PMID(sorted ascending)
pattern of transcription of the genome of equine infectious anemia virus.the pattern of expression of the equine infectious anemia virus (eiav) genome in a persistently infected canine cell line was determined. five eiav-specific transcripts (8.2, 5.0, 4.0, 2, and 1.8 kilobases [kb]) were detected by using subgenomic restriction enzyme fragments of eiav dna and eiav-specific oligonucleotides as probes. the 8.2-kb mrna could be shown to represent viral genomic rna, whereas the smaller transcripts were generated by splicing events. evidence was obtained that indicated ...19902157066
analysis of antibody reactivities in elisa using protein blots as antigen substrates: s-elisa.we describe here a novel immunoassay procedure, designated strip-elisa (s-elisa), in which specific antigens are purified by sds-page, transferred to support membranes, and utilized in situ as substrate in routine elisa procedures. using two different lentivirus systems, simian immunodeficiency virus and equine infectious anemia virus, we demonstrate the utility of s-elisa for screening hybridoma supernatants during production of monoclonal antibodies and for the dissection of polyclonal antibod ...19902157766
identification of sequences encoding the equine infectious anemia virus tat gene.equine infectious anemia virus (eiav), a lentivirus, encodes a trans-activator (tat) which stimulates gene expression directed by the viral long terminal repeat (ltr). this function has been previously shown by us and others to be encoded by sequences within the middle region of the eiav genome in which two short open reading frames, s1 and s2, reside. in the present study, by using in vitro mutagenesis, we show that disruption of s1, but not s2, completely abolished trans-activation. addition o ...19902158694
equine infectious anemia virus (eiav) humoral responses of recipient ponies and antigenic variation during persistent infection.three ponies were inoculated with plasma containing 10(4.8) tcid50 of equine infectious anemia virus (eiav) and observed for 165 to 440 days. each pony developed a febrile response within 3 weeks of infection during which a plasma viremia greater than or equal to 10(3.5) tcid50/ml was observed. analyses of four isolates from sequential febrile episodes in a single pony were conducted by two-dimensional tryptic peptide maps and with monoclonal antibodies in immunoblots. structural and antigenic a ...19902162160
cloning and characterization of cdnas encoding equine infectious anemia virus tat and putative rev proteins.we isolated and characterized six cdna clones from an equine infectious anemia virus-infected cell line that displays a rev-defective phenotype. with the exception of one splice site in one of the clones, all six cdnas exhibited the same splicing pattern and consisted of four exons. exon 1 contained the 5' end of the genome; exon 2 contained the tat gene from mid-genome; exon 3 consisted of a small section of env, near the 5' end of the env gene; and exon 4 contained the putative rev open readin ...19902164593
synthesis and processing of the transmembrane envelope protein of equine infectious anemia virus.the transmembrane (tm) envelope protein of lentiviruses, including equine infectious anemia virus (eiav), is significantly larger than that of other retroviruses and may extend in the c-terminal direction 100 to 200 amino acids beyond the tm domain. this size difference suggests a lentivirus-specific function for the long c-terminal extension. we have investigated the synthesis and processing of the eiav tm protein by immune precipitation and immunoblotting experiments, by using several envelope ...19902164597
comparative evaluation of the agar gel immunodiffusion test and two commercial elisa kits for the serodiagnosis of equine infectious anemia.selected sets of serum samples of horses were tested blindly in a comparative investigation for antibodies against equine infectious anemia (eia) virus. three commercial kits were used, a well-established agar-gel immuno-diffusion kit which our laboratory has been using routinely for 14 years on one hand, a competitive elisa kit (celisa) and a non-competitive elisa kit on the other hand. the american eia reference laboratory in ames cotested 56 serum samples with the same 3 products, with highes ...19902169689
selection against cpg dinucleotides in lentiviral genes: a possible role of methylation in regulation of viral expression.extremely low frequencies of cpg dinucleotides are found in the genomes of the lentivirus subfamily of retroviruses, including the human, simian and feline immunodeficiency viruses (hiv1, hiv2, siv, and fiv, respectively), equine infectious anemia virus (eiav), and the ovine lentivirus, visna. the occurrence of cpg dinucleotides is greater in the 2-3 (ncg) than in the 1-2 (cgn) codon-defined frame, as well as in the gag and env genes, compared to the more conserved pol gene. these differences su ...19902170945
distribution of equine infectious anemia in equids in southeastern united states.state veterinarians in 11 southeastern states completed a questionnaire designed to determine the proportion of equids in the region that were seropositive for equine infectious anemia (eia). cases of eia were diagnosed in each of the states surveyed. distinct geographic clusters of cases were apparent in tennessee and kentucky adjacent to the mississippi river, in the piedmont of north carolina at the virginia border, in north central georgia, and throughout the florida peninsula. it is suggest ...19902173692
equine infectious anemia virus derived from a molecular clone persistently infects horses.a full-length molecular clone of equine infectious anemia virus (eiav) was isolated from a persistently infected canine fetal thymus cell line (cf2th). upon transfection of equine dermis cells, the clone, designated cl22, yielded infectious eiav particles (cl22-v) that replicated in vitro in both cf2th cells and an equine dermis cell strain. horses infected with cl22-v developed an antibody response to viral proteins and possessed viral dna in peripheral blood mononuclear cells, as determined by ...19902173767
the open reading frame orf s3 of equine infectious anemia virus is expressed during the viral life cycle.the genome of equine infectious anemia virus (eiav) contains several small open reading frames (orfs), the importance of which in the development of the virus is not clear. we investigated the possibility that the largest of these orfs (orf s3) is expressed during the course of the viral infection. the orf s3 information was expressed in escherichia coli, and the antigen was used to raise monospecific antiserum. a 20-kda protein expressed in cells producing eiav was identified as the gene produc ...19902173797
topoisomerase i activity associated with human immunodeficiency virus (hiv) particles and equine infectious anemia virus the present study, we found a topoisomerase i (topo i) activity in two strains of human immunodeficiency virus type 1 (hiv-1) and equine infectious anemia virus (eiav) particles. the topo i activity was located in the eiav cores and differed from the cellular topo i in its ionic requirements and response to atp, indicating that these were two distinct forms of this enzyme. topo i activity was removed from the viral lysates and viral cores by anti-topo i antiserum. the only protein recognized ...19902174357
immunopathogenesis of equine infectious anemia lentivirus disease.virus replication and subsequent viremia are clearly correlated with clinical disease in eiav infected horses. termination of viremia is the result of specific immune responses. recurrences of viremia are associated with antigenic variation of neutralization-sensitive epitopes. immunosuppression experiments indicate that the eventual control of eiav and development of carriers is mediated by the immune system. even though the immune response to eiav has a protective effect, immune responses also ...19902178127
structure and expression of the equine infectious anemia virus transcriptional trans-activator (tat).equine infectious anemia virus (eiav) encodes a tat gene which is closely related to the trans-activators encoded by the human and simian immunodeficiency viruses. nucleotide sequence analysis of eiav cdna clones revealed that the tat message is composed of three exons; the first two encode tat and the third may encode rev.. interestingly, eiav tat translation is initiated at a non-aug codon in the first exon of the message, perhaps allowing an additional level of gene regulation. the deduced am ...19902178129
equine infectious anemia: prospects for control.equine infectious anemia has been managed in most countries by the imposition of testing and quarantine regulations. in the united states, about 700,000 of the more than 7,000,000 horses are tested annually. as long as the status of greater than 90% of the horse population remains unknown and horses are transported and congregate in a relatively unrestricted manner, eia will continue to exact its toll. therefore, it is incumbent on the scientific community to continue to develop and refine pract ...19902178130
studies on the regulation and pattern of expression of the equine infectious anemia virus genome. 19902178131
the viral hypothesis of alzheimer's disease. absence of antibodies to evaluate the possible role of lentiviruses in alzheimer's disease we searched for cross-reactive antibodies to human immunodeficiency virus type 1, caprine arthritis encephalitis virus, and equine infectious anemia virus in alzheimer's disease, down's syndrome, and related dementing illnesses in serum samples and cerebrospinal fluid samples and in healthy age-matched control subjects. no cross-reactive antibodies were detected.19902302089
human t-cell lymphotropic virus type iii: immunologic characterization and primary structure analysis of the major internal protein, p24.the major internal structural protein of human t-cell lymphotropic virus type iii (htlv-iii), a virus etiologically implicated in acquired immunodeficiency syndrome (aids), was purified to homogeneity. this 24,000-molecular-weight protein (p24) was shown to lack immunologic cross-reacting antigenic determinants shared by other known retroviruses, including htlv-i and htlv-ii, with the exception of equine infectious anemia virus (eiav). a broadly reactive competition immunoassay was developed in ...19852410630
reversible staining and peptide mapping of proteins transferred to nitrocellulose after separation by sodium dodecylsulfate-polyacrylamide gel electrophoresis.we describe a staining technique, using ponceau s in very mild conditions, by which proteins can be visualized on nitrocellulose replicas without being permanently fixed to the membrane itself, thus allowing subsequent procedures such as immunoblotting or preparative elution of the proteins to be performed. this staining technique can detect 250 to 500 ng protein, which is essentially the same sensitivity seen for coomassie blue staining of proteins on nitrocellulose. the ponceau s staining tech ...19862429581
shedding and interspecies type sero-reactivity of the envelope glycopolypeptide gp120 of the human immunodeficiency virus.two glycopolypeptides with molecular weights 160,000 and 120,000 (gp120) are regularly recognized by human immunodeficiency virus (hiv)-specific antisera in lysates of cells persistently infected with hiv. in the present study, gp120 was characterized as the major envelope glycopolypeptide of hiv. gp120 was identified as the external viral glycoprotein by radiosequencing and by its presence in purified virus. however gp120 was predominantly shed as a soluble protein into the culture fluid. furth ...19862431105
lentivirus genomic organization: the complete nucleotide sequence of the env gene region of equine infectious anemia virus.the nucleotide sequence of the envelope (env) gene region of equine infectious anemia virus (eiav), a member of the lentivirus subfamily of retroviruses, has been determined from a clone of integrated proviral dna for which the gag and pol sequences have been reported previously. the env gene is 859 codons in length and the sequence reported here is consistent with the published biochemical properties of eiav glycoproteins. the env gene region of eiav shares considerable structural similarities ...19862431539
is scrapie prp 27-30 related to aids virus? 19872433599
hybridoma cell lines secreting monoclonal antibodies against equine infectious anemia virus.a monoclonal anti-equine infectious anemia virus (anti-eiav) antibody (1b15) has been generated by fusion of x63 ag 8.653 myeloma cells and spleen cells from mice hypersensitized with viral antigen p29. ouchterlony double-diffusion analysis indicated that antibody 1b15 is of the igg class. the specificity of the immune reaction for p29 was confirmed by cross-over immunoelectrophoresis and disc-gel electrophoresis. mab 1b15 was used to devise a solid-phase 'capture' ria for eiav-p29 antigen. the ...19872435751
lav/htlv-iii gag gene product p24 shares antigenic determinants with equine infectious anemia virus but not with visna virus or caprine arthritis encephalitis virus.antigenic cross-reactivity of the human acquired immunodeficiency disease syndrome virus lav/htlv-iii with the lentiviruses visna virus, caprine arthritis encephalitis virus (caev), and equine infectious anemia virus (eiav) was determined with indirect enzyme-linked immunosorbent assays, immunoblot analysis, and virus-specific polyclonal antisera. nonreciprocal cross-reactivity was seen between the gag gene products p24 of lav/htlv-iii and p28 of eiav. reciprocal cross-reactivity was seen betwee ...19862438251
antigenic analysis of equine infectious anemia virus (eiav) variants by using monoclonal antibodies: epitopes of glycoprotein gp90 of eiav stimulate neutralizing antibodies.monoclonal antibodies produced against the prototype cell-adapted wyoming strain of equine infectious anemia virus (eiav), a lentivirus, were studied for reactivity with the homologous prototype and 16 heterologous isolates. eighteen hybridomas producing monoclonal antibodies (mabs) were isolated. western blot (immunoblot) analyses indicated that 10 were specific for the major envelope glycoprotein (gp90) and 8 for the transmembrane glycoprotein (gp45). four mabs specific to epitopes of gp90 neu ...19872442410
role of the host immune response in selection of equine infectious anemia virus variants.equine infectious anemia virus was isolated from peripheral blood leukocytes collected during two early febrile cycles of an experimentally infected horse. rnase t1-resistant oligonucleotide fingerprint analyses indicated that the nucleotide sequences of the isolates differed by approximately 0.25% and that the differences appeared randomly distributed throughout the genome. serum collected in the interval between virus isolations was able to distinguish the isolates by membrane immunofluorescen ...19872446008
antigenic mapping of the envelope proteins of equine infectious anemia virus: identification of a neutralization domain and a conserved region on glycoprotein 90.monoclonal antibodies (mcabs) were used to dissect the antigenic sites of the surface glycoproteins of the prototype cell-adapted wyoming strain of equine infectious anemia virus (eiav). serologic reactivities of these mcabs were determined by elisa, additive elisa, competitive elisa, and western blot assays. the results indicated that antigenic reactivity of gp90 was localized on at least four distinct epitopes, two of which were important in neutralization. our studies also revealed that these ...19882450529
change in host cell tropism associated with in vitro replication of equine infectious anemia virus.similar to other human and animal lentiviruses, equine infectious anemia virus (eiav) is detectable in vivo in cells of the monocyte-macrophage lineage. owing to their short-lived nature, horse peripheral blood macrophage cultures (hmc) are rarely used for in vitro propagation of eiav, and equine dermal (ed) or kidney cell cultures, which can be repeatedly passed in vitro, are used in most studies. however, wild-type isolates of eiav will not grow in these cell types without extensive adaptation ...19892470916
animal lentivirus replication and reverse transcriptase inhibitors.we summarize the pathogenesis of animal lentiviruses (visna-maedi virus, caprine arthritis and encephalitis virus, and equine infectious anemia virus), which have raised considerable interest since the discovery of human lentiviruses. the human lentiviruses possess structural, genetic, and clinical properties similar to those of animal lentiviruses. we describe the different mechanisms of and the principal work on reverse transcriptase inhibitors of animal lentiviruses, such as hpa-23, phosphono ...19892479076
qualitative analyses of cellular immune functions in equine infectious anemia show homology with aids.equine infectious anemia (eia) is a disease caused by a lymphocytotropic lentivirus which belongs to the same subfamily as hiv. because of the very close relationship of their predicted gag and pol gene products and similarities in clinical manifestations of the disease, eia served as a model to study immunological events involved in the host defence against lymphocytotropic viral infections. the existence of antibody dependent cell-mediated cytotoxicity against autologous eia virus infected lym ...19892523215
[a western blot test for the serological diagnosis of equine infectious anemia].after electrophoretic separation in sds-page structural proteins of the virus of equine infectious anemia (eia) were easily blotted by the semi-dry-blotting method onto nitrocellulose filters. strips of these filters were used for antibody demonstration, and positive reactions thereof were intensified by a biotin-avidin-peroxidase system. sensitivity of this system was so high as to allow readable interpretation of bands up to the dilution of 1:6,400 of a strongly positive serum. frequently this ...19892538978
the preparation and biochemical characterization of intact capsids of equine infectious anemia virus.capsids of equine infectious anemia virus have been isolated as cone-shaped particles 60 x 120 nm in size. detergent treatment of whole virus followed by two cycles of rate-zonal centrifugation in ficoll produces these capsids in a yield of approximately 10%. the major protein components are the gag-encoded p11 nucleocapsid protein and p26 capsid protein, which are present in equimolar amounts. substantial cleavage of p11 to p6 and p4 can be observed under conditions where the viral protease pac ...19892541703
development of an enzyme-linked immunosorbent assay for equine infectious anemia virus detection using recombinant provide more sensitive and convenient methods for the detection of equine infectious anemia virus (eiav), we developed an enzyme-linked immunosorbent assay (elisa) employing the eiav gag precursor (pr55gag) produced by using recombinant dna techniques. the antigenic reactivity of the recombinant eiav pr55gag was found to be equivalent to that of the virion p24gag and elicited high-titered antiserum in rabbits. when a large number of horse sera were analyzed for the presence of antibodies to e ...19892546970
occurrence of equine infectious anaemia in india. 19892547265
feline immunodeficiency virus infection.feline immunodeficiency virus (fiv) (formerly feline t-lymphotropic lentivirus or ftlv) was first isolated from a group of cats in petaluma, california in 1986. the virus is a typical lentivirus in gross and structural morphology. it replicates preferentially but not exclusively in feline t-lymphoblastoid cells, where it causes a characteristic cytopathic effect. the major structural proteins are 10, 17 (small gag), 28 (major core), 31 (endonuclease?), 41 (transmembrane?), 52 (core precursor pol ...19892549690
analysis of regulatory elements of the equine infectious anemia virus and caprine arthritis-encephalitis virus long terminal repeats.we analyzed the equine infectious anemia virus (eiav) long terminal repeat (ltr) for sequences that influence its promoter activity and ability to be trans-activated by the eiav tat gene product. a series of ltr deletion mutants and recombinants between ltr and simian virus 40 (sv40) regulatory sequences were used for these studies. we were able to identify the eiav promoter region and showed that sequences within the u3 region significantly inhibited ltr-directed transcription. however, when pl ...19892552171
localization of conserved and variable antigenic domains of equine infectious anemia virus envelope glycoproteins using recombinant env-encoded protein fragments produced in escherichia coli.previous characterizations of equine infectious anemia virus (eiav) glycoprotein variation by dna sequence analysis and epitope mapping using monoclonal antibodies (mabs) have revealed the presence of conserved and variable regions within the eiav env gene. to extend these studies, fragments of the eiav envelope proteins gp90 and gp45 were expressed in escherichia coli and used in western blot analysis with a diverse panel of equine immune sera to identify antigenic segments. all sera from eiav- ...19892552661
viral dna in horses infected with equine infectious anemia virus.the amount and distribution of viral dna were established in a horse acutely infected with the wyoming strain of equine infectious anemia virus (eiav). the highest concentration of viral dna were found in the liver, lymph nodes, bone marrow, and spleen. the kidney, choroid plexus, and peripheral blood leukocytes also contained viral dna, but at a lower level. it is estimated that at day 16 postinoculation, almost all of the viral dna was located in the tissues, with the liver alone containing ab ...19892555550
progress in vaccines against aids. 19892555922
cross-neutralizing and subclass characteristics of antibody from horses with equine infectious anemia virus.antibody responses in horses with equine infectious anemia virus (eiav) were examined to determine their cross-neutralizing capacity. antibodies induced by infection with any of six biologically cloned variants of eiav cross-neutralized multiple variants from the group. anti-eiav antibody was found in both the igg and igg(t) subclasses in plasmas with virus-neutralizing activity and the majority of antiviral antibody was of the igg(t) subclass. depletion of igg(t) did not increase the neutraliza ...19892559537
comparison of diagnostic tests for the detection of equine infectious anemia antibody.two diagnostic tests are approved for detecting antibody to equine infectious anemia virus: the agar-gel immunodiffusion (agid) test and the competitive enzyme-linked immunosorbent assay (elisa). a total of 420 sera from national veterinary services laboratories check sets were tested with the agid and competitive elisa. a 100% correlation was obtained. the agid and competitive elisa were further used to test difficult samples with low levels of equine infectious anemia antibody (weak positives) ...19892562211
nucleotide sequence analysis of feline immunodeficiency virus: genome organization and relationship to other lentiviruses.we determined the complete nucleotide sequence of an infectious proviral molecular clone (fiv-14) of the feline immunodeficiency virus (fiv). fiv-14 has a genome organization similar in complexity to other lentiviruses. in addition to three large open reading frames representing the gag, pol, and env genes, at least four small open reading frames are present in the pol-env intergenic, env, and env-3' long terminal repeat regions. nucleotide and deduced amino acid sequence alignments of the fiv c ...19892813380
the visna virus genome: evidence for a hypervariable site in the env gene and sequence homology among lentivirus envelope proteins.the complete nucleotide sequence of the visna virus 1514 genome was determined. our sequence confirms the relationship of visna virus and other lentiviruses to human immunodeficiency virus (hiv) both at the level of sequence homology and of genomic organization. sequence homology is shown to extend to the transmembrane proteins of lentivirus env genes; this homology is strongest in the extracellular domain, suggesting that close structural and functional similarities may also exist among these e ...19872824836
localization of sequences responsible for trans-activation of the equine infectious anemia virus long terminal repeat.we used the escherichia coli chloramphenicol acetyltransferase gene (cat) to study sequences that influence expression of the equine infectious anemia virus (eiav) genome. the eiav long terminal repeat (ltr) directed cat activity in a canine cell line, but at levels much lower than those achieved with other eucaryotic viral promoters. in the same cells infected with eiav or cotransfected with molecularly cloned eiav genomic dna, ltr-directed activity was markedly enhanced. comparison of cat mrna ...19882824840
antigenic variation and lentivirus persistence: variations in envelope gene sequences during eiav infection resemble changes reported for sequential isolates of hiv.the extent and nature of genomic variation among nine antigenically distinct eiav isolates recovered during sequential clinical episodes from two experimentally infected ponies were examined by restriction fragment analysis and nucleotide sequencing. only minor variations in restriction enzyme patterns were observed among the viral genomes. in contrast, env gene sequences of four isolates from one pony revealed numerous clustered base substitutions. divergence in env gene nucleotide and deduced ...19872825406
bloodmeal residues on mouthparts of tabanus fuscicostatus (diptera: tabanidae) and the potential for mechanical transmission of pathogens. 19872826787
rapid detection of viral-specific antibodies by enzyme-linked immunosorbent assay (elisa).the development of three separate rapid elisas for detecting antibodies in host serum to three different viruses is described. these include: 1. a direct antigen assay using enzyme labelled anti-canine ig for detecting antibodies to canine parvovirus, 2. a competitive elisa using a feline infectious peritonitis virus-specific monoclonal antibody labelled with enzyme, and 3. a competitive elisa using an equine infectious anemia virus-specific monoclonal antibody and enzyme labelled antigen, p. 26 ...19872829416
antigenic variation of equine infectious anemia virus as detected by virus neutralization. brief report.the antigenic structure of 16 viruses isolated from four horses which were inoculated with a clone of equine infectious anemia (eia) virus was compared by the neutralization test. the antigenic structure of viruses isolated after development of neutralizing antibody differed from virus to virus. back mutation of the antigenic structure was also demonstrated by serial passage of the virus in horses. these results suggest that eia virus is subject to multidirectional antigenic variation. the possi ...19882829799
lentivirus antigen purification and characterization: isolation of equine infectious anemia virus gag and env proteins in one step by reverse phase hplc and application to human immunodeficiency virus glycoproteins.we describe here a one step hplc technique for purifying the four gag proteins (p26, p15, p11 and p9) and two env glycoproteins (gp90 and gp45) from purified equine infectious anemia virus (eiav), a member of the lentivirus subfamily of retroviruses. the purification procedure employs a reverse-phase phenyl radial-pak cartridge contained in a high pressure radial compression chamber in which a shallow, multistep acetonitrile gradient is applied at ambient temperatures. the purified proteins are ...19882836462
antigenic variation in lentiviral diseases. 19882838047
characterization of the serological cross-reactivity between glycoproteins of the human immunodeficiency virus and equine infectious anaemia virus.the reported serological relatedness between the major glycoproteins of human immunodeficiency virus (hiv gp120) and equine infectious anaemia virus (eiav gp90) was examined using purified antigens in radioimmunoprecipitation (rip), radioimmunoassay (ria) and immunoblot assays with reference serum from acquired immunodeficiency syndrome (aids) patients, an anti-gp120 goat serum and eiav-infected horse serum. to assess the contributions of glycoprotein oligosaccharide and peptide components to an ...19882839603
identification of gag precursor of equine infectious anaemia virus with monoclonal antibodies to the major viral core protein, p26.monoclonal antibodies (mabs) against the major core protein p26 of equine infectious anaemia virus (eiav) were produced and characterized. sensitive enzyme-linked immunosorbent assay and western blot immunoassay were employed to confirm the specificity of these mabs. western blot analysis also indicated that mabs to p26 reacted with another eiav protein of 55,000 apparent mr (designated here as pr55gag) present in density gradient-purified virus preparations. rabbit antiserum prepared against p2 ...19882839604
immune responses are required to terminate viremia in equine infectious anemia lentivirus infection.six normal and four immunodeficient horses were injected with a cloned variant of equine infectious anemia virus (eiav). the six normal horses had detectable eiav in their plasma by 7 days postinjection. during their primary viremic episode, which was accompanied by fever and anemia, maximum titers of eiav in plasma ranged from 10(3.8) to 10(4.8) 50% tissue culture infective doses per ml. all six normal horses cleared detectable virus from their plasma by 21 to 35 days after injection. horses wi ...19882839723
cis- and trans-acting regulation of gene expression of equine infectious anemia virus.deletion analysis of the equine infectious anemia virus long terminal repeat revealed that sequences responsive to virus-specific transactivation are located within the region spanning the transcriptional start site (-31 to +22). in addition, an active exon of a trans-acting factor (tat) was identified downstream of pol and overlapping env (nucleotides 5264 to 5461). activation by tat is accompanied by an increase in the steady-state levels of mrna directed by the equine infectious anemia virus ...19882841502
eiav genomic organization: further characterization by sequencing of purified glycoproteins and cdna.nucleotide sequence analyses of two different proviral clones of equine infectious anemia virus (eiav), designated lambda 12 (k. rushlow et al., 1986, virology 155, 309-321) and 1369 (t. kawakami et al., 1987, virology 158, 300-312), indicate significant differences in the organization of two critical regions of the viral genome, i.e., in the short open reading frames in the pol-env intergenic region and in the 5'-end of the env gene. to determine the correct structure of the eiav genome, we hav ...19882841805
the lentiviruses: maedi/visna, caprine arthritis-encephalitis, and equine infectious anemia. 19882843016
a perspective on equine infectious anemia with an emphasis on vector transmission and genetic analysis. 19882847392
a propagating epizootic of equine infectious anemia on a horse epizootic of equine infectious anemia (eia) involved 35 horses on a farm in south georgia. during a 126-day period, 21 of these horses became seropositive for eia. after the initial diagnosis in july, the horses were tested every 7 to 10 days. at least one additional horse was found to be seropositive on each testing day. as soon as they were determined to be seropositive, the horses were removed from the herd and sent to slaughter. the removal of the seropositive horses, however, did not sto ...19882848789
equine infectious anemia virus: immunopathogenesis and persistence.equine infectious anemia (eia) is a chronic, relapsing infectious disease of horses caused by a nononcogenic retrovirus. virus persists in infected animals for life and can be reliably detected by serologic tests that measure levels of antibody to the major structural protein of the virus. periodic virus replication in macrophages leads to an immunologically mediated acute disease characterized primarily by severe anemia. recrudescence of acute eia is the result of antigenic variation of the sur ...19852984759
prospective study of progeny of inapparent equine carriers of equine infectious anemia virus.progeny of a band of horses, positive by the agar-gel immunodiffusion (agid) test for equine infectious anemia (eia) antibody, were observed through their weaning over a 4-year period. sentinels (agid test-negative) were allowed to mingle with eia-infected mares and their foals in pasture situations in an area with high populations of potential vectors. of 27 adult sentinels, 8 (30%) seroconverted in annual rates ranging from 0% to 75%. in contrast, only 2 of 31 (6%) foals weaned became infected ...19852988379
nucleotide sequence evidence for relationship of aids retrovirus to lentiviruses.lentiviruses are a subfamily of retroviruses which have been aetiologically linked to the induction of arthritis, encephalitis, progressive pneumonia and slow neurological diseases in certain species. relatively little is known about their genome structure, mechanisms of pathogenesis or evolutionary relationships with other retroviral subfamilies. in an effort to understand better the mechanisms by which these viruses induce such a variety of chronic diseases, we have molecularly cloned and phys ...19852995822
lymphadenopathy-associated virus: from molecular biology to pathogenicity.recent data indicate that the lymphadenopathy-associated virus (lav) is morphologically similar to animal lentiviruses, such as equine infectious anemia and visna viruses. this finding, together with the cross-reactivity of the core proteins of lav with those of the equine infectious anemia virus and a similarity in genome structure and biological properties, allows lav to be placed in the retroviral subfamily of lentivirinae. molecular data indicate a high degree of genetic variation of the vir ...19852996400
rapid solid-phase radioimmunoassay for detection of equine infectious anemia viral antigen and antibodies: parameters involved in standardization.solid-phase radioimmunoassays (spria) are described for the detection of equine infectious anemia (eia) viral antigen and antibodies. protein-antigen p29 currently used in the agar-gel immunodiffusion (agid) test was used as antigen in the spria. rabbit sera selected from positive agid test data were used to standardize the method. briefly, wells of flexible microtitre plates coated with antigen were incubated with antiserum followed by a secondary labelled antibody. the radioactivity remaining ...19853001113
rapid emergence of novel antigenic and genetic variants of equine infectious anemia virus during persistent infection.previous results from our laboratory have demonstrated that equine infectious anemia virus displays structural variations in its surface glycoproteins and rna genome during passage and chronic infections in experimentally infected shetland ponies (montelaro et al., j. biol. chem. 259:10539-10544, 1984; payne et al., j. gen. virol. 65:1395-1399, 1984). the present study was undertaken to obtain an antigenic and biochemical characterization of equine infectious anemia virus isolates recovered from ...19863001367
equine infectious anemia virus gag and pol genes: relatedness to visna and aids virus.comparison of htlv-iii, the putative aids virus, with other related viruses, may help to reveal more about the origin of aids in humans. in this study, the nucleotide sequence of the gag and pol genes of an equine infectious anemia virus (eiav) proviral dna clone was determined. the sequence was compared with that of htlv-iii and of visna, a pathogenic lentivirus of sheep. the results show that these viruses constitute a family clearly distinct from that of the type c viruses or the blv-htlv-i a ...19863003905
the persistent infection of a canine thymus cell line by equine infectious anaemia virus and preliminary data on the production of viral antigens.equine infectious anaemia virus (eiav) was adapted to the cf2th cell line, a heterologous malignant line from canine thymus. a persistent infection was monitored for 100 serial passages by demonstrating the presence of virus and viral antigens at each 10th passage by electron-microscopy, immunodiffusion and immunofluorescence. chromosome analysis of eiav-infected cells indicated they had a karyotype resembling the control cells of similar passage history. virus-infected cells, grown in roller cu ...19863018020
comparison of glycoproteins by two-dimensional mapping of glycosylated peptides.we describe here a two-dimensional mapping procedure which is capable of resolving glycopeptides isolated by lectin affinity chromatography from radioiodinated tryptic digests of glycoproteins. glycopeptide maps were successfully produced for the model proteins alpha 1-acid glycoprotein and fetuin, as well as for the two surface glycoproteins gp90 and gp45 from equine infectious anemia virus (eiav). differences were detected in the glycopeptide maps obtained for the gp90 and gp45 components from ...19863021020
nucleotide sequence and transcriptional activity of the caprine arthritis-encephalitis virus long terminal repeat.caprine arthritis-encephalitis virus (caev) and visna virus are pathogenic lentiviruses of goats and sheep which share morphologic features and sequence homology with human t-cell lymphotropic virus type iii (htlv-iii), the etiologic agent of the acquired immune deficiency syndrome. the nucleotide sequence of the caev long terminal repeat (ltr) was determined, and it was found to be 450 base pairs long, with u3, r, and u5 regions of 287, 85, and 78 base pairs, respectively. portions of the caev ...19863021973
isolation of a lentivirus from a macaque with lymphoma: comparison with htlv-iii/lav and other lentiviruses.a retrovirus has been isolated on the human t-cell line hut 78 after cocultivation of a lymph node from a pig-tailed macaque (macaca nemestrina) that had died with malignant lymphoma in 1982 at the university of washington primate center. this isolate, designated mniv (wprc-1) (m. nemestrina immunodeficiency virus, washington primate research center) shows the characteristic morphology of a lentivirus and replicates to high titers in various lymphocyte lines of human and primate origin. sodium d ...19863021982
characterization of equine infectious anemia virus long terminal repeat.the long terminal repeats (ltrs) of equine infectious anemia virus (eiav) were examined with respect to their ability to function as transcriptional promoters in various cellular environments. nucleotide sequence analyses of the ltrs derived from two unique proviral clones revealed the requisite consensus transcription and processing signals. one of the proviruses possessed a duplication of a 16-base-pair sequence in the ccaat box region of the ltr which was absent in the other provirus. to asse ...19873027401
chemical and immunological characterizations of equine infectious anemia virus gag-encoded proteins.the viral core proteins (p15, p26, p11, and p9) of equine infectious anemia virus (eiav) (wyoming strain) were purified by reverse-phase high-pressure liquid chromatography. each purified protein was analyzed for amino acid content, n-terminal amino acid sequence, c-terminal amino acid sequence, and phosphoamino acid content. the results of n- and c-terminal amino acid sequence analysis of each gag protein, taken together with the nucleotide sequence of the eiav gag gene (r. m. stephens, j. w. c ...19873029406
course and extent of variation of equine infectious anemia virus during parallel persistent infections.comparisons of peptide and oligonucleotide maps of glycoproteins and rna from nine isolates of equine infectious anemia virus (eiav) that were generated during parallel infections of two shetland ponies revealed that each isolate was structurally unique. each eiav isolate contained a unique subset of variant peptides, oligonucleotides, or both, indicating that structural variation in eiav is a random and noncumulative process and that a large spectrum of possible eiav variants can be generated i ...19873029423
nucleotide sequence analysis of equine infectious anemia virus proviral dna.the nucleotide sequence of the integrated form of the genome of the equine infectious anemia virus was determined. by comparison with ltr sequences of other retroviruses, signals for the control of viral gene transcription and translation could be identified in the eiav ltr. open reading frames for gag and pol genes were identified and their sequences matched very closely to those determined previously by others. however, in the present study, the pol gene reading frame was open throughout its e ...19873035786
complement-mediated hemolysis of horse erythrocytes treated with equine infectious anemia erythrocytes treated with equine infectious anemia virus hemagglutinin were found to be lysed after incubation with fresh horse serum at 37 degrees c. fresh guinea pig serum induced more efficient hemolysis than horse serum. direct immunofluorescence test revealed the adsorption of complement factors on the surface of the erythrocytes. calcium and magnesium ions were necessary for the hemolysis to take place. antibody against equine infectious anemia virus enhanced the virus-induced comple ...19873036045
phagocytosis of horse erythrocytes treated with equine infectious anemia virus by cultivated horse erythrocytes treated with equine infectious anemia virus hemagglutinin were phagocytized by cultivated horse leukocytes (mainly macrophage-like cells and partly polymorphonuclear cells) after incubation with fresh horse serum but not with inactivated horse serum. the phagocytosis began as soon as the erythrocytes were added to the leukocyte cultures, and the majority of the reaction proceeded within 30 minutes. addition of antiserum showed a slightly suppressing but no enhancing effect on ...19873036046
a review of antigenic variation by the equine infectious anemia virus. 19873040337
studies on viral-induced anemia in horses infected with equine infectious anemia virus. 19883386089
dna sequence (h) curves of the human immunodeficiency virus 1 and some related viral genomes.the complete nucleotide sequences of several human immunodeficiency virus 1 (hiv-1) genomes were converted by computer to respective h curves. these three-dimensional space curves embody all the information contained in the sequence due to their abstract vectorial structure. for one sequence (hiv-1 isolate bru) special efforts were made to maximize the available resolution (the number of nucleotides visually discernible within a unit length of the curve) when making a hard, master copy of the h ...19883402311
a quantitative bioassay for hiv-1 based on trans-activation.a bioassay that is based on trans-activation has been developed for the detection and quantitation of the human immunodeficiency virus type 1 (hiv-1). indicator cell lines were constructed that contain the hiv-1 long terminal repeat ligated to the chloramphenicol acetyltransferase (cat) gene. infection of these cells by hiv activates the expression of cat protein. isolates of hiv-1 with divergent nucleotide sequences activated the indicator cell lines to a similar extent, approximately 500- to 1 ...19883422113
molecular cloning and physical characterization of integrated equine infectious anemia virus: molecular and immunologic evidence of its close relationship to ovine and caprine lentiviruses.molecular clones of the integrated form of the genome of equine infectious anemia virus (eiav), the etiologic agent of a naturally occurring, worldwide disease of horses, were obtained. the restriction map of a full-length genome was determined. additional evidence for the close evolutionary relationship between eiav and a prototype lentivirus (caprine arthritis encephalitis virus) was acquired by southern blotting and immunological analyses. an interspecies radioimmunoassay was developed in whi ...19863750842
observations of tabanid feeding on mares and foals.the occurrence of tabanid feeding between mares and foals was observed. when mares and foals were observed freely moving within a pasture situation, foals had 2.43% (4 flies in 77 observations vs 297 flies in 139 observations) of the tabanid feeding occurrences of the mares. this difference in tabanid burden varied due to herd size, herd location, and tabanid species. lower tabanid burden of foals was indicated as a practical protective mechanism against pathogenic agents mechanically transmitte ...19854003887
antigenic drift of equine infectious anemia virus in chronically infected horses. 19734123810
preparation of equine infectious anemia antigens for diagnosis. 19734128832
equine infectious anemia: detection of infections virus-antibody complexes in the serum. 19724141690
pathological studies on bone marrow in equine infectious anemia. 3. cytlogical findings of bone marrow aspirates. 19684182535
physicochemical studies of equine infectionus anemia virus. 3. purification and electron microscopic observation of the virus. 19694195623
electron microscopic observations of equine infectious anemia (eia) virus in cultivated horse leukocytes. (brief report). 19694195626
[study of precipitogens of equine infectious anemia virus]. 19734198632
equine infectious anemia. new problems. 19664288554
[infectious anemia of horses. questions and answers on infectious anemia of horses]. 19664290778
complement fixation test of equine infectious anemia. i. specificity of the test. 19664292231
complement fixation test of equine infectious anemia. ii. relationship between cf antibody response and the disease. 19664292232
serial passages of equine infectious anemia virus in horse leukocyte culture. 19674293211
physicochemical studies on equine infectious anemia virus. examination of purification methods. 19674293212
pathological studies on bone marrow in equine infectious anemia. i. macroscopical findings on whole longitudinal sections of bone marrow. 19674293213
propagation and titration of equine infectious anemia virus in horse leukocyte culture. 19674293214
pathological studies on bone marrow in equine infectious anemia. ii. histopathology of vertebral, sternal and femoral bone marrow. 19674294929
equine infectious anemia occurring in hokkaido, japan--its histopathology and a critical view of the occurrence and diagnosis of this disease. 19674294930
specificity of assay of equine infectious anemia virus in horse leukocyte culture. 19674295385
gas chromatographic detection of in vivo activity of equine infectious anaemia virus. 19684298814
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