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direct virus inactivation of tachyplesin i and its isopeptides from horseshoe crab hemocytes.direct virus inactivation of tachyplesin i and related isopeptides, which are antimicrobial peptides isolated from the hemocytes of the horseshoe crab (tachypleus tridentatus and limulus polyphemus), was examined against several viruses. vesicular stomatitis virus (vsv) was inactivated by incubation with tachyplesin i and its isopeptides. influenza a (h1n1) virus was slightly inactivated by tachyplesin i, whereas herpes simplex virus 1 and 2, adenovirus 1, reovirus 2 and poliovirus 1 were resist ...19911666545
[cloning and expression of the 3c-proteinase gene from the poliomyelitis virus in e. coli cells].expression of the 3c protease gene of poliovirus type 1 (mahoney) in e. coli cells using various vectors was studied. the 3c gene was shown to be expressed effectively upon its cloning in hindii/hindii (bases 5240 to 6770) and in hindii/hindiii (bases 5240 to 6056) fragments of poliovirus cdna in pttq8 vector containing tac-promoter and laci-repressor gene. products of processing at the n-terminal 3c protease gln-gly site and polypeptides formed upon translation from an alternative methionine, w ...19911666949
[isolation and purification of 3c-proteinase from the poliomyelitis virus. identification of an active form of the enzyme].all the forms of 3c protease previously found were isolated and purified. a 3d polymerase's fragment covalently bound with 3c protein does not affect the specific proteolytic activity of the enzyme, whereas the elimination of 26 n-terminal amino acid residues of 3c protease leads to its inactivation.19911666950
[a method for recovery of enteroviruses from milk].a method of detection of enteric viruses in milk was studied. the high protein content of milk and the protein nature of enterovirus allowed the detection of these viruses using the organic acid flocculation method. the poliovirus type 1 (mahoney strains) and the e.c.h.o.1 isolated from the environment were used as virus model and were inoculated to creamed, half-creamed and whole uht commercialized milk. the method consists on a milk sample clarification with acid precipitation and centrifugati ...19911668634
virus-receptor interaction in poliovirus entry and pathogenesis.knowledge of the three-dimensional structure of poliovirus has provided insight into many aspects of poliovirus infection. however, the structure alone cannot answer questions about how the virus interacts with the receptor to lead to release of the genome into the cell. genetic and biochemical analysis of virus mutants are required to understand these steps in infection. the availability of cdna clones of the poliovirus genome and pvr enables the isolation of virus and pvr mutants that can be u ...19911670545
poliovirus can enter and infect mammalian cells by way of an intercellular adhesion molecule 1 pathway.mouse fibroblast cell lines were transfected with truncated forms of the human poliovirus receptor (pvr) cdna and tested for the expression of functional receptors for poliovirus. several receptor constructs, all containing the coding region of the first 143 amino acids of pvr, were able to render mouse cells susceptible to poliovirus infection. a deletion of 65 amino acids in the first extracellular domain of pvr prevented virus attachment and infection. these data suggest that domain 1 is nece ...19911673787
safety and immunogenicity of multiple conventional immunizations administered during early hiv infection.twenty-one asymptomatic adults who had recently received multiple polysaccharide, live viral, and protein-derived vaccines were identified as being infected with human immunodeficiency virus (hiv). the mean subject age was 24 years (range 18-33); 20 of 21 (95%) were male. the mean t4 count was 523/mm3 with a mean t4/t8 ratio of 0.6. serologic responses to immunization with meningococcus group c, adenovirus types 4 and 7, tetanus, and diphtheria were evaluated for the hiv seropositive subjects an ...19911675680
the use of bacteriophage ms2 as a model system to evaluate virucidal hand disinfectants.a model system which would closely reflect the resistance of poliovirus but could be easily performed in any microbiology laboratory would offer considerable advantages for rapidly screening hand decontamination products. the use of the bacteriophage ms2 as a simple model for virucidal testing has been evaluated. in suspension tests the sensitivity of ms2 to alcohols, organic acids and alkalis generally reflected that observed in studies using poliovirus. ms2 could be applied and recovered from ...19911677653
the natural genomic variability of poliovirus analyzed by a restriction fragment length polymorphism assay.the genomic variability of poliovirus was examined by analyzing the restriction fragment length polymorphism of a reverse-transcribed genomic fragment amplified by the polymerase chain reaction. the fragment was a 480-nucleotide sequence of the poliovirus genome coding for the n-terminal half of the capsid protein vp1, including antigenic site 1. the identification of a pair of generic primers flanking this fragment allowed its amplification in practically all the poliovirus strains tested so fa ...19911679577
improved distribution of antigenic site specificity of poliovirus-neutralizing antibodies induced by a protease-cleaved immunogen in mice.previous studies showed that the distribution of antigenic site specificity of neutralizing antibodies to type 3 poliovirus obtained with the inactivated poliovirus vaccine can be deficient as compared with that obtained following poliovirus infection. this observation was shown by the relatively low capacity of sera from inactivated-poliovirus-vaccine-immunized persons to neutralize poliovirus cleaved at antigenic site 1. we investigated possibilities for improving the situation in a mouse mode ...19901688625
translation by the adenovirus tripartite leader: elements which determine independence from cap-binding protein complex.the adenovirus tripartite leader is a 200-nucleotide-long 5' noncoding region which facilitates translation of viral mrnas at late times after infection. the tripartite leader also confers the ability to initiate translation independent of the requirement for cap-binding protein complex or eif-4f without any requirement for adenovirus gene products. to elucidate the manner by which the tripartite leader functions, the primary determinants of leader activity were investigated in vivo by testing a ...19901692346
differences in conformation of type 3 poliovirus antigenic sites on non-infectious empty particles and infectious virus.a panel of monoclonal antibodies which react with empty non-infectious type 3 poliovirus particles (c antigen) but not infectious virus (d antigen) were characterized for their reactivity with c antigen particles derived from neutralization-resistant virus strains which had single amino acid substitutions at each of the antigenic sites. antibodies were identified which failed to bind to variant viruses with modifications at each of antigenic sites 2b, 3b and 4 indicating that the same amino acid ...19901693661
crystallization of genetically engineered active maltose-binding proteins, including an immunogenic viral epitope insertion.three mutants of the maltose- or maltodextrin-binding protein encoded by the male gene of escherichia coli, with extensive genetic changes, have been purified and crystallized in different crystal forms. two of these mutant proteins, male178 and male341, carry net deletions of seven and 13 residues, respectively, near the surface of the molecule. these mutations have very little effect on either the transport activity of the mutant strains or the sugar-binding activity of the purified mutant pro ...19901694248
critical role of neighbouring sequences on the immunogenicity of the c3 poliovirus neutralization epitope expressed at the surface of recombinant bacteria.the c3 neutralization epitope of poliovirus type 1 (pv-1) is a continuous epitope comprised within residues 93-103 of capsid protein vp1. these residues form a loop at the surface of the virus particle. the authors compared the immunogenicity of two peptides which contain this epitope, when presented at the surface of escherichia coli by genetic insertion in the outer membrane protein lamb. one peptide was 13 residues long (vp1:93-103) and the other one contained flanking sequences increasing it ...19901694613
mutation frequencies at defined single codon sites in vesicular stomatitis virus and poliovirus can be increased only slightly by chemical mutagenesis.mutagenesis by a variety of chemical mutagens conferred only 1.1- to 2.8-fold increases in mutation frequencies at defined single base sites in vesicular stomatitis virus and poliovirus.19901695258
virucidal activity of hypericin against enveloped and non-enveloped dna and rna viruses.hypericin is a polycyclic anthrone first isolated from the plant st. johnswort and was shown to have dramatic anti-retroviral activity against friend leukemia virus and radiation leukemia virus in mice. hypericin displayed marginal activity (ic50 = 6 micrograms/ml) against moloney murine leukemia virus (mo-mulv) in vitro. hypericin did not display selective antiviral activity against herpes simplex virus, influenza a, adenovirus, or poliovirus. the 50% cytotoxic concentration was approximately 2 ...19901699494
modelling of poliovirus. hiv-1 antigen chimaeras.we have used laboratory-based molecular modelling to identify structural features of antigen chimaeras of poliovirus expressing epitopes from human immunodeficiency virus (hiv-1) that may affect virus viability. chimaeras were constructed by replacement of antigenic site 1 of vp1 by sequences corresponding to epitopes from hiv-1. loop volume, estimated by approximating the loop to an ellipsoid was significantly (p less than 0.001) lower in viable (2062.1 a3 +/- 400.2) than in non-viable (3617 a3 ...19901699798
an improved method for sequencing of rna templates. 19901700370
assignment of seven genes to distinct intervals on the midportion of human chromosome 19q surrounding the myotonic dystrophy gene region.hybridization studies using a panel of somatic cell hybrids with subchromosomal segments of 19q have localized the genes encoding hormone-sensitive lipase (lipe), carcinoembryonic antigen (cea), and small nuclear ribonucleoprotein polypeptide a (snrpa) to various regions of 19q13.1; the cellular receptor for poliovirus sensitivity (pvs) to 19q13.2; and the genes coding for prostate-specific antigen (aps), human pancreatic kallikrein (klk1), and small nuclear ribonucleoprotein 70-kd polypeptide ( ...19901701111
type 3 poliovirus/finland/1984 is genetically related to common mediterranean strains.strains of poliovirus type 3 isolated in finland in 1984 and 1985 (p3/fin/84) are known to differ considerably from the type 3 vaccine strains in both nucleotide sequence and antigenic properties. in the search for the origin of the outbreak we first tested 80 type 3 strains that had been isolated elsewhere in the world during the years 1953 to 1986. an oligonucleotide probe complementary to a highly variable 17 nucleotide interval in the 5' non-coding region of the genomic rna of p3/fin/84 reac ...19901701473
antigenic structure of chimeras of type 1 and type 3 poliovirus involving antigenic site 1.chimeric polioviruses have been prepared in which part of the antigenic site 1-encoding sequence of the sabin strain of type 1 poliovirus has been replaced by sequences based on those found in the homologous region of the sabin type 3 strain. the chimeras were analysed for their reaction with polyclonal and monoclonal antibodies raised against type 1 and type 3 viruses, and with polyclonal antipeptide sera, as well as for their immunogenicity in animals. the effectiveness with which the type 3 s ...19901701474
antigenic regions of poliovirus type 3/sabin capsid proteins recognized by human sera in the peptide scanning technique.we used the peptide scanning technique to identify regions of poliovirus type 3/sabin capsid proteins that bind antibodies from human immune sera. several reactive regions were seen in vp1, vp2, and vp3 while peptides resembling vp4 did not bind antibodies. peptides derived from sequences of the previously known antigenic sites 1 and 3 were recognized to a moderate degree. peptides imitating the four loops in the closed ends of the beta barrels or the alpha helical cd insertions of vp1, vp2 or v ...19911701949
permissive sites and topology of an outer membrane protein with a reporter epitope.we are developing a genetic approach to study with a single antibody the folding and topology of lamb, an integral outer membrane protein from escherichia coli k-12. this approach consists of inserting the same reporter foreign antigenic determinant (the c3 epitope from poliovirus) at different sites of lamb so that the resulting hybrid proteins have essentially kept the in vivo biological properties of lamb and therefore its cellular location and structure; the corresponding sites are called pe ...19911702781
identification of a t-cell epitope adjacent to neutralization antigenic site 1 of poliovirus type 1.proliferative t-cell responses to poliovirus in various strains of mice have been analyzed by using either killed purified virus or capsid protein vp1 synthetic peptides. following immunization of mice with inactivated poliovirus type 1 (pv1), a specific proliferative response of their lymph node cd4+ t cells was obtained after in vitro stimulation with purified virus. in mice immunized with pv1, pv2, or pv3, a strong cross-reactivity of the t-cell responses was observed after in vitro stimulati ...19911702841
the trat lipoprotein as a vehicle for the transport of foreign antigenic determinants to the cell surface of escherichia coli k12: structure-function relationships in the trat protein.the trat protein is a surface-exposed lipoprotein, specified by plasmids of the incf group, that mediates serum resistance and surface exclusion. the structure and function of the trat protein determined by plasmid r6-5 was probed by genetic insertion of a foreign antigenic determinant, the c3 epitope of polio virus, at residues 61, 125, 180, 200 or 216 of the protein. the chimaeric proteins were transported to the outer membrane and, in three cases, immunoassays with an anti-c3 monoclonal antib ...19901704095
characterization of mengo virus neutralization epitopes.a set of four monoclonal antibodies which neutralized the infectivity of mengo virus was used to select 20 non-neutralizable (escape) mutants. altered amino acids were identified by sequence analyses of the capsid-coding regions of the mutant virus genomes. mutations were found predominantly in proteins vp2 and vp3, while mutations in vp1 were detected only as second mutations. the mengo virus vp2 mutations at amino acid residues 2144, 2145, 2147, and 2148 align with site nlm ii in human rhinovi ...19911704653
down regulation of poliovirus receptor rna in hela cells resistant to poliovirus infection.a line of hela cells (sofia) was previously isolated that is resistant to poliovirus infection and does not express functional virus binding sites at the cell surface. the expression of the poliovirus receptor (pvr) gene in sofia cells was examined to determine the molecular basis for the failure of these cells to express pvrs. southern blot analysis of genomic dna revealed that the pvr gene in sofia cells did not contain gross alterations. however, pvr transcripts were not detected in northern ...19911705991
analysis of neutralization-escape mutants selected from a mouse virulent type 1/type 2 chimeric poliovirus: identification of a type 1 poliovirus with antigenic site 1 deleted.a chimeric type 1/type 2 poliovirus (v510), in which the antigenic site 1 (ag1) of poliovirus type 1 (pv-1) mahoney was replaced by the corresponding site of poliovirus type 2 (pv-2) lansing, is known to be neurovirulent for mice and neutralized by both type 1 and type 2 monoclonal antibodies. neutralization-escape mutants to monoclonal antibodies specifically recognizing the pv-2 sequence were obtained from v510. the nucleotide sequence and the mouse neurovirulence of mutants were determined. a ...19911707949
virus-induced interferon production in human leukocytes: a low responder to one virus can be a high responder to another virus.we measured the amounts of interferon (ifn) induced by four wild-type strains and two attenuated vaccine strains of poliovirus, testing each virus in 12-58 separate batches of human peripheral blood leukocytes. there were big and consistent differences in the mean amounts of ifn formed by leukocytes from different donors in response to all these polioviruses. almost invariably, the wild-type polioviruses gave rise to more ifn than the corresponding attenuated strains, but overall, the amounts in ...19911709416
chimeric polioviruses that include sequences derived from two independent antigenic sites of foot-and-mouth disease virus (fmdv) induce neutralizing antibodies against fmdv in guinea pigs.five poliovirus recombinants containing sequences corresponding to foot-and-mouth disease virus (fmdv) antigenic sites were constructed. viable virus was recovered from four of these plasmids, in which the vp1 beta b-beta c loop (antigenic site 1) of poliovirus type 1 sabin had been replaced with sequences derived from the vp1 beta g-beta h loop (antigenic site 1) of fmdv o1 kaufbeuren (o1k), chimera o1.1 (residues 141 to 154), chimera o1.2 (residues 147 to 156), and chimera o1.3 (residues 140 t ...19911709696
effects of poliovirus replication on undifferentiated and differentiated monocytic u937 cells: comparative studies with human macrophages.poliovirus infection of either undifferentiated or differentiated u937 cells produced a decrease in the percentage of cells positive for the surface expression of the cd4, cd11c, cd14, or 8e11 antigens. the number of 4f2 surface molecules per cell increased in infected normal u937 cells, but was unaffected in differentiated cells. the level of o2- production in infected differentiated u937 cells was approximately 50% of that found when not infected. finally, poliovirus rna levels and infectious ...19911710210
the effect of site and mode of expression of a heterologous antigenic determinant on the properties of poliovirus hybrids.the antigenic site normally situated in the ef loop of vp2 (2ef) of poliovirus type 2 (lansing) [pv2 (l)] was expressed in 2ef or in the bc loop of vp1 (1bc) of pv1 (mahoney) [pv1 (m)]. a hybrid virus expressing the site in 2ef of pv1 (m) is known to be neutralizable by pv2 (l)-specific antisera and to induce neutralizing antibodies against pv-2 (l). in contrast, a hybrid expressing a related sequence in 1bc of pv1 (m), which maintained the length of the native bc loop, was not neutralizable by ...19911713280
the effect of poliovirus proteinase 2apro expression on cellular metabolism. inhibition of dna replication, rna polymerase ii transcription, and translation.infection of cells with poliovirus results in a rapid inhibition of host rna and protein synthesis. concordant with this shutoff, the p220 subunit of the cap-binding protein complex is cleaved, probably indirectly, by the poliovirus proteinase p2a (2apro). to elucidate the mechanism of action of 2apro in inhibiting protein synthesis in vivo, we studied the effect of transient expression of 2apro in cos-1 monkey kidney cells. in cells transfected with a 2apro expression plasmid, p220 was cleaved ...19911713590
presentation of foreign antigenic determinants at the bacterial cell surface using the trat lipoprotein.the trat protein is an oligomeric outer membrane lipoprotein, specified by plasmids of the incf group, that is very highly exposed at the bacterial cell surface. we have investigated the feasibility of using the protein as a carrier of foreign antigenic determinants by genetic insertion of the c3 epitope of type 1 poliovirus into defined sites in the protein. several of the hybrid proteins constructed had features characteristic of the native protein and one in particular retained the ability of ...19901714091
structure of viral b-cell epitopes.four categories of viral epitopes can be distinguished that have been designated cryptotopes, neotopes, metatopes and neutralization epitopes. specific examples of each epitope type are presented and the methods used for locating their positions in viral proteins are described. the epitopes of four well-characterized viruses, namely poliovirus, foot-and-mouth disease virus, influenza virus and tobacco mosaic virus are briefly described.19901714092
immunogenicity of foreign peptide epitopes expressed in bacterial envelope proteins.we have used two bacterial proteins from escherichia coli to express heterologous peptides. both proteins are situated in the e. coli cell envelope but have different properties: lamb is an integral outer membrane protein, and male a soluble periplasmic protein. the peptides were expressed as genetic inserts within "permissive sites" of these recipient proteins, i.e. sites which allow the insertion of foreign peptides without affecting the biological properties of the host protein. in this paper ...19901714094
covariance of lowered capacity to induce interferon in human leukocytes and temperature sensitivity of type 3 poliovirus.attenuated poliovirus strains induce less interferon-alpha (ifn-alpha) in human leukocyte cultures than their parental wild-type strains or other neurovirulent strains. we have used a set of type 3 leon/sabin recombinant poliovirus strains to show that production of ifn in this system is closely associated with the genomic region that codes for capsid protein vp3; a mutation in this gene also causes the temperature sensitivity of the attenuated sabin 3 strain and is partly responsible for the lo ...19911714485
identification of residues in vp2 that contribute to poliovirus neutralization antigenic site 3b.amino acid substitutions were placed at residues 74, 243, and 246 in capsid protein vp2 of poliovirus serotype 1, using site-specific mutagenesis methods. the proximity of these residues to those previously identified in neutralization site 3b suggests that these residues may also contribute to neutralization site 3b and potentially be under antibody selective pressure to mutate. however, sequence analyses of independent serotype 1 isolates indicate high sequence conservation at these residues, ...19911714663
cytotoxic effects of children's faeces: relation to diarrhoea due to clostridium difficile and other enteric pathogens.cytotoxicity of faecal extracts was demonstrated in 47 of 88 children (54%) referred for microbiological investigation of stools. cytotoxic clostridium difficile and vertotoxigenic escherichia coli (vtec) were the pathogens identified most commonly but cytotoxicity was also found in association with campylobacter jejuni, salmonella spp, shigella sonnei, giardia lamblia, rotavirus, adenovirus and poliovirus type 1 which had been acquired by oral immunization. in two patients, one of whom had cyst ...19911715139
a comparison of win 51711 and r 78206 as stabilizers of poliovirus virions and procapsids.the thermal denaturation of poliovirus virions and procapsids in the 42 to 48 degrees c range was studied using n- and h-specific monoclonal antibodies. the half-life of the n antigen of mahoney and sabin 1 virions was extended 50- to 250-fold by either 10 microm win 51711 or r 78206. the minimum concentrations required for full stabilization at 46 degrees c (1.0 microm for win 51711, 0.2 microm for r 78206) were independent of the strain or serotype of the virus; 30 to 60 molecules of stabilize ...19911716654
antigenic structure of chimeras of type 1 and type 3 polioviruses involving antigenic sites 2, 3 and 4.chimeric polioviruses have been made in which regions of the type 1 sabin strain corresponding to antigenic sites 2, 3 and 4 have been replaced by the corresponding regions of the type 3 sabin strain. manipulation of one site or a component of it generally did not affect the reactions of the others, suggesting that they form independent structural features. the extent to which the inserted site expressed the antigenic properties of type 3 could be assessed by reaction with polyclonal or monoclon ...19911717641
generation of virus genetic lineages during an outbreak of poliomyelitis.wild poliovirus type 3 isolates collected during the finnish outbreak (1984 to 1985) in different geographical locations were compared by partial rna sequencing. the entire 5' non-coding end and a discontinuous part of the capsid coding region were sequenced from 15 isolates. combining the present sequence data with previously published data and analysing these by the maximum parsimony method showed that the epidemic strains had diverged in cocirculating lineages. genetic comparison of strains i ...19911717642
the cellular location of a foreign b cell epitope expressed by recombinant bacteria determines its t cell-independent or t cell-dependent characteristics.we have targeted two foreign b cell antigenic determinants to different locations in the escherichia coli cell to examine what effect this had on antibody responses elicited by the recombinant bacteria. the two epitopes were the 132-145 peptide from the pres2 region of hepatitis b virus and the c3 neutralization epitope of poliovirus type 1. they were each expressed in two forms either on the surface, as part of the outer-membrane protein lamb, or soluble in the periplasm, as part of the peripla ...19911719080
poliomyelitis control by annual immunization campaigns with oral polio-virus vaccine in a rural area of india.the effectiveness of oral polio vaccine (opv) delivered in annual immunization campaigns in reducing the prevalence of poliomyelitis was evaluated in january 1989 by conducting a sample survey in 66 villages in northern india with a population of 42,000. the prevalence of residual paralytic poliomyelitis was 13.4 per 1,000 children born during 1974-1978; this is 2.7 times higher than the rate of 5.0 per 1,000 born in 1979-1983 and 9.6 times higher than the rate of 1.4 per 1,000 born during 1984- ...19911750118
aaem case report #23: acute paralytic poliomyelitis.a 56-year-old man with acute paralytic poliomyelitis is described. the illness started with fever and diarrhea after an overseas trip, and an enterovirus other than poliovirus was isolated from the patient's stool. the onset of weakness was rapid and asymmetric, with primary involvement of the lower extremities. nerve conduction studies revealed low amplitude motor responses after the first week, with normal results for sensory studies. serial electromyographic studies were performed, documentin ...19911766446
mucosal immunity following oral poliovirus vaccine and enhanced potency inactivated poliovirus vaccine immunization.mucosal immunity is considered to be an important barrier for inhibiting person-to-person transmission of naturally occurring (wild type) poliovirus infection. this review briefly summarizes the results of a previously published study in which 79 oral poliovirus vaccine (opv) vaccinated children and 93 enhanced-potency inactivated poliovirus vaccine (ipv) children were challenged with one of two doses of type 1 opv virus to test the oropharyngeal and gastrointestinal mucosal immunity conferred b ...19911766726
use of modified diatomaceous earth for removal and recovery of viruses in water.diatomaceous earth was modified by in situ precipitation of metallic hydroxides. modification decreased the negative charge on the diatomaceous earth and increased its ability to adsorb viruses in water. electrostatic interactions were more important than hydrophobic interactions in virus adsorption to modified diatomaceous earth. filters containing diatomaceous earth modified by in situ precipitation of a combination of ferric chloride and aluminum chloride adsorbed greater than 80% of enterovi ...19911768124
comparison of serum and salivary antibodies in children vaccinated with oral live or parenteral inactivated poliovirus vaccines of different antigen concentrations.a new antigen-rich inactivated poliovirus vaccine (ipv) in ordinary (ipv1), double (ipv2) and quadruple (ipv4) antigen concentrations was given in 2 doses to 6 and 18 week old pakistani infants. the immune responses to poliovirus types 1 and 3 were compared to those in infants given three doses of oral poliovirus vaccine (opv) at 6, 12 and 18 weeks of age. enzyme-linked immunosorbent assay, elisa, was used to estimate igg and iga in serum and secretory iga (siga) in saliva. two to three years la ...19911785289
specific antibodies to poliovirus type i in breastmilk of unvaccinated mothers before and seven years after start of community-wide vaccination of their infants with live, oral poliovirus vaccine.secretory iga (siga) antibodies against poliovirus type 1 were determined using the elisa method in breastmilk samples obtained each month from 100 young, healthy, unvaccinated mothers living in urban slum areas of lahore, pakistan. the study covered two different groups, one in 1980-1981 and the other in 1987, before and seven years after a nation-wide expanded programme of childhood immunization (epi) had started. the siga titres did not change neither with duration of lactation nor with time ...19911785290
virus inactivation: lessons from the past.the organizers of this meeting have assigned two tasks to me. the first is to describe the state of affairs in 1955 when several lots of salk poliovaccine, which had been formalin-inactivated according to government regulation and had been released for use in children, were subsequently found to have retained a small amount of live virulent virus. the second task is to describe a series of experiments that we conducted 25 to 35 years ago on the influence of cations on the thermostability of viru ...19911794629
[an analysis of the medical contraindications for poliomyelitis vaccination in a district of the city of bucharest].the authors report on the results of the analysis of frequency, motives and possible consequences associated to the medical contraindication of inoculations with tpdv (thermal polio-destroyed virus) during the antipoliomyelitis vaccination in the spring of 1989 in district 3 of bucharest. the failure share in the first antipoliomylitis vaccination was of 2.2% in the 2,500 children selected: 46 (83.6%) were cim in one of the inoculations and 9 (16.4%) in both inoculations with tpdv of the vaccina ...19911802288
immunologic parameters in early-stage hiv-seropositive subjects associated with vaccine responsiveness.twenty-one asymptomatic hiv-seropositive subjects and 20 hiv-seronegative controls were assessed for their serologic response to multiple live attenuated viral, protein (toxoid), and polysaccharide vaccine antigens. extensive in vivo and in vitro immunologic evaluations were performed. factors predictive of immunogen responsiveness by hiv-seropositive patients were found by correlating vaccine responses with results of t- and b-cell functional assays. eleven hiv-seropositive patients (hiv nonres ...19911824786
antibody to human t-lymphotropic virus in a patient with guillain-barré syndrome (case report)serum sample obtained from a male, 12 year old patient suffering from guillain-barré syndrome (gbs) was positive for human t-lymphotropic virus (htlv-i) antibody by the enzyme-linked immunosorbent assay (elisa) and the western blot analysis (wb). attempts to isolate enteroviruses (including poliovirus) from faecal material in both tissue culture and suckling mice were unsuccessful; in addition, acute and convalescent paired serum samples did not show any evidence of recent poliovirus infection w ...19911844957
mucosal immunity induced by enhance-potency inactivated and oral polio vaccines.oral polio vaccine (opv) is recommended for routine immunization in the united states in part because of its ability to induce intestinal and pharyngeal immunity to reinfection. mucosal immunity produced by opv and enhanced-potency inactivated polio vaccine (e-ipv) was compared by challenging vaccines with type 1 opv. fewer opv (25%) than e-ipv (63%) vaccinees excreted opv virus in stool after challenge. the mean stool virus titer was higher and the duration of shedding longer among e-ipv excret ...19911845806
the role of secretory immunity in hepatitis a virus infection.because the role of intestinal immunity remains uncertain in hepatitis a, samples of feces and saliva from infected primates and humans were tested for virus neutralizing activity. only two of eight owl monkeys infected by the intragastric route developed neutralizing antibody detectable in extracts of feces collected up to 88 days after viral challenge, although serum neutralizing antibody was present in all monkeys by day 33. similarly, neutralizing antibody was detected in fecal extracts from ...19911845810
catalysis of poliovirus vp0 maturation cleavage is not mediated by serine 10 of vp2.the maturation of the poliovirus capsid occurs as the result of a single unexplained proteolytic event during which 58 to 59 copies of the 60 vp0 capsid protein precursors are cleaved. an autocatalytic mechanism for cleavage of vp0 to vp4 and vp2 was proposed by arnold et al. (e. arnold, m. luo, g. vriend, m. g. rossman, a. c. palmenberg, g. d. parks, m. j. nicklin, and e. wimmer, proc. natl. acad. sci. usa 84:21-25, 1987) in which serine 10 of vp2 is activated by virion rna to catalyze vp4-vp2 ...19911845893
correlation between amount of virus with altered nucleotide sequence and the monkey test for acceptability of oral poliovirus vaccine.production of live attenuated oral poliomyelitis vaccine (opv) requires rigorous neurovirulence safety testing of each vaccine lot, currently carried out in monkeys. it has been reported that a change from 472-u to 472-c in the type 3 opv rna is associated with an increased histologic lesion score produced upon intraspinal inoculation of the mutant virus in monkeys. we have developed a method, based on polymerase chain reaction, for measuring the relative abundance of these mutant sequences dire ...19911846038
susceptibility and resistance to poliovirus-induced paralysis of inbred mouse strains.susceptibility to human poliovirus-induced disease in different inbred mouse strains was analyzed after intracerebral inoculation of two mouse-adapted type 2 polioviruses, the attenuated w-2 strain and the virulent lansing strain. in contrast to inoculation with the lansing strain, which was invariably lethal, inoculation with the w-2 strain defined three groups of mice with high, intermediate, or low disease incidence. those in the high-disease-incidence group, the dba/1j and dba/2j mice, exhib ...19911846183
an rna hairpin at the extreme 5' end of the poliovirus rna genome modulates viral translation in human cells.several mutations were introduced into an infectious poliovirus cdna clone by inserting different oligodeoxynucleotide linkers into preexisting dna restriction endonuclease sites in the viral cdna. ten mutated dnas were constructed whose lesions mapped in the 5' noncoding region or in the capsid coding region of the viral genome. eight of these mutated cdnas did not give rise to infectious virus upon transfection into human cells, one yielded virus with a wild-type phenotype, and one gave rise t ...19911846205
use of type 1/type 2 chimeric polioviruses to study determinants of poliovirus type 1 neurovirulence in a mouse model.we previously described the characteristics of a type 1/type 2 (pv-1/pv-2) chimeric poliovirus, v510, which contains the six amino acids specific for pv-2 in the b-c loop of vp1. this virus was found to be mouse-adapted, as pv-2 and in contrast with pv-1. determinants of host range were studied in detail and are reported here. pv-1/pv-2 chimeras containing partial pv-1----pv-2 substitutions in the b-c loop of vp1 were obtained by making use of a mutagenesis cartridge on pv-1 cdna. analysis of mo ...19911846492
characterization of persistent poliovirus mutants selected in human neuroblastoma cells.six sabin-derived persistent poliovirus mutants were selected in human neuroblastoma imr-32 cells. the mutants had a titer 30 to 10(5) times lower in nonneural hep-2c cells than in imr-32 cells. when the growth cycles of persistent viruses in the two cell lines were compared, the most striking feature was a delay of 2 to 4 hr in virus release from hep-2c cells. in hep-2c cells, type 1 mutants could spontaneously establish a persistent infection in the absence of any exogenous viral inhibitor. mu ...19911846495
transgenic mice susceptible to poliovirus.poliovirus-sensitive transgenic mice were produced by introducing the human gene encoding cellular receptors for poliovirus into the mouse genome. expression of the receptor mrnas in tissues of the transgenic mice was analyzed by using rna blot hybridization and the polymerase chain reaction. the human gene is expressed in many tissues of the transgenic mice just as in tissues of humans. the transgenic mice are susceptible to all three poliovirus serotypes, and the mice inoculated with polioviru ...19911846972
substrate requirements of a human rhinoviral 2a proteinase.the genetic information contained within the rna genome of picornaviruses is expressed as a single large open reading frame; processing of the primary translation product begins while translation is still in progress. in rhinoviruses and enteroviruses, two picornavirus genera, the virally encoded proteinase 2a begins the processing cascade, cleaving between the c-terminus of vp1 and its own n-terminus. the natural variation in the amino acid sequences amongst rhinoviruses and enteroviruses at th ...19911847268
4'-hydroxy-3-methoxyflavones with potent antipicornavirus activity.4'-hydroxy-3-methoxyflavones are natural compounds with known antiviral activities against picornaviruses such as poliomyelitis and rhinoviruses. in order to establish a structure-activity relationship a series of analogues were synthesized, and their antiviral activities and cytotoxicities were compared with those of flavones from natural origin. the 4'-hydroxyl and 3-methoxyl groups, a substitution in the 5 position and a polysubstituted a ring appeared to be essential requirements for a high ...19911847431
identification of two determinants that attenuate vaccine-related type 2 poliovirus.the poliovirus p2/p712 strain is an attenuated virus that is closely related to the type 2 sabin vaccine strain. by using a mouse model for poliomyelitis, sequences responsible for attenuation of the p2/p712 strain were previously mapped to the 5' noncoding region of the genome and a central region encoding vp1, 2apro, 2b, and part of 2c. to identify specific determinants that attenuate the p2/p712 strain, recombinants between this virus and the mouse-adapted p2/lansing were constructed and thei ...19911847458
coinfection with recombinant vaccinia viruses expressing poliovirus p1 and p3 proteins results in polyprotein processing and formation of empty capsid structures.the assembly process of poliovirus occurs via an ordered proteolytic processing of the capsid precursor protein, p1, by the virus-encoded proteinase 3cd. to further delineate this process, we have isolated a recombinant vaccinia virus which expresses, upon infection, the poliovirus p1 capsid precursor polyprotein with an authentic carboxy terminus. coinfection of hela cells with the p1-expressing vaccinia virus and with a second recombinant vaccinia virus which expresses the poliovirus proteinas ...19911848318
site-directed mutagenesis of the putative catalytic triad of poliovirus 3c proteinase.based on predictions of the structure of proteinase 3c of poliovirus, mutations have been made at residues that are supposed to constitute the catalytic triad. wild-type and mutant 3c were expressed in escherichia coli, purified to homogeneity, and characterized by the ability to cleave a synthetic peptide substrate or an in vitro translated polypeptide consisting of part of the polyprotein of poliovirus. additionally, the ability of autocatalytic processing of a precursor harboring wild-type or ...19911848550
evidence for dissimilar properties of comoviral and picornaviral rna polymerases.the poliovirus rna polymerase has been synthesized in spodoptera frugiperda cells by using the baculovirus expression system. crude sonicates of these cells exhibited an rna-elongating activity of a synthetic oligo(u) primer with poly(a) or cowpea mosaic virus (cpmv) rna as a template. a similar polymerase activity was found in extracts of insect cells in which foot-and-mouth disease virus (fmdv) proteins, including the putative polymerase, were produced. the analogous cpmv 87k protein and sever ...19911848591
suppressive effect of delta-9-tetrahydrocannabinol on herpes simplex virus infectivity in vitro.delta-9-tetrahydrocannabinol (thc) was found to reduce the infectivity of herpes simplex virus and was without effect against adenovirus type 2 or poliovirus. the effective thc concentration resulting in an 80% decrement in virus viability was dependent upon the presence or absence of serum in the incubation mixture, as a 5% serum concentration decreased the drug activity by approximately 50-fold. thc-mediated inactivation of herpes simplex virus was both time and dose dependent and did not resu ...19911848937
statistical analysis of virus titres obtained in repeated assays of working standard of trivalent oral polio vaccine. 19911848961
analysis of putative active site residues of the poliovirus 3c protease.it was recently suggested that the picornavirus 3c proteases are homologous to the chymotrypsin-like serine proteases. the two structural models proposed differ in one of the postulated active site residues, glu/asp71 or asp85. we changed glu71 of the poliovirus type 1 protease to asp or gln and asp85 to glu by oligonucleotide-directed site-specific mutagenesis of an infectious cdna, and attempted to recover virus after transfection. both glu71 changes were lethal for the virus and proteolytic a ...19911849679
potassium salts influence the fidelity of mrna translation initiation in rabbit reticulocyte lysates: unique features of encephalomyocarditis virus rna translation.it is widely assumed that in vitro translation of mrna is more efficient in the presence of potassium acetate rather than kcl, that the optimum concentration of potassium acetate is higher than for kcl, and that uncapped rnas exhibit a lower optimum salt concentration than capped mrnas. when these assumptions were examined using several different mrna species in four batches of rabbit reticulocyte lysate, some notable exceptions were found. the translation of encephalomyocarditis virus (emcv) rn ...19911849749
adenovirus inhibition of cellular protein synthesis involves inactivation of cap-binding protein.adenovirus (ad) infection results in a marked inhibition of cellular protein synthesis that initiates during the late phase of the viral infectious cycle. we show that the mechanism used for suppression of cellular protein synthesis during cell cycle progression is exploited by ad to repress host and enhance late viral mrna translation. discrimination between cellular and late ad mrnas and inhibition of host protein synthesis are shown to involve viral-mediated underphosphorylation of cap-bindin ...19911849798
myristoylation is important at multiple stages in poliovirus assembly.the n-terminal glycine of the vp4 capsid subunit of poliovirus is covalently modified with myristic acid (c14 saturated fatty acid). to investigate the function of vp4 myristoylation in poliovirus replication, amino acid substitutions were placed within the myristoylation consensus sequence at the alanine residue (4003a) adjacent to the n-terminal glycine by using site-directed mutagenesis methods. mutants which replace the alanine residue with a small hydrophobic residue such as leucine, valine ...19911850017
inhibitors of poliovirus uncoating efficiently block the early membrane permeabilization induced by virus particles.the entry of animal viruses into cells is associated with permeabilization of the infected cells to protein toxins such as alpha-sarcin (c. fernández-puentes and l. carrasco, cell 20:769-775, 1980). this phenomenon has been referred to as "the early permeabilization by animal viruses" (l. carrasco, virology 113:623-629, 1981). a number of inhibitors of poliovirus growth such as win 51711 6-(3,4-dichlorophenoxy)-3-(ethylthio)-2-pyridincarbonitrile (depc) and ro 09-0410 specifically block the unco ...19911850030
role of a viral membrane polypeptide in strand-specific initiation of poliovirus rna synthesis.a molecular genetic analysis has been combined with an in vitro biochemical approach to define the functional interactions required for nucleotidyl protein formation during poliovirus rna synthesis. a site-directed lesion into the hydrophobic domain of a viral membrane protein produced a mutant virus that is defective in rna synthesis at 39 degrees c. the phenotypic expression of this lesion affects initiation of rna synthesis, in vitro uridylylation of the genome-linked protein (vpg), and the i ...19911850038
trans rescue of a mutant poliovirus rna polymerase function.a series of three-nucleotide insertions was engineered into the p2 and p3 coding regions of the t7 expression plasmid pt7(tau)-pv1, which encodes a full-length copy of poliovirus type 1 (mahoney) cdna. when rna derived in vitro from these mutated templates was used to transfect hela cells, viable virus mutants were recovered. one mutant, sel-3d-18, which contained a single amino acid insertion in the 3dpol coding region, was temperature sensitive for growth at 39 degrees c and showed defects in ...19911850039
identification of a consistent pattern of mutations in neurovirulent variants derived from the sabin vaccine strain of poliovirus type 2.complete nucleotide sequencing of the rnas of two unrelated neurovirulent isolates of sabin-related poliovirus type 2 revealed that two nucleotides and one amino acid (amino acid 143 in the major capsid protein vp1) consistently departed from the sequences of the nonneurovirulent poliovirus type 2 712 and sabin vaccine strains. this pattern of mutation appeared to be a feature common to all neurovirulent variants of poliovirus type 2.19911850043
the 5'-terminal nucleotides of hepatitis a virus rna, but not poliovirus rna, are required for infectivity.a series of plasmids containing hepatitis a virus (hav) cdna was constructed such that positive-strand hav rna could be transcribed with t7 rna polymerase. the plasmids differed in the number of 5'-terminal nucleotides representing the junctions between vectors and hav sequences that were present in the transcripts. when these transcripts were used to transfect cultured bs-c-1 cells, it was found that only those transcripts that contained all of the 5'-terminal hav nucleotides, in addition to on ...19911850050
host range determinants located on the interior of the poliovirus capsid.the inability of certain poliovirus strains to infect mice can be overcome by the expression of human poliovirus receptors in mice or by the presence of a particular amino acid sequence of the b-c loop of the viral capsid protein vp1. we have identified changes in an additional capsid structure that permit host-restricted poliovirus strains to infect mice. variants of the mouse-virulent p2/lansing strain were constructed containing amino acid changes, deletions and insertions in the b-c loop of ...19911850692
vaccinia virus-mediated expression and identification of the human poliovirus receptor.we have used cdna encoding the cellular receptor for poliovirus (pvr) to prepare polyclonal antisera against beta-galactosidase pvr fusion proteins. one of these antisera allowed identification of a glycoprotein doublet band of about 67 kda in membrane preparations of hela cells and in a pvr cosmid-bearing mouse cell line. in vitro translation of pvr-specific transcripts gave rise to a protein of 46 kda; the product had a molecular weight of 67 kda when microsomal membranes were added to the cel ...19911850905
poliovirus translation initiation: differential effects of directed and selected mutations in the 5' noncoding region of viral rnas.we have analyzed the translational defects of a number of mutations in the 5' noncoding region of poliovirus type 1 rna. these mutations fall into three categories: (1) two mutations which resulted in temperature sensitive (ts) viruses, (2) the second-site mutations responsible for the reversion of the two ts viruses, and (3) mutations which were lethal to virus production. rnas containing either of the ts mutations translated in vitro at levels significantly lower than wild-type levels. rnas co ...19911850926
cellular and humoral immune responses to poliovirus in mice: a role for helper t cells in heterotypic immunity to poliovirus.immunization of balb/c mice with a single dose of the sabin type 1, type 2 or type 3 poliovirus vaccine strains stimulated cross-reactive t helper cell responses detected by both in vitro proliferation and interleukin (il)-2/il-4 production. although the polyclonal t cell responses were cross-reactive, the results also suggest that a proportion of the t cells were directed against serotype-specific determinants. in contrast, neutralizing antibodies, assayed in the serum from the same animals, we ...19911851808
a gly1 to ala substitution in poliovirus capsid protein vp0 blocks its myristoylation and prevents viral assembly.capsid protein vp4 of poliovirus is acylated with myristic acid via an amide linkage to its n-terminal glycine residue. our previous studies suggested that myristic acid plays a role in poliovirus assembly and in the early events of infection. in order to understand better its role in the assembly process, we introduced a gly1 to ala amino acid substitution in the myristoylation signal sequence of vp4. this substitution prevented vp0 myristoylation in vivo and abolished the infectivity of genomi ...19911851815
specificity of the polioviral proteinase 3c towards genetically engineered cleavage sites in the viral capsid.in a study of the cleavage specificity of poliovirus proteinase 3cpro, two mutant polioviruses were constructed to include putative 3cpro cleavage sites in the bc loop of vp1. the bc loop of vp1 in the wild-type virus is the neutralization antigenic site ia, consisting of a continuous chain of nine amino acids (asttnkdkl). the first mutant, w1-1d-bc1, has four altered amino acids in the bc loop (astqgpgkl); the second mutant, w1-1d-bc2, has an insertion of nine amino acids in the bc loop (astgta ...19911851816
expression of human immunodeficiency virus type 1 (hiv-1) gag, pol, and env proteins from chimeric hiv-1-poliovirus minireplicons.recent studies have demonstrated that genomes of poliovirus with deletions in the p1 (capsid) region contain the necessary viral information for rna replication. to test the effects of the substitution of foreign genes on rna replication and protein expression, chimeric human immunodeficiency virus type 1 (hiv-1)-poliovirus genomes were constructed in which regions of the gag, pol, or env gene of hiv-1 were substituted for regions of the p1 gene in the infectious cdna clone of type 1 mahoney pol ...19911851859
improved method for detecting poliovirus negative strands used to demonstrate specificity of positive-strand encapsidation and the ratio of positive to negative strands in infected cells.we have developed a ribonuclease protection method suitable for sensitive detection of an rna species in the presence of a large excess of its complementary strand, as for the detection of negative strands of positive-strand rna viruses. by using this method to probe for poliovirus negative strands in virions, we found that positive strands are present in at least 40,000-fold excess over negative strands. thus, we have confirmed that poliovirus encapsidation is highly specific for positive stran ...19911851886
functional domains of the poliovirus receptor.a number of mutant cdnas of the human poliovirus receptor were constructed to identify essential regions of the molecule as the receptor. all mutant cdnas carrying the sequence coding for the entire n-terminal immunoglobulin-like domain (domain i) confer permissiveness for poliovirus to mouse l cells, but a mutant cdna lacking the sequence for domain i does not. the transformants permissive for poliovirus were able to bind the virus and were also recognized by monoclonal antibody d171, which com ...19911851992
childhood infection and adult disease.in england and wales there is a strong geographical relation between current mortality from chronic bronchitis and emphysema in adults and infant mortality from bronchitis and pneumonia 50 years ago. follow-up studies of infants and children show that certain pulmonary infections cause persisting abnormalities of lung function. this suggests that infection of an organ system during a period of rapid growth may have permanent deleterious effects. long-term consequences of infection may also depen ...19911855418
poliovirus proteinase 3c converts an active form of transcription factor iiic to an inactive form: a mechanism for inhibition of host cell polymerase iii transcription by poliovirus.in hela cells, rna polymerase iii (pol iii)-mediated transcription is severely inhibited by poliovirus infection. this is due primarily to a reduction in the transcriptional activity of tfiiic, a transcription factor which binds in a sequence specific manner to the internal promoter of pol iii genes. using gel retardation assays, we have shown previously that inhibition of pol iii transcription by poliovirus is correlated with disappearance of a transcriptionally active form of tfiiic (complex i ...19911915271
[plants as a source of research in antiviral activity. example of the haemanthus albiflos bulb].the antiviral potency of an hydroalcoholic extract from haemanthus albiflos (amaryllidaceae) bulb was investigated. experimentations were conducted on continuous cell lines (bgm, ma 104, hep 2) seeded in microplates. three viruses from the rna group (poliovirus type i, vesicular stomatitis virus type 11 and simian rotavirus sa 11) and two from the dna group (adenovirus type 5, herpes simplex virus type 1) were tested. important reduction in yield of viral infectivity was observed with the rna gr ...19911933468
the use of bacteriophages of bacteroides fragilis as indicators of the efficiency of virucidal products.the potential use of bacteriophage b40-8 of bacteroides fragilis for the evaluation of the virucidal activity of antiseptics or disinfectants was investigated. the antiviral activity of two antiseptics and two disinfectants was evaluated according to a standard guideline. the effect of the virucidal agents was assessed on (i) viruses usually spread by direct contact with surfaces with contaminated secretions, i.e. herpes virus 1 and 2, and vaccinia virus, and (ii) viruses transmitted by the feca ...19911936937
[vaccination schedule in malaga. differences between the basic health zones of the city].vaccination coverages of the children's cohort born in 1988 and 1989 living on the city of málaga are presented. this coverages are obtained by universal registration of the immunizations. vaccination coverages were: 87.8% for the first dose of polio-dtp, 76.4% for the third, 63.8% for triple-virus and 60.5% for polio-dt. this fall down of coverages in the consecutive doses has been detected as an essential problem. important differences of coverages are founded between some of the basic health ...19911952467
paralytic poliomyelitis outbreak in gizan, saudi arabia.an outbreak of paralytic poliomyelitis occurred in the southern region of saudi arabia between april and august of 1989. poliovirus type 1 (wild type) was isolated from the stool of 4 out of 11 patients and 10 out of the 11 patients had a high neutralizing antibody to the isolated virus (greater than or equal to 256). the results were confirmed by the centers for disease control (cdc), atlanta. the fact that the outbreak occurred despite a high level of immunization coverage and that all our cas ...19911960781
measures and countermeasures in the modulation of initiation factor activities by viruses.animal viruses have co-evolved with their hosts for millions of years. during this time, the viruses have developed intricate mechanisms to utilize efficiently their host's metabolic pathways, especially those involving macromolecular synthesis, for virus propagation. in particular, many different viruses modulate and usurp their host's translational machinery for use in the synthesis of their own proteins. however, the infected hosts have developed or adapted cellular mechanisms to interdict vi ...19901963082
potential use of new poliomyelitis vaccines: memorandum from a who meeting.largely due to the intensive use of sabin attenuated oral vaccines, the incidence of poliomyelitis is continuing to decline, particularly in the western hemisphere. in developing and tropical countries, use of trivalent attenuated vaccine may, however, sometimes produce suboptimal antibody responses, especially to type 1 and 3 polioviruses. epidemics of poliomyelitis continue to occur in some countries with high vaccination coverage, though these are rare, and cases of vaccine-associated paralys ...19901963117
immunogenicity of oral poliomyelitis vaccine (opv) against variants of wild poliovirus type 3.serological investigations of three groups of children from the german democratic republic (gdr) and from czechoslovakia who had different immunization histories against poliomyelitis indicated that the immunity induced by oral poliovaccine (opv) is effective against both the wild poliovirus saukett strain and a new wild variant of poliovirus type 3 that was isolated during an outbreak of poliomyelitis in finland in 1984. there is therefore no obvious risk that individuals in the gdr or czechosl ...19901963118
poliovirus-mediated entry of pokeweed antiviral protein.infection of hela cells with poliovirus results in cell permeabilization to pokeweed antiviral protein. cell permeabilization was dependent on the integrity of virus capsid proteins and directly proportional to the multiplicity of infection. this study demonstrates that virus adsorption is sufficient for the entry of pokeweed antiviral protein into poliovirus-infected cells.19901963293
inhibitory effect of a new antibiotic, guanine 7-n-oxide, on the replication of several rna viruses.guanine 7-n-oxide (g-7-ox) was examined for its antiviral activity against 9 viruses based on plaque reduction, neuraminidase activity reduction, a fluorescent antibody technique or elisa. the following viruses were included in the tests: influenza, sendai, simian virus 5 (sv5), respiratory syncytial, western equine encephalitis, japanese encephalitis, vesicular stomatitis, rabies and polio. g-7-ox showed broad anti-rna viral activity against all viruses tested, except for poliovirus. inhibition ...19901964374
[levels of type 1 polioviruses in food in an experimental model].the author concentrated from contamined foodstuffs poliovirus type 1--vaccine strain--by means of negative pressure or overpressure filtration across membranes with a different porosity and by means of an ultracentrifuge. foods - milk, meat, meat products and vegetables were contaminated by the virus so that various doses corresponded approximately to 1.2 or 4 pfu per gram of specimen. the virus in concentrates was detected on cell cultures on the vero line by the plaque method. the virus extrac ...19901964630
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