Publications

preliminary survey for antibodies against caprine arthritis-encephalitis virus (caev) using recombinant gag proteins: studies among small ruminant populations in north-eastern nigeria.	a total of 1000 serum samples were obtained from small ruminants in maiduguri, borno state, nigeria and tested for the presence of antibodies against caprine arthritis-encephalitis virus (caev) using enzyme-linked immunosorbent assay (elisa) based on p17 and p28 recombinant gag proteins. the distribution of the sera tested was as follows: 900 serum samples collected at slaughter from 700 goats and 200 sheep in the municipal abattoir as well as 100 sera obtained from 50 each of goats and sheep in ...	2000	10818314
the detection of proviral dna by semi-nested polymerase chain reaction and phylogenetic analysis of czech maedi-visna isolates based on gag gene sequences.	a semi-nested polymerase chain reaction (snpcr) for detecting proviral dna of ovine lentivirus (ovlv) in peripheral blood mononuclear cells was developed. primers for snpcr were situated within the gag gene of the maedi-visna virus (mvv) genome. a comparison between the snpcr and serological tests (agar gel immunodiffusion test, immunoblot) were performed using 98 ovine blood samples. thirty (30.6%) of the 98 sheep examined had antibodies specific for the mvv. pcr showed 21 of them to be positiv ...	2000	10829575
variability and immunogenicity of caprine arthritis-encephalitis virus surface glycoprotein.	the complete surface glycoprotein (su) nucleotide sequences of three french isolates of caprine arthritis-encephalitis virus (caev) were determined and compared with those of previously described isolates: three american isolates and one french isolate. phylogenetic analyses revealed the existence of four distinct and roughly equidistant evolutionary caev subtypes. four conserved and five variable domains were identified in the su. the fine specificities of antibodies produced against these doma ...	2000	10846103
lack of functional receptors is the only barrier that prevents caprine arthritis-encephalitis virus from infecting human cells.	barriers to replication of viruses in potential host cells may occur at several levels. lack of suitable and functional receptors on the host cell surface, thereby precluding entry of the virus, is a frequent reason for noninfectivity, as long as no alternative way of entry (e.g., pinocytosis, antibody-dependent adsorption) can be exploited by the virus. other barriers can intervene at later stages of the virus life cycle, with restrictions on transcription of the viral genome, incorrect transla ...	2000	10954533
sequence similarity between the envelope surface unit (su) glycoproteins of primate and small ruminant lentiviruses.	sequence similarity has been previously described in the transmembrane domain unit of envelope glycoproteins of primate and non-primate lentiviruses but similarity between the surface unit (su) glycoprotein of these viruses is less clear or absent. here we describe a consistent and significant sequence-similarity between the ovine/caprine lentivirus surface glycoprotein gp135 and the primate lentivirus gp120 in the region between variable loops v2 and v3. the biological relevance of this sequenc ...	2000	10989185
b-cell epitopes of the envelope glycoprotein of caprine arthritis-encephalitis virus and antibody response in infected goats.	goats infected with caprine arthritis-encephalitis virus (caev) develop high titres of antibodies to env. not only is no consistent neutralizing response found but anti-env antibodies have even been associated with disease in infected goats. to identify the continuous antigenic determinants involved in this atypical anti-env response, we mapped caev-co env by screening an epitope expression library with infected goat sera. in addition to the four previously described epitopes, seven novel antige ...	2000	11086124
activation of small ruminant aortic endothelial cells after in vitro infection by caprine arthritis encephalitis virus.	small ruminants infected by the lentiviruses caprine arthritis-encephalitis virus (caev), originally isolated from a goat, or maedi-visna virus, originally from sheep, typically develop an organising lymphoid infiltration of affected tissues. this could reflect modulation of the migration pattern of lymphocytes in infected animals. possible active contribution by vascular endothelial cells was investigated using an in vitro model. low-passage cultured ovine aortic endothelium proved susceptible ...	2000	11124093
crossreactive neutralizing antibodies induced by immunization with caprine arthritis-encephalitis virus surface glycoprotein.	four saanen goats were immunized with affinity purified gp135 surface glycoprotein (su) of caprine arthritis-encephalitis virus isolate 79-63 (caev-63) and evaluated for homologous and crossreactive serum neutralizing antibodies. caev-63 neutralizing antibodies were detected in all goats after seven immunizations with su in quil a adjuvant. sera from three goats neutralized an independent caev isolate (caev-co). however, serum from one goat did not detectably neutralize heterologous caev-co and ...	2000	10649630
a labelled avidin-biotin elisa to detect antibodies to caprine arthritis-encephalitis virus in goats' sera.	a labelled avidin-biotin elisa (lab-elisa) was developed and compared with indirect elisa (i-elisa) and agar-gel immunodiffusion assay (agid) for its efficacy in detecting antibodies against caprine arthritis-encephalitis virus (caev) in goat sera. the enzyme immunoassays were standardized using 113 sera from caev-negative goat flocks. the tests were compared using the results from 339 serum samples. the lab-elisa showed the greatest number of positive results (94/339) as compared with agid (51) ...	1999	10672968
"hidden" dutpase sequence in human immunodeficiency virus type 1 gp120.	a coding region homologous to the sequence for essential eukaryotic enzyme dutpase has been identified in different genomic regions of several viral lineages. unlike the nonprimate lentiviruses (caprine arthritis- encephalitis virus, equine infectious anemia virus, feline immunodeficiency virus, and visna virus), where dutpase is integrated into the pol coding region, this enzyme has never been demonstrated to be present in the primate lentivirus genomes (human immunodeficiency virus type 1 [hiv ...	1999	9847382
concealed locations of lentiviruses in caprine arthritis encephalitis system.	ultrastructural examinations of ovine and caprine tissue culture cell lines infected with a molecular sheep lentivirus clone kv72 revealed typical cytoplasmic a type retrovirus particles and budding particles from plasma cell membrane. blood examinations of a heavily caprine arthritis encephalitis virus-afflicted herd revealed that three goats, which on previous blood examinations had showed a high level of infection, had become negative. two of these goats underwent a necropsy. the main finding ...	1999	9887313
gag protein epitopes recognized by cd4(+) t-helper lymphocytes from equine infectious anemia virus-infected carrier horses.	antigen-specific t-helper (th) lymphocytes are critical for the development of antiviral humoral responses and the expansion of cytotoxic t lymphocytes (ctl). identification of relevant th lymphocyte epitopes remains an important step in the development of an efficacious subunit peptide vaccine against equine infectious anemia virus (eiav), a naturally occurring lentivirus of horses. this study describes th lymphocyte reactivity in eiav carrier horses to two proteins, p26 and p15, encoded by the ...	1999	10196322
goat milk epithelial cells are highly permissive to caev infection in vitro.	the main route of small ruminant lentivirus dissemination is the ingestion of infected cells present in colostrum and milk from infected animals. however, whether only macrophages or other cell subtypes are involved in this transmission is unknown. we derived epithelial cell cultures, 100% cytokeratin positive, from milk of naturally infected and noninfected goats. one such culture, derived from a naturally infected goat, constitutively produced a high titer of virus in the absence of any cytopa ...	1999	10364490
ovine lentivirus-infected macrophages mediate productive infection in cell types that are not susceptible to infection with cell-free virus.	ovine lentiviruses and caprine arthritis-encephalitis virus (caev) are prototypic lentiviruses that replicate predominantly in macrophages of infected animals. in situ hybridization of pathologically affected tissues from diseased animals has shown that viral rna exists in permissive macrophages as well as in non-macrophage cell types that do not support productive virus replication. these findings raise questions about the cellular tropism of these viruses in vivo and how this may relate to the ...	1999	10374961
inducible nitric oxide synthase is expressed in joints of goats in the late stage of infection with caprine arthritis encephalitis virus.	we have studied the expression of the inducible form of nitric oxide synthase (inos) in joints of goats infected with the caprine arthritis encephalitis virus (caev). nitric oxide generated by inos is thought to play an important role in the pathogenesis of various types of arthritis, especially rheumatoid arthritis (ra) in humans. surprisingly, inos immunoreactivity was found only in joints of long-term infected goats with severe clinical arthritis, whereas-despite the presence of high numbers ...	1999	10403918
conserved sequence motifs involving the tat reading frame of brazilian caprine lentiviruses indicate affiliations to both caprine arthritis-encephalitis virus and visna-maedi virus.	the sequence variation in small ruminant lentiviruses from brazilian herds of milking goats was sampled in a representative region of the pol gene and in a region including the entire tat open reading frame. clones were amplified from cdna derived from virus produced in vitro using primers targetting conserved sequences of the pol gene. iterative sequencing of clones indicated that animals from two herds in the minas gerais area were infected by a caprine arthritis-encephalitis virus (caev)-like ...	1999	10423125
a new sensitive serological assay for detection of lentivirus infections in small ruminants.	lentivirus infections in small ruminants represent an economic problem affecting several european countries with important sheep-breeding industries. programs for control and eradication of these infections are being initiated and require reliable screening assays. this communication describes the construction and evaluation of a new serological screening enzyme-linked immunosorbent assay (elisa) for the detection of antibodies to maedi-visna virus (mvv) in sheep and to caprine arthritis encepha ...	1999	10473527
characterization of the immunodominant cross-reacting epitope of visna maedi virus and caprine arthritis-encephalitis virus capsid antigen.	maedi visna (mv) and caprine arthritis-encephalitis (cae) are two retroviral infections distributed world wide. antigenic cross reactions between the viruses have been demonstrated in gag and env encoded structural proteins. antigens from ovine lentiviruses are easier to produce in cell culture systems and therefore have been used in the development of diagnostic tests for both infections. antigenically relevant epitopes have been characterised in the transmembrane protein, but little informatio ...	1999	10475088
isolation of caprine arthritis encephalitis virus from goats in mexico.	a lentivirus was isolated from 2 goats in mexico that were seropositive to caprine arthritis encephalitis virus (caev) by the agar gel immunodiffusion (agid) test. the lentivirus was identified as caev by the observation of giant multinucleated cells (syncytia) in goat synovial membrane (gsm) monolayers co-cultivated with blood mononuclear (bmn) cells from the seropositive goats, and by amplifying a dna segment of the caev gag gene using the polymerase chain reaction (pcr) technique. subsequentl ...	1999	10480464
proviral dna in the brains of goats infected with caprine arthritis-encephalitis virus.	archive paraffin wax-embedded sections of brain from goats and kids naturally infected with caprine arthritis-encephalitis virus (caev) were examined. severe leucoencephalitis was present, with infiltration of lymphocytes, plasma cells and macrophages into the white matter, meninges and choroid plexus. on both caev-positive and negative (control) tissues, in-situ polymerase chain reactions were used to amplify a dna sequence specific to the proviral pol region. in the infected tissues, strong hy ...	1999	10486163
infection of primary cultures of mammary epithelial cells by small ruminant lentiviruses.	the caprine arthritis-encephalitis virus (caev) and visna maedi virus cause persistent infections with long latent periods and induce degenerative and chronic inflammatory lesions of the central nervous system, joints, lungs and udder. monocyte/macrophage lineage is the main target cell for caev and visna maedi virus but we speculate that mammary epithelial cells may also be infected. primary cultures of milk cells, mammary tissues of experimentally and naturally infected goats and ewes were use ...	1999	10543381
how to succeed as a virus: strategies for dealing with the immune system.	viruses may be viewed as genetic information whose success depends on avoiding elimination from individual hosts, or, if this is not possible, in persisting in the population of their hosts. the immune system represents the crucial defense mechanism responsible for the elimination of viruses from individual hosts and for the establishment of immunity that prevents a recurring infection by the same virus. herd immunity, i.e., immunity of the population against infection resulting from the immunit ...	1999	10614500
[detection of caprine arthritis encephalitis virus in sperm of experimentally infected bucks].	shedding of caprine arthritis encephalitis virus (caev) was assessed in semen and blood mononuclear cells of six bucks (four boers and two saanens) experimentally contaminated with a viral strain (caev cork) and on three non-infected controls. caev was identified by polymerase chain reaction (pcr) in blood mononuclear cells of all infected animals but only in seminal fluid and non-spermatic cells of one buck and in non-spermatic cells of another. presence of caev in semen could have implications ...	1998	9851015
control of caprine arthritis-encephalitis virus and corynebacterium pseudotuberculosis infection in a norwegian goat herd.	a control programme for caprine arthritis-encephalitis virus (caev) and corynebacterium pseudotuberculosis (c. pseudotuberculosis) infection was established in a norwegian goat herd comprising approximately 100 milking goats. the herd seroprevalences of antibodies against caev and c. pseudotuberculosis were 97% and 94%, respectively. kids were removed from the infected flock at birth, avoiding any contact between dam and kid. the kids were kept completely segregated from the seropositive flock a ...	1998	9592951
defective rna packaging is responsible for low transduction efficiency of caev-based vectors.	replication defective retroviral vectors are regularly used for transfer and expression of exogenous genes into dividing cells and in animals. since lentiviruses are able to infect terminally differentiated and non-dividing cells, their use to produce replication defective vectors may overcome this limitation. we developed two replication-defective lentiviral vectors based on the genome of caprine arthritis encephalitis virus (caev). the first vector (pbnl2) carries the neo and lacz marker genes ...	1998	9638141
priming with tat-deleted caprine arthritis encephalitis virus (caev) proviral dna or live virus protects goats from challenge with pathogenic caev.	we previously reported that infection of goats with caprine arthritis encephalitis virus (caev) tat- proviral dna or virus results in persistent infection, since the animals seroconverted and direct virus isolation from cultures of blood-derived macrophages was positive. in this study we wanted to determine whether goats injected with caev tat- proviral dna or virus were protected against challenge with the pathogenic homologous virus and to investigate whether caev tat- was still pathogenic. al ...	1998	9658128
phylogenetic analysis of small ruminant lentiviruses.	based on available sequence data, a phylogeny of small ruminant lentiviruses (srlv) was established for env, pol, gag and ltr fragments using maximum likelihood, neighbour-joining and minimum evolution reconstruction techniques. to reconstruct topologies as accurately as possible, phylogenetic parameters like base composition, percentage divergences, kappa, the gamma shape parameter alpha and codon position-specific rates were estimated prior to the reconstruction of trees. divergences between f ...	1998	9714243
pcr detection of lentiviral gag segment dna in the white blood cells of sheep and goats.	a pcr assay for the detection of small ruminant lentiviral gag dna (provirus) in the white blood cells of sheep and goats was developed and compared with a serological test (agidt). a sample of the dna prepared from the white blood cells in 3 ml of blood from 208 sheep and goats from 18 different flocks was subjected to pcr assay. one of 85 animals from flocks accredited under the dutch national mvv/caev control programme was positive by pcr while none was positive by agidt. in infected flocks, ...	1998	9778781
maedi-visna virus and caprine arthritis-encephalitis virus: distinct species or quasispecies and its implications for laboratory diagnosis.	the lentiviruses responsible for causing maedi-visna or ovine progressive pneumonia in sheep and caprine arthritis-encephalitis in goats have long been considered distinct, albeit related, viral species. evidence, primarily in the form of nucleic acid sequence data, suggests this distinction may not be as absolute as once thought. these lentiviruses might better be viewed in the context of viral quasispecies whose individual members exhibit varying host range and pathogenic capabilities. implica ...	1998	9798087
use of a recombinant maedi-visna virus protein elisa for the serologic diagnosis of lentivirus infections in small ruminants.	highly purified recombinant gag and env proteins derived from icelandic strain 1514 of maedi-visna virus were used in an indirect enzyme immunoassay (elisa) to detect antibodies to small ruminant lentiviruses in sheep and goat sera. the recombinant protein-based elisa performed very well relative to whole maedi-visna virus and whole caprine arthritis-encephalitis-virus-based elisas in its ability to detect anti-maedi visna virus and anti-caprine arthritis-encephalitis virus antibodies, despite t ...	1998	9798098
[identification of caprine arthritis encephalitis virus using histopathological, immunohistochemica, and ultrastructural examination of tissues from seropositive goats in mexico].	this study demonstrated the presence of viral particles suggestive of arthritis-encephalitis virus through the clinic, serologic, pathologic, immunohistochemic and ultrastructural studies in dairy goats. in the postmortem studies the tissues used were: synovial membrane, lungs and mammary gland from goats with clinical signs characteristic of the disease and positive for serum antibodies to the virus.	1998	10932732
immunohistology of the early course of lentivirus-induced arthritis.	caprine arthritis encephalitis (cae) is a lentiviral infection of goats characterized by mononuclear cell infiltration of various tissues, most prominently the joints, mammary glands and, in young animals, the brain. we have investigated the early stages of arthritis induced by intracarpal and intravenous infection with molecularly cloned cae virus. analysis of the synovial membranes by immunohistological methods showed that the proportion of cd8+ t cells peaked around day 12 post-infection. cd4 ...	1998	9486408
caprine arthritis-encephalitis in an indigenous spanish breed of dairy goat.	the presence of caprine arthritis and encephalitis (cae) in spain has never been officially acknowledged but it is suspected. goats have been imported from other european countries with a high prevalence of the disease, mainly france, and they might have introduced the disease into the indigenous goat population. a serological survey of caprine arthritis and encephalitis virus antibodies was carried out in 22 volunteer dairy murciano-granadina goat herds; 2513 lactating goats were tested with an ...	1998	9507648
cloning and expression of caprine interferon-gamma.	caprine interferon-gamma (ifn-gamma) cdna was cloned from mitogen stimulated peripheral blood mononuclear cell (pbmc) rna utilizing the reverse transcription-polymerase chain reaction (rt-pcr). the cdna open reading frame (orf) is 498bp, encoding a putative 166 amino acid (aa) protein (19327da). the predicted aa sequence homology of caprine ifn-gamma and the corresponding ovine, bovine and cervine cytokine is 98.8%, 95.2% and 92.8%, respectively. ifn-gamma cdna was subcloned and expressed in two ...	1998	9524237
antibody reactivity to the transmembrane protein of the caprine arthritis encephalitis virus correlates with severity of arthritis: no evidence for the involvement of epitope mimicry.	serum and synovial antibody reactivities of caprine arthritis encephalitis virus (caev) infected goats were assessed by western blotting against purified caev antigen and the greatest intensity of reactivity in the serum of arthritic goats was to the gp45 transmembrane protein (tm). the extracytoplasmic domain of the tm gene was cloned into a pgex vector and expressed in escherichia coli as a glutathione s transferase fusion protein (gst-tm). this clone was found to be 90.5 and 89.2% homologous ...	1997	9533272
laboratory diagnostic tests for retrovirus infections of small ruminants.	the most practical and reliable approach to confirming a diagnosis of oppv or caev infection is a combination of serology and clinical evaluation. although serology represents the most cost effective method of diagnosing persistently infected, clinically normal animals, testing errors occur; the frequency of error depends on the performance data of the particular serologic assay being used. when pcr detection of oppv and caev becomes routinely available, this detection method can be used in rigo ...	1997	9071743
risk factors for transmission and methods for control of caprine arthritis-encephalitis virus infection.	the major route of transmission of caprine-encephalitis virus (caev) is through the ingestion of caev-infected colostrum or milk. less efficient routes of transmission are associated with prolonged contact with infected goats and are reviewed in this article. prevention of caev is based on the removal of kids from their dam at birth, and feeding the kids heat-treated colostrum and pasteurized milk until weaning. serologic testing and segregation or culling of seropositive goats is necessary to m ...	1997	9071745
stat1 pathway is involved in activation of caprine arthritis-encephalitis virus long terminal repeat in monocytes.	the caprine arthritis-encephalitis virus (caev) long terminal repeat (ltr) is activated by gamma interferon (ifn-gamma) in promonocytic cells. we have previously shown that a 70-bp element is necessary and sufficient for the response of the caev ltr to this cytokine. at the 5' end, this 70-bp ifn-gamma response element contains sequence similarity to the gamma activated site (gas). here we demonstrate that the putative gas element in the caev ltr binds specifically to a cellular factor induced b ...	1997	8985415
rt-pcr detection of lentiviruses in milk or mammary secretions of sheep or goats from infected flocks.	in this study we evaluated a reverse transcriptase polymerase chain reaction (rt-pcr) technique for detecting lentiviral infection in milk or mammary secretions from small ruminants. initial observations on seven goats infected with cloned caprine arthritis-encephalitis virus (caev) showed that rt-pcr on milk cells is as reliable as coculture for detecting viral infection, and is quicker and simpler. with a suitable choice of redundant primers followed by a semi-nested amplification, it proved p ...	1997	9112733
productive replication of caprine arthritis-encephalitis virus is associated with induction of apoptosis.	caprine arthritis-encephalitis virus (caev), an ungulate lentivirus, causes a natural infection in goats. the present report demonstrates that in vitro, caev infection is associated with apoptosis, characterized by morphological changes such as condensation of chromatin and the appearance of apoptotic bodies. the presence of dna fragments was documented by the appearance of a dna 'ladder' in agarose gel electrophoresis, as well as by in situ end-labelling of dna ends. in addition, flow cytometri ...	1997	9129652
dutpase-minus caprine arthritis-encephalitis virus is attenuated for pathogenesis and accumulates g-to-a substitutions.	the importance of the virally encoded dutpase for caev replication, invasiveness, pathogenesis, and genetic stability was investigated in goats infected by viruses with single point (du-g) and deletion (du-1) mutations of the dutpase gene (du gene). the du gene was found to be dispensable for caev replication in vivo as judged by times taken to seroconvert, frequencies of viral isolation, and tissue distribution of viral rnas. du- reversion at week 34 in one of three goats infected with the sing ...	1997	9151845
caprine arthritis-encephalitis virus: detection of proviral dna in lactoserum cells.		1997	9160533
immunohistochemical identification of caprine arthritis-encephalitis virus in paraffin-embedded specimens from naturally infected goats.	the expression of caprine arthritis-encephalitis virus capsid protein was studied in seropositive naturally infected asymptomatic goals (10< seropositive naturally infected encephalitic kids (12) and goats (4), and noninfected control goats (3). rabbit antiserum to recombinant viral capsid and matrix proteins were used in a biotin-streptavidin-alkaline phosphatase complex immunohistochemical method on sections of formalin- and ethanol-fixed tissue specimens. macrophages in inflamed areas of the ...	1997	9163873
looking for leads in hiv's battle with immune system.		1997	9182329
immortalization of caprine fibroblasts permissive for replication of small ruminant lentiviruses.	to establish immortalized caprine fibroblastic cell lines permissive for replication of small ruminant lentiviruses.	1997	9185961
evaluation of selected antibiotic residue screening tests for milk from individual goats.	because somatic cell counts (scc) of caprine milk are higher than scc of bovine milk, the performance of antibiotic residue tests for screening bovine milk was investigated for caprine milk. eighty-five does that were free of antibiotic usage for at least 30 d and that were free of clinical mastitis were sampled at three milkings during a 37-d period. at each sampling, foremilk was collected for bacteriological analysis, and composite bucket milk samples were collected for antibiotic testing and ...	1997	9201581
immune responses in goats to caprine arthritis-encephalitis virus.	in this study, goats were experimentally infected with caprine arthritis-encephalitis virus (caev). anti-caev antibodies were detected in vivo using indirect enzyme-linked immunosorbent assay (elisa) and western blot assays. the results showed that the sensitivity of detection of anti-caev antibodies using indirect elisa was relatively high, whereas western blotting was very sensitive for detection of p28 anti-caev antibody as 4 days postinfection. apparently, because of high immunogenicity of p ...	1997	9210285
changes in the leukocyte phenotype profile of goats infected with the caprine arthritis encephalitis virus.	the proportions of different sub-populations of leukocytes in five healthy goats and five goats infected with the caprine arthritis encephalitis virus (caev) were examined using immunofluorescence and flow cytometry. a panel of monoclonal antibodies that identified a monocytegranulocyte marker (gmi); the cd4, cd8, igm, mhc class i, mhc class ii and t19 antigens, and the gamma delta (gamma delta) t cell receptor was used. we observed a significant (p = 0.016) reduction in the proportion of monocy ...	1997	9220584
type 1 and type 2 cytokine gene expression by viral gp135 surface protein-activated t lymphocytes in caprine arthritis-encephalitis lentivirus infection.	peripheral blood mononuclear cells (pbmc) from saanen goats experimentally infected with the lentivirus caprine arthritis-encephalitis virus (caev) were evaluated by semiquantitative reverse transcriptase pcr for gamma interferon (ifn-gamma), interleukin-4 (il-4), and il-2 gene expression following in vitro stimulation with purified caev gp135 surface protein (su). studies examined three goats with chronic arthritis and four clinically asymptomatic goats at 5 years postinfection. su-responsive i ...	1997	9223529
genomic heterogeneity of small ruminant lentiviruses: existence of heterogeneous populations in sheep and of the same lentiviral genotypes in sheep and goats.	we have recently shown that french small ruminant lentiviruses (srlv) from sheep are more similar to caprine arthritis encephalitis virus (caev) than to visna maedi virus (vmv) in a conserved region of the pol gene. to extend these results, we have examined sequences from a variable region of the env gene in french srlv. we found that they were nearly equally distant from both caev and vmv strains, suggesting a considerable divergence since the initial introduction of the virus. analysis of sepa ...	1997	9229003
t-lymphocyte populations in the blood of caprine arthritis encephalitis virus-infected goats.	the effect of natural infection by caprine arthritis encephalitis virus on the phenotypic pattern of t lymphocytes in peripheral blood was studied in a herd of 127 milking goats by flow cytometry. total leukocyte and t-lymphocyte numbers tend to decrease with age, with only small changes in the cd4/cd8 ratio. the lymphocyte phenotypes show no strong correlation with seropositivity to caev or the presence of clinical symptoms, suggesting that this macrophagetropic lentivirus does not greatly effe ...	1997	9239842
caev infection does not affect prevalence of bacterial mastitis in goats.		1997	9257456
caprine arthritis encephalitis virus dysregulates the expression of cytokines in macrophages.	caprine arthritis encephalitis virus (caev) is a lentivirus of goats that leads to chronic mononuclear infiltration of various tissues, in particular, the radiocarpal joints. cells of the monocyte/macrophage lineage are the major host cells of caev in vivo. we have shown that infection of cultured goat macrophages with caev results in an alteration of cytokine expression in vitro. constitutive expression of interleukin 8 (il-8) and monocyte chemoattractant protein 1 (mcp-1) was increased in infe ...	1997	9311828
expression of cytokine mrna in lentivirus-induced arthritis.	infection of goats with the lentivirus caprine arthritis encephalitis virus (caev) leads to persistent infection and development of chronic arthritis. we analyzed the expression of cytokines and viral rna in the joints of goats at early time points after experimental infection with caev and in those of animals suffering from chronic arthritis as a result of natural infection. in situ hybridization experiments showed that the pattern of cytokine expression in caprine arthritis was similar to that ...	1997	9327739
north american and french caprine arthritis-encephalitis viruses emerge from ovine maedi-visna viruses.	the full extent of genetic diversity among small ruminant lentiviruses (srlvs), i.e., caprine arthritis encephalitis viruses (caevs) and maedi-visna viruses (mvvs), remains unknown. this is due in part to the fact that few sequences of caev are available. to contribute to this knowledge, gag, pol, and env nucleotide sequences from an srlv named ca680 originating from a goat from western france were determined. this analysis revealed that this virus is closely related to the cork and 63 caev amer ...	1997	9356342
effects of infection by caprine arthritis-encephalitis virus on milk production of goats.	the effects of caprine arthritis-encephalitis virus on lactational performance of goats were examined. the results of an elisa for antibodies against caprine arthritis-encephalitis virus were compared with milk production records. mean production of milk, protein, fat, and lactose and somatic cell counts were compared for seropositive and seronegative goats of similar ages. the results from 1799 lactating goats from 66 herds suggested that milk production was similar for 1-yr-old goats that test ...	1997	9361211
envelope glycoprotein nucleotide sequence and genetic characterization of north american ovine lentiviruses.	ovine lentiviruses (ovlv) resemble human immunodeficiency viruses in genomic organization, viral heterogeneity, and spectrum of cytophenotypic expression. to gain a better understanding of the relationship of north american ovlv isolates with other characterized ovlv strains, the complete dna nucleotide sequence of the env region of a highly lytic (rapid/high) ovlv strain (85/34) was determined and compared with the sequence of amplicons within env of three other ovlv strains of varying cytophen ...	1997	9375017
cytokine production in vitro by macrophages of goats with caprine arthritis-encephalitis.	the response of caprine macrophages to exposure to caprine arthritis-encephalitis virus (caev) and lipopolysaccharide (lps) was investigated in female nubian and nubian crossbreed of goats. macrophages were matured in vitro from monocytes isolated from blood of control and caev-infected goats and the concentrations of tumor necrosis factor (tnf-alpha) and interleukin-6 (il-6) in culture supernatant after exposure of cells to lps and virus were assayed. though barely detectable in unstimulated ce ...	1997	9449535
expression of tnf alpha in arthritis caused by caprine arthritis encephalitis virus.	goats infected with caprine arthritis encephalitis virus (caev) develop chronic arthritis sharing many features with human rheumatoid arthritis (ra). tnf is thought to be a key mediator contributing to the formation of the arthritic lesion in ra. we studied this cytokine in goats suffering from chronic arthritis. tnf alpha expressing cells were detected by in situ hybridization in synovial membranes of arthritic carpal joints. expression of tnf alpha did not correlate with the degree of viral re ...	1996	8988874
the response of goat brain cells to infection by caprine arthritis-encephalitis virus.	caprine arthritis-encephalitis virus is a lentivirus of goats causing encephalomyelopathy acutely in young goats and occasionally in late stages of chronically infected adult goats. to determine the specific brain cells infected by the virus and the response of other cell types, goat cerebrum explant cultures prepared from newborn goat kids were infected by virus application. infection of brain cultures was also possible by coculture with virus-infected macrophages. predominantly, microglia cell ...	1996	8997523
activation of caprine arthritis-encephalitis virus long terminal repeat by gamma interferon.	caprine arthritis-encephalitis virus (caev) is a lymphotropic lentivirus whose replication increases during monocyte maturation. we examined gene expression directed by the caev long terminal repeat (ltr) in a promonocytic cell line stimulated with several agents. our results demonstrate that the caev ltr is activated by treatment of immature monocytes with gamma interferon (ifn-gamma) or a phorbol ester but not with tumor necrosis factor alpha or lipopolysaccharide. the cis-acting element in th ...	1996	8523577
replication properties of dutpase-deficient mutants of caprine and ovine lentiviruses.	the virion-associated dutpase activities of caprine arthritis-encephalitis virus (caev) and visna virus were determined by using an assay which measure the actual ability of the dutpase to prevent the dutp misincorporations into cdna during reverse transcription. we showed that the caev molecular clone from the cork isolate was dutpase defective as a result of a single amino acid substitution. using this point mutant and deletion mutants of caev as well as a deletion mutant of visna virus, we de ...	1996	8551582
hiv and human endogenous retroviruses: an hypothesis with therapeutic implications.	the enzyme dutp pyrophosphatase (dutpase, ec 3.6.1.23) is essential for cellular dna replication and cell viability by virtue of its role in reducing the availability of dutp as a substrate for dna polymerases. several members of the onco- and lentivirus families of retroviruses encode dutpases and mutant strains of these viruses defective in this enzyme exhibit suboptimal replication kinetics. among the lentiviruses there exists a surprising phylogenetic discontinuity in the distribution of dut ...	1996	9104494
two species of rev proteins, with distinct n termini, are expressed by caprine arthritis encephalitis virus.	several cdna clones representing alternatively spliced rev-specific transcripts were isolated from a cdna library prepared from himalayan tahr cells infected with caprine arthritis encephalitis virus (caev). we previously characterized two rev-like cdna species, d1 and d2, and a tat e1 cdna containing the rev coding sequence downstream to the tat. in these cdnas, the rev coding domain derives its amino terminus from the n terminus of env, which is spliced to the 3' open reading frame encoding th ...	1996	8642706
a long term study of goats naturally infected with caprine arthritis-encephalitis virus.	the caprine arthritis-encephalitis virus (caev) is a big problem in dairy goat industry. little is known about its characteristics in naturally infected goat herds. the aims of this study were: 1) to study how antibody expression, measured by agar gel immunodiffusion test (agidt), varied over time in naturally infected, seropositive goats, 2) to observe clinical signs in seropositive adult goats and 3) to follow seroconversion and gamma globulin concentration in goat kids artificially reared on ...	1996	8659344
-pcr for the detection of lentiviruses from small ruminants-.	the polymerase chain reaction has all attributes of a promising diagnostic technique. it is rapid, simple to perform and extremely sensitive. in a pcr developed for the detection of small ruminant lentiviruses (srlv), we found under ideal conditions a detection on sensitivity up to less than 10 template dna copies. the diagnostic application of pcr was not fully satisfying, even when the technique was refined by the use of a panel of suitable primer pairs. the reliability of pcr in blood and mil ...	1996	8720734
restrictive type of replication of ovine/caprine lentiviruses in ovine fibroblast cell cultures.	caprine arthritis-encephalitis virus (caev) is a natural lentivirus pathogen of goats. caev, like all members of the ovine/ caprine lentivirus family, has an in vivo tropism for cells of the monocyte/macrophage cell lineage and activation of viral gene expression is observed only following differentiation of monocytes to macrophages. in addition to cells of the monocyte/ macrophage lineage, caev and the closely related maedi visna virus of sheep (mvv) can also replicate productively in fibro-epi ...	1996	8806484
variations in lentiviral gene expression in monocyte-derived macrophages from naturally infected sheep.	seventy-nine 1-year-old lambs from three individual farms and a feedlot were examined for natural lentivirus infection. we used three different methods to detect infection and to identify the stage of the ovine lentivirus life cycle in blood-derived macrophages. cytopathic infectious virus was obtained from 14/14 border leicester animals obtained from a naturally infected flock. neither virus particles, virus proteins, virus specific antibodies nor viral dna were detected in samples from 34 lamb ...	1996	8811001
requirement of caprine arthritis encephalitis virus vif gene for in vivo replication.	replication of vif-caprine arthritis encephalitis virus (caev) is highly attenuated in primary goat synovial membrane cells and blood-derived macrophages compared to the wild-type (wt) virus. we investigated the requirement for caev vif for in vivo replication and pathogenicity in goats by intra-articular injection of either infectious proviral dna or viral supernatants. wild-type caev dna or virus inoculation induced persistent infection resulting in severe inflammatory arthritic lesions in the ...	1996	8862419
replication in goats in vivo of caprine arthritis-encephalitis virus deleted in vif or tat genes: possible use of these deletion mutants as live vaccines.		1996	8882321
highly sensitive qualitative and quantitative detection of reverse transcriptase activity: optimization, validation, and comparative analysis with other detection systems.	an ultra-sensitive assay for reverse transcriptase (rt) activity called amp-rt has been developed. an in vitro transcribed heteropolymeric rna sequence was used as a template, and polymerase chain reaction (pcr) amplification with southern-blot hybridization served as a detection system for the cdna product of the reaction. titration of mg2+ and mn2+ concentrations using the human immunodeficiency virus type 1 (hiv-1) and the human t lymphotropic virus type 1 (htlv-i), respectively, showed optim ...	1996	8882946
detection of caprine arthritis--encephalitis virus rna in macrophages by in situ hybridization using fluorescein-labelled single-stranded rna probes.	the use of in situ hybridization (ish) for the detection of caprine arthritis-encephalitis virus (caev) rna with fluorescein-11-utp-labelled single-stranded rna probes is described. three different probes were made by pcr amplification of proviral caev dna (strain 75-g63). the pcr products were cloned into the plasmid pam-18, and labelled single-stranded rna probes were synthesized by the use of rna polymerase. the ltr probe was able to detect viral rna in caev-infected, cultured caprine macroph ...	1996	8914248
genetic characterization of two phenotypically distinct north american ovine lentiviruses and their possible origin from caprine arthritis-encephalitis virus.	ovine and caprine lentiviruses are closely related genetically and antigenically although the diseases that these viruses cause in their respective host animals can vary greatly. in sheep, syndromes consist primarily of interstitial pneumonia with rare occurrences of arthritis and encephalitis, whereas in goats, the disease expresses mainly as arthritis in adult animals with rare cases of encephalitis in newborns. experimentally, viruses from either sheep or goats can infect animals of the recip ...	1996	8918528
retroviruses and systemic lupus erythematosus.	in some animal models of autoimmune diseases the roles of exogenous and endogenous retroviruses are clearly defined. in ungulates caprine arthritis encephalitis virus, equine infectious anemia virus or maedi-visna virus infections cause a well-defined autoimmune disease and the appearance of seropositivity of the animals is of diagnostic value. likewise, in mrl lpr/lpr mice insertion of a retrotransposon into the fas gene could clearly be shown to cause survival of autoreactive lymphocytes. desp ...	1996	8930671
definition of the rre binding and activation domains of the caprine arthritis encephalitis virus rev protein.	caprine arthritis encephalitis virus (caev) is a lentivirus which is closely related by nucleotide sequence and biological properties to visna virus and is more distantly related to the human aids virus, hiv-1. previous studies indicated that the caev rev protein (rev-c) functions as a trans-activator of mrna cytoplasmic transport and expression. the function of rev-c is mediated through an rna element (rre-c) present between nucleotides (nt) 7906 and 8110 in the caev env gene. in this study, rn ...	1996	8941328
serologic diagnosis of caprine arthritis-encephalitis by elisa with two recombinant proteins in a parallel testing format.	a scheme for screening sera for antibodies to caprine arthritis-encephalitis virus (caev) was evaluated for its ability to identify positive and negative samples in a population with heterogeneous risk factors, using the criteria of sensitivity, specificity and positive predictive value. five hundred caprine serum samples were tested using a transmembrane recombinant-based elisa. those that gave positive results were considered positive, while those with equivocal or negative results were retest ...	1995	8567987
changes in serum antioxidant concentrations during infection with caprine lentivirus.	we are currently using caprine arthritis encephalitis virus (caev) infection in goats as a model to understand changes in some clinical parameters and host response to infection with human immunodeficiency virus (hiv). the objective of this study was to measure changes in serum antioxidant activities in various age groups of goats infected with caev. serum from caev-infected goats had significantly higher catalase activity (105.47 +/- 5.96 ku/l) than serum from healthy control goats (79.92 +/- 1 ...	1995	8574149
prevalence, spread and control of caprine arthritis-encephalitis virus in dairy goat herds in new south wales.	a study of the prevalence, spread and control of caprine arthritis-encephalitis virus (caev) in dairy goat herds in new south wales (nsw) during 1986-1988 found that 56.8% of 1484 goats in 14 dairy herds were infected with caev. the prevalence of caev infection within most herds not implementing control measures increased during the study. at the end of the study, 59.7% of 1322 goats were infected. the prevalence of caev increased with age. differences between breeds were less apparent. within s ...	1995	8585848
[serologic investigations on the occurrence of maedi-visna antibodies in game ruminants].	the lentiviruses of small domestic ruminants (maedi-visna and caprine arthritis-encephalitis virus) have been shown to be infective for each other. there are only few investigations of virus susceptibility of other species of animals. the aim of our study reported here was to evaluate sera of wild animal species for lentivirus antibodies. 344 sera of capreolus capreolus, cervus elaphus and dama dama from a territory with known sheep populations prevalence were tested in the agar gel immunodiffus ...	1995	8593775
comparative studies of bacterially expressed integrase proteins of caprine arthritis-encephalitis virus, maedi-visna virus and human immunodeficiency virus type 1.	integrase (in) proteins mediate an essential step in retroviral life cycles, the integration of reverse-transcribed viral dna into the host genome. to create tools for direct comparative investigations, hexahistidine-tagged in proteins of the phylogenetically related lentiviruses caprine arthritis-encephalitis virus (caev), maedi-visna virus (mvv) and human immunodeficiency virus type 1 (hiv-1) were expressed in escherichia coli. after purification by affinity chromatography, the active enzymes ...	1995	9049371
characteristics of ovine and caprine lentivirus infections.	a majority of ovine lentivirus (ovlv) infections seen on farms develop after long incubation and a slow progression of disease to death but in nature they may also have short latency and cause acute leukoencephalitis and/or acute arthritis and pneumonia in young kids or lambs with exceptionally high mortality. histopathologically, ovlv diseases may be characterized by lymphoid infiltration, lymphoid hyperplasia with germinal centers and plasmocytosis in the lungs and/or in the cns, joints and ud ...	1995	7475326
genetic and antigenic characterization of caev (caprine arthritis-encephalitis virus) recombinant transmembrane protein.	the env gene fragment of an italian strain of caprine arthritis encephalitis virus (caev) coding for the hydrophilic region of transmembrane protein was amplified, cloned and expressed in prokaryotic system as fusion protein with glutathione-s-transferase. sequence analysis revealed 63 to 66% amino acid homology, when compared with three ovine lentiviruses and 83% when compared with one caprine lentivirus. the recombinant transmembrane protein was efficiently expressed, purified under denaturing ...	1995	7483249
t and b cell responses to mycobacterial 65-kda heat-shock protein in sheep infected with maedi visna virus.	sheep infected with maedi visna virus were tested for immune reactivity to recombinant hsp65 and tuberculin ppd from mycobacteria. the results showed that both naturally and experimentally infected animals had elevated igm but not igg or iga antibodies to hsp65 from mycobacterium leprae or m. bovis. in experimentally infected animals, the elevated igm antibodies appeared in blood from about 3 to 4 weeks postinfection. increased t cell proliferative responses to hsp65 and ppd were also found in b ...	1995	7532120
bacterial expression of the caprine arthritis-encephalitis virus gag and env proteins and their use in enzyme-linked immunosorbent assay.	the core protein and the transmembrane protein, encoded for the structural genes gag and env, respectively, of caprine arthritis-encephalitis virus were amplified by use of polymerase chain reaction, cloned into a pgex-2t vector, and expressed in escherichia coli as fusion proteins with the glutathione s-transferase at their c-terminus. the recombinant proteins were purified and evaluated by use of an elisa. sera from 269 goats were tested, and the results were compared with those obtained by us ...	1995	7574148
selected models of hiv-induced neurological disease.		1995	7587361
glycosylation of igg during potentially arthritogenic lentiviral infections.	agalactosyl igg [gal(0)] was first discovered in patients with rheumatoid arthritis (ra). however, the proportion of this glycoform is also raised in tuberculosis and leprosy. this has helped reinforce the suggestion that ra may be triggered by a mycobacterium-like slow bacterial infection. on the other hand, arthritis can occur in mycobacterial diseases, so raised gal(0) could be associated with a tendency to arthritis, rather than with a particular type of infection. therefore, we wished to fi ...	1995	7597380
the caprine arthritis encephalitis virus tat gene is dispensable for efficient viral replication in vitro and in vivo.	caprine arthritis encephalitis virus (caev) is a lentivirus closely related to visna virus and more distantly to other lentiviruses, such as human immunodeficiency virus. the genomes of visna virus and caev contain a tat gene encoding a protein able to weakly transactivate its own long terminal repeat, suggesting that transactivation may be a dispensable function for viral replication. three different tat gene mutants of an infectious molecular clone of caev were used to study their replication ...	1995	7636990
the tendency of lentiviral open reading frames to become a-rich: constraints imposed by viral genome organization and cellular trna availability.	human immunodeficiency virus type 1 (hiv-1) and other lentiviridae demonstrate a strong preference for the a-nucleotide, which can account for up to 40% of the viral rna genome. the biological mechanism responsible for this nucleotide bias is currently unknown. the increased a-content of these viral genomes corresponds to the typical use of synonymous codons by all members of the lentiviral family (hiv, siv, biv, fiv, caev, eiav, visna) and the human spuma retrovirus, but not by other retrovirus ...	1995	7666442
the vif gene is essential for efficient replication of caprine arthritis encephalitis virus in goat synovial membrane cells and affects the late steps of the virus replication cycle.	complex retrovirus genomes contain a variable number of accessory genes, among which is the vif gene. we investigated in vitro the role of the vif gene of caprine arthritis encephalitis virus (caev) by studying the phenotype of five vif mutants after infection of primary goat synovial membrane (gsm) cells and blood-derived monocytes/macrophages. any deletion introduced into the vif gene resulted in slow and low viral replication and production of virions with an infectious titer lower than that ...	1995	7745671
erratic g-->a hypermutation within a complete caprine arthritis-encephalitis virus (caev) provirus.	the complete nucleotide sequence of an integrated provirus of caprine arthritis-encephalitis virus (caev) has been determined. the provirus was defective due to extensive g-->a hypermutation. rather than being a smooth phenomenon distributed throughout the genome it was highly erratic with hypermutated and normal regions being juxtaposed, probably reflecting local fluctuations in the intracellular dctp pool during reverse transcription of the caev genome. the pattern of sequence variation within ...	1995	7778264
immunopathology of chronic lentivirus-induced arthritis.	this study evaluated histopathology and mononuclear cell phenotypes in synovial lesions of chronic arthritis induced by experimental infection of saanen goats with caprine arthritis-encephalitis lentivirus. histological examination of carpal joint synovium of three infected goats with clinical arthritis revealed progressive lesions consisting of membrane villus hypertrophy with extensive angiogenesis and mononuclear cell infiltration and degenerative changes of membrane villus necrosis associate ...	1995	7778682
genomic heterogeneity in the pol region of ovine lentiviruses obtained from bronchoalveolar cells of infected sheep from france.	in order to determine the genomic heterogeneity of ovine lentiviruses, we analysed eight isolates from naturally infected sheep from one geographical region of france. a 475 nt fragment in the region of the pol gene coding for reverse transcriptase was amplified by rt-pcr from rna directly extracted from uncultured bronchoalveolar lavage cells. the resulting pcr fragments were analysed by restriction enzyme digestion, cloned in a ta vector and sequenced. restriction enzyme analysis showed distin ...	1995	7782784
chemiluminescent detection of caprine arthritis encephalitis virus with a pcr-generated single stranded nonradiolabelled probe.	a 814-bp digoxigenin-labelled single stranded dna probe was produced and utilized in slot-blot hybridization for detection of caprine arthritis encephalitis virus (caev) in goat synovial membrane (gsm) cell culture infected with caev. the sensitivity of a pcr-generated probe was compared with a random primer labelled probe. the probe with digoxigenin-dutp incorporated in the pcr reaction mixture was more sensitive for rna detection than the random primer probe and it was much simpler to use. the ...	1995	7785189
infection of lactating goats by mammary instillation of cell-borne caprine arthritis-encephalitis virus.	the possibility of transmission of caprine arthritis-encephalitis virus between lactating goats by the transfer of infected cells during milking has been examined experimentally. four virus-free saanen goats were infected, two in full lactation and two during the drying off period, by instillation of infected allogeneic cells into the milk canal of one-half of the udder. all four goats became infected, as shown by the isolation of virus from peripheral blood monocytes, seroconversion, and presen ...	1995	7790575
peripheral blood and synovial fluid mononuclear cell phenotypes in lentivirus induced arthritis.	to identify the phenotypes and activation status of peripheral blood (pb) and synovial fluid (sf) mononuclear cells associated with caprine arthritis encephalitis virus (caev) induced arthritis in goats.	1995	7699688
depressed cd4+ t lymphocyte proliferative response and enhanced antibody response to viral antigen in chronic lentivirus-induced arthritis.	the proliferative response of peripheral blood mononuclear cells (pbmc) stimulated with caprine arthritis-encephalitis virus (caev) surface glycoprotein (su) was depressed 4- to 20-fold in saanen goats with chronic caev-induced arthritis compared with asymptomatic goats. phytohemagglutinin-stimulated responses were not depressed. complement depletion of pbmc with anti-cd4 or anti-cd8 monoclonal antibodies identified cd4+ t lymphocytes as the antigen-responsive cells in both high-responder asympt ...	1995	7844368
antibody prevalence of caprine arthritis encephalitis virus (caev) in goats in turkey.	in this study, a serological survey in goat herds for antibodies against caprine arthritis encephalitis virus (caev) in turkey is described. 808 serum samples were collected from three state farms and seven private flocks in different regions of turkey. the serologic examination was performed by agar gel immunodiffusion (agid) technique. 16 (1.9%) out of 808 sera deriving from two state farms (n = 14) and one private herd (n = 2) were found to be serologically positive. the findings are discusse ...	1994	7851298
caprine arthritis encephalitis virus infection changes caprine blood monocyte responsiveness to lipopolysaccharide stimulation in vitro.	the effects of caprine arthritis encephalitis virus (caev) infection on cytokine activity of caprine monocytes stimulated with escherichia coli lipopolysaccharide (lps) were examined. compared with supernatants from lps-stimulated monocytes of caev-negative goats, supernatants from caev-positive goats stimulated less proliferation of murine thymocytes in the mtt (3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide) assay, showed about 50% less il-1 activity on the il-1-dependent cell li ...	1994	7856074
[caprine arthritis-encephalitis in algeria].	during an outbreak of caprine arthritis-encephalitis on an experimental farm, the virus responsible for this disease was isolated from imported animals. a serological survey was then carried out with the purpose of determining the prevalence of the disease among other imported herds of goats, local herds and mixed herds. positive serological results were found at relatively high levels in both imported and mixed herds. all the local herds, however, yielded negative serological results, suggestin ...	1994	7863063
comparative functional analysis of the various lentivirus long terminal repeats in human colon carcinoma cell line (sw480 cells) and feline renal cell line (crfk cells).	basal promoter activities of various lentiviral long terminal repeats (ltrs) in a human colon carcinoma cell line (sw480 cells) and a feline renal cell line (crfk cells) were examined by the chloramphenicol acetyltransferase (cat) assay using the ltr-cat reporter plasmids. in sw480 cells, the basal promoter activities induced by ltrs of visna virus, caprine arthritis-encephalitis virus (caev), and simian immunodeficiency virus (sivagm) were moderate, and those induced by ltrs of human immunodefi ...	1994	7865591