Autoradiographische Untersuchungen über das Verhalten der Desoxyribonucleinsäure in Herpesvirus-infizierten Zellen

Herpes-simplex-Virus- (Herpes virus humanus) infizierte HeLa-Zellen wurden autoradiographisch untersucht. In Kernen, die vor der Infektion 3H-Thymidin in ihre DNS eingebaut hatten, findet sich die Markierung nach der Infektion in der Peripherie, im sog. Randchromatin wieder. Bei 3H-Thymidin-Zugabe nach der Infektion wird dieses nur noch in den Kerninnenbereich aufgenommen. Das Randchromatin bleibt frei. Daraus geht hervor, daß der zelleigene DNS-Stoffwechsel unterbrochen wurde und nur noch im Kerninnenbereich ein DNS-Stoffwechsel für die Virus-Neubildung abläuft.

Carbohydrate masking of an antigenic epitope of influenza virus haemagglutinin independent of oligosaccharide size

Comparison of the haemagglutinins (HA) of the pathogenic avian influenza viruses A/FPV/Dutch/27 (H7N7) and A/FPV/Rostock/34 (H7N1) revealed 94.7% nucleotide and 93.8% amino acid sequence homologies. Six of the seven N-glycosidic oligosaccharides of the Rostock HA are at the same positions as the six carbohydrates of the Dutch strain. The additional oligosaccharide side chain of the Rostock strain, which is of the complex type, is attached to asparagine149 in antigenic epitope B. The accessibility of this antigenic epitope has been analysed by using rabbit antisera raised against synthetic peptides comprising amino acids 143-162. The carbohydrates of the HA of the Rostock strain have been modified (i) to truncated cores by expression in insect cells using a baculovirus vector, (ii) to oligomannosidic side chains by growth in the presence of the trimming inhibitor methyldeoxynojirimycin and (iii) to a single N-acetylglucosamine residue by removal of the oligomannosidic sugar with endo-beta-N-acetylglucosaminidase H. Neither the authentic nor the modified oligosaccharides allowed antibody binding, as indicated by enzyme-linked immunosorbent assay (ELISA) and Western blot analyses. Reactivity was observed, however, after complete removal of the carbohydrate from HA of the Rostock strain by digestion with peptide-N-glycosidase F. HA of the Dutch strain was reactive without prior peptide-N-glycosidase F treatment. These results demonstrate that a single N-acetyl-glucosamine at asparagine149 is sufficient to prevent recognition of the peptide epitope.

Structure and assembly of hemagglutinin mutants of fowl plague virus with impaired surface transport

Five temperature-sensitive mutants of influenza virus A/FPV/Rostock/34 (H7N1), ts206, ts293, ts478, ts482, and ts651, displaying correct hemagglutinin (HA) insertion into the apical plasma membrane of MDCK cells at the permissive temperature but defective transport to the cell surface at the restrictive temperature, have been investigated. Nucleotide sequence analysis of the HA gene of the mutants and their revertants demonstrated that with each mutant a single amino acid change is responsible for the transport block. The amino acid substitutions were compared with those of mutants ts1 and ts227, which have been analyzed previously (W. Schuy, C. Will, K. Kuroda, C. Scholtissek, W. Garten, and H.-D. Klenk, EMBO J. 5:2831-2836, 1986). With the exception of ts206, the changed amino acids of all mutants and revertants accumulate in three distinct areas of the three-dimensional HA model: (i) at the tip of the 80-A (8-nm)-long alpha helix, (ii) at the connection between the globular region and stem, and (iii) in the basal domain of the stem. The concept that these areas are critical for HA assembly and hence for transport is supported by the finding that the mutants that are unable to leave the endoplasmic reticulum at the nonpermissive temperature do not correctly trimerize. Upon analysis by density gradient centrifugation, cross-linking, and digestion with trypsin and endoglucosaminidase H, two groups can be discriminated among these mutants: with ts1, ts227, and ts478, the HA forms large irreversible aggregates, whereas with ts206 and ts293, it is retained in the monomeric form in the endoplasmic reticulum. With a third group, comprising mutants ts482 and ts651 that enter the Golgi apparatus, trimerization was not impaired.

HSV-1 gB and VZV gp-II crossreactive antibodies in human sera

The specificity and prevalence of human IgG antibodies crossreactive between HSV-1 (ANG) and VZV (Ellen) was examined in immunoblots. Using antibody fractions purified on HSV- and VZV-coated affinity chromatography columns and by preadsorption of sera with HSV and/or VZV lysates a crossreactivity between HSV-1 gB and VZV gp-II was demonstrated. Crossreaction of human IgG antibodies among other structural and nonstructural viral proteins, however, was not detected. The frequency of human IgG antibodies crossreactive between HSV-1 gB and VZV gp-II was highest in HSV-seropositive patients experiencing an acute primary VZV infection (4 out of 5 sera tested). In contrast, no crossreactive antibodies were found in sera of HSV-seronegative patients with acute primary VZV infection (0/6) or in sera from individuals with acute recurrent HSV or VZV infection (0/12). Analysis of sera from individuals with previous HSV and/or VZV infection showed the presence of antibodies crossreactive between HSV-1 gB and VZV gp-II in 3 out of 30 sera tested.

Conserved organization of an avian histone gene cluster with inverted duplications of H3 and H4 genes

The organization of histone gene clusters of the duck Cairina moschata was studied in the DNA inserts of two recombinant phage that overlap and feature identical histone gene arrangements but differ in sequence details and in the extent of repetition of an AT-rich motif in one of the nontranscribed spacer regions. These few but substantial differences between otherwise nearly identical histone gene groups suggest that we have independently isolated alleles of the same site of the duck genome or that this gene arrangement occurs (with slight variations) more than once per haploid genome. Within the histone gene cluster described, H3 and H4 genes are duplicated (with inverted orientation), whereas one H1 gene is flanked by single H2A and H2B genes. The arrangement of duck histone genes described here is identical to a subsection of the chicken genome but differs from any other published histone gene cluster.

Removal of N-linked carbohydrates decreases the infectivity of herpes simplex virus type 1

Purified preparations of herpes simplex virus type 1 Angelotti were digested with the exoglycosidases sialidase, beta-galactosidase, N-acetyl-beta-D-glucosaminidase and alpha-mannosidase, and with the endoglycosidases Endo-H and Endo-F. It was found that treatment of virions with Endo-F specifically decreased viral infectivity by a factor of 10. This reduction in titre was not associated with any measurable differences in virus adsorption, suggesting a role of N-linked complex type oligosaccharide chains in penetration. In contrast, a reduction in titre observed upon digestion of virions with exoglycosidases could be attributed to a proteolytic contamination in these enzyme preparations. Treatment of virions with Endo-H, demonstrated to be free of proteolytic contamination, did not reduce viral infectivity. Analysis of endoglycosidase-digested virions by monospecific antibodies and immunoblotting revealed a susceptibility of all four major glycoproteins (gC, gB, gE and gD) to Endo-F, but only gB was susceptible to Endo-H treatment. In contrast, of all the exoglycosidases used only sialidase was found to be active towards native viral glycoproteins. Upon analysis of endoglycosidase-digested virions we could not find any evidence for proteolysis, degradation or altered protein composition of viral envelopes. In contrast, vigorous inhibition of glycoprotein glycosylation by tunicamycin led to the formation of physically intact virions almost completely lacking all major glycoproteins. These data show that digestion of intact virions with glycosidases allows an analysis of the functional relevance of carbohydrate residues without any obvious alterations in the virion glycoprotein composition.

Homology of the HSV-2 "a-sequence" to cellular sequences

Bgl-II fragments of the genome of Herpes simplex virus type 2 (HSV-2) HG-52 were cloned into the vector p-Neo and were used to screen the complete HSV-2 genome for regions cross-hybridizing with the genome of HEL cells. Most extensive cross-hybridizing activity was observed with a 530 bp SstII subfragment of the viral BamHI G DNA-fragment (contained in Bgl II F), which spans the joint and the viral a-sequence. From a lambda-L47 library, a cellular 15 kb HindIII DNA fragment was subcloned in pBR 322 which contained a 1920 bp SstII subfragment having strong cross-hybridizing activity with the 530 bp Sst II fragment of HSV-2 BamHI G. Within this 1920 bp Sst II fragment the cross-hybridizing activity was confined to a 230 bp Bgl I/Hpa II subfragment. This 230 bp fragment (including the flanking sequences) was analyzed in comparison to the viral a-sequence. Sequence data revealed a (G + C) content of 66% in the cellular and 81% in the viral DNA fragment, which is mainly determined by an extremely (G + C) rich 16-fold direct repeat (DR2) at the 5'-end. The homology between both DNA-fragments varies between 56% and 79% within the L-S inversion region. Both sequences, furthermore, show homology to the human c-myc protooncogene.

Analysis of the IgM and IgG antibody response against herpes simplex virus type 1 (HSV-1) structural and nonstructural proteins

In the present study the reactivity of IgG and IgM antibodies against HSV-1 structural and nonstructural proteins was analyzed by Western blot analysis (WBA) and radioimmunoprecipitation followed by polyacrylamide gel electrophoresis (RIPA-PAGE). It was demonstrated that IgM and IgG antibodies were directed against viral immediate-early, early, and late proteins. Following acute primary HSV infection, the early IgM antibody response in general was found to be directed against nonglycosylated structural proteins, viral early and immediate-early polypeptides. IgM antibodies against viral glycoproteins were found inconsistently. IgG antibodies against viral glycoproteins and other structural proteins with an apparent molecular weight of 56 kD, 45 kD, and 39 kD could be detected early in infection. Viral early and immediate-early proteins were poorly recognized by IgG antibodies in acute primary infections. In recurrent HSV infections, IgM antibodies revealed a less complex reaction with viral polypeptides. Thus, such IgM antibodies reacted predominantly with viral nonglycosylated structural proteins. In contrast, IgG antibodies from patients with recurrent infections strongly recognized viral structural, early, and immediate-early proteins. In seropositive individuals without obvious symptoms of acute infection, the most prominent antibody response was directed against gB and gD.

Human cytomegalovirus replicates in primary human bone marrow cells

As an attempt to elucidate further the pathogenesis of human cytomegalovirus (HCMV) infection the replication of HCMV in primary human bone marrow cells (BMC) has been investigated. It was found that BMC held in culture in general were susceptible to HCMV infection. Compared to human embryonic lung cells, however, the replicative cycle of HCMV AD169 in BMC as determined by the analysis of viral protein and DNA synthesis was delayed and productive virus infection was restricted to a subset of BMC not exceeding 21% of the total cell population. Both of these phenomena may explain the short-term persistence of HCMV in BMC cultures which was observed over 3 months. By experiments with specifically enriched and depleted cell populations and by indirect double immunofluorescence experiments we found that both bone marrow fibroblasts and a subset of bone marrow stem cells supported productive virus infection. The finding that HCMV replicates in early stem cells of the human bone marrow may explain important aspects of the pathogenesis of HCMV infection including the presence of HCMV in peripheral blood leukocytes.

Low back strain in Danish semi-skilled construction work

Danish semi-skilled construction workers (SC-workers) perform a variety of tasks in building construction, civil engineering and rebuilding. A previous epidemiologic study indicated a high occurrence of low back pain (LBP) among these workers. The study was designed to quantify the major occupational risk factors associated with the development of LBP, i e, inclined postures, repetitive movements, heavy lifts, pushing/pulling motions, sudden unexpected strains and whole body vibrations in this group of construction workers. Firstly a study of occupational activity of 112 SC-workers on height construction sites during two separate five-days periods was carried out. This was followed by an observational study of the nine work tasks most common to SC-workers. Heavy lifts, pushing/pulling motions and sudden unexpected strain occurred most frequently in the work, while inclined postures, repetitive movements and whole body vibrations characterised different parts of the work. Assessments of the strain were made on the basis of techniques given in the literature.

la-positive T lymphocytes are the producer cells of interferon gamma

The production of gamma-interferon (IFN gamma) in human peripheral blood T lymphocytes was induced by stimulation with PHA. For identification of the producer cell of IFN gamma, double fluorescence studies were undertaken and titers of interferon were determined in preparatively separated T-cell subpopulations reactive with one of the monoclonal antibodies OKT3, OKT4, OKT8, and OKIal . Production of IFN gamma was found in OKT3+, OKT4+, and OKT8+ cells. However, IFN gamma production occurred only in T cells also reactive with the monoclonal antibody OKIal . Addition of macrophages had no substantial effect on interferon titers in these subpopulations. It is suggested that the T cell subset producing IFN gamma is characterized by its reactivity with the monoclonal antibodies OKT3, OKT4 or OKT8, and OKIal .

Replication of herpes simplex virus in human T lymphocytes: characterization of the viral target cell

Herpes simplex virus (HSV) replicated in mitogen-stimulated human T cells. Virus replication was obtained in highly enriched mitogen-stimulated T cells of the OKT 3+, OKT 4+, or OKT 8+ subtype, in stimulated B cells, and in macrophages precultured for 7 days. In contrast, no virus replication was obtained in unstimulated T or B cells, in macrophages grown in culture for 1 day, in Null/NK cells, or in granulocytes. Infectious center assays revealed that below 1% of the infected T cell subpopulations supported virus replication, whereas up to 42% of infected B cells and 80% of macrophages cultured for 1 wk were able to replicate HSV. By indirect double immunofluorescence studies, complement-mediated mass cytolysis, and positive selection experiments, it was shown that only T cells expressing Ia antigen actively replicated the virus. T cells activated in the mixed lymphocyte culture and with UV-inactivated HSV were also susceptible to HSV infection. Several human leukocyte cell lines were tested for their ability to support virus replication and were tested for a correlation with the expression of Ia antigen. Only cell lines expressing Ia antigen on more than about 5% of the total population produced new progeny virus. Ia-expressing T cells that spontaneously replicated HSV without any mitogenic prestimulation were found to occur in variable numbers in human cord blood. It is suggested, that such T cells, permissive for HSV replication, might contribute to an outspread of viral infection in vivo.

Replication of herpes simplex virus in human T lymphocytes: characterization of the viral target cell

Herpes simplex virus (HSV) replicated in mitogen-stimulated human T cells. Virus replication was obtained in highly enriched mitogen-stimulated T cells of the OKT 3+, OKT 4+, or OKT 8+ subtype, in stimulated B cells, and in macrophages precultured for 7 days. In contrast, no virus replication was obtained in unstimulated T or B cells, in macrophages grown in culture for 1 day, in Null/NK cells, or in granulocytes. Infectious center assays revealed that below 1% of the infected T cell subpopulations supported virus replication, whereas up to 42% of infected B cells and 80% of macrophages cultured for 1 wk were able to replicate HSV. By indirect double immunofluorescence studies, complement-mediated mass cytolysis, and positive selection experiments, it was shown that only T cells expressing Ia antigen actively replicated the virus. T cells activated in the mixed lymphocyte culture and with UV-inactivated HSV were also susceptible to HSV infection. Several human leukocyte cell lines were tested for their ability to support virus replication and were tested for a correlation with the expression of Ia antigen. Only cell lines expressing Ia antigen on more than about 5% of the total population produced new progeny virus. Ia-expressing T cells that spontaneously replicated HSV without any mitogenic prestimulation were found to occur in variable numbers in human cord blood. It is suggested, that such T cells, permissive for HSV replication, might contribute to an outspread of viral infection in vivo.

Replication of herpes simplex virus in human T lymphocytes

The replication of herpes simplex virus (HSV) in cultures of human T lymphocytes was investigated. Virus replication occurred only in lymphocyte cultures prestimulated with mitogen. At least one of the factors responsible for this phenomenon is adsorption of the virus to the cells, which was 5 times less efficient in nonstimulated cells than in stimulated cultures. Growth of virus in infected cultures was restricted to lymphocytes of T origin. This was shown by successful infection of highly purified T-cell cultures and by virus replication in four continuous T-cell lines. No virus production was obtained in cultures of lymphocytes of other than T-cell origin. Virus titers in T-lymphocyte cultures reached 10(7) PFU/ml, which was a four log10 step increase over the input dose. Lymphocytes infected with a syn strain of HSV, HSV-ANG, induced polykaryocyte formation in the cultures and therefore generated a CPE visible by microscopic examination. Infection with syn+ strains of HSV (i.e., strains which do not cause cell fusion) did not lead to such phenomena. Not more than 1% of infected T cells was replicating HSV, as revealed by infectious center assays. In contrast, about 5% of these cells showed positive immunofluorescence with anti-HSV antibodies, indicating the presence of cells which express viral protein but do not actively produce infectious virus.

Rapid separation of T cell subpopulations with monoclonal antibodies and affinity chromatography

A rapid method for isolation of highly enriched helper and suppressor T cell subsets and their corresponding helper and suppressor cell depleted cell populations is described. The method is based on the binding of monoclonal antibodies to helper and suppressor cells and subsequent affinity chromatography with covalently bound rabbit anti-mouse antibodies. As assessed by indirect immunofluorescence, purity of the enriched subpopulations exceeds 90%, whereas no contamination with helper or suppressor cells is detectable in populations depleted of the respective subsets. The cells isolated by this method show no functional defects in helper and suppressor assays and respond with increased DNA synthesis to stimulation with phytohemagglutinin (PHA) plus 2-mercaptoethanol (2-ME).

The incidence of disability pensions and mortality among semi-skilled construction workers in Copenhagen. A retrospective cohort study with two control groups

The aim of the present study was to discover whether the incidence of disability pensions and mortality was higher amongst semi-skilled construction workers (SCW) in Copenhagen than in two control groups from the same geographic area. The population investigated consisted of a fixed cohort of 3537 SCW from Copenhagen as per 1/5/1975. The two control groups comprised 3818 Copenhagen members of the Warehouse Workers' union and a group of Copenhagen members of the Semi-skilled Worker's Union age-matched to the SCW cohort, both as per 1/5/75. Up to 31/12/79, a total of 102 SCW were granted disability pensions, compared with 89 and 77 in the two control groups respectively, i.e. a significantly higher frequency of award of disability pension among SCW than among warehouse workers (p less than 0.05). This was due especially to a higher frequency of disability pensions granted because of musculoskeletal diseases and cancer in SCW. The number of deaths was recorded from 1/5/75 to 30/11/78. No differences in overall mortality were found among the three groups, although slightly fewer deaths from lung cancer and ischaemic heart diseases and more suicides were observed among the construction workers. Selection bias and the effect of the working environment are discussed against the background of a concurrent investigation of the state of health and working conditions of SCW.

Alterations in protein and glycoprotein composition of rat embryo fibroblasts transformed by herpes simplex virus type 2

Total and superficially exposed plasma membrane components of tumorigenic herpes-simplex-virus (HSV)-transformed fibroblasts were studied. As a result of oncogenic HSV transformation, a significant decrease of polypeptides 230,000, 180,000, 56,000 and 43,000 daltons was found. These changes were accompanied by a significant increase in superficial exposition of several sialopeptides and two peptides of 30,000 and 15,000 daltons. It was suggested that these two peptides may represent virus-coded components of HSV-transformed fibroblasts. The present results indicate that the HSV-transformed tumorigenic cell clone meets all previously described criteria for oncogenically transformed cells.

Comparison of different methods for the detection of rubella-specific IgM antibodies

The rubella specific IgM titer in the serum specimens originating from healthy persons and from patients with clinical signs of rubella infection was determined by hemagglutination inhibition or hemagglutination reduction after IgM separation with the following methods: (a) density gradient centrifugation; (b) polyacrylamide agarose gel chromatography; (c) ion exchange chromatography with diethylaminoethyl cellulose columns; (d) solid-phase immunosorbent technique using microplates; (e) solid-phase immunosorbent technique using polyacrylamide microimmunobeads. Alternatively, we removed IgG and IgA by the use of protein A, anti-IgG, and anti-IgA, covalently coupled to controlled-pore glass (f). The titers obtained by the different methods showed qualitatively good correlations when combined with mercaptoethanol reduction. The quantitative measurement of specific IgM titers, however, revealed a lower sensitivity of column chromatography and methods of removal of IgG/IgA.

Experimental infection and the state of viral latency of adult tupaia with herpes simplex virus type 1 and 2 and infection of juvenile Tupaia with temperature-sensitive mutants of HSV Type 2

The susceptibility of adult Tupaia Belangeri to infection with herpes simplex virus (HVS) was investigated. Adult animals were inoculated intraperitoneally with HSV type 1 or 2. With the exception of HSV-2, strain HG-52, 10(5)--10(6) PFU of all HSV strains caused lethal infection irrespective of the age of the animals. Infections HSV was recovered from the spinal cord of those animals which had survived infection with a low dose of virus. The DNA of the recovered viruses was compared to the DNA of the inoculated HSV. The viral genome of the recovered HSV was unchanged as judged by analysis of the fragment pattern of the viral DNA's using restriction endonucleases. Animals which had survived the first HSV infection were protected against a second infection even at highly lethal doses of HSV-1 or 2. Juvenile Tupaia survived infection with temperature-sensitive mutants of HSV-2, strain HG-52, which induced protection against a second infection with lethal doses of HSV-1 or 2.

Protection of mice against viral infection by Corynebacterium parvum and Bordetella pertussis

Mice could be significantly protected against infection with herpes simplex virus (HSV) by i.p. or i.v. injection of killed Corynebacterium parvum 7 days before infection. This protection was seen in inbred strains of mice with a different degree of sensitivity to HSV and after both i.p. and i.v. infection. Resistant mice immunosuppressed by X-irradiation and showing an increased susceptibility to HSV could also be protected by a previous injection of C. parvum. Elevated levels of interferon were demonstrated in the serum of mice injected with C. parvum 5 to 12 days previously. Four different strains of anaerobic coryneforms were compared and only those which were able to induce a systemic activation of the lymphoreticular system (as reflected by splenomegaly) protected against HSV infection. Protection against HSV-infection could also be demonstrated by using killed Bordetella pertussis. C. parvum also protected against Semliki Forest virus infection in two different strains of mice.

Transformation of skin fibroblast cells of a cystinotic patient by simian virus 40: evidence for an establishment of a permanent cell clone which retains the original metabolism defect

Human skin fibroblast cells derived from a juvenile patient with nephropathic cystinosis were transformed by simian virus 40. Transformed cell clones were isolated and established in tissue culture. In comparison to the parental cystinotic cells, the newly isolated, transformed cell clones had a higher plating efficiency, a modal chromosome number of 68, grew in soft agar, and showed a nuclear immunofluorescence typical for SV 40-specific tumor (T) antigen. The content of intracellular, unbound cystine in the transformed cell clone was of the same level (6.1 nmol 1/2 cystine/mg protein) as in the parental cystinotic cells (7.4 nmol). Control cells (SV 80 and WI-38) contained normal levels of cystine (0.31 and 0.47 nmol 1/2 cystine/mg protein). The growth characteristics make the transformed cystinotic cell clone suitable for large scale preparation of cellular constituents, i.e. lysosomes which seem to be affected in cystinotic patients.

Experimental infection of Tupaia belangeri (tree shrews) with herpes simplex virus types 1 and 2

The susceptibility of Tupaia belangeri (tree shrews, which are primitive prosimian primates) to infection with herpes simplex virus (HSV) and the pathogenesis of HSV in these animals were investigated. Juvenile (28--45 days old) and adult (150 days old) animals were inoculated intravenously, intraperitoneally, or subcutaneously with HSV type 1 or 2 (25--10(5) plaque-forming units per animal). Clinical illness usually appeared in juvenile animals on the second day after inoculation, and the animals died between two and 14 days after inoculation. High titers of infectious HSV were recovered from liver and spleen. The histopathologic examination always showed severe liver changes with numerous necrotic areas. The morphologic events in the liver were designated as herpetic hepatitis. The next most common morphologic findings were encephalitis and fibrosis in the spleen. These results demonstrate the high pathogenicity of HSV types 1 and 2 in juvenile T. belangeri. In contrast, adult animals did not develop acute clinical disease and survived the HSV infection.

Immunological studies of hsv-infection of resistant and susceptible inbred strains of mice

DBA/2 mice were found to be quite susceptible to infection with herpes simplex virus (HSV) while C57BL/6 mice and F1 hybrids between the 2 strains were relatively resistant. This difference was most marked after ip infection, but could also be demonstrated after intracerebral, intravenous or subcutaneous infection. In both strains the LD50 was considerably higher after ip infection than after iv infection, and a dose of X-irradiation was required to kill the mice by sc infection. A/J and BALB/c mice were equally susceptible after ip infection but differed significantly after iv infection. C57BL/6 were made susceptible to ip infection by immunosuppression with antilymphocyte serum or cyclophosphamide. LPS, when given simultaneously with HSV also markedly increased the susceptibility of C57BL/6 mice. Susceptible DBA/2 mice which surrvived a low dose of HSV ip were not immune but C57BL/6 mice surviving a high dose were immune against rechallenge. Both strains of mice could be protected by an apathogenic, tissue-culture-attenuated strain of HSV against infection with the virulent strain. They could also be protected by iv injection of a sublethal dose against a lethal ip infection.

Activation of an endogenous C-type RNA virus in rat embryo cells after transformation by herpes simplex virus types 1 and 2

Reverse transcriptase activity was detected in the supernatants of rat embryo fibroblast cell cultures transformed by HSV types 1 and 2 at either the sub-optimal temperature of 20 degrees C or the supra-optimal temperature of 42 degrees C. Rat cells clones which had been transformed at 20 degrees C contained higher levels of C-type virus DNA polymerase than did cell clones which had been transformed at 42 degrees C. Syncytia formation typical for C-type RNA viruses occurred at passages higher than 24. The activation of endogenous C-type RNA viruses was independent of the virus and transformation method used.

Detection of SV40 T antigen with labelled antibodies: radioimmunoassay and autoradiography

SV40 T antigen, partially purified from SV80, a human cell line, has been used to develop a sensitive solid phase radioimmunoassay. In this assay SV40 T antigen was immobilized on microtiter plates, reacted with hamster anti-SV40 T antibody and subsequently with 14C-labelled anti-hamster IgG. The test detected approximately 20 ng of partially purified SV40 T antigen and is rapid and more convenient than the complement fixing reaction. An immunoautoradiographic method which permits the determination of the cellular localization of SV40 T antigen and which is possibly more sensitive than the indirect immunofluorescence method is also described.

Protection against herpes simplex virus infection in mice by Corynebacterium parvum

Corynebacterium parvum administered in mice prior to herpes simplex virus (HSV) infection significantly protected them against lethal encephalitis. This was seen both with a mouse strain highly susceptible to HSV and with one relatively resistant to HSV. Mice immunosuppressed by cyclophosphamide and showing an increased mortality after HSV infection were also protected by C. parvum pretreatment. However, C. parvum given simultaneously with or after HSV infection did not exert a therapeutic effect.

Morphological transformation of rat embryonic fibroblasts by abortive herpes simplex virus infection: increased transformation rate correlated to a defective viral genotype

Rat embryo fibroblasts were abortively infected with various stocks of herpes simplex virus type 1 strain ANG at 42 degrees. In uninfected controls all of the cells died during an 8-day incubation period at the elevated temperature, whereas varying numbers of cells in the infected cultures survived and formed colonies during subsequent incubation for 3--4 weeks at 37 degrees. All of the survivors appeared to be morphologically transformed. Two types of survivors, epithelial- and spindle-like cells, which occurred at a ratio of approximately 1:1 in all assays, could be distinguished. The observed survival rates increased from about 1 x 10-7 to 3 x 10-5, corresponding to increasing fractions (0--50%) of a defective genotype present in the infecting virus stocks. The individual survival rates do not depend exclusively on the quantity of defective virions. The existence of different subtypes of defective genomes as a further parameter is discussed.

Scanning electron microscopic studies of herpes simplex virus transformed cells

The surface morphology of herpes simplex virus transformed cells was examined by scanning electron microscopy in exponentially growing and density inhibited rat embryo fibroblast cultures. The cell surface of oncogenically-transformed cells became more villated and many microvilli showed branching. C-type virus particles budding from the cell surface were commonly observed. Virus induced cytopathic effects observed by scanning electron microscopy, included rounding up and detachment of degenerating cells from the substrate.

Replication of herpes simplex virus in mouse spleen cell cultures stimulated by lipopolysaccharide

Replication of HSV was demonstrated in spleen cell cultures of D2 and several other strains of mice after prestimulation with mitogenic doses of LPS for 2 days. No viral replication occurred in unstimulated cultures or in cultures prestimulated with PHA and Con A, whereas there was some viral replication in spleen cell cultures of D2 mice after prestimulation with Poly I-C. Spleen cells of B6 mice did not support replication of HSV under any of the conditions we have tested thus far. The reasons for this defect are not clear, but it was obviously not caused by a defective lymphoproliferative response to LPS or by an active anti-viral principle elaborated by B6 spleen cells. F1 hybrids between B6 and D2 mice were capable of HSV replication to the same extent as were spleen cells of D2 mice. Several strains of both HSV-1 and HSV-2 could be replicated in D2 spleen cells cultures. Nylon column treatment of D2 spleen cells removed the ability to replicate HSV, whereas macrophage removal from the spleens by plastic adherence was without effect. Purified peritoneal exudate cells from D2 mice did not support replication of HSV. Together these data suggest that B cells activated by LPS represent the target cell of HSV replication in mouse spleen cell cultures.

Neoplastic transformation of rat embryo cells with herpes simplex virus

Sprague Dawley rat embryo cells (REF) were transformed by inoculation with herpes simplex virus (HSV) and incubation at 42 degrees C for 8 days. The infected cultures were subsequently returned to 37 degrees C and two types of cell clone were isolated from foci of growing cells after 4 weeks. One of the clones consisted of epithelial-like cells and did not produce HSV (REF-Tep-NP). The second consisted of spindle-shaped cells and cultures of these cells persistently developed small areas of degeneration where production of infectious HSV (REF-Tsp-P) took place. An additional clone which did not produce any more HSV (REF-Tsp-NP) was isolated from REF-Tsp-P in the presence of HSV-antiserum. REF-Tsp-P and REF-Tsp-NP grew more rapidly than REF and also formed foci in soft agar. REF-Tep-NP had a growth rate between that of normal rat embryo cells and that of both REF-Tsp-NP and REF-Tsp-P and did not form foci in soft agar. REF-Tsp-NP cells, in contrast to REF-Tep-NP cells, were resistant to superinfection with HSV types 1 and 2. REF-Tsp-P and REF-Tsp-NP produced metastasizing sarcomas in rats. After inoculation of 10(3) REF-Tsp-NP cells into 1-day-old rats tumours developed rapidly. REF-Tep-NP cells did not induce tumours in rats. The parental REF cells produced no tumours, even when 10(8) cells were inoculated into the rats. Positive immunofluorescence was observed in all three transformed cells only with the hyperimmune rabbit sera but not with human anti-HSV reconvalescence immune sera.

Effect of poly I:C-induced interferon on herpes virus hominis infection in vitro and in vivo

In this study the effect of poly I : C-induced interferon on Herpesvirus hominis (HVH) infection in vitro and in vivo was investigated.

The in vitro results revealed a significant effect of interferon on infections of HVH strains of different origin in mouse embryonic cells.

The in vivo experiments performed in the HVH-mouse system indicate that the effective induction of interferon in an aminal increases its resistance to subsequent infection with HVH.