TitleAbstractYear(sorted ascending)
immunoglobulin g subclass [igg and igg(t)] interaction with the p26 group specific antigen of equine infectious anemia virus: immunodiffusion and complement-fixation reactions.isolated equine immunoglobulin (ig)g(t) antibodies to equine infectious anemia virus p26 antigen did not precipitate with antigen when the ratio of antibody to antigen was high. however, at lower ratios of antibody to antigen precipitation occurred. in addition, complement-fixation by igg and p26 antigen was inhibited by high concentrations of igg(t). the unusual reaction pattern noted with igg(t) antibodies was still detectable by the immunodiffusion test for equine infectious anemia virus. in ...1977195493
inactivation of equine infectious anemia virus by chemical disinfectants.twelve chemicals and commercial disinfectants were tested for inactivation of equine infectious anemia virus. in the presence of 10% bovine serum, all chemicals inactivated 4 log10 (based on 0.1 ml) of the virus within 5 minutes at 23 c. a reduction of at least 4 log10 was observed when the virus was exposed for 1 minute to substituted phenolic disinfectants (3 commercial preparations and sodium orthophenylphenate), halogen derivatives (iodophor and sodium hypochlorite), chlorhexidine, and 70% e ...1977199094
characterization of rna from equine infectious anemia virus.the genome of equine infectious anemia virus, a nononcogenic retrovirus, has been characterized by velocity sedimentation, electrophoresis in polyacrylamide gels, buoyant density in cs2so4, and susceptibility to nuclease digestion. the nucleic acid of purified virus was resolved by sedimentation analysis into a fast-sedimenting genome component, which comprises about two-thirds of the virion rna, and a slow-sedimenting rna, which is probably comprised of host-derived trna and a trace amount of 5 ...1977199735
demonstration of equine infectious anemia virus in primary leukocyte cultures by electron microscopy.electron microscopy was used to demonstrate the presence of viral particles in primary cultures of leukocytes taken from a horse after sc inoculation with the wyoming strain of equine infectious anemia virus. unlike previous studies, the exposure virus was not passaged through cell culture prior to horse inoculation. cultures were begun approximately 1 week before and 1 week after the 1st pyrexic period after inoculation. in both samples, viral particles and cytoplasmic alterations were observed ...1977202180
electron microscopic studies on equine infectious anemia virus (eiav). brief report.morphological studies of eiav reveal knobs on the surface of the particles, conically and tubularly shaped cores, budding particles with dense crescents directly underlying the plasma membrane, and distinct intracytoplasmic structures in infected cells.1977202230
the structural polypeptides of equine infections anemia virus.the structural polypeptides and glycoproteins of equine infectious anemia virus were identified following electrophoresis in sds-page. the major non-glycosylated polypeptides had molecular weights of 25,000, 14,000 and 11,000 daltons. two glycoproteins of 80,000 and 40,000 daltons were also detected. the relationship of these components to the structural elements of mammalian c-type oncoviruses is discussed.1978202575
induction of a cell membrane antigen by equine infectious anemia virus.equine fibroblasts persistently infected with equine infectious anemia virus acquire a new cell membrane antigen demonstrable by indirect radioimmunoassay, using infected horse serum as an antibody source.1978205145
preparation of hemagglutinating antigen of equine infectious anemia virus from infected equine leukocyte cultures. 1978206841
[cytomorphological aspects of the blood experimentally induced with inoculation of equine infectious anemia virus]. 1978208135
detection of proviral dna in horse cells infected with equine infectious anemia virus.equine infectious anemia virus (eiav) recently has been shown to possess a high-molecular-weight rna genome and a virion reverse transcriptase. we completed the demonstration that eiav is a retrovirus by showing the presence of proviral dna in equine cells infected in vitro, but not in normal horse dna. these studies were performed by using a highly representative cdna probe synthesized by the virion polymerase. it was found that this cdna reassociated extensively, and with high thermal stabilit ...1978209211
scanning and transmission electron microscopic study of equine infectious anemia virus.scanning and transmission electron microscopy were used to study in detail the morphogenesis and replication of equine infectious anemia virus (eiav) in cultured, persistently infected equine fetal kidney fibroblasts. the eiav was shown by thin-section electron microscopy to resemble morphologically more closely the members of the genus lenti-virus in the family retroviridae than other genera. scanning electron microscopy demonstrated budding virus on only about 5% of the equine fetal kidney fib ...1978215061
structural proteins of equine infectious anemia virus.equine infectious anemia virus was found to be comprised of fourteen polypeptides of molecular weight ranging from 10,000 to 79,000. eighty percent of the virion protein was accounted for by five polypeptides, including two non-glycosylated components (p29 and p13) comprising one-half of the virion protein and three glycoproteins (gp77/79, gp64, and gp40).1978215790
simple method for preparation of specific antisera against viral proteins: rabbit antisera against equine infectious anemia virus proteins p26 and p16.a simple method for preparation of highly specific antisera against equine infectious anemia virus proteins p26 and p16 is described. viral proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the motility of the viral proteins in the gel was compared with standards. unstained portions of the slab gel were sliced into 5-mm bands, emulsified with freund's complete adjuvant, and injected into rabbits to produce specific antisera.1978216292
failure to propagate equine infectious anemia virus in mosquitoes and culicoides variipennis.laboratory-colonized mosquitoes, culex tarsalis, aedes aegypti, culiseta inornata, and anopheles free-borni, and the biting gnat, culicoides variipennis, were exposed to equine infectious anemia virus. exposure to the virus was by intrathoracic inoculation for mosquitoes and by oral ingestion of an infective blood meal through a membrane for c variipennis. after various intervals, groups of 15 to 20 insects were homogenized and inoculated into susceptible ponies. positive immunodiffusion test r ...197831831
role of horse flies in transmission of wquine infectious anemia from carrier ponies.equine infectious anemia virus was transmitted from an acutely ill and an inapparently infected pony to uninfected ponies by the interrupted feeding of horse flies (tabanids). transmission from acutely ill ponies was not accomplished following: (1) the interrupted feeding of a single horse fly, (2) bites of horse flies that had fed on an acutely affected pony 24 hours earlier, (3) bites of horse flies that had oviposited after feeding on an acutely affected pony, or (4) the inoculation of larval ...1978621184
specificity of response to viral proteins in horses infected with equine infectious anemia virus.three structural proteins of equine infectious anemia virus were purified, labeled with 125i, and utilized in radioimmunoassays with horse sera and antisera to heterologous retroviruses. whereas radioimmunoassay titers for the major protein, p25, were 500- to 1,000-fold higher than titers in immunodiffusion, for clinical purposes these two procedures were equivalent. antibodies to two low-molecular-weight proteins, p12 and p10, were also found in infected horses, but with a lower frequency and l ...1979217831
equine infectious anemia: current knowledge. 1979218920
prevalence of antibodies to equine viruses in the netherlands.the prevalence of antibodies to various viruses was investigated in a series of serum samples collected from horses in the netherlands between 1963 and 1966 and from 1972 onwards. neutralizing antibodies to equine rhinopneumonitis virus, equine arteritis virus and to equine rhinovirus types 1 and 2 were detected in respectively 76%, 14%, 66% and 59% of the equine serum samples tested. the observed incidence of serum samples positive to equine adenovirus in the complement fixation test was 39%. p ...1979219560
serologic survey for equine infectious anemia virus in 1975, a survey was conducted in east baton rouge parish, louisiana, to determine the prevalence of equine infectious anemia. using the agar gel immunodiffusion test, 94 of 1,398 horses (6.7%) were found to be infected. infection rates were especially high in areas where clinical cases of equine infectious anemia had been diagnosed. clinical signs compatible with the disease were noted in 1 of the 94 seropositive horses. the sample set of 1,398 horses represented 22% of the census population o ...1979221447
equine infectious anemia virus: development of a simple reproducible method for titrating infectivity of the cell-adapted equine dermal cell line between the 14th and 30th subpassages was used to develop a reproducible method of titrating the infectivity of the cell-adapted strain of equine infectious anemia virus (eiav). cells inoculated with eiav were subcultured or fed once each week and were monitored for the production of p26 antigen of eiav in supernatant fluids. ultrathin sections were prepared once each week and were examined for the detection of budding virus-like particles (vlp). the vlp could not be d ...1979223479
leukocyte cytotoxicity in a persistent virus infection: presence of direct cytotoxicity but absence of antibody-dependent cellular cytotoxicity in horses infected with equine infectious anemia virus.antibody-dependent cellular cytotoxicity and direct cytotoxicity assays were performed with equine infectious anemia virus-infected target cells, equine leukocytes, and equine anti-equine infectious anemia virus antibody to determine whether these mechanisms play a role in controlling viral replication in equine infectious anemia. direct cytotoxicity was observed by using peripheral blood mononuclear cells from 7 of 10 infected horses. antibody-dependent cellular cytotoxicity was not observed. t ...1979223981
responses in horses infected with equine infectious anemia virus adapted to tissue culture. 1979228570
characterization of the infection of equine fibroblasts by equine infectious anemia virus.equine dermal fibroblasts persistently infected with equine infectious anemia virus (eiav) show no alterations in cell morphology or growth kinetics when compared to uninfected cells. the percentage of cells immunofluorescent positive for viral proteins fluctuated, depending upon the stage of the cell cycle, while production of extracellular virus was uniform throughout the cell cycle, increasing only as the cell number increased. this was shown in log versus stationary phase cultures as well as ...1979228638
synthesis of long complementary dna in the endogenous reaction by equine infectious anemia the endogenous reverse transcriptase reaction, equine infectious anemia virus is able to synthesize complementary dna (cdna) of 8,000 nucleotides in high yield. after 2 h in 50 mum dntp, about 2.8 mug of cdna per mg of protein is produced, almost 30% of which is long cdna. the system thus compares favorably with the other two well-characterized endogenous reaction systems, moloney murine leukemia virus and avian sarcoma virus. elongation rates of 100 to 150 nucleotides per min have been obser ...197987522
immunology of a persistent retrovirus infection--equine infectious anemia. 197995154
the role of stable flies and mosquitoes in the transmission of equine infectious anemia virus. 19806118874
isolation and characterization of low-molecular-weight dna-binding proteins from retroviruses. 19806249039
equine infectious anemia virus, a putative lentivirus, contains polypeptides analogous to prototype-c oncornaviruses. 19806256947
orientation of structural polypeptides of equine infectious anemia virus.lactoperoxidase iodination of intact and disrupted equine infectious anemia virus revealed that glycopeptide gp79 is the major surface component of this virus, whereas glycopeptides gp64 and gp40 as well as the principle nonglycosylated structural polypeptides p29 and p13 are internal. virus 'envelope' particles, banding in isopycnic centrifugation at approximately 1.10 g/cm3, contained the glycopeptides but no internal nonglycosylated proteins. glycopeptides gp79, gp64 and gp40 and core polypep ...19806259082
[comparative investigations on the serological diagnosis of the equine infectious anemia (author's transl)]. 19816262037
hemagglutination of several strains of equine infectious anemia virus.six strains of equine infectious anemia (eia) virus propagated in equine leukocyte cultures were found to agglutinate horse erythrocytes. concentrated virus material containing about 20 units of complement fixation (cf) titer showed hemagglutinating (ha) titers ranging from 4 to 8 units. the ha activity remained stable after ether treatment and was reduced by trypsin, formaldehyde and kio4. cesium chloride equilibrium density gradient centrifugation revealed two populations of hemagglutinin, one ...19816263225
transmission of equine infectious anaemia virus from a horse negative to agar gel immunodiffusion testing. 19816265206
the immune system in slow disease due to persistent submicrobial (viral) infection. 19816270625
propagation of equine infectious anemia virus in horse cell cultures. 19816272480
high-performance gel permeation chromatography of proteins in denaturing solvents and its application to the analysis of enveloped virus polypeptides. 19816272599
prevalence of equine infectious anaemia (swamp fever) in guyana. 19816272928
serological survey for equine infectious anaemia. 19816275830
studies with equine infectious anemia virus: transmission attempts by mosquitoes and survival of virus on vector mouthparts and hypodermic needles, and in mosquito tissue culture.biological and mechanical transmission trials with psorophora columbiae (dyar and knab) and aedes sollicitans (walker) and ponies acutely infected with equine infectious anemia virus (eiav) were negative. the eiav antigen was detected by radioimmunoassay in ae sollicitans immediately after the mosquitoes had fed on an acutely ill pony, but not 14 days after feeding. psorophora columbiae mosquitoes had detectable eiav antigen as determined by radioimmunoassay 24 hours after they fed on an acutely ...19816119953
hemagglutination-inhibition tests with different strains of equine infectious anemia virus.the serologic relationships between 6 strains of equine infectious anemia (eia) viruses were investigated by hemagglutination-inhibition (hi) tests. cross hi tests, using sera from horses in the early stage of infection, revealed that all strains were inhibited only by homologous strain antisera and that hi antibody was always detectable before virus-neutralizing antibody. in the later stages of infection, both homologous and heterologous hi antibodies were detected in a sera of most of the hors ...19816175255
in vitro host range of equine infectious anemia virus.equine infectious anemia virus (eiav) was successfully inoculated onto cell cultures of canine and feline origin, resulting in chronic infections in these cultures. infection of equine cell cultures, which were the previous sole in vitro source demonstrated for virus production, was also performed for comparative purposes. determination of the nature of the virus produced in the heterologous as well as the equine cells was accomplished in several ways. sds-page of purified virus from the differe ...19816177659
propagation of equine infectious anemia virus in horse cell cultures.the wyoming strain of equine infectious anemia virus was adapted to cell cultures by 7 passages in horse leukocytes and 14 passages in fetal equine dermal and kidney cells. the virus was made evident by electron microscopy and immunodiffusion tests with antigens prepared from culture fluids.19816306910
isolation and comparative biochemical properties of the major internal polypeptides of equine infectious anemia virus.we describe procedures for the large-scale production of equine infectious anemia virus (eiav) and for the isolation of the four major non-glycosylated virion proteins, designated p26, p15, p11, and p9. comparisons of the purified proteins by peptide mapping procedures and by enzyme-linked immunosorbent assays demonstrated the unrelatedness of the four proteins. the characteristic properties of each purified protein were examined by determining isoelectric points and amino acid compositions. we ...19826178843
transmission of equine infectious anemia virus from horses without clinical signs of disease.twenty seven adult horses positive to the agar gel immunodiffusion (agid) test for equine infectious anemia (eia), but with no history of clinical eia, were used in transfusion studies to determine whether infectious eia virus was present in 1 to 5 ml of their blood. of 27 recipients, 21 (78%) became agid test-positive at an average of 24 days after inoculation. two horses that were initially negative when screened were retested and found to carry infectious virus in 5-300 ml of whole blood; the ...19826276353
detection of equine infectious anemia virus in a horse with an equivocal agar gel immunodiffusion test reaction.a horse whose serum reacted equivocally in the agar gel immunodiffusion (agid) test for equine infectious anemia was studied over a 3-year period. the horse remained afebrile and virus was detected in only 1 of 6 horse inoculation tests. the intensity of agid test reactions increased temporarily following this evidence for virus. although the agid test reaction was equivocal and 5 of the 6 transmission attempts failed, the 1 successful transmission proved the horse was infected.19826276354
indirect hemagglutination test in equine infectious indirect hemagglutination was developed for the diagnosis of equine infectious anemia using sheep red blood cells coated with group specific virus antigen which had been highly purified by affinity chromatography. the presence of indirect hemagglutination antibodies was demonstrated in horses with equine infectious anemia since the cells were specifically agglutinated by all the serum samples obtained from experimentally infected horses. antibodies appeared within 35 days after inoculation, a ...19826280821
antigenic stimulation of t lymphocytes in chronic nononcogenic retrovirus infection: equine infectious anemia.equine infectious anemia is a chronic disease of horses caused by a nononcogenic retrovirus. studies were undertaken to determine the types of cells involved in the in vitro lymphoproliferative response to viral antigens and the dynamics of this reaction. it was observed that reactive lymphocytes were present at unpredictable times in the peripheral blood of infected horses. this reaction was shown to be specific for the interaction of equine infectious anemia virus and t lymphocytes. enriched b ...19826281191
persistent infection by equine infectious anemia virus: asymmetry of nucleotide sequence reiteration in the integrated provirus of persistently infected cells. 19826281971
dna sequence relationship of the baboon endogenous virus genome to the genomes of other type c and type d retroviruses.baboon endogenous virus (baev) is a type c retrovirus present in multiple proviral copies in the dna of baboons. although interspecies antigenic determinants present on reverse transcriptase and gag proteins are shared among all mammalian type c viruses, no nucleic acid homology between baev and other type c viruses (except rd-114) has been found in conventional liquid hybridization experiments. in this study, we used restriction fragments of cloned baev dna immobilized on nitrocellulose to test ...19826284972
virulence and in vitro growth of a cell-adapted strain of equine infectious anemia virus after serial passage in ponies.five serial passages of a cell-adapted strain of equine infectious anemia (eia) virus were conducted in shetland ponies. the 13 recipient ponies became agar-gel immunodiffusion test-positive by 25 days after they were inoculated. the virulence of the cell-adapted strain of eia virus markedly increased through 3 serial passages, although individual variation within passages was high. the 1st serial-passage recipient remained afebrile through 200 days, whereas a febrile episode occurred about ever ...19826293349
equine infectious anaemia: detection of antibodies using an immunofluorescence indirect immunofluorescence test for detecting antibodies to equine infectious anaemia virus is presented. using monolayers of equine dermal cells within a defined period after infection, discrete fluorescent spots were observed in the cytoplasm of as many as 95 per cent of the cells. these inclusions appeared as ring-like structures when high titred sera were employed but became spots when the sera were diluted. cells showing optimal antigen fluorescence were used immediately or after storag ...19826296954
mechanical transmission of equine infectious anemia virus by deer flies (chrysops flavidus) and stable flies (stomoxys calcitrans). 19836297339
isolation of equine infectious anemia virus glycoproteins. lectin affinity chromatography procedures for high avidity glycoproteins.lectin affinity chromatography procedures were evaluated for the isolation of enveloped virus glycoproteins. the major glycoprotein of equine infectious anemia virus (eiav) bound to concanavalin a (con a)-sepharose through interactions which could not be reversed by alpha-methylglucoside, but elution could be accomplished with buffers containing guanidine hydrochloride or sodium dodecyl sulfate. these denaturants, however, also released about one-half of the con a protein from the sepharose matr ...19836309879
effects of common radioiodination procedures on the binding of glycoproteins to immobilized lectins.representative glycoproteins including fetuin, protein a, ovalbumin, alpha 1 acid glycoprotein, and the major glycoprotein of equine infectious anemia virus were labelled with 125i by the chloramine-t or bolton-hunter procedure and their binding to immobilized con a or lentil lectin compared to untreated samples of each glycoprotein. glycoprotein modification was no greater than one substituted residue per protein molecule. yet the radioiodinated glycoproteins typically displayed only 0-50% of t ...19836838504
genomic alterations associated with persistent infections by equine infectious anaemia virus, a retrovirus.the unique periodic nature of equine infectious anaemia (eia) is believed to result from the ability of the infecting virus. eiav, to undergo relatively rapid antigenic variations which circumvent host immune responses resulting in distinct virus populations in sequential clinical episodes in the persistently infected horse. this model was examined by oligonucleotide mapping comparisons of the rna genomes of selected isolates of eiav. variations in oligonucleotide maps could be reproducibly demo ...19846086822
enzyme-linked immunosorbent assay for detection of equine infectious anemia antibody to purified p26 viral indirect enzyme-linked immunosorbent assay (elisa) was developed for the detection of equine infectious anemia (eia) antibody in horse sera. purified p26 viral protein was the antigen; alkaline phosphatase linked to rabbit anti-horse immunoglobulin g was the conjugate. the elisa detected eia antibodies in horse sera as early as 11 to 14 days after experimental inoculations. there was full agreement between the results of elisa and the agar-gel immunodiffusion tests on eia proficiency test ser ...19846089620
transmission and clinical evaluation of an equine infectious anemia herd and their offspring over a 13-year period. 19846321418
an overview of equine infectious anemia control and regulation in the united states. 19846321419
studies on equine infectious anemia virus transmission by insects.there are several factors involved in the mechanical transmission of equine infectious anemia (eia) virus by insects. large hematophagous insects, especially tabanids, which feed from extravascular sites (ie, pool feeding) appear to be the most efficient vectors. the biology of the host-seeking and blood-feeding behavior of the vectors are important variables that have been overlooked in the mechanical transmission of pathogens like eia virus. the biology, population levels, and diversity of the ...19846321420
detection of equine infectious anemia virus in horse leukocyte cultures derived from horses in various stages of equine infectious anemia viral infection.the enzyme-linked immunosorbent assay (elisa) antigen-positive and agar-gel immunodiffusion test (agid)-negative horses do not have infective equine infectious anemia (eia) virus. the elisa testing of horse leukocyte culture (hlc) supernatants did detect eia virus in a hlc that was infected with the wyoming strain of eia virus and in hlc derived from horses in febrile, acute, or subacute stages of eia infection. in supernatants of hlc derived from chronic and inapparent carrier horses, eia virus ...19846322623
structural proteins of equine infectious anemia virus and their antigenic activity.using purified equine infectious anemia (eia) virus labeled with 3h-glucosamine or 14c-protein hydrolysate, structural proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. as a result, 2 glycoproteins and 10 proteins with molecular weights (mol wt) ranging from 12,000 to 115,000 daltons were demonstrated. of 12 structural proteins, 3 proteins, namely a glycoprotein with mol wt of 76,000 (gp76) and 2 proteins with mol wt of 25,000 (p25) and 12,000 (p12), respective ...19846322625
cytoplasmic inclusions in cells infected with the virus of equine infectious anemia (eiav).after infection with equine infectious anemia virus (eiav) equine dermal (ed) cells revealed fluorescent spots in their cytoplasm which were detected with an indirect immunofluorescence technique. to characterize the nature of these cytoplasmic inclusions, comparative light and electron microscopic studies were performed. the cytoplasmic location of the spots observed in the indirect immunofluorescence assay coincided with the location of structures detected with the electron microscope. in ultr ...19846325195
enzyme-linked immunosorbent assay for detection of equine infectious anemia virus p26 antigen and antibody.a sensitive specific enzyme-linked immunosorbent assay utilizing purified p26 antigen was developed for the detection of antibodies to equine infectious anemia virus in naturally and experimentally infected horses. generally, antibodies to the virus could be detected by the enzyme-linked immunosorbent assay 3 to 4 days earlier than by the standard agar gel immunodiffusion test, and they could be detected more reliably in horses with weak or equivocal agar gel immunodiffusion test reactions. the ...19846325488
characterization of monoclonal antibodies directed against the envelope proteins of feline leukemia virus.monoclonal antibodies directed against the feline leukemia virus (felv) envelope proteins, gp70 and p15e, were identified by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. six of these monoclonal antibodies were specific for the gp70; two for the p15e. enzyme-linked immunosorbent assay binding assays against felv subtypes a, b, and c showed that most of the monoclonal antibodies bound to more than one subtype but have a greater affinity for subtype b. one ...19846331649
carriers of equine infectious anemia virus.presently available data continue to support the idea that once a horse is infected with equine infectious anemia virus it remains infected indefinitely. infection may not always be demonstrated by inoculation of plasma, serum, or whole blood transfusions into susceptible recipients, but transfusions of fresh whole blood will be infective in at least 95% of the horses testing positive in the agar gel immunodiffusion test. for detection of infectivity in a small percentage of inapparent carriers, ...19846421787
antigenic reactivity of the major glycoprotein of equine infectious anemia virus, a retrovirus.the immunogenic contributions of the carbohydrate and peptide portions of the major envelope glycoprotein of equine infections anemia virus, eiav gp90, were analyzed by measuring the effects of specific glycosidase and protease digestions on the reactivity of the glycoprotein with immune sera from infected horses. the results of both direct and competitive radioimmunoassay demonstrated that immune sera contained antibodies reactive with both the carbohydrate and protein moieties of eiav gp90, wi ...19846205503
antigenic variation during persistent infection by equine infectious anemia virus, a retrovirus.the recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (eiav) during persistent infection under selective immune pressures. this model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strain ...19846206055
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
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
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
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
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
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
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
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
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
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
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
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