| enteroviral infection in end stage dilated cardiomyopathy. | in order to evaluate the role of enteroviral infections in end stage dilated cardiomyopathy, rna was isolated from left ventricular myocardium of patients with dilated cardiomyopathy explanted during heart transplantation (n = 6) and from control hearts (n = 8), then probed using a dot blot procedure with two well-defined enteroviral cloned cdna probes. one of the cardiomyopathic heart samples hybridized with the enteroviral probes, while rna samples from the other diseased heart and the control ... | 1990 | 2175375 |
| [effect of anionic detergents sodium dodecyl sulfate and alkylbenzyl sulfonate on adsorption and transport behavior of several enterotropic viruses in the soil under model conditions]. | the adsorption of poliovirus 3, coxsackievirus b1, and coliphage f2 on soil from an irrigation field loaded for years with waste water and sandy soil from an aquifer was investigated under the influence of two anionic detergents, sodium dodecylsulphate (sds) and alkylbenzolsulphonate (abs). the investigation was carried out through batch and column experiments under simulated conditions. the concentrations of both detergents found generally in surface water (0.2-10 mg/l) had no effect on the ads ... | 1990 | 2175613 |
| an assay for the detection of interferon dependent and interferon independent antibody activities. | a spectrophotometric assay is described for the detection of interferon (ifn) dependent antibody (ida) activity (i.e., antibodies that act with ifn to synergistically inhibit virus infection) and ifn independent antibody (iia) activity (i.e., antibodies that act additively with ifn to inhibit virus infection). four neutralizing monoclonal antibodies (mab) against poliovirus type 1 (pv-1) were tested. three mab exhibited ida activity and one mab exhibited iia activity against pv-1 strain sabin. c ... | 1990 | 2175749 |
| eukaryotic initiation factor 3 is required for poliovirus 2a protease-induced cleavage of the p220 component of eukaryotic initiation factor 4f. | after cultured cells are infected with poliovirus, cellular mrna fails to bind to ribosomes, and synthesis of the majority of cellular proteins ceases. the defective step has been localized to the cap-dependent activity of the eukaryotic translation initiation factor 4f. inactivation of this factor correlates with the cleavage of its largest subunit, p220, into characteristic products observed in infected cells. this cleavage is mediated by the poliovirus protease 2apro. previous work suggests t ... | 1990 | 2175904 |
| [the possibility for the sanitary removal of enteroviruses from water reservoirs in the case of intensive irrigation agriculture]. | the efficacy of elimination of enteric viruses from water in the process of exploitation of a closed irrigating system is evaluated. experimental and natural observations showed the half-life of the index virus in the water objects of the irrigating system to be 1.57 days. the potentials of using a temperature-dependent variant of poliomyelitis virus as the internal control in studies of the prevalence of enteric virules among human subjects and in the environment under conditions of intensive i ... | 1990 | 2176423 |
| detection of immunoglobulin g, m, and a antibodies to enterovirus structural proteins by immunoblot technique in echovirus type 4-infected patients. | paired serum specimens from 24 patients with echovirus (ev) type 4 infection by virus isolation were tested by the immunoblot technique for the presence of igg, igm, and iga antibodies to ev4 structural proteins. single sera from 20 patients without neutralizing enterovirus igm were used as controls. all the sera from ev4-infected patients had igg antibodies to vp1 of ev4 but also 13 out of the 20 controls. 23 out of 24 ev4-infected patients elicited igm and iga specific antibodies to vp1, a pat ... | 1990 | 2176661 |
| poliovirus mutants resistant to neutralization with soluble cell receptors. | poliovirus mutants resistant to neutralization with soluble cellular receptor were isolated. replication of soluble receptor-resistant (srr) mutants was blocked by a monoclonal antibody directed against the hela cell receptor for poliovirus, indicating that the mutants use this receptor to enter cells. the srr mutants showed reduced binding to hela cells and cell membranes. however, the reduced binding phenotype did not have a major impact on viral replication, as judged by plaque size and one-s ... | 1990 | 2177226 |
| cross contamination of viral specimens related to shell vial caps. | a cluster of poliovirus type 3-positive specimens cultured in shell vials led to the discovery of significant cross contamination between vials related to the type of vial cap. simulated testing with colored media in the shell vials indicated that the most contamination occurred with the plastic snap cap and that the least occurred with the screw cap. measures to prevent cross contamination in clinical virology laboratories are discussed. | 1990 | 2177755 |
| virus excretion and mutation by infants following primary vaccination with live oral poliovaccine from two sources. | the excretion of virus by 30 children was followed over a period of 28 days after their first vaccination with live oral poliovaccine. the type 1 and type 2 strains were isolated at similar high frequencies throughout this period, while the type 3 strain was not excreted by most children after day 2 post vaccination. mutations in the 5' non-coding region associated with the attenuated phenotype reverted most rapidly for type 3 and least rapidly for type 1. the data are consistent with different ... | 1990 | 2177777 |
| depuration of mytilus galloprovincialis experimentally contaminated with hepatitis a virus. | mussels (mytilus galloprovincialis) were contaminated with known amounts of laboratory strains of hepatitis a virus and poliovirus 1 and the effectiveness of a self-cleansing mechanism was studied using a pilot depuration system. both viruses were rapidly bioaccumulated by mussels and the maximal concentration of about 10(4) tcid50/ml was reached within 1.5 hours. depuration was carried out up to 24 h; infectivity titer decreased to 10(2) tcid50/ml and 10(3.2) tcid50/ml within 6 h in hepatitis a ... | 1990 | 2177996 |
| molecular biology and the control of viral vaccines. | the live attenuated vaccines against poliomyelitis developed by sabin are among the safest and most effective antiviral vaccines in current use and have eliminated poliomyelitis as a public health problem in many countries. they form the main basis of the who intention to eliminate poliomyelitis from the world by the year 2000, and the molecular basis of their attenuated phenotype and some of its virological consequences are increasingly clear. nonetheless, the data reviewed here show how poorly ... | 1990 | 2178354 |
| 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. ... | 1990 | 2188834 |
| polio trial: an early efficient clinical trial. | the salk vaccine field trial was a randomized, placebo-controlled trial designed to test the efficacy of the salk killed virus vaccine. although the trial was not without some problems, both in design and analysis, none was important enough to raise serious questions about the results. thus, the design of the field trial was well adapted to the demanding requirements. the trial owes its success in a large part to substantial public involvement. in designing future, large-scale, simple trials, we ... | 1990 | 2189187 |
| changes in cutaneous kaposi's sarcoma in a patient infected with the human immunodeficiency virus: follow-up to a controlled hyperimmunization trial. | | 1990 | 2189364 |
| a feasible strategy for a health care package. | the national health policy adopted in india in 1982 proposed primary health care involving the community and relying on maternal-child health (mch) services. the bhore committee stressed similar priorities in 1946, but implementation was deficient. in 1988 there were 100.000 sub-centers (sc), 15.000 primary health centers (phc), and 800 community health centers (chc). the 7th 5-year plan envisioned a village health guide (vhg) and trained worker for 1000 people. a sc was to serve 5000 peopl ... | 1990 | 2210817 |
| perspectives and limits in the eradication of infectious diseases. | eradication of an infectious disease on a global scale means that transmission of the disease has been completely vanished and the disease caused by the infection has totally disappeared. regional eradication represents disappearance of an infection from a certain area or region whereas elsewhere it continues to be transmitted. smallpox which was finally eradicated in 1977 had been progressively eliminated from one continent after another in the preceding years. at the present time regional elim ... | 1990 | 2236820 |
| potential use of live viral and bacterial vectors for vaccines. who meeting, geneva, 19-22 june, 1989. | the use of vaccinia virus vector for the delivery of antigens was first described by moss and paoletti and their colleagues in 1982. such vaccines could be of particular value in developing countries because they would be cheap, stable, easy to administer and provide long-lasting immunity. who recognized the potential value of such a delivery system by convening two meetings, one at the national institutes of health, usa in november 1984 and the second at who headquarters, geneva, switzerland in ... | 1990 | 2251869 |
| fecal iga antibody responses after oral poliovirus vaccination in infants and elder children. | we investigated fecal iga antibody responses after oral polyvalent poliovirus vaccination. infants were given vaccines twice with an interval of 6 weeks. specific iga antibodies in the feces were determined by enzyme-linked immunosorbent assay, and viruses were isolated in tissue cultures. we found that, after the first vaccination, antibody responses seemed to be elicited only against the serotypes of isolated viruses. after the second vaccination, however, antibodies were detected to all three ... | 1990 | 2280725 |
| safety of live oral poliovirus vaccine and the origin of hiv infection in man. | | 1990 | 2294621 |
| chromosomal aberrations in germ cells of male mice immunised with attenuated viral vaccines (human). | the cytogenetic effects of two attenuated viral vaccines (yellow fever vaccine and oral poliomyelitis vaccine) were assessed by means of the analysis of meiotic spermatocyte chromosomes in mice. in a dose of 0.5 ml, but not 0.1 ml, both vaccines induced a significant percentage of chromosomal aberrations after 7, 14 and 30 days. euploidy was the major abnormality produced by yellow fever vaccine. the various abnormalities produced by oral polio vaccine were significant when pooled, but not when ... | 1990 | 2304066 |
| an epidemic of poliomyelitis in southern kerala. | an epidemic of poliomyelitis was recognized in may 1987 when there was a sharp increase in the number of children with acute paralytic poliomyelitis admitted to the sat hospital in trivandrum in kerala state. from may through september, 392 cases were admitted; the total admitted cases in 1987 were 458 in contrast to 119 in 1986. evidence for type 1 poliovirus infection was found in 33 (85%) of the 39 children in whom virological investigations were done during the epidemic. in addition, evidenc ... | 1990 | 2351513 |
| non-immunological facets of poliovirus vaccines. | failures of oral poliovirus vaccine lots in developing countries are explained by interference during their 'take' by other enteroviruses colonizing the host intestinal system. oral poliovirus vaccines, on their part, have also exerted an interfering effect on multiplication of other enteroviruses. apart from the intrafamilial enterovirus interference, oral poliovirus vaccine has not spared rotaviruses. | 1990 | 2363296 |
| immunological response of moroccan children and newborns to oral poliovirus vaccine prepared on vero cells. | immunogenicity of the oral poliovirus vaccine prepared on vero cells (vero opv) has been assessed in a two-stage study conducted in rabat, morocco. during the first stage, the vaccine produced seroconversion in most of the 200 children vaccinated in a three dose primary immunization, and in most of the 56 children boostered. during the second stage, four doses were given at 0, 6, 10 and 14 weeks of age to 55 newborns. at the same time, 50 control newborns were given reference opv prepared on pri ... | 1990 | 2396469 |
| the use of polylysine during negative staining of viral suspensions. | the use of 0.1% aqueous solution of polylysine (poly-l-lysine) is proposed as a prior step to negative staining of viral or particle suspensions. particles spread better on films precoated with polylysine than with other substances used for the same purpose. this applies particularly to samples from sucrose or cscl gradients. the use of negative contrast substances is discussed. | 1985 | 2409100 |
| [inhibition of poliovirus replication by an extract of matricaria chamomilla (l)]. | hydroalcoholic extract of matricaria chamomilla added during the early stage of poliovirus development inhibits cellular and viral rna synthesis. this inhibition is partially reversible. | 1985 | 2411365 |
| characterization and assembly of poliovirus-related 45 s particles. | using detergents, 45 s particles could be extracted from poliovirus-infected vero and human embryonic kidney monolayer cells, but not from hela suspension cells. they were composed of the capsid proteins vp0, vp1, and vp3, devoid of rna, and extremely sensitive to heat or to a slightly alkaline ph. the 45 s particles possessed neutralization epitopes of the n1 and n2 classes, as well as a vp3-linked epitope. the n2 epitopes were lost upon denaturation. in the presence of cell extracts 45 s parti ... | 1985 | 2412342 |
| study of interferon production during pregnancy in mice and antiviral activity in the placenta. | although the mortality rate after herpes simplex virus type 2 inoculation was not significantly different between pregnant mice and nonpregnant mice, systemic interferon production was very high during late pregnancy compared with that in nonpregnant mice. antiviral activity was detected in placentas from all noninfected pregnant mice (80 to 320 u/ml in 20% suspension). the antiviral activity had a broad spectrum and was also effective in the cells of other species; an antiviral effect was shown ... | 1985 | 2413760 |
| induction by synthetic peptides of broadly reactive, type-specific neutralizing antibody to poliovirus type 3. | a region of virus capsid protein vp1 located 89-100 amino acids from the n-terminus has been proposed to comprise a major antigenic site involved in the neutralization of poliovirus type 3. synthetic peptides 10-18 amino acids in length, containing all or part of this sequence, were tested for their ability to induce antiviral antibodies. rabbits, but not guinea pigs or mice, immunized with the most active peptide, developed hightitered, type-specific, neutralizing antibodies for a wide range of ... | 1985 | 2414909 |
| mutations conferring resistance to neutralization with monoclonal antibodies in type 1 poliovirus can be located outside or inside the antibody-binding site. | antigenic variants resistant to eight neutralizing monoclonal antibodies were selected from wild (mahoney) and attenuated (sabin) type 1 infectious poliovirions. cross-immunoprecipitation revealed interrelationships between epitopes which were not detected by cross-neutralization. operational analysis of antigenic variants showed that seven of eight neutralization epitopes studied were interrelated. only one neutralization epitope, named kc, varied independently from all the others. this latter, ... | 1986 | 2416957 |
| purification of a terminal uridylyltransferase that acts as host factor in the in vitro poliovirus replicase reaction. | poliovirus rna polymerase requires a host factor to initiate rna synthesis in vitro. the host factor was previously purified to near homogeneity from hela cells but was not assigned an enzymatic activity. this report describes the purification of a terminal uridylyltransferase that can act as host factor. by all criteria examined it is identical to the factor purified previously. it has the same molecular weight (68,000), chromatographic properties, and cellular localization. we present evidence ... | 1986 | 2417240 |
| in vitro and in vivo antipicornavirus activity of some phenoxypyridinecarbonitriles. | nineteen phenoxypyridinecarbonitriles were initially evaluated for their in vitro activity against rhinoviruses (rv) 1a, 2, and 64 and coxsackievirus (cox) a21 and for their oral prophylactic and therapeutic activity in swiss albino mice challenged with cox a21. on the basis of the results of these studies, one compound, 6-(3,4-dichlorophenoxy)-3-(ethylthio)-2-pyridinecarbonitrile, was selected for further evaluation. expanded in vitro spectrum of activity studies showed that the mic causing a 5 ... | 1985 | 2417545 |
| immunological aspects of virology. who working group. | this article summarizes the conclusions of a who working group concerning progress towards an improved understanding of the mechanisms of natural and vaccine-induced immunity to viral infection in man. particular attention is given to the role of humoral immunity, non-specific cellular and virus-specific t-cell responses, interferons and lymphokines in the immune response to virus infection. detailed knowledge of the immune responses relevant to protection by vaccines is important for a rational ... | 1985 | 2419001 |
| antigenic and molecular evolution of the vaccine strain of type 3 poliovirus during the period of excretion by a primary vaccinee. | a 4 month old child was immunized with a vaccine containing the sabin live attenuated vaccine strains of all three serotypes of poliovirus. the antigenic and molecular evolution of the sabin strain of poliovirus type 3 was then followed throughout the entire period of virus excretion. novel strains appeared at 8, 42 and 52 days post-vaccination and were the products of both intertypic recombination between type 2 and type 3 poliovirus in regions of the genome coding for non-structural proteins a ... | 1986 | 2420925 |
| from jenner to jerne: towards idiotype vaccines. | | 1986 | 2422113 |
| definition of human cytomegalovirus-specific target antigens recognized by cytotoxic t cells generated in vitro by using an autologous lymphocyte system. | we developed an in vitro system for the generation of human cytomegalovirus (cmv)-specific cytotoxic t cells (ctl) that avoids the necessity of constituting a panel of hla-typed fibroblasts. autologous donor leucocytes were coated with cmv antigens and were used as both stimulator and target cells. with the use of this system, cmv-specific effector cells were efficiently generated from seropositive but not seronegative donors. these cmv-specific effectors were hla-restricted and had characterist ... | 1986 | 2423608 |
| antigenic structure of polioviruses of serotypes 1, 2 and 3. | the antigenic sites recognized by monoclonal antibodies with neutralizing activity for the sabin vaccine strains of poliovirus of serotypes 1, 2 and 3 have been studied by the isolation and characterization of mutants resistant to neutralization by antibody. three distinct sites have been identified which are designated site 1, site 2 and site 3. site 1 includes a region of 12 amino acids of vp1, from residues 89 to 100, and a corresponding region of vp1 has been identified as an antigenic site ... | 1986 | 2425046 |
| a poliovirus neutralization epitope expressed on hybrid hepatitis b surface antigen particles. | the hepatitis b virus (hbv) envelope protein carrying the surface antigen (hbsag) is assembled with cellular lipids in mammalian cells into empty viral envelopes. in a study to evaluate the capacity of such particles to present foreign peptide sequences in a biologically active form, in-phase insertions were created in the s gene encoding the major envelope protein. one of the sequences inserted was a synthetic dna fragment encoding a poliovirus neutralization epitope. mammalian cells expressing ... | 1986 | 2425433 |
| use of gold igg complexes and human antisera for electron microscopic identification of hepatitis a virus and polioviruses. | an indirect immunogold staining technique was used for identification of hepatitis a virus and poliovirus types 1,2 and 3 by electron microscopy. human convalescent antisera against hepatitis a virus and the three poliovirus types were used as primary antibodies and goat anti-human igg gold complexes, with an approximate gold granule size of 15 nm, as secondary antibody. hepatitis a virus was specifically labelled with the homologous antiserum. no labelling was observed when antiserum against po ... | 1986 | 2426295 |
| reactivity of anti-peptide and anti-poliovirus type 3 monoclonal antibodies with synthetic peptides. | monoclonal antibodies were prepared from mice immunized with an 18-residue synthetic peptide with an amino acid sequence from a major antigenic sequence involved in the neutralization of type 3 poliovirus. approximately 250 hybridomas secreted antibodies that reacted with the peptide but not the virus, two antibodies reacted with the virus but not the peptide and no antibody reacted with both. conversely 26 monoclonal antibodies prepared from mice immunized with type 3 poliovirus and known to be ... | 1986 | 2431104 |
| probing the topology of a bacterial membrane protein by genetic insertion of a foreign epitope; expression at the cell surface. | the lamb protein is a trimeric integral outer membrane protein from escherichia coli k12 which functions as a pore for maltodextrins and a receptor for bacteriophages. when inserted into two selected sites of lamb, a foreign antigen, the c3 epitope from poliovirus, was exposed at the cell surface with its normal antigenic properties. since these genetic insertions did not affect in any essential way the routing, activity and folding of the lamb protein, we conclude that the two corresponding lam ... | 1986 | 2431904 |
| different virus-precipitating activities of neutralizing monoclonal antibodies that recognize distinct sites of poliovirus particles. | two neutralizing monoclonal antibodies (4 c 4 and 4 f 2) against type 1 poliovirus, mahoney strain, recognized distinct antigenic sites of the virus particles; 4 c 4 antibody bound to vertices of native and heated (56 degrees c, 30 minutes) virus of mahoney strain, while 4 f 2 antibody reacted with specific surface protrusions of native virus of mahoney and sabin strains. the difference in the location of neutralization epitopes with which the two antibodies react was confirmed in the neutraliza ... | 1987 | 2432854 |
| [a model of the secondary structure and distribution of antigenic determinants in the vp1 protein of hepatitis a virus]. | a comparative analysis of amino acid sequence of the proteins vp1 of hepatitis a virus and poliovirus of the 1 type was carried out. a model is proposed of structural organization of vp1 of hepatitis a virus providing the presence of a bilayer core formed by 8 antiparallel beta-strands. probable candidates for surface antigenic determinants are the amino acid sequences located in unordered fragments of the polypeptide chain (residues 101-106 and 115-125), and alpha-helical region (residues 127-1 ... | 1986 | 2432945 |
| neutralization escape mutants define a dominant immunogenic neutralization site on hepatitis a virus. | hepatitis a virus is an hepatotrophic human picornavirus which demonstrates little antigenic variability. to topologically map immunogenic sites on hepatitis a virus which elicit neutralizing antibodies, eight neutralizing monoclonal antibodies were evaluated in competition immunoassays employing radiolabeled monoclonal antibodies and hm-175 virus. whereas two antibodies (k3-4c8 and k3-2f2) bound to intimately overlapping epitopes, the epitope bound by a third antibody (b5-b3) was distinctly dif ... | 1987 | 2433464 |
| binding site of neutralizing monoclonal antibodies obtained after in vivo priming with purified vp1 of poliovirus type 1 is located between amino acid residues 93 and 104 of vp1. | three hybridomas obtained after in vitro stimulation of spleen cells of mice primed in vivo with purified vp1 of poliovirus type 1 (mahoney) with the homologous virus produced antibodies which reacted with vp1 and immunoprecipitated and neutralized only the homologous virus. evidence for the location of their binding sites was obtained by inhibition of virus neutralization and virus binding by a synthetic peptide comprising the amino acid sequence 93-104 of vp1 of poliovirus type 1 (mahoney). | 1987 | 2435056 |
| evolution of poliovirus during an outbreak: sequential type 3 poliovirus isolates from several persons show shifts of neutralization determinants. | an outbreak of poliomyelitis in finland resulted in the widespread circulation of wild-type 3 poliovirus strains that had antigenic properties distinct from the strains used to produce the attenuated and inactivated vaccines. considerable variation was observed in the ability of broadly reacting monoclonal antibodies directed against type 3 poliovirus to neutralize the 54 strains examined. sequential isolates from several persons showed an antigenic drift with these monoclonal antibodies and sel ... | 1987 | 2437244 |
| serum polio antibodies in unimmunized preschool children in a rural village in ghana: before active immunization programme. | the finding of the neutralizing antibodies against poliovirus in unimmunized preschool children confirms the endemicity of the disease in the rural community. the predominant polio antibody types were types 1 and 2. in children under 4 months of age, 82% were seropositive to type 1, 91% to polio type 2 and 55% to polio type 3; evidence of maternal transplacental antibodies. there were fewer seropositives in the age group 4-9 months, 28%, 44% and 12% to the types 1, 2 and 3, respectively. however ... | 1987 | 2438996 |
| [use of monoclonal antibodies for the intratypic differentiation of strains of poliomyelitis type i virus]. | six clones of mouse hybridomas producing highly specific antibodies to the vaccine lsc 2ab strain of poliomyelitis virus type i have been derived. the clone 10c5 antibodies were used for intratypic serodifferentiation of 75 poliomyelitis virus type i strains from the collection of the institute of poliomyelitis and viral encephalitides of the ussr acad. med. sci. which had been isolated in the ussr from children with paralytic poliomyelitis in 1950-1983. general large-scale vaccination campaigns ... | 1987 | 2440185 |
| action of 3-methylquercetin on poliovirus rna replication. | 3-methylquercetin is a natural flavone that powerfully blocks poliovirus replication. this compound inhibits selectively poliovirus rna synthesis both in infected cells and in cell-free systems. poliovirus double-stranded rna (replicative forms) is still made in the presence of this inhibitor, whereas the synthesis of single-stranded rna and the formation of replicative intermediates are drastically blocked. | 1987 | 2442414 |
| antigenic and biochemical characterization of poliovirus type 2 isolated from two cases of paralytic disease. | three isolates of poliovirus type 2 were obtained from rectal and pharyngeal swabs of two patients with paralytic poliomyelitis from southern italy (1981/1983). neither one of the patients had received oral poliovirus vaccine, although a systematic vaccination campaign is conducted in the area. neutralization tests with strain-specific antisera and analysis of the structural proteins by sds-page indicated that the three isolates were typical sabin-like poliovirus type 2. moreover, neutralization ... | 1987 | 2447031 |
| comparison of antigen assay and reverse transcriptase assay for detecting human immunodeficiency virus in culture. | we compared an antigen capture assay (abbott laboratories, north chicago, ill.) with a reverse transcriptase assay to identify and quantify human immunodeficiency virus (hiv) in culture. in direct comparisons of serial dilutions of lymphadenopathy-associated virus type 1, the antigen assay was 100-fold more sensitive than the reverse transcriptase assay in detecting the virus. the antigen assay reacted strongly with 60 different hiv isolates but did not cross-react with human t-cell lymphotropic ... | 1987 | 2448334 |
| use of crna probes for the detection of enteroviruses by molecular hybridization. | subgenomic fragments of cdna from poliovirus type 1 were inserted downstream from the sp6 or the t7 promoter in a gemini riboprobe vector and their in vitro synthesized rna transcripts were used as radiolabeled probes for the detection of enteroviral rnas by molecular hybridization. the crna transcripts appeared to be more sensitive probes than the corresponding cdnas. in vitro transcripts of the 5' noncoding region (5' nc riboprobe) were able to detect all of 14 reference enterovirus strains te ... | 1988 | 2448419 |
| [the nature of virus strains isolated from patients with poliomyelitis in the byelorussian ssr 1967-1985]. | oligonucleotide mapping of the rna genome was applied for analysis of poliovirus clinical isolates in byelorussia in 1967-1985. all the maps have been clearly shown to resemble the reference maps of the corresponding vaccine strains. examination of the oligonucleotide maps of poliovirus isolates provides a measure of distribution of some of the mutations over the viral genome. | 1987 | 2448613 |
| antigen chimaeras of poliovirus as potential new vaccines. | polioviruses occur as three distinct serotypes, 1, 2 and 3, and are composed of a single-stranded positive-sense rna genome of approximately 7,450 nucleotides enclosed in an icosahedral particle of diameter 27 nm. the three-dimensional crystallographic structure of poliovirus type 1 has been determined at 2.9 a resolution, providing a detailed knowledge of the folding and arrangement of the individual virus proteins, vp1-vp4. from this and the characterization of monoclonal antibody-resistant mu ... | 1988 | 2450279 |
| a monoclonal antibody specific for the cellular receptor for the group b coxsackieviruses. | a 50-kilodalton receptor protein (rp-a) for the group b coxsackieviruses (cb) was isolated in a virus-receptor complex from detergent-solubilized hela cells (j. e. mapoles, d. l. krah, and r. l. crowell, j. virol. 55:560-566, 1985). it was used as an immunogen for preparation of a mouse monoclonal antibody (rmcb) which protected hela cells and buffalo green monkey kidney cells from infection by all six serotypes of cb. rmcb did not protect hela cells from infection by poliovirus, echovirus 6, or ... | 1988 | 2451756 |
| three-dimensional structure of poliovirus serotype 1 neutralizing determinants. | antigenic mutants of poliovirus (sabin strain, serotype 1) were isolated by the resistance of the virus to anti-sabin neutralizing monoclonal antibodies. the amino acid replacements within the capsid protein sequence causing the altered antigenicity were identified for each of 63 isolates. the mutations cluster into distinct nonoverlapping peptide segments that group into three general immunological phenotypes on the basis of cross-neutralization analyses with 15 neutralizing anti-sabin monoclon ... | 1988 | 2451757 |
| presentation and immunogenicity of the hepatitis b surface antigen and a poliovirus neutralization antigen on mixed empty envelope particles. | insertion of a synthetic dna fragment encoding a poliovirus neutralization epitope into the s gene encoding the major envelope protein of hepatitis b virus has yielded hybrid (hbspolioag) particles closely resembling authentic 22-nm antigen (hbsag) particles by expression of the modified gene in mammalian cells. in mice, these hybrid particles induce neutralizing antibodies against poliovirus but only weak immune response to hbsag (f. delpeyroux, n. chenciner, a. lim, y. malpièce, b. blondel, r. ... | 1988 | 2451759 |
| [infection defense antigens against pathogenic viruses to human. infection defense antigens and genetic code--trend and progress of study on biomolecular analysis. c. infection defense antigens of poliovirus]. | | 1987 | 2452260 |
| expression of a poliovirus neutralization epitope at the surface of recombinant bacteria: first immunization results. | we devised a procedure to construct strains of escherichia coli which expose at their surface a foreign antigen genetically inserted into lamb, an outer membrane protein. in particular, we showed that amino acid residues 93-103 of poliovirus type 1 capsid polypeptide vp1, which correspond to the c3 neutralization epitope, when inserted into two different external loops of lamb (after residues 153 and 374 of the mature protein), yielded the synthesis of stable hybrid proteins named, respectively, ... | 1988 | 2454645 |
| antigenic sites on foot-and-mouth disease virus type a10. | a set of monoclonal antibodies was used to isolate nonneutralizable foot-and-mouth disease virus variants, and the rnas of the variants were sequenced. cross-neutralization studies and mapping of the amino acid changes indicated two major antigenic sites. the first site was trypsin sensitive and included the vp1 140 to 160 sequence. the second site was trypsin insensitive and included mainly vp3 residues. two minor sites were located near vp1 169 and on the c terminus of vp1. comparison with pol ... | 1988 | 2455819 |
| nucleic acid sequence relationships between enterovirus serotypes. | forty-eight different enterovirus serotypes were analysed by a nucleic-acid hybridization test using probes derived from the 3' end of coxsackievirus a21 (ca21) and b3 (cb3), poliovirus 3 (p3) and enterovirus 70 (e70). more than 90% of the serotypes could be detected with this collection of reagents. the cb3 probe reacted with all the coxsackie b viruses, with all three poliovirus serotypes, and with almost all of the 30 echo virus types tested. in addition some of the coxsackie a viruses and th ... | 1987 | 2456458 |
| [variability of poliomyelitis virus strains in nature and significance of this factor for the prevention of poliomyelitis]. | | 1988 | 2457986 |
| [test of the potency of trivalent oral polio vaccines: comparison of 2 methods of reading]. | trivalent oral poliovaccine is used in argentina to prevent poliomyelitis. its potency is tested by infectivity titration of the three viruses in susceptible cell cultures (hep-2 cell line). in order to compare the conventional reading method of cytopathic effect (cpe) with the staining technique of cell monolayers with crystal violet-formol, the reference viruses and several lots of trivalent vaccines were titrated. between 3 and 10 days post-infection (pi) the plates were read under microscope ... | 1987 | 2459727 |
| engineering a poliovirus type 2 antigenic site on a type 1 capsid results in a chimaeric virus which is neurovirulent for mice. | poliovirus type 2 (pv-2) lansing strain produces a fatal paralytic disease in mice after intracerebral injection, whereas poliovirus type 1 (pv-1) mahoney strain causes disease only in primates. atomic models derived from the three-dimensional crystal structure of the pv-1 mahoney strain have been used to locate three antigenic sites on the surface of the virion. we report here the construction of type 1-type 2 chimaeric polioviruses in which antigenic site 1 from the pv-1 mahoney strain was sub ... | 1988 | 2460345 |
| ribozymes and their medical implications. | certain rna molecules can mediate their own cleavage or splicing or act as enzymes to promote reactions on substrate rna molecules. thus, rna is not restricted to being a passive carrier of genetic information but can have an active role in directing cellular biochemistry. these findings suggest the possibility that other cellular rnas, including the rna components of small nuclear ribonucleoproteins, of the ribosome, and of various ribonucleoprotein enzymes, are catalysts. rna enzymes (ribozyme ... | 1988 | 2460649 |
| identification of an immunodominant antigenic site involving the capsid protein vp3 of hepatitis a virus. | hepatitis a virus, an hepatotropic picornavirus, is a common cause of acute hepatitis in man for which there is no available vaccine. competitive binding studies carried out in solid phase suggest that neutralizing monoclonal antibodies to hepatitis a virus recognize a limited number of epitopes on the capsid surface, although the polypeptide locations of these epitopes are not well defined. neutralization-escape mutants, selected for resistance to monoclonal antibodies, demonstrate broad cross- ... | 1988 | 2460866 |
| addition of a foreign oligopeptide to the major capsid protein of poliovirus. | insertion mutants of type 3 poliovirus (sabin strain) were constructed that encode additional amino acid sequences at the level of residue 100 of the capsid polypeptide vp1 within the neutralization site 1, corresponding to a loop on the capsid surface. the addition of a tri- or hexapeptide did not hamper virus viability. the antigenic pattern of insertion mutants was only modified locally: all mutants lost reactivity of neutralization site 1 with the corresponding monoclonal antibodies, while t ... | 1988 | 2460875 |
| measurement of poliovirus rna polymerase binding to poliovirion and nonviral rnas using a filter-binding assay. | the binding of the purified poliovirus rna-dependent rna polymerase to viral and nonviral rnas was studied using a protein-rna nitrocellulose filter binding assay. a cellular poly(a)-binding protein was found in viral polymerase preparations, but was easily separated from the polymerase by chromatography on poly(a) sepharose. optimal conditions for the binding of purified polymerase (fraction 5-pas) to 32p-labeled poliovirion rna were determined. the binding of purified polymerase to 32p-labeled ... | 1988 | 2461545 |
| [current concepts of the antigenic structure and attenuation mechanisms of the poliomyelitis virus]. | | 1988 | 2461613 |
| construction and characterization of hybrid hepatitis b antigen particles carrying a poliovirus immunogen. | the hepatitis b surface antigen (hbsag) has the unique property of assembling with cellular lipids into spherical or elongated particles of 22 nm diameter which are secreted by mammalian cells expressing hbsag. we have studied the structural requirements for particle formation and secretion by creating in-phase insertions into different regions of the s gene of the hepatitis b virus, coding for hbsag. modified genes were integrated into an appropriate vector and expressed in mouse l cells. vario ... | 1988 | 2465786 |
| nasopharyngeal secretory antibody response to poliovirus type 3 virion proteins exhibit different specificities after immunization with live or inactivated poliovirus vaccines. | by using immunoblotting, neutralization, and elisa, the development of secretory antibody responses to poliovirus type 3 virion proteins (vp1, vp2, vp3) and to intact or trypsin-treated poliovirus type 3 was studied in the nasopharyngeal secretions in groups of infants after immunization with live attenuated poliovirus vaccine (opv), enhanced potency inactivated poliovirus vaccine (ipv-ep), or after combined vaccination with ipv-ep followed by opv. after three doses of vaccine, infants in all va ... | 1989 | 2470831 |
| n-agib of poliovirus type 1: a discontinuous epitope formed by two loops of vp1 comprising residues 96-104 and 141-152. | analysis of resistant mutants to neutralizing monoclonal antibodies revealed a discontinuous neutralization epitope on vp1 of poliovirus type 1, mahoney. the epitope has the unique property of being also part of a sequential epitope within neutralization antigenic site i (n-agi). it is formed by residues in the loop 96-104 connecting the b and c strand and in the loop 141-152 connecting the d and e strand of vp1. because of strong analogy to neutralization immunogen ib (nimib) of human rhinoviru ... | 1989 | 2471354 |
| sulfated polysaccharides are potent and selective inhibitors of various enveloped viruses, including herpes simplex virus, cytomegalovirus, vesicular stomatitis virus, and human immunodeficiency virus. | several sulfated polysaccharides (dextran sulfate, pentosan polysulfate, fucoidan, and carrageenans) proved to be potent inhibitors for herpes simplex virus, human cytomegalovirus, vesicular stomatitis virus, sindbis virus, and human immunodeficiency virus. they were moderately inhibitory to vaccinia virus but not inhibitory to adenovirus, coxsackievirus, poliovirus, parainfluenza virus, and reovirus. these results indicate that, with the exception of parainfluenza virus, enveloped viruses are s ... | 1988 | 2472775 |
| preparative separation of poliovirus structural polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, copper staining and electroelution, and induction of monospecific antisera. | viral polypeptides were prepared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) followed by copper staining and electroelution from gel slices. poliovirus capsid polypeptide vp 1 isolated by this procedure induced monospecific antibodies in rabbits, i.e., antisera reacting only with the homologous polypeptide. our results demonstrate the applicability of the described copper staining method as a rapid visualization step for preparing viral proteins after sds-page. | 1989 | 2472959 |
| expression of a poliovirus type 1 neutralization epitope on a diphtheria toxin fusion protein. | the diphtheria toxin (dt) secreted by corynebacterium diphtheriae is used after formolization as an efficient vaccine against diphtheria. in an attempt to evaluate its capacity to present heterologous peptide sequence in a recognized form, we created in-phase insertion in the gene encoding the non-toxic mutant protein crm228 of dt. the sequence chosen for insertion was the synthetic dna fragment encoding a poliovirus neutralization epitope. tripartite fusion proteins comprising the mutant dt, th ... | 1989 | 2473577 |
| modification of an adenovirus major late promoter-binding factor during poliovirus infection. | to further characterize the mechanism involved in poliovirus-induced inhibition of hela cells mrna synthesis, in vitro formation of dna-protein complexes between nuclear upstream stimulatory transcription factor (usf) and the adenovirus type 2 major late promoter upstream promoter element (upe; located between -45 and -65 base pairs) was studied. using the gel shift assay, we found differences between the upe-protein complex formed with partially purified nuclear extracts from poliovirus-infecte ... | 1989 | 2474675 |
| insertion of short hepatitis virus a amino acid sequences into poliovirus antigenic determinants results in viable progeny. | in an infectious poliovirus cdna construct, the determinant encoding antigenic epitope n-ag1 (in a loop located between two beta-strands in poly-peptide vp1) was altered by site-directed mutagenesis, to be partially similar with the determinants for presumptive epitopes in polypeptides vp1 or vp3 of hepatitis a virus (hav). the modified constructs proved to be infectious. however, another construct, in which the same locus encoded a 'nonsense' and a relatively hydrophobic amino acid sequence, ex ... | 1989 | 2479578 |
| construction of a poliovirus type 1/type 2 antigenic hybrid by manipulation of neutralization antigenic site ii. | there are three serotypes of poliovirus, poliovirus type 1 (pv-1), pv-2, and pv-3. these viruses each display four distinct neutralization antigenic sites, designated n-agi, n-agii, n-agiiia, and n-agiiib. it has been demonstrated previously that part of n-agi can be replaced with heterogeneous amino acid sequences, resulting in hybrid viruses expressing heterogeneous antigenic determinants. to study whether hybrid viruses could be constructed by modifying another antigenic site, a part of n-agi ... | 1989 | 2479772 |
| kinetic of the antibody titers to tetanus toxoid (tt), diphtheria toxoid (dt), measles virus, poliomyelitis virus and s. pneumoniae after marrow grafting. | | 1989 | 2480304 |
| monoclonal anti-idiotypic antibody vaccines against poliovirus, canine parvovirus, and rabies virus. | | 1989 | 2481213 |
| [molecular genetic analysis of poliovirus infection]. | molecular genetic studies of the antigenicity and the attenuation phenotype of type 1 poliovirus were described. antigenic sites were identified on the genome of type 1 poliovirus by the determination of nucleotide sequence of the genome of variants that were not neutralized by the neutralizing monoclonal antibodies. the solution of the crystal structure of poliovirus revealed that all mutations found as above are located at the surface of the virion and cluster into three distinct sites. these ... | 1989 | 2481725 |
| prediction of secondary structure, spatial organization and distribution of antigenic determinants for hepatitis a virus proteins. | on the basis of the secondary structure calculations from the known amino acid sequence we came to the conclusion that hepatitis a virus capsid proteins have the typical antiparallel beta-sheet bilayer structure. the predicted secondary structure of the hav proteins can be well aligned with those of the poliovirus (type 1 mahoney) and human rhinovirus (type 14). it enabled us to use the x-ray structure of the pv-1m and hrv-14 proteins as a template and then, firstly, to localize the positions of ... | 1987 | 2482756 |
| [the fate of pathogens in waste-waters]. | a large variety of pathogenic organisms capable of transmission by the faecal-oral route may be found in wastewaters. among the bacteria salmonella, shigella, vibrio cholerae, yersinia and campylobacter are the important agents of concern. also the human enteric viruses (poliovirus, coxsackievirus, echovirus, hepatitis a virus, rotavirus) have been shown to be present in domestic waste and may not be completely removed by conventional sewage treatment processes, including chlorination. discharge ... | 1989 | 2484470 |
| a lambda gt11-cdna clone specific for chronic hepatitis c generated from pooled serum presumably infected by hepatitis c virus. | a lambda gt11-random-primed-cdna clone specific for chronic hepatitis c was isolated from pooled serum presumably infected by hepatitis c virus. the translation product of the clone detect 50% of patients with chronic hepatitis c in 4 test panels but none of the patients with acute hepatitis c, other liver diseases or normal controls was positive for the peptide. the nucleotide sequence of the cdna clone, the size of which is 66 bp, has no homology to the complete sequences of known human viruse ... | 1989 | 2509279 |
| purification and properties of poliovirus rna polymerase expressed in escherichia coli. | a cdna clone encoding the rna polymerase of poliovirus has been expressed in escherichia coli under the transcriptional control of a t7 bacteriophage promoter. the poliovirus enzyme was designed to contain only a single additional amino acid, the n-terminal methionine. the recombinant enzyme has been purified to near homogeneity, and polyclonal antibodies have been prepared against it. the enzyme exhibits poly(a)-dependent oligo(u)-primed poly(u) polymerase activity as well as rna polymerase act ... | 1989 | 2535728 |
| isolation and characterization of hela cell lines blocked at different steps in the poliovirus life cycle. | cotransfection of poliovirus rna and r1, a poliovirus subgenomic rna containing a deletion of nearly all of the capsid region, resulted in surviving cells, in contrast to the complete cell death observed after transfection with viral rna. cells that survived the cotransfection grew into colonies, produced infectious poliovirus, and underwent cycles of cell lysis (crisis periods) where less than 1% of the cells survived, followed by periods of growth. poliovirus evolved during the persistent infe ... | 1989 | 2535745 |
| the deletion of 41 proximal nucleotides reverts a poliovirus mutant containing a temperature-sensitive lesion in the 5' noncoding region of genomic rna. | we generated a number of small deletions and insertions in the 5' noncoding region of an infectious cdna copy of the poliovirus rna genome. transfection of these mutated cdnas into cos-1 cells produced the following phenotypic categories: (i) wild-type mutations, (ii) lethal mutations, (iii) mutations exhibiting slow growth or low-titer properties, and (iv) temperature-sensitive (ts) mutations. the deletion of nucleotides 221 to 224 produced a ts virus, 220d1. mutant 220d1 was found to have a dr ... | 1989 | 2536107 |
| post-translational modifications of poliovirus proteins. | the post-translational modifications of poliovirus proteins have been investigated by analysis of glycosylation, sulphation, phosphorylation and acylation of the proteins made in the infected hela cells. no glycosylation or sulphation of proteins specific for virus-infected cells was apparent. a number of changes in the pattern of phosphorylated proteins took place. the specific myristylation of the structural protein vp4 and its precursors was clearly apparent. acylation of viral proteins with ... | 1989 | 2536278 |
| activation of double-stranded rna-dependent kinase (dsl) by the tar region of hiv-1 mrna: a novel translational control mechanism. | all mrnas of human immunodeficiency virus 1 (hiv-1) contain in their 5' untranslated region a sequence termed tar that responds to trans-activation by the tat (trans-activating) protein. this rna sequence assumes a stable secondary structure, and its cap structure is relatively inaccessible. here we report that these structural properties of the tar sequence underlie the ability of tar to inhibit in trans the translation of other mrnas. this mechanism of translation inhibition involves the activ ... | 1989 | 2536299 |
| ultrafiltration: an efficient second step for hepatitis a virus and poliovirus concentration. | the efficiency of seeded hepatitis a virus and poliovirus recovery from 1 l of dechlorinated tap water or different buffer was evaluated using a molecular filtration system. all the experiments were performed using a polysulfonate membrane of 10,000 molecular weight limit. under standard conditions hepatitis a virus recovery was 100% of the input, but the percentage was reduced dramatically when the inflow pressure was increased. in contrast, poliovirus recovery was low under standard conditions ... | 1989 | 2536381 |
| genetic variation occurring on the genome of an in vitro insertion mutant of poliovirus type 1. | an insertion sequence of 72 nucleotides prepared from a polylinker sequence of plasmid puc18 was introduced at nucleotide position 702 of the 5' noncoding sequence (742 nucleotides long) of the genome of the sabin strain of poliovirus type 1 by using an infectious cdna clone of the virus strain. the insertion mutant thus obtained showed a small-plaque phenotype compared with that of the parent virus. apparent revertants (large-plaque variants) were easily generated from the insertion mutant. nuc ... | 1989 | 2536821 |
| determinants in the 5' noncoding region of poliovirus sabin 1 rna that influence the attenuation phenotype. | a number of recombinants between the virulent mahoney and attenuated sabin strains of type 1 poliovirus were constructed by using infectious cdna clones of the two strains. to identify a strong neurovirulence determinant(s) residing in the genome region upstream of nucleotide position 1122, these recombinant viruses were subjected to biological tests, including monkey neurovirulence tests. the results of the monkey neurovirulence tests suggested the important contribution of an adenine residue ( ... | 1989 | 2536835 |
| genetic basis of attenuation of the sabin type 3 oral poliovirus vaccine. | the poliovirus type 3 sabin oral poliovirus vaccine strain p3/leon/12a1b differs in nucleotide sequence from its neurovirulent progenitor p3/leon/37 by just 10 point mutations. the contribution of each mutation to the attenuation phenotype of the vaccine strain was determined by the construction of a series of recombinant viruses from infectious cdna clones. the neurovirulence testing of recombinant viruses indicated that the attenuation phenotype is determined by just two point mutations: a c t ... | 1989 | 2536836 |
| conserved structural domains in the 5'-untranslated region of picornaviral genomes: an analysis of the segment controlling translation and neurovirulence. | a model of secondary structure common for the central part (ca. 400 nucleotides) of the 5'-untranslated regions (5'-utr) of all the so far sequenced genomes of polioviruses, coxsackieviruses, and rhinoviruses was derived on the basis of evolutionary and thermodynamic considerations. according to the model, this part of the genome comprises three domains, which appear to be involved, at least in the poliovirus genome, in the control of viral neurovirulence and in vitro translation. some salient f ... | 1989 | 2536978 |
| a point mutation in the poliovirus polymerase gene determines a complementable temperature-sensitive defect of rna replication. | we have previously described the isolation of a rna- temperature-sensitive (ts) mutant of poliovirus type 1, ts035, after chemical mutagenesis by 5-fluorouracil. the ts defect of ts035 correlated with defective rna replication, since the two characters corevert in the case of spontaneous revertants. the alteration of a trans-acting replication function of ts035 was suggested by significant rescue following mixed infection with another ts mutant, ts221, or with wild-type virus. protein synthesis ... | 1989 | 2536984 |
| recovery of structurally intact and infectious poliovirus type 1 from hela cells during receptor-mediated endocytosis. | poliovirus type 1 enters hela cells by receptor-mediated endocytosis as an intact virus. up to 30 min after adsorption complete virus particles still containing vp4 and sedimenting with 156 s could be recovered from the cells. these virus particles were n-antigenic and infectious. thirty minutes after adsorption the recovery of intact and infectious virus decreased. this decrease presumably reflects viral uncoating in the acidic endosomes and/or lysosomes because virus particles could be localiz ... | 1989 | 2536990 |
| intestinal immunity to poliovirus develops only after repeated infections in monkeys. | to establish gut immunity in monkeys to polio-virus type 1, we fed four juvenile bonnet monkeys (macaca radiata) with 100 median infectious doses of the mahoney strain of virus. the duration of viral shedding in the throat and faeces and the titre of virus in faeces were measured. eighteen days after the last monkey stopped shedding virus, they were inoculated once again with the same amount of virus. all monkeys got re-infected; the duration and titres of viral shedding were very similar to tho ... | 1989 | 2537880 |
| replication of poliovirus in human mononuclear phagocyte cell lines is dependent on the stage of cell differentiation. | both wild-type and attenuated strains of poliovirus type 3 were found to replicate in the u-937 cells, an established cell line derived from human histiocytic lymphoma. however, preincubation of the cells with phorbol ester (pma) that brought about the typical adherent macrophage-like appearance of the cultures, converted the cells to practically nonpermissive for poliovirus, while their ability to replicate vesicular stomatitis virus was not impaired. rc2a, another human cell line derived from ... | 1989 | 2537885 |
| viral receptors of the immunoglobulin superfamily. | | 1989 | 2538240 |
| cellular receptor for poliovirus: molecular cloning, nucleotide sequence, and expression of a new member of the immunoglobulin superfamily. | restriction of poliovirus replication to a few sites in the infected primate host appears to be controlled by the expression of viral receptors. to learn more about these binding sites and their role in viral tissue tropism, cdna clones encoding functional poliovirus receptors were isolated. the predicted amino acid sequence reveals that the human poliovirus receptor is an integral membrane protein with the conserved amino acids and domain structure characteristic of members of the immunoglobuli ... | 1989 | 2538245 |
| initiation of protein synthesis by internal entry of ribosomes into the 5' nontranslated region of encephalomyocarditis virus rna in vivo. | expression vectors that yield mono-, di-, and tricistronic mrnas upon transfection of cos-1 cells were used to assess the influence of the 5' nontranslated regions (5'ntrs) on translation of reporter genes. a segment of the 5'ntr of encephalomyocarditis virus (emcv) allowed translation of an adjacent downstream reporter gene (cat) regardless of its position in the mrnas. a deletion in the emcv 5'ntr abolishes this effect. poliovirus infection completely inhibits translation of the first cistron ... | 1989 | 2538648 |