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significance of premature stop codons in env of simian immunodeficiency virus.the location of the translational termination codon for the transmembrane protein (tmp) varies in three infectious molecular clones of simian immunodeficiency virus from macaques (sivmac). the sivmac251 and sivmac142 infectious clones have premature stop signals that differ in location by one codon; transfection of these dnas into human hut-78 cells yielded virus with a truncated tmp (28 to 30 kilodaltons [kda]). the sivmac239 infectious clone does not have a premature stop codon in its tmp-codi ...19892795718
sequence of a novel simian immunodeficiency virus from a wild-caught african mandrill.since the isolation of an hiv-2-related virus from captive macaques (sivmac), the origin of human immunodeficiency viruses, a much debated subject, has been attributed to monkeys. the sequence of sivagm, which is derived from a naturally infected african green monkey, shows equal relatedness to hiv-1 and hiv-2, suggesting that the derivation of these viruses from sivagm is unlikely. recent sequence analysis of siv from a captive sooty mangabey (sivmac), however, shows its close relatedness to hi ...19892797181
the gag precursor of simian immunodeficiency virus assembles into virus-like particles.to examine the potential role of the gag precursor polyprotein in morphogenesis and assembly of the simian immunodeficiency virus (siv), we have expressed the gag gene of sivmac using a baculovirus expression vector. infection of insect cells with recombinant virus containing the entire gag gene results in high expression of the gag precursor protein, pr57gag. the recombinant protein is myristylated and is released in the culture supernatant in an insoluble particulate form. a point mutation in ...19892684654
molecularly cloned simian immunodeficiency virus sivagm3 is highly divergent from other sivagm isolates and is biologically active in vitro and in vivo.simian immunodeficiency viruses have been isolated from african green monkeys originating from ethiopia. a molecular clone, termed sivagm3, was found to be highly divergent from sivagmtyo-1 in terms of its restriction map and partial nucleotide sequence. a premature stop codon present in the transmembrane protein of sivagm tyo-1 was absent in sivagm3. sivagm3 was biologically active in vitro and in vivo and displayed characteristics reminiscent of the wild-type virus. biological activity was dem ...19892685353
aids vaccines: concepts and first trials.two categories of obstacles impede the development of an aids vaccine. virological obstacles are due to lentiviruses, to which hiv and siv belong, having developed strategies to escape the immune responses of infected hosts and establish persistent infection. these strategies are based on two mechanisms: latency corresponding to restriction of viral gene expression that renders the virus antigenically invisible, and variability, the consequences of which are antigenic shift and permanent adaptat ...19892698645
hiv-2 in rhesus monkeys: serological, virological and clinical results.diseases induced by animal retroviruses are not considered to be good models for the human acquired immunodeficiency syndrome (aids) at present. the lack of an animal model for the human immunodeficiency virus (hiv) infection presents a main problem in the complete understanding of the pathogenesis of hiv-mediated diseases. because of the homologies between simian immunodeficiency virus (siv) and hiv-2, we inoculated rhesus monkeys with hiv-2 and hiv-2 adapted in vitro to monkey cells. one of th ...19892708010
[isolation of hiv-2 from aids patient in ghana and analysis of sero-reactive patterns of ghanaian sera].institute for virus research, kyoto university, and noguchi memorial research institute in ghana jointly isolated hiv-2 from a ghanaian aids patient. ghanaian hiv-2[gh-1] was similar in genomic organization to, but different in restriction enzyme maps from the first isolated case, french lav-2 (hiv-2rod). this fact is significant in suggesting multiplicity of hiv-2 virus. hiv-2[gh-1] was different from lav-2 in its antigenicity of envprotein. sero-reactive patterns of 125 ghanaians inc ...19892724559
site-directed enzyme-linked immunosorbent assay with a synthetic simian immunodeficiency virus sivmac peptide identifying antibodies against the hiv-2 transmembrane glycoprotein.a 23-amino-acid-long peptide (aiekyledqaqlnawgcafrqvc) representing the transmembranous protein gp32 in sivmac was used in site-directed enzyme-linked immunosorbent assay (elisa) for detection of hiv-2-specific antibodies in 567 sera from bissau, guinea bissau. ninety out of the 567 sera were identified to contain hiv-2 antibodies by whole antigen elisa and western blot assays. the peptide elisa correctly identified 89 out of these 90 seropositives (sensitivity 98.9%). three sera falsely interpr ...19892469436
selective replication of simian immunodeficiency virus in a subset of cd4+ lymphocytes.although all cd4+ cells theoretically are at risk for infection by human immunodeficiency viruses or the related simian immunodeficiency viruses found in old world monkeys, only a small proportion of cd4+ lymphocytes from infected individuals have detectable virus. this suggests that immunodeficiency viruses may replicate predominantly in a minor subset or activated form of cd4+ t cells, a possibility we examined in macaques infected with a simian immunodeficiency virus isolate, siv/mne. macaque ...19892470099
functional role of human immunodeficiency virus type 1 vpu.to investigate the role of vpu in the replication and cytopathicity of human immunodeficiency virus type 1 (hiv-1), infectious proviruses were constructed that were isogenic except for the ability to produce the protein product of vpu. the vpu-encoded protein is shown to decrease the rate of syncytium formation and cell killing in infected cd4+ human t cells, to increase greatly the export of virus particles from infected cells, and to reduce the rate of accumulation of cell-associated viral pro ...19892472639
detection of simian immunodeficiency virus in macaque lymph nodes with a sivmac envelope probe.a tritium-labeled dna envelope gene probe was used to detect simian immunodeficiency virus in formalin fixed lymph nodes from rhesus monkeys experimentally inoculated with sivmac251. cells containing siv rna produced strong hybridization signal and were present in small numbers in biopsy specimens and in much greater numbers in lymph nodes collected at autopsy. siv-infected cells were morphologically identified as lymphocytes and macrophages.19892547958
transmission of the simian immunodeficiency virus sivmne in macaques and baboons.a primate lymphotropic lentivirus was isolated on hut 78 cells after cocultivation of a lymph node from a macaque that died with malignant lymphoma. in earlier studies siv/mne was inoculated into 17 macaques and two baboons. all of the macaques became viremic and seropositive. fifteen of the macaques succumbed to a classic aids-like disease, whereas the baboons did not become viremic. the siv/mne virus has now been molecularly cloned and inoculated into macaca nemestrina and baboons. a new trans ...19892547959
epitope mapping of monoclonal antibodies against human immunodeficiency virus type 1 structural proteins by using peptides.murine monoclonal antibodies directed against the structural proteins p17 and p24 of human immunodeficiency virus type 1 were investigated in an epitope mapping system. overlapping peptides consisting of 15 amino acids of the p17 and p24 protein, respectively, were used as competitors in an enzyme-linked immunosorbent assay. three different immunogenic regions (a, b, and c) could be defined, one on p17 and two on p24. twenty monoclonal antibodies reacted with the human immunodeficiency virus typ ...19892473220
the productive infection of alveolar macrophages by simian immunodeficiency virus.alveolar macrophages obtained from healthy rhesus monkeys were infected with siv in vitro as documented by the appearance of reverse transcriptase activity in the cell-free supernatant, electronmicroscopy, and immunohistochemical methods detecting siv-related core protein. the results demonstrate permissive infection of alveolar macrophages with siv in vitro and define a system for studying macrophage-siv interactions.19892474655
the morphology of simian immunodeficiency virus as shown by negative staining electron microscopy.negative staining electron microscopy was used to study sucrose gradient-purified preparations of the simian immunodeficiency virus (sivmac251). both isolated and aggregated virus particles were observed together with some free-lying virus cores. the cores were 110 nm long and 25 to 50 nm wide and were mainly conical or wedge-like in shape. surface projections were seen on the envelope membrane of many of the virus particles; the knobs were approximately 6 nm in length, 10 nm wide and from an en ...19892475583
phosphorylation of 3'-azido-2',3'-dideoxyuridine and preferential inhibition of human and simian immunodeficiency virus reverse transcriptases by its 5'-triphosphate.3'-azido-2',3'-dideoxyuridine-5'-triphosphate was found to be a potent and highly selective inhibitor of human immunodeficiency virus type 1 and simian immunodeficiency virus reverse transcriptases. the affinity of 3'-azido-2',3'-dideoxyuridine-5'-triphosphate for the reverse transcriptases was similar to that observed for 3'-azido-3'-deoxythymidine-5'-triphosphate. both compounds were competitive inhibitors with respect to the normal substrate dttp and served at least 100 times better as substr ...19892480079
the chemistry of site-directed serology for hiv infections.the advent of site-directed serology has provided a specific and simplified means of distinguishing antibody responses to the two types of human immunodeficiency virus (hiv) in an outbred population. remarkably, human sera containing hiv antibodies and simian sera containing simian immunodeficiency virus (siv) antibodies had a very narrow amino acid dependence in the 23 residue long peptide, 582ala-604cys, used as antigen. a single dominating antigenic site was demonstrated in the c-terminal par ...19892480152
cd4-pseudomonas exotoxin hybrid protein blocks the spread of human immunodeficiency virus infection in vitro and is active against cells expressing the envelope glycoproteins from diverse primate immunodeficiency retroviruses.we previously described an unusual recombinant protein, designated cd4(178)-pe40, containing the gp120 binding region of human cd4 linked to active regions of pseudomonas exotoxin a. the ability of this molecule to selectively inhibit protein synthesis in cells expressing the surface envelope glycoprotein of human immunodeficiency virus (hiv) suggested this molecule may be useful in treating infected individuals. to further evaluate its therapeutic potential, several in vitro properties of this ...19892480605
structural variability of the external glycoprotein of simian immunodeficiency virus propagated in cell cultures.we examined the structural variability of the external glycoprotein (gp130) of a cloned simian immunodeficiency virus (siv) in culture. cloned sivmac142 was either permanently propagated in hut-78 cells or sequentially passaged in mt-2 cells. after 12, 24 and 60 passages of permanent or lytic cell-culture systems, virus was harvested, gp130 was isolated and peptide mapped. comparison of gp130 peptide maps of sivmac142 by computer graphic analysis revealed a variation in relative spot intensity o ...19892508710
isolation and partial characterization of an hiv-related virus occurring naturally in chimpanzees in gabon.two cases of wild-born chimpanzees which were positive for hiv-1 antibodies were observed in gabon. these animals were never experimentally exposed to hiv-1 and had no history of inoculation with human blood products. a retrovirus was isolated from one of these chimpanzees. several of the viral proteins from this virus, designated sivcpz-gab-1 (simian immunodeficiency virus from chimpanzee), differed in molecular weight from the known corresponding hiv/siv proteins. the major gag protein of sivc ...19892512955
effect of recombinant soluble cd4 in rhesus monkeys infected with simian immunodeficiency virus of macaques.the cd4 molecule is a high-affinity cell-surface receptor for the human immunodeficiency virus (hiv-1) and a soluble truncated form of cd4 produced by recombinant dna technology is a potent inhibitor of hiv-1 replication and hiv-1-induced cell fusion in vitro. rhesus monkeys infected with the simian immunodeficiency virus of macaques (sivmac), a virus closely related to hiv-1, develop an aids-like syndrome, and so provide an important model for the evaluation of potential aids therapies. we have ...19892536140
cellular localization of simian immunodeficiency virus in lymphoid tissues. i. immunohistochemistry and electron microscopy.simian immunodeficiency virus (siv) is a lentivirus with genetic relatedness to the human immunodeficiency viruses (hiv-1 and hiv-2). it induces a fatal syndrome in rhesus monkeys that closely parallels the clinical course of aids in humans. the authors used double-labeling immunohistochemical procedures on rhesus lymph node and spleen taken during different time periods after siv infection to localize the p27 gag protein to specific cellular immunophenotypes. in animals with follicular hyperpla ...19892537016
cellular localization of simian immunodeficiency virus in lymphoid tissues. ii. in situ hybridization.lymph nodes and spleens were collected at autopsy and by biopsy from 29 rhesus monkeys infected with simian immunodeficiency virus (siv). lymph nodes were classified morphologically into stages of follicular hyperplasia, follicular involution, follicular depletion with normal or expanded paracortices, follicular and paracortical depletion, granulomatous lymphadenitis, or normal. the distribution of siv rna was determined by in situ hybridization using a nick translated, 35s labeled, sivmac dna p ...19892537017
the visna virus long terminal repeat directs expression of a reporter gene in activated macrophages, lymphocytes, and the central nervous systems of transgenic mice.visna virus is a lentivirus which causes a slow progressive disease involving the immune system and the central nervous system. to determine the role of the viral long terminal repeat (ltr) in targeting the virus to specific host cells and tissues, transgenic mice were constructed which contained the visna virus ltr directing expression of the bacterial gene encoding chloramphenicol acetyltransferase (cat). analysis of the transgenic mouse tissues for cat activity revealed that the viral ltr was ...19892539492
experimental infection of rhesus monkeys with siv isolated from african green monkeys.to establish an animal model for aids, 6 juvenile rhesus monkeys were infected intravenously with cell-free sivagmtyo-1, 5, or 7. one animal was infected with siv of known pathogenicity isolated from a sooty mangabey (sivsmm). the 2 animals infected with tyo-1, 1 of 2 infected with tyo-7 and the 1 infected with sivsmm seroconverted within 4-8 weeks after infection and infectious virus could be recovered 8-10 or 44 weeks after infection. three of the 4 seroconverted monkeys developed a persistent ...19892540114
no evidence for the contamination of live oral poliomyelitis vaccines with simian immunodeficiency virus. 19892540773
the biology and epidemiology of hiv infections.the world now has a pandemic of infection by the human immunodeficiency virus type i (hiv-1). more recently, a focus of epidemic hiv-2 infection in west africa has been noted and this too is spreading internationally. hiv-2 closely resembles a simian lentivirus, siv; siv isolates have now been made from african (but not asian) old world monkeys and siv infection in macaques may provide the best animal model for hiv. all of these viruses share a tropism for the cd4 molecule, which is intimately i ...19892541125
nonhuman primates and the acquired immunodeficiency syndrome: a union of necessity.because of the close phylogenetic relationship, nonhuman primates are highly susceptible to human pathogens, including infection of chimpanzees by the human immunodeficiency virus (hiv), the causative agent of aids. this, and the existence of a highly related simian virus, siv, which causes an aids-like disease in macaques, emphasizes the continued importance of using nonhuman primates as model systems for identifying and developing prophylaxis and therapy for infectious agents and, in particula ...19892541246
multiple functional domains of tat, the trans-activator of hiv-1, defined by mutational analysis.the tat gene of hiv-1 is a potent trans-activator of gene expression from the hiv long terminal repeat (ltr). to define the functionally important regions of the product of the tat gene (tat) of hiv-1, deletion, linker insertion and single amino acid substitution mutants within the tat coding region of strain sf2 were constructed. the effect of these mutations on trans-activation was assessed by measuring the expression of the bacterial chloramphenicol acetyltransferase (cat) reporter gene linke ...19892542902
antibody recognition of sivmac envelope peptides in plasma from macaques experimentally infected with siv/mne.four stretches of amino acid sequences encoded in conserved hiv-1 env domains and four parallel regions of the sivmac env (two from gp120 and two from gp41/p32e) were fused to the nh2 terminus of beta-galactosidase by recombinant dna techniques and used to analyze sera from three macaque species experimentally infected with siv/mne. all sivmac env sequences were recognized by sera from the siv/mne-inoculated macaques. western blot analysis performed with whole siv/mne, sivmac, sivagm, and hiv-1 ...19892543433
immunopathology of lentiviral infections in ungulate animals.the immunopathogenesis of lentiviral lesions in sheep and goats requires continuous replication of the virus in tissues of the animal. this entails escape from various defense mechanisms of the host. viral expression occurs mainly in tissue-specific macrophage populations and viral proteins produced by the cells induce and combine with antibodies to form immune complexes. these may be pathogenic locally. infected macrophages also present lentiviral antigens to t lymphocytes and this results in a ...19892561343
the biology and immunopathology of simian immunodeficiency virus infection. 19892561344
seroprevalence of htlv-i in portugal and evidence of double retrovirus infection of a healthy donor.the prevalence of antibodies to htlv-i in 5,475 portuguese from 6 regions spanning the country was studied. overall seroprevalence was 0.55%, indicating that portugal is not an endemic area for this virus. seropositives were distributed throughout the country, and no geographic clustering was observed. the seroprevalence of individuals who had lived in former portuguese colonies in africa (0.7%) was significantly higher than that of individuals who had not been in africa (0.36%). an increase in ...19892563718
prevalence of antibodies to siv in baboons in their native habitat.we have documented rare infection of baboons in their native habitat with simian immunodeficiency virus (siv). of 124 sera collected from yellow baboons in central tanzania, two gave high readings by sivagm elisa (greater than 1.0) and moderate by sivmac elisa (0.5-1.0). these two sera gave strong reactions to the major sivagm proteins, including gp130, by western blot analysis; their reactivity to sivmac protein was considerably weaker. similar testing of 155 sera from olive baboons of ethiopia ...19892543434
structure of simian immunodeficiency virus regulatory genes.three full-length cdna clones were obtained from cells infected with the simian immunodeficiency virus (siv) isolated from captive macaques (sivmac). nucleotide sequence analyses suggested that these represented mrna for the siv mac genes tat, rev (formerly, art/trs), and nef (formerly, 3'orf). the putative tat-specific clone was active in trans-activation of the siv mac long terminal repeat in cos-1 and jurkat cells. in contrast, the human immunodeficiency virus 1 long terminal repeat was signi ...19892544874
the open reading frame s of visna virus genome is a trans-activating gene.soon after infection of ovine cell cultures, visna virus expression is first indicated by the accumulation of two multi-spliced transcripts of 1.2 and 1.6 kb that at present we have renamed 1.4 and 1.7 kb according to their exact length. the early 1.4-kb mrna encodes for a protein which increases the level of transcripts directed from visna virus long terminal repeat (trans-activation). this trans-activating protein was previously called vep1 and at present is renamed as the product of the rev g ...19892545028
experimental infection of cynomolgus monkeys (macaca fascicularis) with simian immunodeficiency virus (sivsm).five healthy cynomolgus monkeys were inoculated intravenously with simian immunodeficiency virus (sivsm) propagated in human lymphocytes. all five animals became infected. virus was recovered from blood mononuclear cells and viral antigen was detected in serum 12 days postinoculation (pi) in all inoculated animals. virus was also isolated in all five animals tested 74 to 226 days pi. antibodies to different structural proteins of siv and hiv-2 were demonstrated by elisa, western blot, and radioi ...19892547056
interactions between simian immunodeficiency virus and mycobacterium leprae in experimentally inoculated rhesus monkeys.thirty-four rhesus monkeys were inoculated with mycobacterium leprae inoculum isolated from sooty mangabey monkeys with leprosy. later it was learned that one of the m. leprae-donor mangabeys was asymptomatically infected with simian immunodeficiency virus (siv). thus, five of the rhesus monkey were coinoculated with m. leprae and siv. three of the five became siv-positive and developed signs of leprosy and an aids-like illness. two animals remained healthy. the coinoculated leprosy-positive rhe ...19892547881
guidelines for the prevention of simian immunodeficiency virus infection in laboratory workers and animal handlers.the authors are members of a working group that formulated guidelines to minimize transmission of simian immunodeficiency virus (siv) infection to man. biosafety level (bsl) 2 standards are recommended for handling of clinical specimens and housing of siv inoculated animals. manipulation of siv preparations may be performed in a bsl 2 facility with additional bsl 3 practices and equipment; for large volume or concentrated preparations of siv bsl 3 containment is necessary. written policies regar ...19892547954
infection of macaque monkeys with simian immunodeficiency virus from african green monkeys: virulence and activation of latent infection.the virulence of three isolates of simian immunodeficiency virus from african green monkeys (sivagm) was studied in rhesus and pigtailed macaques. none of 15 rhesus monkeys and one of four pigtailed monkeys died from infection during the time they were studied (up to 33 months). sivagm was only isolated from rhesus monkeys for up to 2 months after inoculation. however, when these animals were secondarily infected with simian acquired immunodeficiency syndrome retrovirus type 1 (srv-1), sivagm wa ...19892547960
genetic analysis and infection of sivagm and sivmnd.recently, the authors determined the partial sequence of simian immunodeficiency virus (siv) from the mandrill (sivmnd) and found sivmnd to be a new member of the hiv/siv group, equidistant from other members, including sivagm. experimentally, the african green monkey and cynomolgus monkey could be infected with sivagm and the cottontop tamarin with sivmnd. however, no clinical sign of an aids-like disease was observed in these monkeys.19892547961
genetic diversity among simian immunodeficiency virus isolates from african green monkeys.to characterize isolates further within the sivagm subtype, we studied four sivagm isolates by cross-hybridization, molecular cloning, and nucleotide sequencing. our results indicate an unexpected degree of genetic variation among isolates within the sivagm subtype comparable to the variation between sivmac and hiv-2.19892547962
molecular characterization and comparison of simian immunodeficiency virus isolates from macaques, mangabeys, and african green monkeys.simian immunodeficiency virus (siv)/mne has been inoculated into three species of macaques and into baboons. virus was isolated from all the macaques who subsequently died at 15 to 120 weeks (mean 80 weeks) with various manifestations of immune deficiency. individual animals varied in their viral antibody profile as a function of time after infection. independent siv isolates obtained from african green monkeys and magabeys were compared to siv/mne for their ability to replicate in lymphocytes a ...19892547964
rhesus macaques inoculated with molecularly cloned simian immunodeficiency virus.we have isolated a biologically active molecular clone of simian immunodeficiency virus (siv), sivmac 1a11, originally obtained from a rhesus macaque at the new england regional primate research center. virus derived from cells transfected with this clone is cytopathic for rhesus peripheral blood mononuclear cells, replicates in cultures of rhesus macrophages, and infects rhesus macaques when inoculated intravenously. six macaques inoculated with sivmac 1a11 all became infected and produced anti ...19892547965
postexposure immunotherapy of simian immunodeficiency virus (siv) infected rhesus with an siv immunogen.an inactivated whole simian immunodeficiency virus (siv) immunogen given to healthy, seropositive rhesus macaques 4 months after infection had no effect on the humoral immune response to siv, the presence of antigenemia, cell-associated viremia, or disease course. further immunotherapeutic trials in this highly susceptible animal model should be carried out sooner after exposure, before significant loss of cd4 cells has occurred. the siv infected macaque model will continue to serve an essential ...19892547966
vaccine protection against simian immunodeficiency virus infection.rhesus monkeys were immunized by multiple inoculations with purified, disrupted, noninfectious simian immunodeficiency virus (siv) in adjuvant. immunized monkeys developed anti-siv antibodies detectable by whole-virus elisa and by immunoblot reactivity; these antibodies had weak neutralizing activity. one week after the last immunization, monkeys were challenged with 200-1000 animal infectious doses of uncloned, live siv. the same strain of siv that was used for vaccination was also used for cha ...19892548210
urinary neopterin concentrations in rhesus monkeys after infection with simian immunodeficiency virus (sivmac 251).two rhesus monkeys were infected with sivmac 251. elevated urinary neopterin concentrations were observed as the first sign of infection. virus-specific antibodies were detected 14 days after infection, when neopterin concentrations were already decreasing. the neopterin levels of one animal remained elevated and the virus was repeatedly isolated. urinary or serum neopterin concentrations appear to be early markers for siv infection and viremia in rhesus monkeys.19892548536
immunological reactivities of ghanaian sera with hiv-1, hiv-2, and simian immunodeficiency virus sivagm.to learn more about the relative prevalence of viruses from the human immunodeficiency virus (hiv)/simian immunodeficiency virus (siv) groups in ghana, serum samples were collected in 1986 from 47 men and women with acquired immunodeficiency syndrome (aids) or aids-related complex (arc), 57 apparently healthy individuals, and 11 aids-free hospital inpatients. western blot analysis revealed a total of 46 reactive sera. 43 of the 47 serum samples from those with aids or arc were positive; 6 were ...19892551342
increased peripheral lymphocytes, lymphoid hepatitis and anaemia in african vervet monkeys seropositive to retroviruses.wild-caught african vervet monkeys are commonly infected by simian t-lymphotropic virus i (stlv1) and simian immunodeficiency virus (siv), yet the natural histories of these infections are largely unknown. seropositivity was associated with increased total, t and atypical lymphocytes. in seropositive females there was mild, normocytic, normochromic anaemia. lymphoid hepatitis was present in seven seropositive cases. african vervets used in biomedical research, vaccine production and organ transp ...19892551937
phenotypic and functional differences in nk and lak cells in the peripheral blood of sooty mangabeys and rhesus macaques.greater than 75% of the sooty mangabey monkeys at the yerkes regional primate research center are naturally infected with siv without any apparent clinical symptomology. on the other hand, experimental infection of rhesus macaques with siv results in a clinical syndrome similar to human aids. these differences with regard to siv infection prompted us to examine the natural immunosurveillance system of peripheral blood mononuclear cells (pbmc) from siv-infected and uninfected monkeys of these two ...19892553275
a formalin-inactivated whole siv vaccine confers protection in macaques.a vaccine against human immunodeficiency virus (hiv) would be highly effective in stopping the acquired immunodeficiency syndrome (aids) epidemic. a comprehensive evaluation of potential vaccine methodologies can be made by means of the simian model for aids, which takes advantage of the similarities in viral composition and disease potential between simian immunodeficiency virus (siv) infection of rhesus macaques and hiv infection in humans. immunization with a formalin-inactivated whole siv va ...19892555923
nf-kappa b activation of the cytomegalovirus enhancer is mediated by a viral transactivator and by t cell stimulation.the expression of cytomegalovirus alpha (immediate early) genes is under control of an enhancer that carries signals for strong constitutive expression as well as response elements for transactivation by viral proteins. we have used synthetic oligonucleotides representing the 16, 18 and 19 bp repeat elements within the enhancer to investigate the role of virus-induced cellular transcription factors in enhancer activation. we show that the transcription factor nf-kappa b, which binds to the 18 bp ...19892556267
animal models of aids.animal models of aids are essential for understanding the pathogenesis of retrovirus-induced immune deficiency and encephalopathy and for development and testing of new therapies and vaccines. aids and related disorders are etiologically linked to members of the lentivirus subfamily of retroviruses; these lymphocytopathic lentiviruses are designated human immuno-deficiency virus type 1 (hiv-1) and human immuno-deficiency virus type 2 (hiv-2). the only animals susceptible to experimental hiv-1 in ...19892556312
use of simian immunodeficiency virus for evaluation of aids vaccine strategies. 19892558686
lentiviral encephalitides in the immature host: a comparison of human immunodeficiency virus type 1 (hiv-1) and simian immunodeficiency virus (siv) brain infection.the human immunodeficiency virus (hiv) and the simian immunodeficiency virus (siv) are members of the lentivirus subfamily of retroviruses. both are capable of establishing persistent infection in the nervous system and both demonstrate increased virulence in the immature of their respective host species. brain infection with these primate lentiviruses share common virologic and neuropathologic features. the available evidence to date suggests that viral factors may determine neuroinvasiveness a ...19892559621
use of simian immunodeficiency viruses for aids research.despite frequent statements to the contrary, there are good animal models for aids. in this review, we summarize the properties of one of the most useful animal models: infection of rhesus monkeys with simian immunodeficiency virus (siv). the sivs are an extensive group of hiv-related lentiviruses of nonhuman primates. they closely resemble the human aids viruses, hiv-1 and hiv-2, in both genetic sequence and biological properties. some siv isolates, most notably those derived from macaques and ...19892559900
characterization of simian immunodeficiency virus-specific t-cell-mediated cytotoxic response of infected rhesus macaques.four juvenile rhesus macaques were infected with simian immunodeficiency virus (siv)mac-freshly isolated peripheral blood mononuclear cells (pbmc) from these sivmac-infected and from uninfected control macaques were assessed for cytotoxic t-lymphocyte (ctl) activity monthly for 7 consecutive months, beginning 2 months after infection. target cells consisted of major histocompatibility complex (mhc) haploidentical parental pbmc which were stimulated with mitogen and then pulsed with heat-killed s ...19892561053
genetic diversity of simian immunodeficiency virus.we have demonstrated that the genetic diversity of simian immunodeficiency virus from african green monkeys (sivagm) is much greater than that observed previously for individual hiv-1, hiv-2, or sivmac isolates. extensive genetic variation among sivagm isolates and the high prevalence of green monkey infection without disease suggest that the virus has been in the green monkey population for a long time. we have also demonstrated that siv from a sooty mangabey monkey (isolate smm-7) is closer to ...19892569537
spectrum of disease in macaque monkeys chronically infected with siv/smm.twelve rhesus and one pig-tailed macaque have been monitored for 28-41 months following experimental infection with 10(4) tcid of siv/smm. twelve of the 13 animals became virus positive and seroconverted within 3 to 6 weeks of exposure; the remaining animal seroconverted at 6 months, but has remained virus negative. six of the 13 animals (46%) died between 14 and 28 months post-infection, following prolonged clinical disease characterized by chronic diarrhea and weight loss, peripheral lymphaden ...19892570479
serological survey for viral diseases in the cayo santiago rhesus macaque population.the free-ranging population of rhesus monkeys (macaca mulatta) on cayo santiago was sero-surveyed for human measles, simian virus 40, b virus (herpes simiae), rhesus cytomegalovirus, human and simian retroviruses and encephalomyocarditis virus to determine the prevalence of these viruses in the colony. the results of this study indicate that the colony is free of sv40, htlviii (hiv-1), stlviii (siv) and srv1; has a low prevalence of measles and emcv; and high prevalence rates for b virus, cmv an ...19892571176
evaluation of human and simian immunodeficiency virus plaque and neutralization assays.a number of cd4+ t cell lines were compared for their ability to act as target cells for human immunodeficiency virus (hiv) infection in syncytium- and plaque-forming assays. mt-4 and c8166 cells were the most sensitive indicator cells for hiv- and simian immunodeficiency virus (siv)-induced cytopathic effects, and gave rise to macroscopic (mt-4) and microscopic (c8166) plaques. the mt-4 plaque assay was evaluated for the measurement of hiv- and siv-neutralizing antibodies.19892575137
immunochemistry of the dominating antigenic region ala582 to cys604 in the transmembranous protein of simian and human immunodeficiency virus.the immunochemistry of two homologous uniquely antigenic peptides representing ala582 to cys604 in the transmembrane proteins of simian immunodeficiency virus of rhesus macaque origin, sivmac (closely related to hiv-2) and hiv-1 (strain htlv-iiib) was characterized at the resolution of single amino acids. five different antigenic sites were identified in the sivmac peptide by use of 34 mab against this peptide and two different sites were similarly demonstrated in the hiv-1 peptide by use of 10 ...19892584709
2',3'-didehydro-2',3'-dideoxy-5-chlorocytidine is a selective anti-retrovirus agent.2',3'-didehydro-2',3'-dideoxy-5-chlorocytidine (d4cc) is, in contrast with 2',3'-dideoxy-5-chlorocytidine (ddclcyd) and 2',3'-didehydro-2',3'-dideoxy-5-chlorouridine (d4cu), a potent and selective inhibitor of the replication of human immunodeficiency virus (hiv) types 1 and 2, simian immunodeficiency virus (siv) and simian aids related virus (srv). d4cc is a poor inhibitor of the phosphorylation of [5-3h]2'-deoxycytidine (dcyd) by partially purified mt-4 cell dcyd kinase (ki: 612 microm). the f ...19892590197
serum reactivity to hiv-1 accessory gene products distinguishes east african from west african hiv strains as infecting agent.the existence of dual infections with human immunodeficiency virus (hiv)-1 and 2 in west african countries has been controversial, although the current consensus is that dual infection is not the cause of the extensive cross-reactivity observed between these 2 viruses. to evaluate the role of antibody reactivity to the hiv-1 accessory gene products in type-specific hiv serology, proteins encoded for nef, tat, rev, vpr, and vpu were developed and used as an antigen. 5 of the 7 exclusively hiv-2 ...19892590553
a highly divergent hiv-2-related isolate.it has been suggested that the human immunodeficiency virus type 2 (hiv-2) and the simian immunodeficiency virus from rhesus macaques (sivmac) evolved from the sooty mangabey virus sivsm (ref. 1). we now describe an hiv-2-related isolate, hiv-2-d205, from a healthy ghanaian woman that is genetically equidistant to the prototypic hiv-2 strains and to sivsm and sivmac. supported by the observation that hiv-2d205 differs in a step of envelope glycoprotein processing, our data indicate that it could ...19892594088
analysis of the function of viral protein x (vpx) of hiv-2.to investigate the function of vpx, a gene in hiv-2 and siv, but not in hiv-1, three site-directed mutants (pmx) were constructed from a functional proviral hiv-2 plasmid clone (pse). transfection of cos-1 cells with all three mutants as well as pse gave rise to equivalent amounts of virus. each virus could be passaged in h9 and cem lymphoid cell lines, peripheral blood lymphocytes, and monocytes with equal efficiency and demonstrated similar cytopathic effects. hybridization data with dan from ...19892596032
genetic relatedness of the human immunodeficiency viruses type 1 and 2 (hiv-1, hiv-2) and the simian immunodeficiency virus (siv). 19892660679
functional comparison of the rev trans-activators encoded by different primate immunodeficiency virus species.the known primate lentiviruses can be divided into two subgroups consisting of the human immunodeficiency virus type 1 (hiv-1) isolates and the related hiv type 2 (hiv-2) and simian immunodeficiency virus (siv) isolates. hiv-1 has been shown to encode a post-transcriptional trans-activator of viral structural gene expression, termed rev, that is essential for viral replication in culture. here, we demonstrate that hiv-2 and sivmac also encode functional rev proteins. as in the case of hiv-1, the ...19892682638
identification of simian immunodeficiency virus sivmac env gene products.a monoclonal antibody recognizing an antigenic determinant on the env transmembrane protein, gp32 of simian immunodeficiency virus sivmac has been developed and designated sf8/5e11. the reactivity of this antibody was found to be type specific, since it did not cross-react with either sivsmm or sivmne transmembrane proteins. the availability of both this antibody and the complete nucleotide sequence of sivmac allowed us to define the organization of the env gene products of this virus. radiolabe ...19892464704
extensive genetic variability of simian immunodeficiency virus from african green monkeys.serological surveys have revealed that 30 to 50% of wild-caught african green monkeys have antibodies reactive to simian immunodeficiency virus (siv), a retrovirus related to human immunodeficiency virus (hiv). although the nucleotide sequence of one sivagm isolate, tyo1, was recently reported, the extent of genetic variability among sivagm isolates remains to be determined. restriction endonuclease mapping of infectious molecular clones of two sivagm isolates (266 and 385), described in this no ...19892467010
molecular cloning of two west african human immunodeficiency virus type 2 isolates that replicate well in macrophages: a gambian isolate, from a patient with neurologic acquired immunodeficiency syndrome, and a highly divergent ghanian isolate.human immunodeficiency virus type 2 (hiv-2)-related viruses were isolated from a gambian dying of exclusively neurological disease (hiv-2d194) and from an asymptomatic ghanian (hiv-2d205). both strains exhibited properties of hiv-1 biological subtype c: they grew slowly and induced few or no syncytia but eventually produced high levels of particle-associated reverse transcriptase in cultures of fresh peripheral blood lymphocytes, and they established stable infection of t-lymphoma (hut-78) and m ...19892467304
isolation of human immunodeficiency virus-related simian immunodeficiency viruses from african green monkeys.we have isolated lentivirus strains that are related to the human immunodeficiency virus (hiv) from african green monkeys (cercopithecus aethiops; agm). although immunologically related, these sivagm are clearly distinct from other simian immunodeficiency virus (siv) isolates, including isolates from macaca mulatta (sivmac) or even from other agm. the sivagm strains described in this communication grow well in a limited number of human t-lymphoma lines. virus density, morphology, and reverse tra ...19892468160
a possible homology between immunodeficiency virus p24 core protein and picornaviral vp2 coat protein: prediction of hiv p24 antigenic sites.with the use of a sensitive sequence comparison algorithm, a homology has been suggested between the primary structures of simian immunodeficiency virus (siv) p24 core protein and foot-and-mouth disease virus (fmd) vp2 coat protein. since the fmd sequence is homologous to picornaviral vp2 sequences with known three-dimensional architecture and since the siv p24 sequence can be convincingly aligned with that from human immunodeficiency virus (hiv), it was possible to predict an eight-stranded bet ...19892498082
siv, stlv-i and type d retrovirus antibodies in captive rhesus macaques and immunoblot reactivity to siv p27 in human and rhesus monkey sera.the prevalence of simian immunodeficiency virus (siv), simian t-cell lymphotropic virus type 1 (stlv-i), and type d retrovirus (srv-d) antibodies was determined for 1229 rhesus monkeys (macaca mulatta) from two research colonies. serum samples were tested by using enzyme-linked immunosorbent assay (elisa), immunoblot (ib), and radioimmunoprecipitation assay (ripa). seropositive results for the three retroviruses tested were 0 for siv, 270 (22%) for stlv-i, and 103 (8.4%) for type d retrovirus. o ...19901706606
cross-reactivity with sivmac in east african hiv-1-positive sera: evidence against double infection with hiv-1 and a sivmac/hiv-2-like virus.igg antibodies reactive with simian immunodeficiency virus isolated from a rhesus monkey suffering from simian acquired immunodeficiency syndrome (sivmac, strain 239, a virus which is very closely related to human immunodeficiency virus type 2-hiv-2) were found in 18 of 120 swedish and 8 of 11 east african confirmed hiv-1 antibody positive (hiv-1 ab+) sera, both by enzyme immunoassay and electrophoretic immunoblotting (p = 1 x 10(-6). in electrophoretic immunoblotting most of the cross-reactivit ...19901703133
characterization of monoclonal antibodies directed against distinct conserved epitopes of human immunodeficiency virus type 1 core proteins.two mouse hybridoma cell lines secreting antibodies to the human immunodeficiency virus (hiv) p25 major core protein and its precursors p55 and p41, were developed after immunization with the highly cytopathic zaïrian hiv-1 isolate, ndk. these monoclonal antibodies also react with the gag gene products from hiv-1-bru prototype and present cross reaction with hiv-2-rod, and siv-agm. they map into topographically distinct areas of p25 and define epitopic regions topographically separated from thos ...19901703272
in vitro screening for antiretroviral agents against simian immunodeficiency virus (siv).simian immunodeficiency virus (siv), which causes an acquired immunodeficiency syndrome in macaques, is a lentivirus that is morphologically, antigenically, genetically, and biologically similar to the human immunodeficiency virus (hiv). because of these similarities, the siv model represents a unique opportunity for in vitro and in vivo testing of antiretroviral agents. since antiretroviral agents may exhibit different properties in different cells in vitro, more than one cell line may be neces ...19901703397
use of simian immunodeficiency virus for vaccine research.rhesus monkeys were immunized with purified, disrupted, noninfectious simian immunodeficiency virus (siv) in adjuvant induced siv neutralizing antibodies. two of six previously vaccinated macaques were protected against infection when challenged with 200-1,000 animal infectious doses of uncloned, pathogenic siv and both have remained free of signs of virus infection for 19 and 30 months. prior vaccination appeared to be of benefit in decreasing the virus load and in delaying the onset of aids in ...19902231691
nef genes of siv.molecular clones of sivmac were constructed that differed only in sequences within the nef gene. deae-transfection of viral dna containing an open from of nef yielded virus that replicated with similar kinetics and to a similar extent in macaque peripheral blood lymphocyte (pbl) cultures as virus with a deletion or stop codon within nef. rhesus monkeys that received each kind of molecularly cloned virus became infected. our results additionally suggest that mutant forms of virus are selected in ...19902231693
molecular changes associated with replication of simian immunodeficiency virus in human cells.the sivmac239 infectious clone does not have a premature stop codon in its transmembrane protein (tmp) region and it produces full-length (41 kilodalton, kda) tmp in macaque peripheral blood lymphocytes (pbl) in vitro and in vivo. however, viruses with truncated forms of tmp (28kda) are selected during propagation in human cell types; truncated forms arise from point mutations, cag (glutamine) to tag (stop), in the viral genome. these results document molecular changes associated with adaptation ...19902231694
comparison of the genomes of two sympatric iridescent viruses (types 9 and 16).a map of the sites in the genome of costelytra zealandica iridescent virus (cziv), using the restriction enzymes bamhi, kpni, and psti, showed the genome size to be 170.2 kbp in length. it was found that the genome was cyclically permuted and that 39% of the genome of cziv contained repetitive sequence elements. the genome was found to hybridize with the genome of another iridescent virus, type 9 (wiv), in dna-dna hybridization experiments. a region of the wiv dna genome (23.4 kbp) did not hybri ...19902241577
human immunodeficiency virus type 2 (hiv2).in the mid 1980's a second human retrovirus, capable of causing the acquired immunodeficiency syndrome (aids), was isolated from patients of west african origin. this virus, now called human immunodeficiency virus type 2 (hiv2), was found to be distinct from human immunodeficiency virus type 1 (hiv1) but closely related to simian immunodeficiency viruses (siv). although the genomes of hiv1 and hiv2 are similar there are significant differences in nucleotide and amino acid sequences, most marked ...19902245251
immunological studies of the basis for the apathogenicity of simian immunodeficiency virus from african green monkeys.potential reasons for the lack of pathogenicity of the simian immunodeficiency virus sivagm in its natural host, the african green monkey (agm, cercopithecus aethiops), were investigated with respect to immunological mechanisms. the functional immune response of monkeys to infection was similar (though not identical) to that of humans to infection with human immunodeficiency virus type 1 (hiv-1). in the sera of infected animals, neutralizing antibodies were found to be low or absent, and in part ...19902247482
purification and secondary structure determination of simian immunodeficiency virus p27.we have developed a novel method for the expression and purification of p27, the major core protein of simian immunodeficiency virus. circular dichroism measurements of purified p27 were used to determine the relative amounts of alpha-helix, beta-sheet and unordered secondary structural elements. these empirically determined values appear to be inconsistent with previously published theoretical models based on homology comparisons.19902254920
construction and characterization of an infectious dna clone and of mutants of simian immunodeficiency virus isolated from the african green monkey.we constructed a full-length molecular clone of simian immunodeficiency virus from an african green monkey. upon transfection, this clone directed the production of virus particles cytopathic and infectious to human cd4+ leukemia cell lines. mutations were introduced by recombinant dna techniques into eight open reading frames of simian immunodeficiency virus from the african green monkey thus far identified. the phenotypes of mutant viruses, i.e., infectivity, cytopathogenicity, transactivation ...19902293665
simian immunodeficiency virus inhibits bone marrow hematopoietic progenitor cell growth.the pathogenic mechanisms underlying the depressed hematopoietic functions seen in human immunodeficiency virus-infected individuals were explored in rhesus monkeys infected with the simian immunodeficiency virus of macaques (sivmac). bone marrow hematopoietic progenitor cell colony formation, both granulocyte/macrophage (cfu-gm) and erythrocyte (bfu-e), was shown to be decreased in number in sivmac-infected rhesus monkeys. sivmac was readily isolated from bone marrow cells of infected monkeys a ...19902296079
mutational analysis of the human immunodeficiency virus type 2 (hiv-2) genome in relation to hiv-1 and simian immunodeficiency virus siv (agm).we constructed an infectious molecular clone of the human immunodeficiency virus type 2 (hiv-2) and generated nine frameshift mutants corresponding to nine open reading frames identified so far. three structural (gag, pol, env) and two regulative (tat, rev) gene mutants were not infectious, whereas vif, vpx, vpr, and nef genes were dispensable for infectivity. all of the mutants except env and rev were cytopathic in cd4+ human leukemia cells. in transfection assays, the expression of hiv-2 long ...19902296082
transmembrane envelope glycoproteins of human immunodeficiency virus type 2 and simian immunodeficiency virus siv-mac exist as homodimers.an 80-kilodalton glycoprotein (gp80) was produced in human immunodeficiency virus type 2 (hiv-2)-infected cells along with three envelope glycoproteins that we have recently reported: the extracellular glycoprotein (gp125), the envelope glycoprotein precursor (gp140), and the transient dimeric form of the precursor (gp300). gp125 and gp80 were detectable after the synthesis of gp140 and the formation of gp300. using a specific monoclonal antibody, we showed here that gp80 is a dimeric form of th ...19902296088
simian immunodeficiency viruses from african green monkeys display unusual genetic diversity.african green monkeys are asymptomatic carriers of simian immunodeficiency viruses (siv), commonly called sivagm. as many as 50% of african green monkeys in the wild may be siv seropositive. this high seroprevalence rate and the potential for genetic variation of lentiviruses suggested to us that african green monkeys may harbor widely differing genotypes of sivagm. to investigate this hypothesis, we determined the entire nucleotide sequence of an infectious proviral molecular clone of sivagm (1 ...19902304139
enhancement of siv infection with soluble receptor molecules.the cd4 receptor on human t cells has been shown to play an integral part in the human immunodeficiency virus type 1 (hiv-1) infection process. recombinant soluble human cd4 (rcd4) was tested for its ability to inhibit sivagm, an hiv-like virus that naturally infects african green monkeys, in order to define t cell surface receptors critical for sivagm infection. the rcd4 was found to enhance sivagm infection of a human t cell line by as much as 18-fold, whereas hiv-1 infection was blocked by rc ...19902309120
a highly conserved rna folding region coincident with the rev response element of primate immunodeficiency viruses.a series of unusual folding regions (ufr) immediately 3' to the cleavage site of the outer membrane protein (omp) and transmembrane protein (tmp) were detected in the envelope gene rna of the human immunodeficiency virus (hiv-1, hiv-2) and simian immunodeficiency virus (siv) by an extensive monte carlo simulation. these rna secondary structures were predicted to be both highly stable and statistically significant. in the calculation, twenty-five different sequence isolates of hiv-1, three isolat ...19902326200
cis-acting elements in the u3 region of a simian immunodeficiency virus.a series of 5' deletions and a point mutation in the binding site for nuclear factor kappa b were introduced into the u3 region of a molecular clone of simian immunodeficiency virus from macaques (sivmac142). the transcriptional activity of the mutated u3 regions was analyzed by transient chloramphenicol acetyltransferase assays. two distinct regions in u3 appeared to contain important cis-acting sequences for transcriptional activity. mutation of the single nuclear factor kappa b site in the si ...19902335831
glycosylation of the envelope glycoprotein gp130 of simian immunodeficiency virus from sooty mangabey (cercocebus atys).the envelope glycoprotein 130 ('130' referring to an mr of 130,000) of simian immunodeficiency virus from sooty mangabey (cercocebus atys) (sivsm) was isolated from the cell-free supernatant of the sivsm-infected human t-cell line h9, metabolically labelled with d-[6-3h]glucosamine. after digestion with staphylococcus aureus v8 proteinase, radiolabelled n-glycans were liberated from resulting glycopeptides by sequential treatment with endo-beta-n-acetylglucosaminidase h and peptide:n-glycosidase ...19902339985
isolation and characterization of simian immunodeficiency viruses from two subspecies of african green monkeys.cercopithecus aethiops (african green monkey), a nonhuman primate species distributed throughout subsaharan africa, has been shown to have high seroprevalence rates of antibodies to simian immunodeficiency virus (siv), and therefore, has been proposed as a natural reservoir for immunodeficiency viruses. our laboratories have isolated siv-like viruses from two east african subspecies of c. aethiops designated grivet and vervet monkeys. analysis of the structural proteins based on the molecular we ...19902340199
human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus env proteins possess a functionally conserved assembly domain.the envelope (env) glycoproteins of human immunodeficiency viruses type 1 (hiv-1) and type 2 (hiv-2) form dimers shortly after synthesis. analysis of the simian immunodeficiency virus (siv) env protein expressed by a recombinant vaccinia virus revealed that it, too, forms stable homodimers. when the hiv-1 and siv env proteins or the hiv-1 and hiv-2 env proteins were coexpressed in the same cells, heterodimers were formed. thus, the env proteins of hiv-1, hiv-2, and siv possess a functionally con ...19902352332
a novel proviral clone of hiv-2: biological and phylogenetic relationship to other primate immunodeficiency viruses.infectious molecular clones of the human immunodeficiency virus type 2 (hiv-2) will be valuable tools for the study of regulatory gene functions and the development of an animal model for the human acquired immunodeficiency syndrome (aids). to this end, we have cloned and sequenced a novel hiv-2 isolate, hiv-2ben. one clone, designated mk6, is infectious for various human t-cell lines and for human and macaque peripheral blood lymphocytes (pbl), allowing molecular studies of hiv-2 infection and ...19902353457
simian immunodeficiency virus displays complex patterns of rna splicing.the human and simian immunodeficiency viruses encode at least six gene products that apparently serve regulatory functions. to evaluate the regulation of simian immunodeficiency virus gene expression at the level of rna splicing, we used the polymerase chain reaction to amplify and clone cdnas corresponding to a large array of mrnas from infected cells. we identified mrnas that used splice acceptor sites upstream of the initiator codons for tat, rev, vpr, nef, vif, and vpx, suggesting that these ...19902384918
studies with canine sera that contain antibodies which recognize human immunodeficiency virus structural proteins.in a serological survey, using the immunoblotting technique, we found that substantial numbers of dog sera from both normal and diseased dogs, including dogs with neoplasia, reacted with one or more human immunodeficiency virus (hiv) recombinant proteins. a total of 144 dog sera were tested, and 72 (50%) of them reacted with one or more hiv recombinant structural proteins. ten dog sera were also tested for reactivity with simian immunodeficiency virus (siv), feline immunodeficiency virus (fiv), ...19902386966
expression of enzymatically active reverse transcriptase of simian immunodeficiency virus in bacteria: sensitivity to nucleotide analogue inhibitors.a fragment of the sivmac251 pol gene was expressed in escherichia coli as a trpe fusion protein. analysis of extracts from bacteria containing this expression plasmid revealed the presence of a reverse transcriptase activity dependent on mg2+ as divalent cation and active on both poly(ra).oligo(dt) and poly(rc.oligo(dg) templates. in comparative studies, the siv and hiv-1 reverse transcriptases expressed in bacteria displayed very similar high sensitivities to the chain terminator inhibitors azt ...19901700544
detection of siv antigens by hiv-1 antigen capture immunoassays.we tested three commercially available hiv-1 antigen capture systems for their ability to detect simian immunodeficiency viruses (siv). all three kits detected antigens from six distinct siv isolates, but with varying degrees of sensitivity. for the overall detection of siv in cell culture, our assay for reverse transcriptase was more sensitive than hiv-1 antigen capture. hiv-1 antigen capture systems were useful for the detection of siv antigenemia in experimentally infected macaques. the limit ...19901688621
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