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Showing papers on "Virus published in 1986"


Journal ArticleDOI
TL;DR: In this paper, an infectious molecular clone of acquired immunodeficiency syndrome-associated retrovirus was constructed, and upon transfection, this clone directed the production of infectious virus particles in a wide variety of cells in addition to human T4 cells.
Abstract: We constructed an infectious molecular clone of acquired immunodeficiency syndrome-associated retrovirus. Upon transfection, this clone directed the production of infectious virus particles in a wide variety of cells in addition to human T4 cells. The progeny, infectious virions, were synthesized in mouse, mink, monkey, and several human non-T cell lines, indicating the absence of any intracellular obstacle to viral RNA or protein production or assembly. During the course of these studies, a human colon carcinoma cell line, exquisitely sensitive to DNA transfection, was identified.

2,894 citations


Book
01 Jun 1986

2,377 citations


Journal ArticleDOI
TL;DR: The vaccinia/T7 hybrid virus forms the basis of a simple, rapid, widely applicable, and efficient mammalian expression system.
Abstract: DNA coding for bacteriophage T7 RNA polymerase was ligated to a vaccinia virus transcriptional promoter and integrated within the vaccinia virus genome. The recombinant vaccinia virus retained infectivity and stably expressed T7 RNA polymerase in mammalian cells. Target genes were constructed by inserting DNA segments that code for beta-galactosidase or chloramphenicol acetyltransferase into a plasmid with bacteriophage T7 promoter and terminator regions. When cells were infected with the recombinant vaccinia virus and transfected with plasmids containing the target genes, the latter were expressed at high levels. Chloramphenicol acetyltransferase activity was 400-600 times greater than that observed with conventional mammalian transient-expression systems regulated either by the enhancer and promoter regions of the Rous sarcoma virus long terminal repeat or by the simian virus 40 early region. The vaccinia/T7 hybrid virus forms the basis of a simple, rapid, widely applicable, and efficient mammalian expression system.

2,136 citations


Journal ArticleDOI
07 Nov 1986-Cell
TL;DR: The studies support a mechanism of AIDS virus infection that initially involves the specific interaction of theAIDS virus with T4 molecules on the cell surface, and find that the T4 gene is expressed in the brain as well as in lymphoid cells, providing an explanation for the dual neurotropic and lymphotropic character of the AIDS virus.

2,074 citations


Journal ArticleDOI
11 Jul 1986-Science
TL;DR: It is suggested that mononuclear phagocytes may serve as primary targets for infection and agents for virus dissemination and that these virus-infected cells may play a role in the pathogenesis of the disease.
Abstract: Cells with properties characteristic of mononuclear phagocytes were evaluated for infectivity with five different isolates of the AIDS virus, HTLV-III/LAV. Mononuclear phagocytes cultured from brain and lung tissues of AIDS patients harbored the virus. In vitro-infected macrophages from the peripheral blood, bone marrow, or cord blood of healthy donors produced large quantities of virus. Virus production persisted for at least 40 days and was not dependent on host cell proliferation. Giant multinucleated cells were frequently observed in the macrophage cultures and numerous virus particles, often located within vacuole-like structures, were present in infected cells. The different virus isolates were compared for their ability to infect macrophages and T cells. Isolates from lung- and brain-derived macrophages had a significantly higher ability to infect macrophages than T cells. In contrast, the prototype HTLV-III beta showed a 10,000-fold lower ability to infect macrophages than T cells and virus production was one-tenth that in macrophage cultures infected with other isolates, indicating that a particular variant of HTLV-III/LAV may have a preferential tropism for macrophages or T cells. These results suggest that mononuclear phagocytes may serve as primary targets for infection and agents for virus dissemination and that these virus-infected cells may play a role in the pathogenesis of the disease.

1,762 citations


Journal ArticleDOI
05 Sep 1986-Science
TL;DR: The identity of an important cell type that supports replication of the AIDS retrovirus in brain tissue was determined in two affected individuals and these cells were mononucleated and multinucleated macrophages that actively synthesized viral RNA and produced progeny virions in the brains of the patients.
Abstract: One of the common neurological complications in patients with the acquired immune deficiency syndrome (AIDS) is a subacute encephalopathy with progressive dementia. By using the techniques of cocultivation for virus isolation, in situ hybridization, immunocytochemistry, and transmission electron microscopy, the identity of an important cell type that supports replication of the AIDS retrovirus in brain tissue was determined in two affected individuals. These cells were mononucleated and multinucleated macrophages that actively synthesized viral RNA and produced progeny virions in the brains of the patients. Infected brain macrophages may serve as a reservoir for virus and as a vehicle for viral dissemination in the infected host.

1,675 citations


Journal ArticleDOI
TL;DR: It is shown that the ability to package virus is conferred at very low frequency to cells infected with virus from these retrovirus packaging cell lines, presumably by low-frequency transmission of the deleted virus genome.
Abstract: Retrovirus vectors can be made in the absence of helper virus by using retrovirus packaging cell lines. Helper-free virus is critical for a variety of gene transfer studies. The most useful packaging cell lines contain helper virus DNA from which the signal required for packaging of the viral RNA genome into virions has been deleted. However, we showed that the ability to package virus is conferred at very low frequency to cells infected with virus from these packaging cell lines, presumably by low-frequency transmission of the deleted virus genome. In addition, these packaging cell lines can interact with some retroviral vectors to yield replication-competent virus. We constructed packaging cell lines containing helper virus DNA that had several alterations in addition to deletion of the packaging signal. The new packaging cells retained the useful features of previously available lines but did not yield helper virus after introduction of any of the vectors tested, and transfer of the packaging function was not detected.

1,504 citations


Journal ArticleDOI
31 Oct 1986-Science
TL;DR: A novel human B-lymphotropic virus (HBLV) was isolated from the peripheral blood leukocytes of six individuals and selectively infected freshly isolated human B cells and converted them into large, refractile mono- or binucleated cells with nuclear and cytoplasmic inclusion bodies.
Abstract: A novel human B-lymphotropic virus (HBLV) was isolated from the peripheral blood leukocytes of six individuals: two HTLV-III seropositive patients from the United States (one with AIDS-related lymphoma and one with dermatopathic lymphadenopathy), three HTLV-III seronegative patients from the United States (one with angioimmunoblastic lymphadenopathy, one with cutaneous T-cell lymphoma, and one with immunoblastic lymphoma), and one HTLV-III seronegative patient with acute lymphocytic leukemia from Jamaica. All six isolates were closely related by antigenic analysis, and sera from all six virus-positive patients reacted immunologically with each virus isolate. In contrast, only four sera from 220 randomly selected healthy donors and none from 12 AIDS patients without associated lymphoma were seropositive. The virus selectively infected freshly isolated human B cells and converted them into large, refractile mono- or binucleated cells with nuclear and cytoplasmic inclusion bodies. HBLV is morphologically similar to viruses of the herpesvirus family but is readily distinguishable from the known human and nonhuman primate herpesviruses by host range, in vitro biological effects, and antigenic features.

1,414 citations


Journal ArticleDOI
18 Jul 1986-Science
TL;DR: It is established that this new retrovirus, here referred to as LAV-II, is distantly related to LAV and distinct from STLV-IIImac, suggesting that the West African AIDS virus may be more closely related to this simian virus than toLAV.
Abstract: The etiological agent of AIDS, LAV/HTLV-III, is common in Central Africa but is not endemic in other areas of that continent. A novel human retrovirus, distinct from LAV/HTLV-III, has now been isolated from two AIDS patients from West Africa. Partial characterization of this virus revealed that it has biological and morphological properties very similar to LAV but that it differs in some of its antigenic components. Although the core antigens may share some common epitopes, the West African AIDS retrovirus and LAV differ substantially in their envelope glycoproteins. The envelope antigen of the West African virus can be recognized by serum from a macaque with simian AIDS infected by the simian retrovirus termed STLV-IIImac, suggesting that the West African AIDS virus may be more closely related to this simian virus than to LAV. Hybridization experiments with LAV subgenomic probes further established that this new retrovirus, here referred to as LAV-II, is distantly related to LAV and distinct from STLV-IIImac.

1,389 citations


Journal ArticleDOI
09 May 1986-Science
TL;DR: The results of these experiments indicate that plants can be genetically transformed for resistance to virus disease development.
Abstract: A chimeric gene containing a cloned cDNA of the coat protein (CP) gene of tobacco mosaic virus (TMV) was introduced into tobacco cells on a Ti plasmid of Agrobacterium tumefaciens from which tumor inducing genes had been removed. Plants regenerated from transformed cells expressed TMV mRNA and CP as a nuclear trait. Seedlings from self-fertilized transgenic plants were inoculated with TMV and observed for development of disease symptoms. The seedlings that expressed the CP gene were delayed in symptom development and 10 to 60 percent of the transgenic plants failed to develop symptoms for the duration of the experiments. Increasing the concentration of TMV in the inoculum shortened the delay in appearance of symptoms. The results of these experiments indicate that plants can be genetically transformed for resistance to virus disease development.

1,325 citations


Journal ArticleDOI
TL;DR: The brains of 12 AIDS patients were studied using in situ hybridization to identify human immunodeficiency virus nucleic acid sequences and immunocytochemistry to identify viral and cellular proteins, suggesting that CNS dysfunction is due to indirect effects rather than neuronal or glial infection.
Abstract: Dysfunction of the central nervous system (CNS) is a prominent feature of the acquired immune deficiency syndrome (AIDS). Many of these patients have a subacute encephalitis consistent with a viral infection of the CNS. We studied the brains of 12 AIDS patients using in situ hybridization to identify human immunodeficiency virus [HIV, referred to by others as human T-cell lymphotropic virus type III (HTLV-III), lymphadenopathy-associated virus (LAV), AIDS-associated retrovirus (ARV)] nucleic acid sequences and immunocytochemistry to identify viral and cellular proteins. Nine patients had significant HIV infection in the CNS. In all examined brains, the white matter was more severely involved than the grey matter. In most cases the infection was restricted to capillary endothelial cells, mononuclear inflammatory cells, and giant cells. In a single case with severe CNS involvement, a low-level infection was seen in some astrocytes and neurons. These results suggest that CNS dysfunction is due to indirect effects rather than neuronal or glial infection.

Journal ArticleDOI
TL;DR: It is shown that a gene introduced into cells of mouse embryos by a retrovirus can serve as a heritable marker for the study of cell lineage in vivo and that several cell types have a pluripotential ancestor and that cell fate is progressively restricted as development proceeds.
Abstract: We show that a gene introduced into cells of mouse embryos by a retrovirus can serve as a heritable marker for the study of cell lineage in vivo. We constructed a defective recombinant retrovirus in which the Escherichia coli beta-galactosidase (lacZ) gene is inserted in the genome of a Muloney murine leukemia virus (M-MuLV). Expression of lacZ was detected with a histochemical stain that can be applied to cultured cells and embryonic tissue. Infection of cultured cells showed that lacZ has no detectable deleterious effects on cell viability or growth, that the enzyme is stably expressed in the progeny of infected cells for many generations in the absence of selective pressure, and that the virus can induce lacZ in a variety of cell types. Following injection of the virus into mid-gestation mouse embryos, clones of lacZ-positive cells were detected in skin, skull, meninges, brain, visceral yolk sac, and amnion. We identified the cell types comprising a series of lacZ-positive clones in the visceral yolk sac and skin to learn the lineage relationships of the labelled cells. In each tissue, we obtained evidence that several cell types have a pluripotential ancestor and that cell fate is progressively restricted as development proceeds.

Journal ArticleDOI
24 Jan 1986-Science
TL;DR: The binding of gp110 to the T4 molecule may be a major factor in HTLV-III/LAV tropism and may prove useful in developing therapeutic or preventive measures for the acquired immune deficiency syndrome.
Abstract: Human T-lymphotropic virus type III (HTLV-III) or lymphadenopathy-associated virus (LAV) is tropic for human T cells with the helper-inducer phenotype, as defined by reactivity with monoclonal antibodies specific for the T4 molecule. Treatment of T4+ T cells with monoclonal antibodies to T4 antigen blocks HTLV-III/LAV binding, syncytia formation, and infectivity. Thus, it has been inferred that the T4 molecule itself is a virus receptor. In the present studies, the surfaces of T4+ T cells were labeled radioactively, and then the cells were exposed to virus. After the cells were lysed, HTLV-III/LAV antibodies were found to precipitate a surface protein with a molecular weight of 58,000 (58K). By blocking and absorption experiments, this 58K protein was identified as the T4 molecule. No cell-surface structures other than the T4 molecule were involved in the antibody-antigen complex formation. Two monoclonal antibodies, each reactive with a separate epitope of the T4 molecule, were tested for their binding capacities in the presence of HTLV-III/LAV. When HTLV-III/LAV was bound to T4+ T cells, the virus blocked the binding of one of the monoclonal antibodies, T4A (OKT4A), but not of the other, T4 (OKT4). When HTLV-III/LAV was internally radiolabeled and bound to T4+ T cells which were then lysed, a viral glycoprotein of 110K (gp110) coprecipitated with the T4 molecule. The binding of gp110 to the T4 molecule may thus be a major factor in HTLV-III/LAV tropism and may prove useful in developing therapeutic or preventive measures for the acquired immune deficiency syndrome.

Journal ArticleDOI
19 Dec 1986-Science
TL;DR: A potential approach to therapy in which autologous CD8 lymphocytes could be administered to individuals to inhibit HIV replication and perhaps progression of disease is suggested.
Abstract: Lymphocytes bearing the CD8 marker were shown to suppress replication of human immunodeficiency virus (HIV) in peripheral blood mononuclear cells. The effect was dose-dependent and most apparent with autologous lymphocytes; it did not appear to be mediated by a cytotoxic response. This suppression of HIV replication could be demonstrated by the addition of CD8+ cells at the initiation of virus production as well as after several weeks of virus replication by cultured cells. The observations suggest a potential approach to therapy in which autologous CD8 lymphocytes could be administered to individuals to inhibit HIV replication and perhaps progression of disease.

Journal ArticleDOI
TL;DR: In this paper, the capacity of purine and pyrimidine nucleoside derivatives to inhibit the infectivity and cytopathic effect of human T-lymphotropic virus type III in vitro was tested.
Abstract: Human T-lymphotropic virus type III (HTLV-III)/lymphadenopathy-associated virus (LAV) is a a newly discovered lymphotropic retrovirus that is cytopathic for helper/inducer T cells in vitro. This virus is the etiologic agent of the acquired immunodeficiency syndrome and related diseases. In the current study, we tested the capacity of purine and pyrimidine nucleoside derivatives to inhibit the infectivity and cytopathic effect of human T-lymphotropic virus type III in vitro. With the ribose moiety of the molecule in a 2',3'-dideoxy configuration, every purine (adenosine, guanosine, and inosine) and pyrimidine (cytidine and thymidine) nucleoside tested suppressed the virus, although the thymidine derivative seemed to have substantially less activity in our system than the others. In general, we observed essentially complete suppression of the virus at doses that were lower by a factor of 10 to 20 than those needed to inhibit the proliferation of the target T cells and the immune reactivity of normal T cells in vitro. An analysis of five adenosine congeners, which differed only in the sugar moiety, revealed that reduction (an absence of hydroxyl determinants) at both the 2' and 3' carbons of the ribose was necessary for an anti-viral effect, and an additional reduction at the 5' carbon nullified the anti-viral activity. These observations may be of value in developing a new class of experimental drugs for the therapy of human T-lymphotropic virus type III infections.

Journal ArticleDOI
01 Jan 1986-Nature
TL;DR: The basis for the specific cytotoxicity of the virus is investigated, and it is reported that high-level expression of the HTLV-III envelope gene induces syncytia and concomitant cell death in T4+ cell lines but not in a B-lymphocyte line.
Abstract: Acquired immune deficiency syndrome (AIDS) is characterized by marked depletion of the T4+ helper subset of T cells. The aetiological agent of the disease, the human T-lymphotropic virus type III (HTLV-III)/lymphadenopathy-associated virus (LAV), specifically kills T4+ cells in vitro. Part of this specificity for the T4+ population residues in the relative efficiency with which HTLV-III infects these cells, as a result of a specific interaction between the T4 molecule and the virus envelope glycoprotein. In addition, the cytotoxic consequences of HTLV-III replication are dependent on cell type, as certain lymphoid and myeloid cells can be productively infected without notable cytopathic effect. Here we investigate the basis for the specific cytotoxicity of the virus, and report that high-level expression of the HTLV-III envelope gene induces syncytia and concomitant cell death in T4+ cell lines but not in a B-lymphocyte line. Syncytium formation depends on the interaction of envelope-expressing cells with neighbouring cells bearing surface T4 molecules. These results explain, at least in part, the specific cytopathic effect of HTLV-III infections.

Journal ArticleDOI
TL;DR: This review concludes that there have been substantial advances in the knowledge of the clinical manifestations, pathogenesis, and treatment of herpes simplex virus infections in the 12 years since the last review.
Abstract: IN the 12 years since the last review of herpes simplex virus (HSV) infections in these pages,1 there have been substantial advances in our knowledge of the clinical manifestations, pathogenesis, a...

Journal ArticleDOI
01 Oct 1986-Nature
TL;DR: It is reported that, in mice and rabbits in vivo, the compound is effective against both local and systemic infections with herpes simplex virus type 1, including herpetic keratitis caused by a TK− mutant which is resistant to the classical anti-herpes drugs.
Abstract: A new compound has been found, (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine ((S)-HPMPA), that has potent and selective activity against a broad spectrum of DNA viruses, including herpes simplex virus (types 1 and 2); varicella zoster virus; thymidine kinase-deficient (TK-) mutants of herpes simplex and varicella zoster virus; human cytomegalovirus; phocid, simian, suid, bovid and equid herpesviruses; African swine fever virus; vaccinia virus; and human adenoviruses. It is also active against retroviruses. We also report that, in mice and rabbits in vivo, the compound is effective against both local and systemic infections with herpes simplex virus type 1, including herpetic keratitis caused by a TK- mutant which is resistant to the classical anti-herpes drugs.

Journal ArticleDOI
TL;DR: It is demonstrated that HTLV-III expression in lymph node and peripheral blood is very low in vivo and the lymph node hyperplasia observed in HT LV-III-associated lymphadenopathy is not directly due to proliferation of HTLV -III-infected lymphocytes.
Abstract: By using in situ hybridization methodology, we have directly examined primary lymph node and peripheral blood from patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex for the presence of human T-lymphotropic virus type III (HTLV-III) viral RNA. Mononuclear cell preparations were hybridized with a 35S-labeled HTLV-III-specific RNA probe and exposed to autoradiographic emulsion for 2 days. HTLV-III-infected cells expressing viral RNA were detected in approximately 86% (6/7) of lymph node and 50% (7/14) of peripheral blood samples studied. However, in all patient samples examined, labeled cells were observed at very low frequency (less than 0.01% of total mononuclear cells). The HTLV-III-infected cells exhibited morphological characteristics consistent with that of lymphocytes and expressed viral RNA at relatively low abundance (20-300 copies per cell). These results demonstrate that HTLV-III expression in lymph node and peripheral blood is very low in vivo. Furthermore, the lymph node hyperplasia observed in HTLV-III-associated lymphadenopathy is not directly due to proliferation of HTLV-III-infected lymphocytes.

Journal ArticleDOI
TL;DR: The possibility that HTLV-III-infected monocyte/macrophages may serve as a vehicle for the dissemination of virus to target organs and as a reservoir for viral persistence, as has been shown for other lentiviruses including visna virus and caprine arthritis encephalitis virus is raised.
Abstract: Normal blood-derived monocyte/macrophages were found to be susceptible to infection in vitro by human T lymphotropic virus type III (HTLV-III), the etiologic agent of the acquired immunodeficiency syndrome. In addition, HTLV-III was recovered from monocyte/macrophages of patients infected with this virus. The above findings raise the possibility that HTLV-III-infected monocyte/macrophages may serve as a vehicle for the dissemination of virus to target organs and as a reservoir for viral persistence, as has been shown for other lentiviruses including visna virus and caprine arthritis encephalitis virus.

Journal ArticleDOI
01 Jan 1986-Nature
TL;DR: It is shown that derivatives of a biologically competent molecular clone of HTLV-III, in which the tat-Ill gene is deleted or the normal splicing abrogated, failed to produce or expressed unusually low levels of virus, respectively, when transfected into T-cell cultures.
Abstract: Studies of the genomic structure of human T-lymphotropic virus type III (HTLV-III) and related viruses, implicated as the causal agent of acquired immune deficiency syndrome (AIDS), have identified a sixth open reading frame in addition to the five previously known within the genome (gag, pol, sor, env and 3′orf)1–4. This gene, called tat-III, lies between the sorand env genes and is able to mediate activation, in a trans configuration, of the genes linked to HTLV-III long terminal repeat (LTR) sequences5–8. We now present evidence that the product of far-III is an absolute requirement for virus expression. We show that derivatives of a biologically competent molecular clone of HTLV-III9, in which the tat-Ill gene is deleted or the normal splicing abrogated, failed to produce or expressed unusually low levels of virus, respectively, when transfected into T-cell cultures. The capacity of these tat-III-defective genomes was transiently restored by co-transfection of a plasmid clone containing a functional tat-III gene or by introducing the tat-III protein itself. As HTLV-III and related viruses are the presumed causal agents of AIDS and associated conditions10–12, the observation that tat-III is critical for HTLV-III replication has important clinical implications, and suggests that specific inhibition of the activity of tat-III could be a novel and effective therapeutic approach to the treatment of AIDS.

Journal ArticleDOI
12 Sep 1986-Cell
TL;DR: Analysis of transfected lymphoid and nonlymphoid cell lines suggests that tat-III-mediated trans-activation of viral gene expression is operative predominantly, if not exclusively, at a posttranscriptional level.

Journal ArticleDOI
28 Mar 1986-Cell
TL;DR: It is concluded that the tat-III gene product is required for efficient replication of HTLV-III in T4+ cells, and for that reason is important for the cytopathic effects of virus infection.

Journal ArticleDOI
01 May 1986-Nature
TL;DR: Observations suggest mechanisms for regulating both the latent and lytic phases of the virus life cycle.
Abstract: Evidence is provided for the existence of a seventh gene in the genome of human T-lymphotropic virus type III/lymphadenopathy-associated virus. The gene is necessary for replication and acts post-transcriptionally to relieve negative regulation of the messenger RNA for the virion capsid and envelope proteins. These observations suggest mechanisms for regulating both the latent and lytic phases of the virus life cycle.


Journal ArticleDOI
23 Oct 1986-Nature
TL;DR: It is demonstrated that cell-surface expression of this protein, in the absence of other HTLV-III/LAV structural or regulatory proteins, is sufficient to induce CD4-dependent cell fusion, leading to cell death, one of the characteristic manifestations of AIDS (acquired immune deficiency syndrome) virus cytopathology.
Abstract: Formation of syncytia, with progression to cell death, is a characteristic feature of in vitro cultures of susceptible cells infected with human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV)1–3. Viral antigen-positive multi-nucleated giant cells have also been observed in histological sections from infected individuals4,5. In vitro, formation of these multinucleated giant cells occurs through cell fusion which is dependent on cell-surface expression of the differentiation antigen CD4 (ref. 1). Utilizing a recombinant vaccinia virus containing the gene for the envelope glycoprotein of HTLV-III/LAV6, we demonstrate that cell-surface expression of this protein, in the absence of other HTLV-III/LAV structural or regulatory proteins, is sufficient to induce CD4-dependent cell fusion, leading to cell death, one of the characteristic manifestations of AIDS (acquired immune deficiency syndrome) virus cytopathology. This process may contribute to the loss of CD4+ T cells seen in AIDS.

Journal ArticleDOI
TL;DR: Positive hybridisation signals, quantified by densitometry, were obtained with 9 of 17 samples from patients with histological evidence of active or healing myocarditis or dilated cardiomyopathy with inflammatory changes, and no Coxsackie-B-virus-specific sequences were detected in 4 samples from Patients in whom a viral aetiology was unlikely and the histological diagnosis was negative for myocardritis.

Journal ArticleDOI
20 Jun 1986-Science
TL;DR: The repeated isolation from a given individual of only highly related viruses raises the possibility that some type of interference mechanism may prevent simultaneous infection by more than one major genotypic form of the virus.
Abstract: In a study of genetic variation in the AIDS virus, HTLV-III/LAV, sequential virus isolates from persistently infected individuals were examined by Southern blot genomic analysis, molecular cloning, and nucleotide sequencing. Four to six virus isolates were obtained from each of three individuals over a 1-year or 2-year period. Changes were detected throughout the viral genomes and consisted of isolated and clustered nucleotide point mutations as well as short deletions or insertions. Results from genomic restriction mapping and nucleotide sequence comparisons indicated that viruses isolated sequentially had evolved in parallel from a common progenitor virus. The rate of evolution of HTLV-III/LAV was estimated to be at least 10(-3) nucleotide substitutions per site per year for the env gene and 10(-4) for the gag gene, values a millionfold greater than for most DNA genomes. Despite this relatively rapid rate of sequence divergence, virus isolates from any one patient were all much more related to each other than to viruses from other individuals. In view of the substantial heterogeneity among most independent HTLV-III/LAV isolates, the repeated isolation from a given individual of only highly related viruses raises the possibility that some type of interference mechanism may prevent simultaneous infection by more than one major genotypic form of the virus.

Journal ArticleDOI
09 Oct 1986-Nature
TL;DR: Evidence based on electron microscopy and electrophoretic behaviour that HDV contains a single stranded circular RNA molecule is presented, which is the first animal virus identified with a circular RNA genome.
Abstract: Hepatitis delta (delta) virus (HDV), a satellite virus of the hepatitis B virus (HBV), causes a severe form of viral hepatitis in humans. Here we present evidence based on electron microscopy and electrophoretic behaviour that HDV contains a single stranded circular RNA molecule. This is the first animal virus identified with a circular RNA genome. Circular RNAs have only been found in plant viruses. We have obtained a partial complementary DNA clone representing approximately 25% of the total genome of HDV. Analysis of this cDNA revealed similarity to two plant viruses that may explain the origin of the virus.

Journal ArticleDOI
01 Aug 1986-Cell
TL;DR: A synthetic peptide analog is recognized by both cell receptors and anti-HBV antibodies and elicits antibodies reacting with native HBV, and is a promising immunogen expected to elicit protective antibodies based on the concept of the attachment blockade pathway of virus neutralization.