposure of 11-day-old pigs to virulent tgev resulted in severe gastroenteritis and virus shedding mainly in feces but also to a limited extent in nasal secretions. prcv and attenuated tgev exposure produced no clinical signs an ... | 1993 | 8386204 |
| comparison of a monoclonal antibody capture elisa (macelisa) to indirect elisa and virus neutralization test for the serodiagnosis of transmissible gastroenteritis virus. | an enzyme-linked immunosorbent assay (elisa) in which the antigen is captured to the plate by monoclonal antibodies (macelisa) was developed for the detection of antibodies to transmissible gastroenteritis virus (tgev). the viral antigen was semipurified from tgev-infected cells by simple ultracentrifugation. macelisa results with 258 field sera were compared with those of a standard indirect elisa and with the virus neutralization test (vnt). sensitivity, specificity, and kappa values of maceli ... | 1993 | 8385500 |
| the application of immunogold silver staining (igss) for the detection of transmissible gastroenteritis virus in fixed tissues. | protein a-gold (pag) and a primary porcine antiserum were used in immunogold silver staining (igss) for the detection of transmissible gastroenteritis virus (tgev) in formalin-fixed paraffin-embedded tissue sections of small intestine originating from infected pigs. immunogold electron microscopy was used to evaluate the reactivity of the prepared pag marker with the specific porcine tgev antiserum. gold particles were closely associated with single virions and immune aggregates of tgev. when ig ... | 1993 | 8385499 |
| transmissible gastroenteritis in pigs in south east spain: prevalence and factors associated with infection. | in the murcia region of south east spain, epidemics of transmissible gastroenteritis-like disease have occurred in pigs every three years since 1980. in 1987 a sero-epidemiological survey was conducted to estimate the prevalence and spread of transmissible gastroenteritis virus (tgev) infection among breeding pigs and farms, and to determine any association between the infection and herd size and geographical zone. the murcia region was divided into four geographical zones and the farms were cla ... | 1993 | 8384735 |
| intestinal protection against challenge with transmissible gastroenteritis virus of pigs immune after infection with the porcine respiratory coronavirus. | an infection of pigs with the porcine respiratory coronavirus (prcv) induces antibodies which neutralize the enteropathogenic transmissible gastroenteritis virus (tgev) and prcv to the same titre. in the present study, 10-week-old seronegative pigs (n = 8), pigs immune following tgev inoculation (n = 4) or pigs immune following aerosol (n = 8) or intragastric inoculation (n = 4) with prcv were challenged with tgev. whereas tgev-immune pigs were completely protected against challenge, all prcv-im ... | 1993 | 8382421 |
| competition elisa, using monoclonal antibodies to the transmissible gastroenteritis virus (tgev) s protein, for serologic differentiation of pigs infected with tgev or porcine respiratory coronavirus. | monoclonal antibodies (mab) to subsite a (25c9) and subsite d (44c11) of the s protein of transmissible gastroenteritis virus (tgev) were used in a blocking elisa on fixed tgev-infected swine testis cells to differentiate sera from pigs experimentally inoculated with either tgev or porcine respiratory coronavirus (prcv). serum samples were obtained from pigs at various intervals from postinoculation day (pid) 0 through at least pid 22 to 40. eleven-day-old pigs, seronegative for tgev-neutralizin ... | 1993 | 8381626 |
| [the isolation and in-vitro cultivation of a virulent strain of the porcine transmissible gastroenteritis virus]. | 1993 | 8303889 | |
| sequence analysis of the porcine epidemic diarrhea virus genome between the nucleocapsid and spike protein genes reveals a polymorphic orf. | in order to investigate the genome organization of the porcine epidemic diarrhea virus (pedv) further, cdna clones covering the region between the nucleocapsid and the spike (s) protein genes were independently constructed and sequenced for the two virulent isolates br1/87 and cv777. of the three major orfs identified, two were found to encode the major and minor coronavirus membrane proteins m and sm. a potentially single orf, designated orf3 according to the pattern of the viral subgenomic mrn ... | 1994 | 8291230 |
| dot-blot hybridization using digoxigenin-labeled cdna probe complementary to the s1 gene of avian infectious bronchitis virus permits discrimination between virus strains. | digoxigenin-dutp-labeled dna probe was prepared from a cdna clone complementary to the gene encoding s1 region of the spike protein of infectious bronchitis coronavirus (ibv) strain m41. the probe exclusively reacted with four strains at 56 degrees c which were grouped to the same serotype as the strain used for the probe. in contrast, at 68 degrees c, the probe reacted only with the homologous strain and did not react even with the strains belonging to the same serotype. the dot-blot hybridizat ... | 1993 | 8286524 |
| antigenic and biological diversity among transmissible gastroenteritis virus isolates of swine. | twenty-four field isolates of transmissible gastroenteritis virus (tgev) were isolated and examined for antigenic and biological characteristics. most tgev isolates produced a typical cytopathic effect (cpe) in swine testis (st) cell culture, which included a ballooning or lifting away of the infected cells from the cell monolayer with heavy granulation evident. minor variations in cpe were observed with one isolate, ia-145. protein profiles of the tgev isolates as determined by sds-page were es ... | 1993 | 8273277 |
| epithelioid and fibroblastic cell lines derived from the ileum of an adult histocompatible miniature boar (d/d haplotype) and immortalized by sv40 plasmid. | intestinal explants were maintained for weeks in a growth medium containing collagenase for progressive digestion to derive finite cell lines from the ileum (64 lines) or from the colon (8 lines) of a boar. two ileal cell lines retaining either a fibroblastic or an epithelioid morphology have been used to derive heteroploid cell lines (ipi-1 and ipi-2) immortalized by transfection with an sv40 plasmid (psv3-neo). the ipi-1 cells were found of fibroblastic lineage. the ipi-2 cell line gave rise t ... | 1993 | 8269973 |
| age-related increase of porcine natural interferon alpha producing cell frequency and of interferon yield per cell. | porcine blood mononuclear cells (pbmc) were shown to secrete interferon alpha (ifn-alpha) after induction by a coronavirus, the transmissible gastroenteritis virus (tgev). ifn-alpha producing cells, referred to as natural interferon alpha producing (nip) cells, were detected by an elispot assay using anti-porcine ifn-alpha monoclonal antibodies. the frequency of nip cells among blood cells is low, at most 40-110 per 10(5) pbmc and each nip cell was found to produce several units of ifn. we have ... | 1993 | 8236791 |
| control of tgev mrna transcription. | coronavirus proteins are translated from a nested set of subgenomic mrnas which have common 3' termini with unique 5' extensions. evidence suggests that coronavirus mrnas are generated by a mechanism of leader primed transcription. leader rna binds to consensus sequences upstream of each gene on full length negative strand viral rna and transcription proceeds to the 5' end of the negative strand to produce the nested set of mrnas. even though this gives rise to polycistronic mrna species only th ... | 1993 | 8209778 |
| genome organization of porcine epidemic diarrhoea virus. | in order to study the organization of the genome of porcine epidemic diarrhoea virus (pedv), we constructed a cdna library in a phage expression vector by using poly(a) rna from pedv-infected vero cells. an anti-pedv hyperimmune serum was used to probe the library. the first isolated clone mapped within the n gene and was subsequently used for rescreening the library. the selected clones allowed us to establish the sequence of the 3'-most 7.4 kb of the pedv genome. analysis of the cdna sequences ... | 1993 | 8209771 |
| an overview of successful tgev vaccination strategies and discussion on the interrelationship between tgev and prcv. | porcine respiratory coronavirus (prcv) is a new variant of tge with an altered pathogenesis. prcv multiplies mainly in tonsilar tissues and the respiratory tract. there are no enteric symptoms and in experimentally infected pigs, even the respiratory tract infection is usually asymptomatic. prcv is spread aerogenically through herds and the significance of prcv as a pathogen in swine has yet to be determined. despite the differences in pathogenesis and tissue tropism, the behavior of tgev and pr ... | 1993 | 8209768 |
| transmissible gastroenteritis virus and porcine respiratory coronavirus: molecular characterization of the s gene using cdna probes and nucleotide sequence analysis. | two transmissible gastroenteritis virus (tgev, miller strain) cdna clones were identified and their nucleotide sequences determined. the clones were non-overlapping and were located in the 5' region of the s glycoprotein gene. the tgev clone pe21 contained 381 bp of the s glycoprotein gene and had > 98% nucleotide and amino acid sequence homology with the purdue (p115) strain of tgev and over 87% sequence homology with feline infectious peritonitis virus (fipv). the tgev clone, pd24, contained 2 ... | 1993 | 8209764 |
| evolution and tropism of transmissible gastroenteritis coronavirus. | transmissible gastroenteritis coronavirus (tgev) is an enteropathogenic coronavirus isolated for the first time in 1946. nonenteropathogenic porcine respiratory coronaviruses (prcvs) have been derived from tgev. the genetic relationship among six european prcvs and five coronaviruses of the tgev antigenic cluster has been determined based on their rna sequences. the s proteins of six european prcvs have an identical deletion of 224 amino acids starting at position 21. the deleted area includes t ... | 1993 | 8209753 |
| n-acetylneuraminic acid plays a critical role for the haemagglutinating activity of avian infectious bronchitis virus and porcine transmissible gastroenteritis virus. | porcine transmissible gastroenteritis virus (tgev) was found to resemble avian infectious bronchitis virus (ibv) in its interaction with erythrocytes. inactivation of the receptors on erythrocytes by neuraminidase treatment and restoration of receptors by reattaching n-acetylneuraminic acid (neu5ac) to cell surface components indicated that alpha 2,3-linked neu5ac serves as a receptor determinant for tgev as has been reported recently for ibv. similar to ibv, the haemagglutinating activity of tg ... | 1993 | 8209748 |
| sequence analysis of ccv and its relationship to fipv, tgev and prcv. | 1993 | 8209747 | |
| the use of pcr genome mapping for the characterisation of tgev strains. | previous studies on different transmissible gastroenteritis virus (tgev) strains, including porcine respiratory coronavirus (prcv), have identified regions within the genome that are polymorphic as regards insertions and deletions. for example the 672 base deletion within the s gene and multiple deletions 5', within and 3' of the orf-3a gene were detected in strains of prcv. the presence of deletions may be associated with a change in the virulence, attenuation or tissue tropism of the isolate. ... | 1993 | 8209745 |
| genomic organisation of a virulent taiwanese strain of transmissible gastroenteritis virus. | transmissible gastroenteritis (tge) infection causes 65% of infectious piglet diarrhoea in taiwan. a virulent taiwanese strain, tfi, of transmissible gastroenteritis virus (tgev) from a field outbreak was isolated in cell culture and plaque purified. phenotypic differences were observed in the ability of tfi to infect certain cell lines. tgev strains tlm-83 (prcv belgium), to-163 (tgev japan) and purdue-115 (tgev usa) infected both st (swine testis) and rptg (pig kidney) cell lines whereas tfi i ... | 1993 | 8209736 |
| molecular mimicry between s peplomer proteins of coronaviruses (mhv, bcv, tgev and ibv) and fc receptor. | in previous studies we have demonstrated molecular mimicry between the s peplomer protein of mouse hepatitis virus (mhv) and fc gamma receptor (fc gamma r) of igg. rabbit igg, but not its f(ab')2 fragments, monoclonal rat and mouse igg and the rat 2.4g2 anti-mouse fc gamma r monoclonal antibody (mab) immunoprecipitated natural and recombinant mhv s protein. on the basis of a number of criteria, mhv s peplomer protein exhibits fc igg binding ability. we report here a molecular mimicry between the ... | 1993 | 8209728 |
| genomic organization and expression of the 3' end of the canine and feline enteric coronaviruses. | the genomic organization at the 3' end of canine coronavirus (ccv) and feline enteric coronavirus (fecv) was determined by sequence analysis and compared to that of feline infectious peritonitis virus (fipv) and transmissible gastroenteritis virus (tgev) of swine. comparison of the latter two has previously revealed an extra open reading frame (orf) at the 3' end of the fipv genome, lacking in tgev, now designated orf 6b. both ccv and fecv possess 6b-related orfs. the ccv orf 6b is colinear with ... | 1993 | 8209715 |
| sequence of the spike protein of the porcine epidemic diarrhoea virus. | the complete sequence of the spike (s) gene of the br1/87 isolate of porcine epidemic diarrhoea virus (pedv) was determined from cdna clones. the predicted polypeptide was 1383 amino acids long, contained 29 potential n-linked glycosylation sites and showed structural features similar to those of the coronavirus spike protein. the pedv s protein, like that of the members of the transmissible gastroenteritis virus (tgev)-related subset, lacks a proteolytic site to yield cleaved amino and carboxy ... | 1994 | 8176382 |
| contribution of antibody-secreting cells induced in mucosal lymphoid tissues of pigs inoculated with respiratory or enteric strains of coronavirus to immunity against enteric coronavirus challenge. | two antigenically related porcine coronaviruses, transmissible gastroenteritis virus (tgev) which infects primarily the intestinal tract and causes severe diarrhea, and porcine respiratory coronavirus (prcv) which infects the respiratory tract and causes subclinical or mild respiratory infections, presented a unique opportunity to study the interrelationship of gut-(galt) and bronchus-associated lymphoid tissues (balt) and their contribution to protective immunity against tgev infection. pigs we ... | 1994 | 8144965 |
| coronavirus transmissible gastroenteritis virus-mediated induction of ifn alpha-mrna in porcine leukocytes requires prior synthesis of soluble proteins. | we studied the expression of interferon alpha (ifn alpha)-mrna in porcine non-adherent peripheral blood mononuclear cells (pbmc) after induction by the coronavirus transmissible gastroenteritis virus (tgev). we found that protein synthesis inhibition by cycloheximide (chx) blocked ifn alpha-mrna expression, except when pbmc were preincubated with a conditioned medium as a potential source of cytokines. these data indicate that ifn alpha-mrna induction by tgev requires de novo synthesis of protei ... | 1994 | 8142954 |
| mhv-a59 fusion mutants are attenuated and display altered hepatotropism. | mouse hepatitis virus strain a59 causes a persistent productive, but nonlytic, infection of cultured glial cells. we have mutants isolated from persistently infected glial cell cultures which have been shown to be fusion-defective due to a histidine to aspartic acid mutation (h716d) near the cleavage site of the peplomer protein, s. here, we examine the pathogenicity of these mutants and show differences in hepatotropism and virulence compared to wild-type virus (wt). two mutants chosen for deta ... | 1994 | 8128613 |
| immunization of pregnant gilts with prcv induces lactogenic immunity for protection of nursing piglets from challenge with tgev. | the level of passive protection against transmissible gastroenteritis virus (tgev) was evaluated by experimentally infecting 12 pregnant gilts with different doses of porcine respiratory coronavirus (prcv) and challenging their litters at 4 days of age. an overall survival rate of 70% was found for piglets nursing the 12 prcv-infected gilts, compared to a 16% survival rate for piglets of nine uninfected control gilts. six of the prcv-infected gilts had adequate levels of immunity to resist infec ... | 1993 | 8128601 |
| coronavirus immunogens. | coronaviruses (cv) infect a variety of livestock, poultry and companion animals. they belong to at least five antigenic groups. cv cause localized infections of the respiratory and/or intestinal tracts, with the exception of feline infectious peritonitis virus (fipv) and hemagglutinating encephalomyelitis (hev) which cause systemic infections. the enteropathogenic cv infect the villous enterocytes resulting in villous atrophy leading to malabsorptive diarrhea. several cv (bovine cv-bcv, porcine ... | 1993 | 8116187 |
| coronavirus m proteins accumulate in the golgi complex beyond the site of virion budding. | the prevailing hypothesis is that the intracellular site of budding of coronaviruses is determined by the localization of its membrane protein m (previously called e1). we tested this by analyzing the site of budding of four different coronaviruses in relation to the intracellular localization of their m proteins. mouse hepatitis virus (mhv) and infectious bronchitis virus (ibv) grown in sac(-) cells, and feline infectious peritonitis virus (fipv) and transmissible gastroenteritis virus (tgev) g ... | 1994 | 8083990 |
| identification of a putative cellular receptor for bovine herpesvirus 1. | recognition of a host cell receptor by a virus is the first and perhaps the most crucial step in initiating the disease process. this study was undertaken to identify the cellular receptor(s) for bovine herpesvirus 1 (bhv-1). previously, we reported the development and characterization of bovine anti-idiotypic antibodies (anti-ids) that induce neutralizing antibodies to bhv-1. these anti-ids inhibit bhv-1 penetration of permissive cells. we have used these anti-ids, which mimic an epitope on the ... | 1994 | 8077928 |
| simulation of the economic impact of transmissible gastroenteritis on commercial pig production in australia. | a simulation model (auspig) was used to predict the effect of an increase in piglet deaths, and a reduction in growth rate and an increase in feed conversion ratio of grower pigs on the profitability of two herds representative of the australian pig industry caused by the introduction of transmissible gastroenteritis virus (tge) into those herds. for each herd, mortality rates for piglets under 1 week of age of 50% and 95% were assumed to represent a 'moderate' and a 'severe' outbreak, respectiv ... | 1994 | 8067950 |
| mouse hepatitis virus gene 5b protein is a new virion envelope protein. | highly purified radiolabeled mouse hepatitis virus (mhv) a59 contained a previously overlooked protein which coelectrophoreses with the gene 5b product immunoprecipitated from infected cells. the gene 5b protein is post-translationally acylated. rabbit antibody raised against a recombinant gene 5b protein expressed in escherichia coli neutralized viral infectivity in the presence of complement, although not in the absence of complement. immunofluorescent staining of mhv-infected cells with two a ... | 1994 | 8030202 |
| lymphocyte proliferation responses of pigs inoculated with transmissible gastroenteritis virus or porcine respiratory coronavirus. | cell-mediated immunity was evaluated in intestinal, respiratory, and systemic lymphoid tissues of pigs exposed when 11 days old to virulent transmissible gastroenteritis virus (tgev), attenuated tgev, or porcine respiratory coronavirus (prcv), 3 antigenically related porcine coronaviruses with distinct enteric and respiratory tissue tropisms. mononuclear cells were prepared from mesenteric lymph nodes (mln), bronchial lymph nodes (bln), and spleens of pigs and tested for virus-specific responses ... | 1994 | 8017695 |
| antiviral activity of interferon against transmissible gastroenteritis virus in cell culture and ligated intestinal segments in neonatal pigs. | segments of jejunum in 5 to 6 days old piglets were surgically ligated, inoculated with transmissible gastroenteritis virus (tgev) and 18 hours later the segments were fixed for histology or suspensions were prepared for plaque assay in swine testis (st) cell cultures to determine the yield of virus. when the virulent purdue strain of tgev was used, villous atrophy was seen and tgev antigen was demonstrated immunohistochemically in the villous enterocytes. the miller m6 strain of virus produced ... | 1994 | 8017030 |
| molecular characterization of attenuated vaccine strains of transmissible gastroenteritis virus. | previous studies in our laboratory demonstrated that 2 attenuated strains of transmissible gastroenteritis virus (tgev) contain deletions affecting messenger (m) rnas 2, 3, or 4. in this report, we have compared mrnas of four modified-live virus vaccines for tgev with the virulent miller pp3 isolate to determine whether any transcriptional patterns are shared among attenuated strains. using northern blot analysis, all vaccine viruses expressed mrnas indistinguishable in size from those of miller ... | 1994 | 8011775 |
| immunogenicity of the s protein of transmissible gastroenteritis virus expressed in baculovirus. | seven fragments of the spike (s) gene cdna of transmissible gastroenteritis virus (tgev), as well as the full length cdna, were cloned and expressed in baculovirus vectors. piglets were immunized with cells infected with the recombinant viruses. each of the recombinants induced tgev-specific antibodies detected in a fixed cell enzyme immunoassay. the amino terminal half of the s protein, containing all four major antigenic sites (a, b, c and d), and encoded by a 2.2 kb fragment of the s gene, in ... | 1994 | 7979998 |
| entry and release of transmissible gastroenteritis coronavirus are restricted to apical surfaces of polarized epithelial cells. | the transmissible gastroenteritis coronavirus (tgev) infects the epithelial cells of the intestinal tract of pigs, resulting in a high mortality rate in piglets. this study shows the interaction of tgev with a porcine epithelial cell line. to determine the site of viral entry, llc-pk1 cells were grown on permeable filter supports and infected with tgev from the apical or basolateral side. initially after plating, the virus was found to enter the cells from both sides. during further development ... | 1994 | 7966587 |
| evidence for a putative second receptor for porcine transmissible gastroenteritis virus on the villous enterocytes of newborn pigs. | aminopeptidase-n (apn) has been identified [b. delmas, j. gelfi, r. l'haridon, l. k. vogel, h. sjostrom, o. noren, and h. laude, nature (london) 357:417-420, 1992] as a major receptor for porcine transmissible gastroenteritis virus (tgev). binding of tgev to villous enterocytes from the jejuna of newborn pigs is saturable and at a higher level than that of binding of virus to newborn cryptal enterocytes or to enterocytes from older piglets (h. m. weingartl and j. b. derbyshire, vet. microbiol. 3 ... | 1994 | 7933108 |
| three new isolates of porcine respiratory coronavirus with various pathogenicities and spike (s) gene deletions. | three new isolates of porcine respiratory coronavirus (prcv) were isolated and partially characterized. these prcv isolates showed a selective tropism for respiratory tissue and were antigenically related to transmissible gastroenteritis virus. pcr amplification of the 5' half of the spike (s) genes of the three prcv isolates indicated that a large deletion, characteristic of prcv, was present. by using cdna probes specific for the transmissible gastroenteritis virus s gene, the pcr products wer ... | 1994 | 7929779 |
| determinants essential for the transmissible gastroenteritis virus-receptor interaction reside within a domain of aminopeptidase-n that is distinct from the enzymatic site. | the swine-specific coronavirus transmissible gastroenteritis virus (tgev) uses pig aminopeptidase-n (papn) as a cellular receptor. we showed that the human aminopeptidase-n (hapn) cannot substitute for papn in this respect, although the two enzymes have 80% amino acid sequence identity. in order to map the tgev binding site on papn, we constructed a series of apn cdna chimeras between papn and hapn and analyzed them for their capacity to confer infectivity. the region between residues 717 and 81 ... | 1994 | 7913510 |
| further characterization of aminopeptidase-n as a receptor for coronaviruses. | we recently reported that porcine aminopeptidase-n (papn) acts as a receptor for transmissible gastroenteritis virus (tgev). in the present work, we addressed the question of whether tgev tropism is determined only by the virus-receptor interaction. to this end, different non-permissive cell lines were transfected with the porcine apn cdna and tested for their susceptibility to tgev infection. the four transfected cell lines shown to express papn at their membrane became sensitive to infection. ... | 1993 | 7911642 |
| prevalence of infections with enzootic respiratory and enteric viruses in feeder pigs entering fattening herds. | the prevalence of infections with h1n1- and h3n2-influenza viruses, porcine respiratory coronavirus (prcv), transmissible gastroenteritis virus (tgev) and porcine epidemic diarrhoea virus (pedv) in feeder pigs shortly after their entry into fattening units was examined. ten groups of pigs with acute respiratory disease during the months september to october 1991 and seven groups of pigs with acute diarrhoea during the months february to march 1992 were investigated. on arrival in the fattening h ... | 1994 | 7900243 |
| pseudorabies and transmissible gastroenteritis: a serological survey in south africa. | two specific and sensitive, indirect enzyme-linked immunosorbent assays (elisas) utilizing a protein g-peroxidase conjugate were developed to detect antibodies to the pseudorabies virus (prv) and the transmissible gastroenteritis virus (tgev) in pig sera. sera from 5,337 pigs, obtained from various abattoirs in south africa, were tested with both elisas. no serological evidence of infection with either prv or tgev was found in any of the pigs tested. | 1994 | 7898899 |
| evaluation of rotavirus infection and diarrhea in iowa commercial pigs based on an epidemiologic study of a population represented by diagnostic laboratory cases. | group a, b, and c rotaviruses were identified in 9% (96/1,048) of pig fecal specimens submitted to the iowa state university veterinary diagnostic laboratory during 1987 and 1988. six of the rotaviruses were group b, 5 were group c, and the remaining 89% were group a. of the rotavirus cases with more than 1 serotype, 5 were multiple group a serotypes, 1 involved a group a and b serotype, and 1 included 2 group c serotypes. a retrospective epidemiologic evaluation of pig diarrhea in herds of orig ... | 1994 | 7858020 |
| complete sequence (20 kilobases) of the polyprotein-encoding gene 1 of transmissible gastroenteritis virus. | the entire nucleotide sequence of cloned cdnas containing the 5'-untranslated region and gene 1 of purdue-115 strain of transmissible gastroenteritis virus (tgev) was determined. this completes the sequence of the tgev genome, which is 28,579 nucleotides long. the gene 1 is composed of two large open reading frames, orf1a and orf1b, which contain 4017 and 2698 codons, respectively (stop excluded). a brief, three-codon-long orf is present upstream of orf1a. orf1b overlaps orf1a by 43 bases in the ... | 1995 | 7856095 |
| immunity to transmissible gastroenteritis virus and porcine respiratory coronavirus infections in swine. | despite the pioneering efforts to identify correlates of passive immunity to transmissible gastroenteritis virus (tgev), effective vaccines for the control of tge in suckling pigs have remained elusive. the initial concept of an enteromammary immunologic axis in monogastrics originated from studies of lactogenic immunity to tgev in swine. these studies revealed that infection of pregnant swine with virulent tgev stimulated high titers of siga antibodies in milk which correlated with protection o ... | 1994 | 7856068 |
| interaction of mouse hepatitis virus (mhv) spike glycoprotein with receptor glycoprotein mhvr is required for infection with an mhv strain that expresses the hemagglutinin-esterase glycoprotein. | in addition to the spike (s) glycoprotein that binds to carcinoembryonic antigen-related receptors on the host cell membrane, some strains of mouse coronavirus (mouse hepatitis virus [mhv]) express a hemagglutinin esterase (he) glycoprotein with hemagglutinating and acetylesterase activity. virions of strains that do not express he, such as mhv-a59, can infect mouse fibroblasts in vitro, showing that the he glycoprotein is not required for infection of these cells. the present work was done to s ... | 1995 | 7815557 |
| paracrine activities of porcine trophoblastic interferons. | interferon-gamma (ifn-gamma) and a type i ifn (spi ifn) are transiently coexpressed by trophoblastic cells of pig conceptuses at implantation between day 12 and day 20 of gestation. the local effects of these trophoblastic ifns were examined on endometrial cells and on trophoblast by measuring antiviral activity and the induction of (2',5')-oligoadenylate synthetase activity. trophoblastic vesicles were shown to be susceptible to infection by vesicular stomatitis virus and transmissible gastroen ... | 1994 | 7799312 |
| tropism and immunoprotection in transmissible gastroenteritis coronaviruses. | 1995 | 7796947 | |
| [lactogenic immunity and vaccinal protection in swine]. | 1995 | 7795689 | |
| mhv-a59 enters polarized murine epithelial cells through the apical surface but is released basolaterally. | coronaviruses have a marked tropism for epithelial cells. entry and release of the porcine transmissible gastroenteritis virus (tgev) is restricted to apical surfaces of polarized epithelial cells, as we have recently shown (j. w. a. rossen, c. p. j. bekker, w. f. voorhout, g. j. a. m. strous, a. van der ende, and p. j. m. rottier, 1994, j. virol. 68, 7966-7973). in this paper we analyze the interactions of mouse hepatitis coronavirus a59 (mhv-a59) with polarized murine kidney cells (mtal) grown ... | 1995 | 7793080 |
| evaluation of a blocking elisa using monoclonal antibodies for the detection of porcine epidemic diarrhea virus and its antibodies. | two blocking enzyme-linked immunosorbent assays (elisas) involving the use of monoclonal antibodies (mab) as capture and detecting agents and an indirect fluorescence test (ift) were used for the detection of porcine epidemic diarrhea virus (pedv) antigen or its antibodies. in the elisa for viral antigen detection, the blocking step is accomplished by incubation of fecal samples, in duplicate wells, with pedv-specific positive or negative serum, whereas in the elisa for antibody detection the bl ... | 1995 | 7779966 |
| molecular mimicry between fc receptor and s peplomer protein of mouse hepatitis virus, bovine corona virus, and transmissible gastroenteritis virus. | we have previously demonstrated molecular mimicry between the s peplomer protein of mouse hepatitis virus (mhv) and fc gamma r (fc gamma r). a monoclonal antibody (mab) to mouse fc gamma r (2.4g2 anti-fc gamma r mab), purified rabbit immunoglobulin, but not their f(ab')2 fragments, as well as mouse and rat igg, immunoprecipitated (1) recombinant s peplomer protein expressed by a vaccinia virus recombinant in human, rabbit, and mouse cells, and (2) natural s peplomer protein from cells infected w ... | 1995 | 7768529 |
| molecular cloning and sequence determination of the peplomer protein gene of feline infectious peritonitis virus type i. | cdna clones spanning the entire region of the peplomer (s) gene of feline infectious peritonitis virus (fipv) type i strain ku-2 were obtained and their complete nucleotide sequences were determined. a long open reading frame (orf) encoding 1464 amino acid residues was found in the gene, which was 12 residues longer than the orf of the fipv type ii strain 79-1146. the sequences of fipv type i and mainly -tpv type ii were compared. the homologies at the n- (amino acid residues 1-693) and c- (resi ... | 1995 | 7733820 |
| ontogeny of interferon alpha secreting cells in the porcine fetal hematopoietic organs. | we examined the ontogeny of ifn-alpha secreting cells (ifn-alpha sc) in different hematopoietic organs and blood of porcine fetuses at different stages of gestation. cells were induced to produce ifn-alpha by incubation with the coronavirus tgev and ifn-alpha sc were detected by elispot. a striking finding was that ifn-alpha sc could be detected in the fetal liver as early as at 26 days of gestation, i.e., during the first quarter of gestation, a period at which t-cell markers could not be detec ... | 1994 | 7721334 |
| sequence comparison of porcine respiratory coronavirus isolates reveals heterogeneity in the s, 3, and 3-1 genes. | four new porcine respiratory coronavirus (prcv) isolates were genetically characterized. subgenomic mrna patterns and the nucleotide sequences of the 5' ends of the s genes, the open reading frame (orf) 3/3a genes, and the orf 3-1/3b genes of these prcv isolates were determined and compared with those of other prcv and transmissible gastroenteritis virus (tgev) isolates. the s, orf 3/3a, and orf 3-1/3b genes are under intense study because of their possible roles in determining tissue tropism an ... | 1995 | 7707547 |
| localization of antigenic sites of the s glycoprotein of feline infectious peritonitis virus involved in neutralization and antibody-dependent enhancement. | the s glycoprotein of feline infectious peritonitis virus (fipv) has been shown to contain the antigenic sites responsible for eliciting both neutralization and antibody-dependent enhancement. to determine the region of s responsible, overlapping dna fragments spanning the entire s gene were cloned and expressed as fusion proteins by in vitro transcription and translation. fusion proteins containing relevant epitopes were identified by radioimmunoprecipitation with neutralizing and enhancing fip ... | 1995 | 7707508 |
| passive protection of piglets by recombinant baculovirus induced transmissible gastroenteritis virus specific antibodies. | sera of pigs immunized with parts of the transmissible gastroenteritis virus (tgev) spike (s) protein expressed by recombinant baculoviruses were tested, together with a tgev hyperimmune antiserum, for their abilities to protect three-day-old piglets against tgev infection. the piglets were infected with virulent tgev and the sera were given orally 3 h before infection, together with the virus, and every 6 h postinfection during the 30 h of the experiment. virus shedding was monitored by tgev is ... | 1995 | 7704846 |
| neutralization and fusion inhibition activities of monoclonal antibodies specific for the s1 subunit of the spike protein of neurovirulent murine coronavirus jhmv c1-2 variant. | the cleavage products of the spike (s) protein, the s1 and s2 subunits, of the highly neurovirulent murine coronavirus (mhv) jhmv c1-2 variant were identified by immunoprecipitation of virus-infected cell lysates after treatment with urea and 2-mercaptoethanol. by this method 14 monoclonal antibodies (mabs) raised against the s protein of the c1-2 variant were revealed to react with the s1 subunit and one with the s2 subunit. these 14 mabs were classified into the following three groups: (a) mab ... | 1993 | 7687650 |
| identification of antigenic sites mediating antibody-dependent enhancement of feline infectious peritonitis virus infectivity. | we have previously demonstrated antibody-dependent enhancement of feline infectious peritonitis virus (fipv) infection of macrophages using both virus-specific antisera and monoclonal antibodies (mabs) to the spike (s) protein of fipv. to increase our understanding of this phenomenon, six representative mabs from a previously documented group of 12 enhancing mabs were used to identify epitopes that mediate antibody-dependent enhancement of fipv infectivity. analysis of the results of kinetics-ba ... | 1993 | 7682252 |
| investigation of the control of coronavirus subgenomic mrna transcription by using t7-generated negative-sense rna transcripts. | the subgenomic mrnas of the coronavirus transmissible gastroenteritis virus (tgev) are not produced in equimolar amounts. we have developed a reporter gene system to investigate the control of this differential subgenomic mrna synthesis. transcription of mrnas by the tgev polymerase was obtained from negative-sense rna templates generated in situ from dna containing a t7 promoter. a series of gene cassettes was produced; these cassettes comprised the reporter chloramphenicol acetyltransferase (c ... | 1995 | 7666523 |
| lactogenic immunity and milk antibody isotypes to transmissible gastroenteritis virus in sows exposed to porcine respiratory coronavirus during pregnancy. | passive protection provided by sows inoculated with the virulent miller strain of transmissible gastroenteritis virus (tgev), or the isu-1 strain of porcine respiratory coronavirus (prcv), or both was evaluated in nursing pigs challenge exposed with virulent tgev. four sows (group b) were inoculated with prcv oronasally twice at 4 and 2 weeks before parturition; 1 sow (group c) was inoculated similarly, but in 2 subsequent pregnancies; and 2 sows (group d) were oronasally primed with prcv at 4 w ... | 1995 | 7653882 |
| quantification of individual subgenomic mrna species during replication of the coronavirus transmissible gastroenteritis virus. | a biotinylated-oligonucleotide-based method was used to isolate the subgenomic mrnas of the coronavirus transmissible gastroenteritis virus (tgev) to investigate the amounts of the mrnas produced at early, middle and late times in the replication cycle. tgev mrna 6, which encodes the n protein, was observed to be the most abundant species throughout the replication cycle. the ratios of mrna 6 to the other mrnas were 1:0.11 (mrna 2), 1:0.16 (mrnas 3 and 4) and 1:0.37 (mrna 5) at 12 h post-infecti ... | 1995 | 7653093 |
| antiviral action of interferon-alpha against porcine transmissible gastroenteritis virus. | swine testis (st) cell cultures were treated with various doses of recombinant human interferon-alpha 2a (ifn), and assayed for 2',5' oligoadenylate synthetase (2-5 a synthetase) activity. treatment with 100 or 1000 units/ml of ifn resulted in increased 2-5 a synthetase activity, but there was no significant response to 1 unit/ml of ifn. titres of porcine transmissible gastroenteritis virus (tgev) were reduced between 6 and 15 hours post-infection in st cells treated with 1000 or 2500 units/ml o ... | 1995 | 7653029 |
| membrane protein molecules of transmissible gastroenteritis coronavirus also expose the carboxy-terminal region on the external surface of the virion. | the binding domains of four monoclonal antibodies (mabs) specific for the m protein of the pur46-mad strain of transmissible gastroenteritis coronavirus (tgev) have been located in the 46 carboxy-terminal amino acids of the protein by studying the binding of mabs to recombinant m protein fragments. immunoelectron microscopy using these mabs demonstrated that in a significant proportion of the m protein molecules, the carboxy terminus is exposed on the external surface both in purified viruses an ... | 1995 | 7636969 |
| a transmissible gastroenteritis coronavirus nucleoprotein epitope elicits t helper cells that collaborate in the in vitro antibody synthesis to the three major structural viral proteins. | four strong t cell epitopes have been identified studying the blastogenic response of lymphocytes from haplotype-defined transmissible gastroenteritis virus (tgev) immune miniswine to sixty-one 15-mer synthetic peptides. three of these epitopes are located on the nucleoprotein (n46, amino acids 46 to 60; n272, amino acids 272 to 286; and n321, amino acids 321 to 335), and one on the membrane protein (m196, amino acids 196 to 210). n321 peptide induced the highest t cell response and was recogniz ... | 1995 | 7571447 |
| site-specific alteration of transmissible gastroenteritis virus spike protein results in markedly reduced pathogenicity. | the pathogenicity of neutralization-resistant mutants of the enteric coronavirus transmissible gastroenteritis virus (tgev) was examined in the newborn piglet. the parental virus (purdue-115 strain), as well as several mutants selected using monoclonal antibodies (mabs) directed to antigenic sites a and b, caused an acute enteritis with 100% mortality. by contrast, most of the site d (mab 40.1) mutants exhibited a strongly reduced enteropathogenicity, leading to the survival of animals inoculate ... | 1995 | 7561760 |
| frequency of interferon-alpha-secreting blood leukocytes in irradiated and bone-marrow-grafted pigs. | the effects of irradiation were studied on porcine interferon-alpha (ifn-alpha) secreting cells (ifn-alpha sc). ifn-alpha sc were characterized by an elispot assay on non-adherent pbmc following incubation with the transmissible gastroenteritis coronavirus. in vitro irradiation of pbmc was followed by a decrease in the number of ifn-alpha sc while ifn-gamma production and cell viability were not affected. these data indicate that porcine ifn-alpha sc are relatively radiosensitive. indeed, the fr ... | 1995 | 7550400 |