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influence of flavonoids on combined experimental infections with emc virus and staphylococcus aureus in mice.activity of elected flavonoids in emc virus and staphylococcus aureus infected mice were investigated, to determine the influence on mortality rate. some of the flavonoids: quercetin, hypoletin, hesperidin, rutin and quercitrin showed significant protective effect given before single as well as combined viral-bacterial infections.19892482663
the role of interferon in the protection of icr swiss male mice by the nondiabetogenic variant of encephalomyocarditis virus against virus-induced diabetes mellitus.the production of murine diabetes mellitus by the diabetogenic variant of encephalomyocarditis virus (emcv-d) is prevented in mice preinfected for 24 h with nondiabetogenic virus (emcv-b). it has been suggested that the protection of the animals is due to the induction of interferon (ifn) by emcv-b. the present study was done to investigate further the role of ifn in the protection of male icr swiss mice against the diabetogenic effects of emcv-d virus. the results show that this mouse strain is ...19892481700
constitutive expression of a 2',5'-oligoadenylate synthetase cdna results in increased antiviral activity and growth suppression.the interferon (ifn)-induced enzyme 2',5'-oligoadenylate (2-5a) synthetase has been implicated in the development of antiviral activity in human and animal cells. however, its role in ifn-mediated growth inhibition remains unclear. to elucidate the function of 2-5a synthetase, we have stably introduced a human 2-5a synthetase cdna into a human glioblastoma cell line (t98g). constitutive expression of the cdna in these cells is associated with increased levels of resistance to infection by enceph ...19892481699
murine cell-mediated immune response recognizes an enterovirus group-specific antigen(s).splenocytes taken from mice inoculated with coxsackievirus b3 (cvb3) (nancy) developed an in vitro proliferative response against cvb3 antigen. this response could not be detected earlier than 8 days postinoculation but could be detected up to 28 days after exposure to cb3. cvb3-sensitized splenocytes responded not only to the cvb3 antigen but to other enteroviruses as well. this response was found to be enterovirus specific in that no response was detected to a non-enteroviral picornavirus, enc ...19892476566
antisense oligonucleotide inhibition of encephalomyocarditis virus rna translation.we report the inhibition of encephalomyocarditis virus (emcv) rna translation in cell-free rabbit reticulocyte lysates by antisense oligonucleotides (13-17-base oligomers) complementary to (a) the viral 5' non-translated region, (b) the aug start codon and (c) the coding sequence. our results demonstrate that the extent of translation inhibition is dependent on the region where the complementary oligonucleotides bind. non-complementary and 3'-non-translated-region-specific oligonucleotides had n ...19892476310
competition binding assay in cell culture for identification of epitopes on enveloped and naked viruses.virus infected monolayers, in wells of 96-well plates, could be used as antigen in competition binding assays to identify epitopes on respectively semliki forest virus, encephalomyocarditis virus and mumps virus.19892476138
differing attachment of diabetogenic and nondiabetogenic variants of encephalomyocarditis virus to beta-cells.the d variant of encephalomyocarditis (emc-d) virus does not induce the production of interferon (ifn) and produces an insulin-dependent diabetes mellitus (iddm)-like syndrome in certain mouse strains. in contrast, the b variant (emc-b) virus, which is serologically identical to emc-d virus, is a good inducer of ifn and is nondiabetogenic. it has been postulated that ifn may play a major role in determining the ability of these two viruses to infect pancreatic beta-cells. however, recent studies ...19892475377
rapid bioassay of human interferon by direct enzyme immunoassay of encephalomyocarditis virus in hep-2 cell monolayers after a single cycle of infection.multiplication of encephalomyocarditis virus (emcv) in human hep-2 cells, and its suppression by interferon (ifn), was demonstrated by direct enzyme immunoassay (eia) in cell culture. emcv was detected in glutaraldehyde fixed hep-2 cell monolayers, in wells of 96-well plates, with a horse radish peroxidase (hrpo) labelled emcv specific monoclonal antibody. multiplication of emcv (multiplicity of infection: 50) was indicated by a steep rise of absorbance values measured against infected monolayer ...19892474560
the antiviral activity of tumor necrosis factor in hela cells is not mediated by interferons. studies with tnf-resistant variants.tumor necrosis factor (tnf) has a relatively modest antiviral activity in hela cells, when compared to that of interferon (ifn). addition of antisera neutralizing ifn-alpha or beta did not reduce the antiviral activity of tnf. furthermore, we determined with a sensitive hybridization assay that less than one molecule of ifn-beta 1 mrna could be present per tnf-treated cell. hela cell variants resistant to the tnf cytocidal activity were selected. these variants had tnf receptors with a dissociat ...19882474237
[interferonogenic activity of low-molecular compounds of plant origin]. 19882470203
interferon production by the preimplantation sheep embryo.ovine trophoblast protein-1 (otp-1), the major product secreted by the trophectoderm of the sheep conceptus between days 13 and 21 of pregnancy, is considered to mediate maternal recognition of pregnancy by maintaining the function of the corpus luteum. its amino acid sequence has 40-55% identity with various mammalian interferons-alpha (ifn-alpha), and it has been shown to have antiviral activity. the present results confirm that otp-1, which at days 15-17 of pregnancy is produced by a single e ...19892469745
inhibited interferon production after space flight.several studies have been performed in our laboratories indicating that interferon production may be impaired in rodents after space flight. using an antiorthostatic suspension model that simulates some of the effects of microgravity seen during space flight, we have shown that interferon-alpha/beta production was inhibited. the inhibition was not due solely to the stress of suspension. the inhibited interferon production was transient, as suspended animals returned to normal caging recovered th ...19882469283
properties of interferons produced by different cell populations. 19882469281
effect of interferons and poly(i):poly(c) on the pathogenesis of the diabetogenic variant of encephalomyocarditis virus in different mouse strains.interferon (ifn) can either prevent or exacerbate the pathogenic effects of the diabetogenic variant of encephalomyocarditis (emc-d) virus. the effect seen is dependent upon the mouse strain and the time of ifn administration. for example, ifn-alpha beta protects swr/j but not icr swiss male mice against the diabetogenic effects of the virus. administration of either ifn-alpha beta or the ifn-inducer poly(i):poly(c) 4 days post infection, results in an exacerbation of the infection in icr swiss ...19882466089
[effect of virus-induced interferon on mast cell resistance to the degranulating action of immune complexes].regularities of endogenous interferon (ifn) induction with newcastle disease virus (ndv) in rats and the effect of this process of the resistance of mast cells to the degranulating effect of immune complexes are described. increased resistance of mast cells to the damaging effect of immune complexes for 72 hours after a single induction of endogenous ifn with virus was demonstrated in experiments in vivo. inoculation of rats with ndv treated at ph = 2.0 did not induce the production of endogenou ...19882464242
enhancement of viral pathogenesis in mice maintained in an antiorthostatic suspension model: coordination with effects on interferon production.both rodents and men returning from spaceflight and the attendent microgravity or weightlessness conditions have exhibited alterations in immune responses and, in particular, interferon production. we have utilized a model for antiorthostatic (20 degrees head-down tilt). hypokinetic, hypodynamic suspension of mice that simulates some aspects of weightlessness. female swiss/webster mice that are normally resistant to infection with the d variant of encephalomyocarditis virus showed a marked incre ...19872461049
[effect of inhibitors that destroy cytoskeleton structures on the antiviral and antiproliferative activity of interferons].the effect of a number of drugs (vincristine, vinblastine, cytochalasin b, colcemid, colchamine) destroying cytoskeleton structures (microtubules and microfilaments) in combination with homologous interferon was studied in l920 and caov cells. the above substances were shown to inhibit the antiviral and enhance (from additivity to synergism) the antiproliferative effect of interferons under study.19882459850
coxsackievirus b-3-induced myocarditis. virus and actinomycin d treatment of myocytes induces novel antigens recognized by cytolytic t lymphocytes.balb/c mice inoculated with 6 x 10(4) plaque-forming units of a myocarditic variant of coxsackievirus, group b, type 3 (cvb3m) developed three distinct ctl populations recognizing putative virion (virus specific ctl, vctl), normally expressed heart (autoreactive ctl, actl), and aberrant metabolic (mctl) ag. induction of the mctl-specific ag on cardiocytes correlated with the ability of the myocarditic viruses and actinomycin d to interfere with cellular metabolism as measured by 3h-uridine and 3 ...19882459248
distinct domains of recombinant human ifn-gamma responsible for anti-viral effector function.a panel of 21 independently isolated neutralizing mab directed against the human rifn-gamma (rhuifn-gamma) was used to characterize those epitopes that are involved in the antiviral function of the rhuifn-gamma. a sandwich competition assay was developed to determine the cross-reactivities between the mab. the 125i-labeled mab were allowed to compete with varying amounts of unlabeled mab for binding to rhuifn-gamma under ag-limiting conditions, and the 50% inhibition endpoints were determined fo ...19882459212
discrimination of determinant specificity of two encephalomyocarditis virus neutralizing monoclonal antibodies by competition, mixed neutralization and anti-idiotypic antibodies.to investigate the epitope(s) on encephalomyocarditis virus (emcv) involved in neutralization, two neutralizing monoclonal antibodies (mas) (ma um 21.1 and ma um 21.2) were tested in a competition binding assay (cba), a mixed neutralization test and an enzyme immunoassay (eia) with specificity for the detection of idiotypes on mas. with a cba in cell culture, using emcv infected l cell monolayers as binding antigen, strong homologous competition was observed between unlabelled mas and horse radi ...19882456299
isolation and characterization of interferon-resistant variants from s49 mouse lymphoma.s49 mouse lymphoma cells were found to be extremely sensitive to the antiproliferative activity of interferon. these characteristics were studied to select for ifn-resistant cell variants. some 0.6% of the parental s49 cell population were resistant to the antiproliferative and cytotoxic activities of ifn. the resistant cells were cloned and analyzed for their responses to several of the activities of ifn, namely, inhibition of encephalomyocarditis (emc) virus, murine leukemia virus (mulv) repli ...19882455652
the interaction of interferon-alpha and -gamma: regulation of (2-5)a synthetase activity.the interaction of ifn-alpha and ifn-gamma on the induction of antiviral, growth inhibitory, and (2-5)a synthetase activities was investigated in t98g and a549 cells. synergistic or inhibitory effects which were host-cell dependent were seen with both simultaneous and sequential ifn treatments. interestingly, ifn-gamma 1 pretreatment affected the levels of ifn-alpha-induced (2-5)a synthetase activity differently in the two cell types. in t98g cells, sequential treatment resulted in an overall de ...19882455384
inhibition of transcription of herpes simplex virus immediate early genes in interferon-treated human cells.the effect of interferon (ifn) treatment on the early stages of herpes simplex virus type 1 (hsv-1) replication in three types of human cells was investigated. interferon pretreatment was shown to reduce the steady state levels of both total and polysomebound hsv-1 immediate early alpha mrnas. using the nuclear run-off transcription assay, we showed that ifn selectively inhibited transcription of the hsv-1 genes, with no effect on transcription of total cellular rna or that of the beta-tubulin r ...19882455018
hiv-1-specific production of ifn-gamma and modulation by recombinant il-2 during early hiv-1 infection.specific cellular immune responses to human immunodeficiency virus type 1 (hiv-1) were assessed in mononuclear leukocyte cultures from homosexual men with documented, early phase hiv-1 infection. cell cultures from men with a mean duration of 1.3 yr (range, 0.3 to 2.2 yr) of hiv-1 infection were treated with uv-inactivated, whole, purified hiv-1 ag together with various concentrations of ril-2. cell supernatants were harvested after 5-day incubation and assayed for ifn activity against encephalo ...19882452186
a fast and sensitive method for detecting specific viral rna in mammalian cells.a quick and sensitive method to quantitate viral rna synthesis has been developed. utilizing glutaraldehyde to fix infected cells onto nitrocellulose paper, viral rna can be probed directly in situ. viral message can be detected from as few as 10(4) infected cells. this technique can be used to study viral gene expression and can be adapted to screen the activity of antiviral agents such as interferon.19882450208
[potentiation of the antiviral activity of human interferons by virazole in in vitro experiments].combination of interferon and virazole results in potentiation of their antiviral activity. this was demonstrated with all three types of natural interferons and the recombinant rl-2-interferon. this effect is retained at a temperature of 37 degrees c and increases when the chemical drug is combined with a mixture of alpha- and gamma-interferon.19872448957
antiviral effects of recombinant human tumor necrosis factor.the antiviral action of recombinant human tumor necrosis factor (tnf) was studied using assay systems to determine inhibition of viral cytopathic effect (cpe), as well as suppression of virus growth measured by plaque assays. tnf was cloned and prepared by asahi chemical industry, japan. antiviral activity against human herpes simplex virus (hsv) types 1 and 2, cytomegalovirus (cmv), varicella-zoster virus (vz), vesicular stomatitis virus (vsv) and encephalomyocarditis virus (emc), was demonstra ...19872448553
physical dependence to morphine diminishes the interferon response in mice.morphine pellet implantation in mice was demonstrated to diminish resistance to encephalomyocarditis virus infections. the variations in the response to three different interferon (ifn) inducers--newcastle disease virus, escherichia coli lipopolysaccharide and a tilorone analogue--were evaluated. a close relationship between morphine dependence and ifn response was detected. a clear inhibition in ifn induction appeared as a concomitant phenomenon with the syndrome of morphine dependence. in the ...19872448267
antibody-nucleic acid interactions. antibodies to psoralen-modified rna as probes of rna structure.antisera elicited by immunization of rabbits with 4'-aminomethyl-trioxsalen (amt)-modified poly(a,u) complexed with methylated bovine serum albumin was characterized in competition radioimmunoassays (ria) and enzyme-linked immunosorbent assays (elisa). amt-poly(a,u) was over 10,000-fold more reactive than unmodified poly(a,u) or amt alone. the antiserum cross-reacted to varying extents with amt-modified-rna's and -dna's. the presence of amt-uridine usually assured strong reactivity. the amino gr ...19872446261
tunicamycin enhances virus replication and inhibits antiviral activity of interferon in mice: correlation with natural killer cells.earlier we reported that tunicamycin (tm) treatment enhances semliki forest virus (sfv) and encephalomyocarditis virus (emcv) replication in swiss mice. interferon (ifn) mediated antiviral protection was also inhibited in mice treated with tm. the in vitro natural killer (nk) cell reactivity of mice was significantly decreased after in vivo administration of tm; however, tm treatment did not affect the response of the same cells to mitogens. tm also inhibited the boosting of nk reactivity by ifn ...19872445942
selection and characterization of interferon-sensitive cells derived from an interferon-resistant nih 3t3 line.we have developed a selection protocol to isolate interferon (ifn)-sensitive subclones directly from an ifn-resistant cell population. the protocol uses encephalomyocarditis virus (emcv) as a selection agent in combination with pretreatment with low doses of ifn and subsequent growth in the presence of virus-neutralizing antiserum. we have applied this protocol to the partially ifn-resistant nih 3t3 clone 1 line and have obtained a number of ifn-sensitive subclones. sensitivity to ifn was restri ...19872445907
clonal derivatives of the rd-114 cell line differ in their antiviral and gene-inducing responses to interferons.the human rhabdomyosarcoma cell line rd-114 is partially responsive to interferons (ifns). in these cells, alpha interferon (ifn-alpha) or gamma interferon (ifn-gamma) inhibits the replication of some viruses but not of others. similarly, some of the ifn-inducible mrnas are induced poorly, whereas others are induced well. here we report the isolation of clonal derivatives of this line which display different spectra of responses to ifns. among the eight extensively characterized clonal lines, on ...19872441075
interferon inducibility and sensitivity of human teratocarcinoma-derived cell lines.three cell lines tera i, tera ii, and pa1, derived from human teratocarcinomas were tested for their capacity to produce interferon (ifn) and for their sensitivity to both human ifn-alpha and ifn-beta. when treated with newcastle disease virus or sendai virus, or a synthetic polyribonucleotide, poly(ri):poly(rc), tera i cells produced no ifn and the 2',5'-oligoadenylate (2-5a) synthetase enzymatic pathway was not activated, although there was an increase in protein kinase. in contrast, tera ii a ...19872440957
interferon induces a 15-kilodalton protein exhibiting marked homology to ubiquitin.immunochemical methods were used to examine the effect of viral infection on the dynamics of intracellular ubiquitin pools. infection of either the human lung carcinoma line a-549 or the mouse fibroblast line l929 with encephalomyocarditis virus had little effect on either the distribution or fractional level of intracellular ubiquitin conjugates. in contrast, viral infection resulted in a significant decline in the steady state content of the mono-ubiquitin conjugate to histone 2a (uh2a). prior ...19872440890
role of interferon, antibodies and macrophages in the protective effect of corynebacterium parvum on encephalomyocarditis virus-induced disease in mice.treatment of mice with corynebacterium parvum enhances their resistance to encephalomyocarditis (emc) virus infection. in emc-virus-infected mice, pretreated with c. parvum, neither interferon production nor antibody responses were increased. a decrease of virus recovery was observed in cultures of macrophages taken from the peritoneum of mice early after injection of c. parvum and infected with emc-virus in vitro. the data suggest that c. parvum acts by increasing intrinsic antiviral activity o ...19872440381
rapid decrease in the levels of the double-stranded rna-dependent protein kinase during virus infections.the double-stranded rna-dependent protein kinase from human cells is a 68,000 molecular weight protein (p68 kinase), the level of which is enhanced significantly in cells treated with interferon. with a monoclonal antibody specific for p68 kinase, here we show the phosphorylation and steady-state levels of p68 kinase during virus infection. the p68 kinase is phosphorylated in interferon-treated cells during infection with encephalomyocarditis virus (emcv), vesicular stomatitis virus (vsv), and v ...19872440179
sensitivity of human germ-cell-tumor cell lines to human interferons.we examined the sensitivity of four human germ-cell-tumor cell lines exhibiting different stages of differentiation to human interferons (ifns) in vitro. the cell lines were derived from two embryonal carcinomas (nec 8 and nec 14), a choriocarcinoma (ima), and a yolk-sac tumor (huot). treatment with poly i:c induced ifn production in ima and huot cells, but not in nec-8 and nec-14 cells. in the two embryonal-carcinoma cell lines, the addition of ifn-alpha, ifn-beta, and ifn-gamma did not prevent ...19872439404
class ii-restricted t cell responses in theiler's murine encephalomyelitis virus (tmev)-induced demyelinating disease. i. cross-specificity among tmev substrains and related picornaviruses, but not myelin proteins.following intracerebral inoculation of theiler's murine encephalomyelitis virus (tmev), susceptible mouse strains develop a chronic demyelinating disease characterized by mononuclear cell-rich infiltrates in the central nervous system. current evidence strongly supports an immune-mediated basis for myelin breakdown, with an effector role proposed for tmev-specific, major histocompatibility class ii-restricted delayed-type hypersensitivity, which temporally correlates with disease onset and remai ...19872438327
helper-inducer t-lymphocytes mediate diabetes in emc-infected balb/c byj mice.diabetes mellitus developing in balb/c byj mice infected with the m variant of encephalomyocarditis (emc) virus is dependent on thymic immune mechanisms. we treated mice with the anti-t-lymphocyte monoclonal anti-l3t4 and anti-lyt2.2 antibodies before virus inoculation and monitored the infection and occurrence of diabetes thereafter. mice depleted of l3t4+ cells exhibited a reduced incidence and severity of diabetes compared with both untreated and anti-lyt2.2-treated animals. all mice sustaine ...19872438180
the influence of high temperature on human cells in culture, their sensitivity to viruses and their interferon-producing capacity.the influence of extremely high temperatures on the course of virus infection in vitro was studied. it has been shown that exposure of human cells (continuous cell line of embryonal skin-muscle tissue, donor blood leukocytes) to 43 degrees c leads to a significant increase in their sensitivity to cytopathic action of the viruses tested. noteworthy, the reproduction of these viruses under tested conditions did not differ from their reproduction in control cells. a dramatic inhibitory effect of hi ...19872437783
antigenic comparison of the polypeptides of foot-and-mouth disease virus serotypes and other picornaviruses.the cross-reactivity of proteins coded for by the seven serotypes of foot-and-mouth disease virus (fmdv) was assessed by reaction of infected cell lysates with polyclonal and monospecific antisera against the structural and nonstructural proteins of fmdv type a12 strain 119ab. it was shown that the homologous polypeptides from most serotypes are antigenically related. the least cross-reactivity occurred between vp1, vp3, and the protease (3c) of type a12 and south african territories types 1 and ...19872437694
accumulation of 2',5'-oligoadenylates in encephalomyocarditis virus-infected mice.levels of 2',5'-oligoadenylates (2-5a) in various tissues of murine encephalomyocarditis virus (emcv)-infected mice were determined and compared with those found in pathogen-free mice and in mice treated with the interferon inducer poly(i).poly(c). in control, pathogen-free mice, liver, spleen, brain, and kidney tissues possessed levels of 2-5a below 1 pmol/g of tissue, demonstrating that 2-5a was not a major component of uninfected mouse tissue. all control tissues had low basal levels (0.3 to ...19872437319
[comparative study of interferon inducers obtained from natural sources].interferon-inducing and antiviral effects of natural dsrna preparations of phage phi 6 and yeast cells were studied in the culture of murine cells l-929 and on random bred albino mice. both the preparations showed interferon inducing activity in the cell culture. however, for realization of their effect modification of the surface cell membrane by polycation exchange resin (deae-dextran) was required. the interferon-inducing activity of both of the natural dsrna in the mice was high. the maximum ...19872436574
loss of (2'-5')oligoadenylate synthetase activity by production of antisense rna results in lack of protection by interferon from viral infections.an expression vector was constructed that carries part of the human bk papovavirus with 0.5 kilobases of (2'-5')oligoadenylate (2-5a) synthetase cdna inserted in inverted orientation downstream from the virion proteins (vp) promoter and the neomycin-resistance gene neo under the control of a simian virus 40 promoter. cells transfected with this vector and selected for resistance to the neomycin derivative g418 synthesized rna complementary to 2-5a synthetase mrna. these cells lacked 2-5a synthet ...19872433688
trypanosoma brucei rhodesiense infection in mice prevents virus-induced diabetes: possible role of interferon and immunological mechanisms.b10.br, dba/2, and balb/c by j mice were infected with trypanosoma brucei rhodesiense (lou tat clone 1). subsequent infection with the d variant of encephalomyocarditis virus (emc-d) resulted in no diabetes or encephalitis, even in the susceptible dba/2 and balb/c by j strains. low levels of circulating interferon (ifn) were detected in trypanosome-infected mice at the time of emc-d infection. all strains were severely immunosuppressed as a result of trypanosome infection, as evidenced by decrea ...19862433362
antigen-specific suppressor t cells prevent cardiac injury in balb/c mice infected with a nonmyocarditic variant of coxsackievirus group b, type 3.two variants of coxsackievirus group b, type 3 (cvb3o and cvb3m) infect balb/c cardiac tissue equally, but only one variant (cvb3m) induces myocarditis. various studies indicate that disease resistance in cvb3o-infected mice results from generation of suppressor cells. low-dose cyclophosphamide (50 mg/kg body weight) treatment enhances inflammation in both cvb3m and cvb3o-infected animals, which clearly demonstrates that cvb3o has the capacity to induce disease, but inhibitory factors must exist ...19862432792
effect of encephalomyocarditis (emc) virus on murine foetal and placental growth monitored by quantification of maternal plasma levels of pregnancy-associated murine protein-2 and alpha-fetoprotein.the present study demonstrates that pregnant mice seem to be more sensitive to encephalomyocarditis (emc) infection than non-pregnant mice, and the infection results in significantly increased maternal plasma levels of insulin and pregnancy-associated murine protein-2 (pamp-2), of placental origin, and alpha-fetoprotein (afp), of foetal origin. maternal plasma levels of pamp-2 and afp are correlated with placental and foetal growth respectively. this indicates that the emc infection and the incr ...19862431595
potentiation by levamisole, methisoprinol, and adenine or adenosine of the inhibitory activity of human interferon against encephalomyocarditis virus.the antiviral action of different human interferons against encephalomyocarditis virus in hela cell cultures was analyzed. cell treatment with levamisole (200 micrograms/ml), methisoprinol (1 mg/ml), or adenine or adenosine (33 or 100 micrograms/ml, respectively) potentiated the anti-encephalomyocarditis virus activity of human interferon by 8- to 32-fold. a higher level of potentiation (256-fold) was achieved either by combined treatments with levamisole plus methisoprinol or by treatment with ...19862428301
the inhibition of nucleic acid synthesis in encephalomyocarditis virus-infected l929 cells: effects on nucleoside transport.picornavirus infection induces a profound inhibition of labelling of newly synthesized rna in some cell lines. emc virus blocks transcription in l929 cells, particularly at early times during infection. this inhibition is not dependent on virus gene expression, since it occurs with uv-inactivated virus and also in the presence of translation inhibitors. the inhibition can be largely accounted for by the blockade of [3h]nucleoside transport, as suggested by the transport kinetics and incorporatio ...19862425245
vaccinia-mediated rescue of encephalomyocarditis virus from the inhibitory effects of interferon.coinfection of mouse l cells with vaccinia virus rescues encephalomyocarditis virus (emc) from the inhibitory effect of interferon (ifn). the vaccinia-mediated rescue of emc growth increases the yield of emc as much as 1000-fold and is optimum when vaccinia is used at a multiplicity of infection of 1. this rescue correlates with a vaccinia-dependent stimulation of emc gene expression. evidence is presented to indicate that the rescue by vaccinia does not involve a block of the 2'-5'a synthetase ...19862424172
immunochemistry, physical chemistry and biology of 2',5'-oligoadenylates.monoclonal antibodies directed against 2-5a were developed and characterized. 2',5'-oligoadenylate-protein complexes possess at least three distinct antigenic surfaces defined primarily by the ribose-phosphate backbone. a schematic model for the three epitopes is presented. antibodies directed against 2-5a, in conjunction with other techniques, were employed to quantify 2-5a in various tissues of pathogen-free mice. levels of 2-5a were in the range of 400-800 fmole/gm. mice injected with poly(i) ...19852421316
the 2-5a system in control and interferon-treated k/balb cells infected with encephalomyocarditis virus. 19852421309
studies on interferon-sensitive cells derived from the interferon-resistant nih 3t3 clone 1 line.from the nih 3t3 clone 1 line which is normally unprotected by interferon (ifn) against lytic virus infection we have selected subclones which show high sensitivity to ifn. the selection procedure was based on encephalomyocarditis virus (emcv) as selection agent. in the ifn-sensitive subclones thus obtained emcv replication was inhibited by ifn to a similar degree as observed in l929 cells. like in the original nih 3t3 clone 1 line, however, replication of vesicular stomatitis virus (vsv) and ce ...19852421304
levels of 2',5'-oligoadenylates in the tissues of pathogen-free mice.2',5'-oligoadenylate (2-5a) has been reported to exist in a variety of cells and tissues. since it has been suggested that these compounds play a role in normal cell metabolism as well as in the interferon response, we sought to determine the levels of 2-5a in healthy mouse tissue. methodology developed to recover 2-5a from tissue included tca extraction, fractionation on silica and and c18 cartridges and hplc. the 2-5a content in hplc fractions was determined by an enzyme-linked immunoassay. th ...19852421302
[interferonogenicity of the bacterial lysates in human and murine cell cultures].the antibacterial jrs vaccine was found to be capable of inducing interferon production in human peripheral blood leukocytes and mouse bone marrow cells. the vaccine induced no interferon in l-929 cells or human diploid m-19 cells. interferon appeared in the culture fluid within 4-6 hours after induction and reached the maximum levels in 18-24 hours. one-hour contact of the vaccine with leukocytes was sufficient for interferon induction. the interferon generated in human blood leukocytes was par ...19852420072
antiviral and antiproliferative effects of interferons in quiescent fibroblasts are dissociable.quiescent mouse swiss 3t3 cells or human fibroblasts treated with interferon for only 2 hr before the addition of serum are effectively protected against virus infection for up to 24 hr after the addition of serum and the removal of interferon. in sharp contrast, exposure of quiescent fibroblasts to interferon only before addition of serum or the peptides epidermal growth factor and insulin, has no inhibitory effect on cell proliferation. further, even when interferon is added after the addition ...19852416119
antiviral activity of prostaglandin a on encephalomyocarditis virus-infected cells: a unique effect unrelated to interferon.antiviral effects of prostaglandins of the a series (pgas) on sendai, vaccinia and vesicular stomatitis viruses have previously been reported and a relationship between the antiviral actions of pgas and interferons has been suggested. we have investigated the antiviral activity of pgas on encephalomyocarditis (emc) virus. using single-cycle assays of virus replication our results indicate that pgas only inhibit when present in the culture medium after the cells are infected, and that they are mo ...19852414395
monoclonal antibodies as structural probes for oligomeric human interferon-gamma.monoclonal antibodies (mab) b1 and b3, specific for human interferon-gamma (ifn-gamma) failed to immunoprecipitate heat-inactivated human ifn-gamma in solution. however, both mab retained some reactivity with denatured ifn-gamma immobilized on vinyl plates. the two mab have been employed in a sensitive immunoradiometric assay (irma). in this irma one mab was bound to polystyrene beads and used as immunoadsorbent. the second mab, labeled with 125i, was used as the tracer to quantitate the amount ...19852414374
analogue inhibitor of 2-5a action: effect on the interferon-mediated inhibition of encephalomyocarditis virus replication.chemically synthesised ch3sp(a2'p)2a2'pp3'och3 has been used to assess the importance of the ppp(a2'p)na (n greater than or equal to 2: 2-5a) system in the antiviral action of interferon against encephalomyocarditis virus (emc). it inhibits activation of the 2-5a-dependent rnase by 2-5a in intact mouse l929 cells and cell-free systems. in interferon-treated, emc-infected l929 cells it inhibits 2-5a-mediated rrna cleavage and partially restores emc rna synthesis and virus yield. activation of the ...19852410258
mildiomycin: a nucleoside antibiotic that inhibits protein synthesis.mildiomycin, a new nucleoside antibiotic, selectively inhibits protein synthesis in hela cells, and is less active in the inhibition of rna or dna synthesis. an increased inhibition of translation by mildiomycin is observed in cultured hela cells when they are permeabilized by encephalomyocarditis virus. this observation suggests that this antibiotic does not easily pass through the cell membrane, as occurs with other nucleoside and aminoglycoside antibiotics. the inhibition of translation is al ...19852409064
theiler's murine encephalomyelitis virus--characterization of newly isolated viruses from japanese mouse colonies.the hemagglutinating-inhibition (hi) test was used to detect antibodies for theiler's murine encephalomyelitis virus (tmev), and the virus was isolated from sero-positive mice derived from colonies in japan. hi antibody was detected in conventional mice (38.7%; 137/354) at titers ranging from 1:8 to 1:512, but it not in spf mice (0/90). to isolate the virus, weanling mice inoculated intracerebrally with samples obtained from sero-positive mice were sacrificed and 10% brain homogenates were subcu ...19902242766
cytoplasmic expression system based on constitutive synthesis of bacteriophage t7 rna polymerase in mammalian cells.a mouse cell line that constitutively synthesizes the bacteriophage t7 rna polymerase was constructed. fluorescence microscopy indicated that the t7 rna polymerase was present in the cytoplasmic compartment. the system provided, therefore, a unique opportunity to study structural elements of mrna that affect stability and translation. the in vivo activity of the bacteriophage polymerase was demonstrated by transfection of a plasmid containing the chloramphenicol acetyltransferase (cat) gene flan ...19902204064
recombinant equine interferon-beta 1: purification and preliminary characterization.equine interferon-beta 1 (eqifn-beta 1) was purified from extracts of recombinant escherichia coli by sequential chromatography on hydroxylapatite, anion-, and cation-exchangers. the resulting protein was greater than 98% pure as determined by sodium dodecylsulfate gel electrophoresis, gel permeation hplc, and reverse-phase hplc. amino-terminal amino acid sequencing revealed that essentially all molecules contained an additional amino-terminal methionine. the specific antiviral activity of eqifn ...19902200832
protein synthesis initiation factor modifications during viral infections: implications for translational control.infection of tissue culture cells with certain viruses results in the shutoff of host cell protein synthesis. we have examined virally infected cell lysates using two-dimensional gel electrophoresis and immunoblotting to ascertain whether initiation factor protein modifications are correlated with translational repression. moderate increases in eukaryotic initiation factor (eif)-2 alpha phosphorylation are detected in reovirus- and adenovirus-infected cells, as reported previously (samuel et al. ...19902188834
selective reduction of insulin mrna in islets infected with encephalomyocarditis virus. 19902177410
evidence for a direct role for sialic acid in the attachment of encephalomyocarditis virus to human erythrocytes.sialic acid residues are required in cellular receptors for many different mammalian viruses. sialic acid could have a direct role, being an integral part of the virus binding site on the receptor. alternatively, negatively charged sialic acid could have an indirect role, being responsible for holding the receptor in the required configuration for virus recognition, for instance, by interacting with positively charged amino acid residues found in the polypeptide chain of receptors. we have inves ...19902176879
sex hormone modulation of interferon (ifn) alpha/beta and gamma production by mouse spleen cell subsets following picornavirus infection.replication of the diabetogenic variant of encephalomyocarditis virus (emcv-d) in spleen cells and its association with subpopulations of spleen cells (l3t4+, lyt-2+, mac 1+, 33d1+ and agm1+ cells) from both sexes of icr swiss mice were examined. virus replication was limited to less than 0.5 log in suspensions of whole spleen cells, nonadherent cells or a b cell subfraction from both sexes of icr swiss mice following infection with emcv-d at an moi of 10; no virus replication was seen in adhere ...19902175195
cap-independent translation of encephalomyocarditis virus rna: structural elements of the internal ribosomal entry site and involvement of a cellular 57-kd rna-binding protein.translation of encephalomyocarditis virus (emcv) mrna occurs by ribosomal internal entry into the 5'-nontranslated region (5' ntr) rather than by ribosomal scanning. the internal ribosomal entry site (ires) in the emcv 5' ntr was determined by in vitro translation with rnas that were generated by in vitro transcription of emcv cdnas containing serial deletions from either the 5' or 3' end of the emcv 5' ntr. regions downstream of nucleotide 403 and upstream of nucleotide 811 of emcv were require ...19902174810
primate viral diseases in perspective.the recent occurrence of fatal herpesvirus simiae (b virus) infection in human subjects has again focused the attention of primatologists on this virus. b virus, however, is only one of a number of viral diseases that plays a role in primate colony management. this report is to emphasize to the primatologist a number of viruses other than h. simiae, with high morbidity and mortality rates, of importance for health management of nonhuman primate animal colonies. this concept is supported by the r ...19902174083
persistent infection of k562 cells by encephalomyocarditis virus.infection of human erythroleukemic k562 cells by encephalomyocarditis virus readily resulted in establishment of persistently infected cultures. in contrast to the usual typical lytic infection by encephalomyocarditis virus, in which trypan blue staining of cells reaches close to 100% by about 15 h postinfection, k562 cell cultures required 3 to 4 days postinfection to reach a maximum of about 80 to 90% cell staining. the proportion of k562 cells taking up stain gradually decreased to about 10% ...19902173779
role of macrophages in the pathogenesis of encephalomyocarditis virus-induced diabetes in mice.pancreatic islets from sjl/j mice infected with the d variant of encephalomyocarditis virus (emc-d virus) showed lymphocytic infiltration with moderate to severe destruction of beta cells. immunohistochemical staining of the islet sections with several monoclonal antibodies, anti-mac-1, anti-mac-2, and f4/80 for macrophages, anti-l3t4 for helper/inducer t cells, and anti-lyt2 for cytotoxic/suppressor t cells revealed that the major population of infiltrating cells at the early stage of viral inf ...19902173763
effects of a diabetogenic strain of encephalomyocarditis (emc) virus on protein synthesis in mouse islets of langerhans.the effects of a diabetogenic strain of encephalomyocarditis (emc) virus on total protein and insulin biosynthesis in mouse islets of langerhans have been studied in tissue culture. in dispersed mouse islets, the rates of protein biosynthesis were assessed by measuring the incorporation of [3h]leucine into proteins. in infected dispersed islets incubated in 20 mm-glucose, both insulin and total protein biosynthesis were decreased at 6 h; only insulin biosynthesis was significantly decreased at 3 ...19902173551
inhibition of the uncoating of bovine enterovirus by short chain fatty acids.short chain fatty acids inhibit the replication of bovine enterovirus but are almost ineffective against poliovirus type 1, coxsackievirus b5, encephalomyocarditis virus and human rhinovirus 1b. lauric acid binds to bovine enterovirus, thereby stabilizing the virus particle to heat degradation. fatty acid-bound virions attach to susceptible cells but fail to undergo cell-mediated uncoating. the inhibitory effect is reversible with chloroform and may result from a hydrophobic interaction between ...19902172446
pharmacokinetics of indium-111-labeled antimyosin monoclonal antibody in murine experimental viral myocarditis.the pharmacokinetics of indium-111-labeled antimyosin monoclonal antibody fab were investigated with use of murine experimental viral myocarditis as a model. the biodistribution of indium-111-labeled antimyosin antibody fab on days 3, 5, 7, 14, 21 and 28 after encephalomyocarditis virus inoculation demonstrated that myocardial uptake increased significantly on days 5, 7 and 14 (maximum on day 7) in infected versus uninfected mice (p less than 0.001). in vivo kinetics in infected mice on day 7 de ...19902172346
a full-length murine 2-5a synthetase cdna transfected in nih-3t3 cells impairs emcv but not vsv replication.treatment of cells with interferons (ifns) induces resistance to virus infection. the 2'-5'oligo a (2-5a) synthetase/rnase l is one of the pathways leading to translation inhibition induced by ifn treatment. a murine cdna encoding the 43-kda 2-5a synthetase was cloned and sequenced. nih-3t3 cell clones transfected with this cdna expressed the enzymatic activity to various extents and exhibited resistance to encephalomyocarditis virus (emcv) but not to vesicular stomatitis virus replication. the ...19902171206
initiation of encephalomyocarditis virus rna translation: the authentic initiation site is not selected by a scanning mechanism.the authentic initiation site on encephalomyocarditis virus (strain r) rna is the 11th aug codon (at nt. 834) from the 5' end of the viral rna, the downstream of the two augs in the sequence....acgaugauaauauggcc... in order to assess the role of ribosome scanning in the selection of the correct initiation site, transcripts of a construct comprising the viral 5' noncoding sequence fused to a reporter gene were translated in vitro and the relative frequency of initiation at these two aug codons, a ...19902170120
an initiation signal in the 5' untranslated leader sequence of encephalomyocarditis virus rna.a 593 nucleotide fragment of the 5' leader of encephalomyocarditis virus rna (emcv-rna) was linked to the sp6 promoter and inserted upstream of the reporter gene chloramphenicol acetyltransferase (cat). the presence of the 5'-utr of emcv-rna in the rna transcripts, made in vitro with the sp6 polymerase, resulted in a strong translational enhancement when tested in the micrococcal nuclease-treated reticulocyte lysate. the transcripts were equally active with or without a 5' methylated capstructur ...19902169887
effect of rearing conditions on encephalomyocarditis (emc) virus-induced diabetes in mice.to compare the incidence in the diabetic syndrome in mice reared under sterile and non-sterile conditions, both conventional and spf dba/2 n male mice were inoculated intraperitoneally with two doses (10(4) tcid50/0.1 ml or 10(5) tcid50/0.1 ml) of encephalomyocarditis (emc) virus m variant. the incidence of diabetic symptoms was higher in mice reared under sterile conditions than under non-sterile conditions. it appeared that a difference in animal rearing conditions would affect the sensitivity ...19902169428
tumour necrosis factor enhances induction by beta-interferon of a ubiquitin cross-reactive protein.tumour necrosis factor alpha (tnf-alpha) elicited an antiviral response in some cell lines (mg-63 and hep-2) but not in others (mdbk). cell lines that generated an antiviral response to tnf-alpha also showed induction of a 15k protein which shared sequence homology with ubiquitin and reacted with an antibody to ubiquitin. this ubiquitin cross-reactive protein (ucrp) had been demonstrated previously to be induced by interferon. the tnf-alpha induction of ucrp occurred at the level of transcriptio ...19902167923
synthesis of functional mrna in mammalian cells by bacteriophage t3 rna polymerase.we found that the 5' nontranslated leader sequence from encephalomyocarditis virus (emcv) allowed transcripts that were synthesized by the t3 rna polymerase in mammalian cells to be translated in a cap-independent fashion. stable mouse cell lines that carry the t3 rna polymerase gene expressed the chloramphenicol acetyltransferase (cat) gene under the control of a phage promoter when the cat gene was fused to the emcv leader and introduced into the cells by transient dna uptake. the level of gen ...19902167433
[encephalomyocarditis syndrome (emc syndrome)].among 28 autopsy-cases with emc had been none diagnosed clinically before. typically we found an interstitial myocarditis and perivenous encephalitis with a preferred participation of the brain stem, eventually resulting in a central failure. there were only 5 cases with meningitis. myelitis was not found. former cardiac, less often cerebral lesions are likely risks for the lethal event.19902165622
paradoxical lessening of autoimmune processes in non-obese diabetic mice after infection with the diabetogenic variant of encephalomyocarditis virus.in order to gain insight into the interaction between autoimmunity and viral infection in the onset of insulin-dependent diabetes, non-obese diabetic (nod) mice which spontaneously develop autoimmune diabetes were inoculated with the diabetogenic variant of the encephalomyocarditis virus (emcv-d) before the onset of the disease. the pre-diabetic period was divided into two phases: the early phase (days 88 to 116) during which development of spontaneous diabetes is rare and the late phase (day 12 ...19902164479
reversibility of acid denaturation of recombinant interferon-gamma.it has been shown that interferon-gamma (ifn-gamma) loses activity after acid treatment and this property can be used to distinguish it from other types of interferons. therefore, reversibility of acid denaturation of ifn-gamma was examined using the recombinant human protein. the fluorescence spectra showed that conformation of the protein is similar before and after acid treatment, suggesting reversibility of the acid denaturation. the antiviral activity of the protein was also identical in th ...19902164426
[an experimental study of human recombinant gamma interferon with a proteolytically reduced c-end area of the protein].the work presents the results of experimental study of gamma interferon obtained by gene engineering techniques on the basis of escherichia coli producer strains. the study has revealed that gamma interferon, whose molecular weight is 15 kd, due to intracellular proteolytic degradation shows the absence of some amino acids at the c-end of protein and is electrophoretically homogeneous, while its antiviral, antiproliferative and immunomodulating effects are less pronounced than those of gamma int ...19902164292
[the effect of high molecular weight interferon inducers (dsrna) on virus adsorption].interrelationship between phosphorylation of plasmatic membrane proteins in brain cells and the rate of mice encephalomyocarditis virus adsorption was studied. phosphorylation of proteins induced by dsrna (laryphane) was most distinctly manifested in membrane fraction and cytosol of rat brain neuronal cells. similarity of molecular mass spectra in dsrna- and camp-dependent phosphorylation enabled to suggest that dsrna activated protein kinase. an increase in the rate of plasmatic membrane protei ...19902163564
gross rearrangements within the 5'-untranslated region of the picornaviral genomes.an analysis of reported nucleotide sequences revealed several cases of gross rearrangements in the 5'-untranslated region (5-utr) of picornaviral genomes. a large (greater than 100 nt) duplication was discovered in a downstream region of poliovirus 5-utr involved in the translational control. properties of the poliovirus mutants with large deletions [kuge and nomoto (1987) j. virol. 61, 1478-1487] show that a single copy of the appropriate repeating unit is compatible with a wild type phenotype ...19902162521
inhibition of rate of tumour growth in rodent species by inoculation of herpesviruses and encephalomyocarditis virus.inoculation of herpesviruses and encephalomyocarditis virus into subcutaneous tumours in hamsters and mice reduced the rate of tumour growth compared to untreated tumours or secondary tumours which had arisen following surgical excision of the primary tumour; in addition, survival times were increased in animals whose tumours were inoculated with virus. it is suggested that the role of virus in the modification of tumour growth merits further exploration.19902160515
diverse patterns of immune and non-immune-mediated disease in emc m-variant-infected mice.the m variant of emc virus exhibits unique tropism for the beta cells of the islets of langerhans. however, the severity and character of the lesion differ in various strains of animals. this paper briefly reviews the features of these lesions and considers their pathogenesis.19902160243
encephalomyocarditis of swine in greece. 19902159671
echovirus 22 is an atypical enterovirus.although echovirus 22 (ev22) is classified as an enterovirus in the family picornaviridae, it is atypical of the enterovirus paradigm, typified by the polioviruses and the coxsackie b viruses. cdna reverse transcribed from coxsackievirus b3 (cvb3) rna does not hybridize to genomic rna of ev22, and conversely, cdna made to ev22 does not hybridize to cvb3 genomic rna or to molecular clones of cvb3 or poliovirus type 1. ev22 cdna does not hybridize to viral rna of encephalomyocarditis virus or to a ...19902159539
the involvement of pineal gland and melatonin in immunity and aging. i. thymus-mediated, immunoreconstituting and antiviral activity of thyrotropin-releasing hormone.circadian, continued treatment with melatonin during the dark cycle produces changes in the blood level of thyroid hormones in aging mice. thyroid-stimulating hormone (tsh) and thyrotropin-releasing hormone (trh) antagonize the involution of the thymus produced by prednisolone. this effect of trh does not seem thyroid dependent. trh restores antibody production in non-responder athymic nude mice but does not exert this effect in neonatally thymectomized mice. moreover, this activity does not cor ...19902159021
blocking by anti-idiotypic antibodies of monoclonal antibody mediated protection in mice against encephalomyocarditis virus induced diabetes and lethal disease.monoclonal antibodies (ma) um 21.1 and um 21.2 protect mice against encephalomyocarditis virus (d-variant) induced diabetes and lethal disease. ma-mediated protection in vivo as well as neutralization in vitro could be specifically blocked by anti-idiotypic antibodies.19902156488
a factor that specifically binds to the 5'-untranslated region of encephalomyocarditis virus rna.a protein factor that specifically binds to the 5'-untranslated region of encephalomyocarditis virus (emcv) rna has been found in extracts of ascites carcinoma krebs-2 cells. this was done using uv-irradiation on extracts supplemented with in vitro synthesized 32p-labelled transcripts followed by analysis of crosslinked proteins by sds-polyacrylamide gel electrophoresis. the transcripts represented the viral rna sequence from nt 315 to 1155, its derivatives with internal deletions or truncated f ...19902155820
inhibition of vesicular stomatitis virus replication in dexamethasone-treated l929 cells.we previously demonstrated that dexamethasone treatment of l929 cells inhibited plaque formation by vesicular stomatitis virus (vsv), encephalomyocarditis virus, or vaccinia virus. we now have characterized the antiviral effects of glucocorticoids in l929 cells. dexamethasone did not directly inactivate vsv nor did steroid treatment of l929 cells affect virion adsorption or penetration. the vsv yield in l929 cells treated with dexamethasone for a period of only 4 or 8 hr was decreased by 50% whe ...19902154755
limited expression of poliovirus by vaccinia virus recombinants due to inhibition of the vector by proteinase 2a.a recombinant vaccinia virus was constructed that expressed poliovirus coat precursor protein p1 fused to about two-thirds of the 2a proteinase. the truncated 2a segment could be cleaved away from the p1 region by coinfecting with poliovirus type 1, 2, or 3 or with human rhinovirus 14 but not with encephalomyocarditis virus. further cleavage of the vector-derived p1 to yield mature poliovirus capsid proteins was not observed. attempts to isolate vaccinia virus recombinants containing portions of ...19902154618
kidney complications in emc virus-induced diabetes in conventional dba/2 male mice.conventional dba/2 male mice of about 9 weeks of age were inoculated by intraperitoneally injecting emc virus m variant (10(4) tcid50/0.1 ml/animal) which is passaged in mice. the mice which tested positive for glycosuria and hyperglycemia were examined histopathologically 2 or 5 months after inoculation. the kidneys were examined for thickening of bowman's capsule and the mesangial matrix. these changes were more clearly observable 5 months after inoculation than they were 2 months after inocul ...19902154384
reproductive and neonatal losses associated with possible encephalomyocarditis virus infection in pigs.a possible infection with encephalomyocarditis virus was investigated on two minnesota pig farms which experienced an increase in stillborn and mummified fetuses, high pre-weaning mortality and reduced farrowing rates. the monthly averages for the numbers of piglets born dead per litter on farms a and b reached 4-6 and 3-6, the pre-weaning mortalities 50 per cent and 31 per cent, and the farrowing rates 52 per cent and 63 per cent, respectively. serological and histopathological examinations sup ...19902154074
genetic transfer of a functional human interferon alpha receptor into mouse cells: cloning and expression of its cdna.a cdna coding for the human interferon alpha receptor has been cloned using a gene transfer approach. this consists of transferring human dna to mouse cells and selecting for cells sensitive to human interferon alpha. the transfected cells expressed the human interferon alpha receptor, and a 5 kb human dna was isolated from a secondary transfectant. this dna defects an mrna present in human cells and was used to clone a 2.7 kb cdna from a library constructed from human daudi cells. the sequence ...19902153461
d variant of encephalomyocarditis virus (emcv-d)-induced diabetes following natural killer cell depletion in diabetes-resistant male c57bl/6j mice.the involvement of natural killer (nk) cells in the development of diabetes in the normally resistant 9-10 week old c57bl/6j male mice by the d variant of encephalomyocarditis virus (emcv-d) was examined. inoculation of purified emcv-d induced maximum nk cell activity in splenic cell populations on day 4 post-inoculation as determined by lysis of yac-1 target cells in a standard 51chromium release microcytotoxicity assay. selective depletion of nk cells by the administration of rabbit anti-asial ...19902153386
construction and characterization of two infectious molecular clones of encephalomyocarditis virus.we constructed and characterized two infectious molecular clones of encephalomyocarditis (emc) virus. both constructs, pdl and pda, were assembled from five overlapping cdna clones derived from the diabetogenic variant of emc virus (emc-d) and from two synthetic oligonucleotide cartridges. pda contained a single point mutation at position 1720 within the "puff" region of capsid protein 1ab that was derived from the nondiabetogenic variant of emc virus (emc-b). this point mutation resulted in an ...19902153252
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