Showing papers on "Virus published in 1970"

Differential Reactivity of Human Serums with Early Antigens Induced by Epstein-Barr Virus

Abstract: Inoculation of 64-10 or Raji cultures with Epstein-Barr virus derived from the HRI-K clone of the P3J Burkitt's lymphoma line caused abortive infections in most of the lymphoblastoid cells with synthesis of "early antigens" but few, if any, capsids. Antibodies to early antigens were detected by indirect immunofluorescence in serums of many patients with infectious mononucleosis, Burkitt's lymphoma, or nasopharyngeal carcinoma. These antibodies were rarely present in other serums even though some of them showed high titers of antibodies to Epstein-Barr virus when assayed on EB3 Burkitt tumor cells; they also prevented synthesis of early antigens, provided the serums were mixed with the virus prior to inoculation. Antibodies to early antigens possibly reflect current or recent disease processes that are associated with the virus.

Proteins Specified by Herpes Simplex Virus II. Viral Glycoproteins Associated with Cellular Membranes

Abstract: Membranes prepared from HEp-2 cells infected with herpes simplex virus and free from soluble proteins, virus, ribosomes, and other cellular constituents were solubilized and subjected to electrophoresis on acrylamide gels. The electropherograms showed the following. (i) The synthesis of host proteins and glycoproteins ceases after infection. However, the spectrum of host proteins in membranes remains unaltered. (ii) Between 4 and 22 hr postinfection, at least four glycoproteins are synthesized and bound to the smooth cytoplasmic membranes. On electrophoresis, these glycoproteins form two major and two minor bands in the gel and migrate with proteins ranging from 50,000 to 100,000 daltons in molecular weight. (iii) The same glycoproteins are present in all membranes fractionated by density and in partially purified virus. The implications of the data are discussed.

Lymphosarcoma: virus-induced thymic-independent disease in mice.

Abstract: Summary A new murine oncogenic virus has been isolated which induces solid lymphoid tumors within a short latent period. A unique feature of this disease is the lack of thymic involvement. Thymic-independent tumor induction distinguishes this virus from the other experimental murine lymphoid leukemia viruses. In addition, massive meningeal tumors, a myelocytic leukemoid reaction, and no evidence of a disseminated leukemia constitute this disease syndrome.

Host-Range Restrictions of Murine Leukemia Viruses in Mouse Embryo Cell Cultures

Abstract: Murine leukemia virus strains fall into three categories with respect to their ability to propagate in cells of National Institutes of Health (NIH) Swiss and BALB/c mouse embryos. Cultures of NIH cells are 100- to 1,000-fold more sensitive to “N-tropic” strains than BALB/c cell cultures, but are 30- to 100-fold less sensitive to “B-tropic” strains. Some virus strains (dually tropic or “NB-tropic”) propagate equally well in both cells. M-MSV pseudotypes show the host-range characteristics of the virus supplying the envelope, both in vitro and in vivo. The host-range characteristics appear to be genetically determined and could not be explained by host-induced modification or virus mixtures. There was no correlation between host range and Gross-AKR or FMR serotype.

Presence of EB virus nucleic acid homology in a "virus-free" line of Burkitt tumour cells.

Abstract: The presence of virus in Burkitt lymphoma cells is hard to confirm, but small amounts of viral DNA have now been revealed by hybridization with DNA from cells of the Raji line of the tumour.

Macrophages and Age-Dependent Resistance to Herpes Simplex Virus in Mice

Abstract: Peritoneal macrophages transferred from adult CBA mice protected suckling syngeneic mice from intraperitoneal infection with herpes simplex virus. Macrophages from adult mice stimulated with proteose-peptone solution were more effective in providing protection than were unstimulated macrophages. The enhanced resistance provided by stimulated macrophages was associated with more efficient phagocytosis and intracellular destruction of virus, and with greater production of interferon. In contrast to the effects of stimulation on the adult mouse, the suckling mouse did not respond to proteose-peptone inoculation with the production of a population of macrophages that ingested more virus, produced more interferon, or more effectively destroyed virus.

Differences between the Ribonucleic Acids of Transforming and Nontransforming Avian Tumor Viruses

Abstract: The 60-70S RNAs of several transforming and nontransforming avian tumor viruses have different electrophoretic mobilities. The RNA of transforming viruses contains two electrophoretically separable subunit classes: a and b. The relative concentrations of these subunits vary with the virus strain. Avian leukosis viruses and nontransforming derivatives of a sarcoma virus lack subunits of class a. It is suggested that the presence of the class a subunit is related to the transforming ability for fibroblasts of the virus.

Selective Effects of Anti-Macrophage Serum, Silica and Anti-Lymphocyte Serum on Pathogenesis of Herpes Virus Infection of Young Adult Mice

Abstract: Weanling mice were treated with relatively specific suppressants of macrophages or lymphocytes and infected intraperitoneally with herpes simplex virus. Ingestion of silica particles or anti-macrophage serum impaired macrophage function and allowed virus to spread to the liver parenchyma with resulting hepatitis and early death. Anti-lymphocytic serum allowed the development of persistent viremia with subsequent spread of virus into the brain and development of fatal meningitis and encephalitis. These results are discussed in relation to the role of macrophage-dependent and lymphocyte-dependent reactions in protection of the host against parenteral virus infections.

Characterization of Bluetongue Virus Ribonucleic Acid

Abstract: An improved purification procedure yielded bluetongue virus free from any single-stranded ribonucleic acid (RNA) component. Double-stranded RNA obtained from purified virus or isolated from infected cells was fractionated into 5 components by means of sucrose gradient sedimentation analysis, and into 10 components by electrophoresis on polyacrylamide gels. The size of these components vary from 0.5 × 106 to 2.8 × 106 daltons, with a total molecular weight estimate of about 1.5 × 107 for the viral nucleic acid. The denaturation of the genome and separation of the resulting fragments are also discussed.

Lassa fever, a new virus disease of man from West Africa. III. Isolation and characterization of the virus.

Abstract: Fourteen isolates of Lassa virus were recovered in Vero cell cultures from material—serum, pleural fluid, urine, and throat washings—of four cases of Lassa fever. Viremia of 1 to 2 weeks' duration, with TCD50 titers ranging from 2 to 4.5 dex per ml, was observed. The agent did not infect the Aedes aegypti and Aedes albopictus continuous cell lines. When newborn and adult mice were inoculated intracerebrally with Lassa virus, complement-fixing and neutralizing antibodies were detected in their serum; in addition, adult mice showed signs closely resembling those seen in adult mice inoculated with lymphocytic choriomeningitis (LCM) virus. Lassa virus was isolated from urine of infected mice as late as 83 days after inoculation. Multiplication of Lassa virus in Vero cell cultures was not inhibited by the incorporation of 5-bromodeoxyuridine in the medium; hence the virus probably contains ribonucleic acid. The finding that the agent is susceptible to the action of sodium deoxycholate suggests the presence of a lipid-containing envelope. Electronmicroscopy studies reveal a spherical shape. Filtration studies indicate a diameter of the virus between 70 and 150 mµ. The 14 isolates, insofar as studied, are indistinguishable from one another. In extensive serologic studies, Lassa virus has been compared with and found distinct from numerous arboviruses and other viruses. By complement-fixation test, it cross-reacts to a low degree with LCM virus, and possibly also with some members of the Tacaribe group.

Mechanisms of recovery from a generalized viral infection: mousepox. I. The effects of anti-thymocyte serum.

Abstract: Agglutination and immunofluorescence tests in vitro showed that the ATS used in these experiments cross-reacted with macrophages and RBC. However, ATS was not toxic in vivo, and small doses given subcutaneously depleted thymus-dependent areas of lymphoid tissues and selectively depressed blood lymphocyte counts without affecting other cell types in the blood. Furthermore, the function of littoral macrophages as indicated by the clearance of blood-borne virus and its subsequent behavior over a 48 hr period in the liver and spleen was not changed by ATS. Thus, the innate resistance of these vital target organs was not depressed. A similar regimen of subcutaneous ATS caused a highly significant increase in mortality from mousepox with an associated failure to control virus growth in the liver and spleen which was manifest by 6 days after infection. The interferon and neutralizing antibody responses were not impaired in ATS-treated mice, but the cell-mediated immune response was significantly suppressed. This evidence, and consideration of the timing of these host responses during the course of infection in relation to the control of virus growth in the liver and spleen, led to the conclusion that cell-mediated immunity probably contributed an essential acquired recovery mechanism. However, no evidence was obtained concerning the nature of this antiviral mechanism.

Host range mutants of polyoma virus.

Abstract: A line of polyoma-transformed mouse cells has been isolated which is fully susceptible to lytic infection by polyoma virus. This line has been used to select virus mutants which have lost most or all of their ability to grow in the untransformed parental line while retaining the ability to grow in the transformed derivative. These virus mutants are also defective in their ability to transform cells of rat or hamster origin. Since the DNA extracted from the mutants has the same host range as the whole virus, the mutants appear to be blocked at some intracellular step which is required both for the completion of virus development in mouse cells and for transformation in rat or hamster cells.

Recovery and characterization of a minute virus of canines.

Abstract: Four antigenically related transmissible agents were recovered from canine fecal specimens. The agents produced cytopathic effects in a continuous dog cell line developed in this laboratory. Increased antibody titers were demonstrated in three of the four dogs which provided the isolates. The virus did not produce cytopathic effects in primary canine kidney or thymus cell cultures, or in cell cultures of human, simian, porcine, bovine, feline, and murine origin. The agent is resistant to ether, chloroform, and heat treatment, and the growth of the virus is inhibited by 5-iodo-2-deoxyuridine. After acridine orange staining, green fluorescent intranuclear inclusions are seen in infected cell cultures. By electron microscopy, the virions measure approximately 20 to 21 nm in overall diameter and are present in the nuclei of infected cells. These properties are consistent with membership in the parvovirus or picodnavirus group. The agent hemagglutinates rhesus red blood cells at 5 C and by hemagglutination-inhibition tests could be readily distinguished from H-1, rat virus, and the minute virus of mice. Canine gamma globulin contains high titers of neutralizing antibody and neutralizing antibody was found in a high percentage of military dogs and in beagles of a breeding colony.

Hong Kong A-2 Influenza Virus Infection among Swine during a Human Epidemic in Taiwan

Abstract: THE role of lower animals in the natural cycle of human strains of influenza virus transmission has been subjected to considerable speculation. With the possible exception of the report of Romvary et al.1, there are few, if any, satisfactorily authenticated cases of human influenza viral strains being isolated from naturally infected animals. That animals could be naturally infected was demonstrated when antibodies against the Asian A-2 strain were found in swine and horses after the 1957 pandemic2.

Observations on Childhood Infections with the Epstein-Barr Virus

Abstract: The Epstein-Barr virus (EBV), a member of the herpes group and first detected in cultures of Burkitt's lymphoma cells [1], has been identified as the probable cause of infectious mononucleosis (IM) [2-4]. Patients who develop IM were found to lack antibodies to EBV prior to illness and to form high levels of antibody during illness, often in rising titer. A history of typical IM could be elicited only from individuals with antibodies [5, 6], and the disease occurred only among laboratory technicians and students who had no antibodies at an earlier time [2-5, 7]. EBV appears to have a growth-stimulating effect on cultured peripheral leukocytes from antibodynegative, healthy donors [8-11], an observation which might explain the ready and rapid establishment of continuous lines of Mastoid cells from

Barley yellow dwarf virus: phenotypic mixing and vector specificity.

Abstract: Although the aphid Rhopalosiphum padi does not regularly transmit the MAV isolate of barley yellow drawf virus from singly infected oats, it often transmits MAV, together with the serologically unrelated RPV isolate, from plants doubly infected by MAV and RPV. Vector specificity of the virus isolates appears to be a function of the virus capsid. Some MAV nucleic acid becomes coated with RPV capsid protein during simultaneous synthesis of the two isolates in the doubly infected plant.

Pathogenesis of chronic disease associated with persistent lymphocytic choriomeningitis viral infection : ii. relationship of the anti-lymphocytic choriomeningitis immune response to tissue injury in chronic lymphocytic choriomeningitis disease

Abstract: Tissue injury (chronic disease) associated with persistent LCM infection is apparently caused by the host immune response to the virus. Employing parabiosis or cell transfer from hyperimmune donors to isologous virus carriers, the tissue injury of chronic disease could be initiated and/or intensified. Furthermore, the transfer of anti-LCM antibody to SWR/J carrier mice results in acute necrotizing inflammatory lesions in regions of viral persistence, followed by chronic mononuclear infiltrates quite similar to those seen after the transfer of immune cells. The pathogenesis of the nonglomerular tissue injury of chronic LCM disease is apparently at least in part related to the interaction of circulating anti-LCM antibody with viral antigen at the tissue site. Trapping of circulating virus-antibody complexes in the glomerular filter is apparently the major cause of the glomerulonephritis.

Infectious-mononucleosis-like Disease with Negative Heterophil Agglutination Test. Clinical Features in Relation to Epstein-Barr Virus and Cytomegalovirus Antibodies

Abstract: Patients with clinical and hematologic signs of infectious mononucleosis (IM) but with a negative heterophil-agglutination test are common. The question has been raised whether cases of this type should be classified as IM. Many clinicians employ the diagnosis, however, even when the heterophil-agglutination test is negative, provided the clinical picture is compatible with IM. This controversy cannot be settled until methods become available for establishing the specific etiologic diagnosis of every case. Recently, a member of the herpes virus group has been strongly implicated as the cause of IM. This virus is now referred to as the Epstein-Barr virus (EBV) after the EB-lines of cells cultured from Burkitt's lymphoma in which the virus was first observed by electron microscopy [1]. Prospective studies have shown that EBV antibodies are lacking in sera taken before development of heterophil-antibody-positive (HA+) IM but are

Cell-free transmission and in vivo replication of Marek's disease virus.

Abstract: Marek's disease virus recovered from the feather follicle of infected chickens was found to be infectious for chickens in cell-free preparations. The virus replicated in epithelial cells of the germinative layer of the feather follicle epidermis, producing both intranuclear and round or diffuse cytoplasmic inclusion bodies in the infected cells. It was found at this site 2 weeks postinoculation and prior to the development of tumor or other gross lesions. In the nucleus, many naked and a few enveloped herpesvirions were found, whereas the cytoplasm contained predominantly enveloped herpesvirions, which were usually within the cytoplasmic inclusion bodies. Approximately 80% of the extracellular virions were enveloped. Studies with both virulent and avirulent strains of the virus revealed a relationship between virulence, contagiousness, and replication of the virus in the feather follicle.