| internalization of intact poliovirus by hela cells as shown by subcellular fractionation in isoosmotic nycodenz gradients. | hela cells were infected with radiolabelled poliovirus at different temperatures, and the intracellular distribution of input radioactivity was studied. to this end, homogenates were fractionated by rate zonal centrifugation in linear isoosmotic (2 to 30%) nycodenz gradients. further purification of subcellular fractions was achieved by recentrifugation to equilibrium in 10 to 30% nycodenz. temperatures were kept below 30 degrees c to prevent virus capsid modification. under these conditions, th ... | 1992 | 1312119 |
| maturation of poliovirus capsid proteins. | | 1992 | 1312265 |
| myristate modification does not function as a membrane association signal during poliovirus capsid assembly. | the myristate moiety is required for poliovirus assembly. unlike most other myristoyl-modified proteins, which are membrane associated, no specific membrane association of the poliovirus capsid proteins or assembly intermediates was observed. furthermore, no apparent differences in membrane association of wild-type and myristoylation deficient mutant viruses could be detected in this analysis. thus, during poliovirus assembly, the myristate modification is not required as a membrane targeting si ... | 1992 | 1312279 |
| the sequence context of the initiation codon in the encephalomyocarditis virus leader modulates efficiency of internal translation initiation. | translation initiation on poliovirus and encephalomyocarditis virus (emcv) mrnas occurs by a cap-independent mechanism utilizing an internal ribosomal entry site (ires). however, no unifying mechanism for aug initiation site selection has been proposed. analysis of initiation of mrnas translated in vitro has suggested that initiation of poliovirus mrna translation likely involves both internal binding of ribosomes and scanning to the first aug which is in a favorable context for initiation. in c ... | 1992 | 1312611 |
| inhibition of poliovirus rna synthesis by brefeldin a. | brefeldin a (bfa), a fungal metabolite that blocks transport of newly synthesized proteins from the endoplasmic reticulum, was found to inhibit poliovirus replication 10(5)- to 10(6)-fold. bfa does not inhibit entry of poliovirus into the cell or translation of viral rna. poliovirus rna synthesis, however, is completely inhibited by bfa. a specific class of membranous vesicles, with which the poliovirus replication complex is physically associated, is known to proliferate in poliovirus-infected ... | 1992 | 1312615 |
| a chimeric poliovirus/cd4 receptor confers susceptibility to poliovirus on mouse cells. | the human poliovirus receptor consists of three extracellular immunoglobulinlike domains, a transmembrane domain, and an intracytoplasmic domain. the amino-terminal variable-type domain (v domain) of the human poliovirus receptor is necessary and sufficient for its function as a viral receptor (h.-c. selinka, a. zibert, and e. wimmer, proc. natl. acad. sci. usa 88:3598-3602, 1991). in this paper, data are presented showing that transfer of the putative poliovirus receptor-binding domain to a tru ... | 1992 | 1312641 |
| cardioviral internal ribosomal entry site is functional in a genetically engineered dicistronic poliovirus. | high mutation rates have driven rna viruses to shorten their genomes to the minimum possible size. mammalian (+)-strand rna viruses and retroviruses have responded by reducing the number of cis-acting regulatory elements, a constraint that has led to the emergence of the polyprotein. poliovirus is a (+)-stranded picornavirus whose polyprotein, encoded by an open reading frame spanning most of the viral rna, is processed by virus-encoded proteinases. despite their genetic austerity, picornaviruse ... | 1992 | 1313153 |
| [virucidal effectiveness of some commercial products for chemothermal disinfection methods for temperature resistant viruses and bacteriophages--evaluation of a test model]. | in the laboratory assay of chemothermal virus disinfection procedures a test system is required which allows to differentiate between the physical effects of the temperature and the chemical effects by the disinfectant used. from the four test viruses recommended by the german association for the control of virus diseases (deutsche vereinigung zur bekämpfung der viruskrankheiten) only sv 40 tumor virus showed a sufficient thermal stability at 55 degrees c to take it in consideration as test viru ... | 1992 | 1313238 |
| identification and molecular cloning of tactile. a novel human t cell activation antigen that is a member of the ig gene superfamily. | we have identified and cloned cdna for a novel cell-surface protein that we have named tactile for t cell activation, increased late expression. it is expressed on normal t cell lines and clones, and some transformed t cells, but no other cultured cell lines tested. it is expressed at low levels on peripheral t cells and is strongly up-regulated after activation, peaking 6 to 9 days after the activating stimulus. it is also up-regulated on nk cells activated in allogeneic cultures. it is not fou ... | 1992 | 1313846 |
| structural and functional characterization of the poliovirus replication complex. | two populations of membrane-bound replication complexes were isolated from poliovirus-infected hep-2 cells by sucrose gradient centrifugation. the two fractions show similar ultrastructural features: the replication complex is enclosed in a rosettelike shell of virus-induced vesicles and contains a very tightly packed second membrane system (compact membranes). the vesicular fraction, which bands in 30% sucrose, contains replicative intermediate (ri) and 36s rna. the fraction banding in 45% sucr ... | 1992 | 1313898 |
| relationship of eukaryotic initiation factor 3 to poliovirus-induced p220 cleavage activity. | the cleavage of the p220 subunit of eukaryotic initiation factor 4f (eif-4f) that is induced by the poliovirus protease 2a has been shown previously to require another translation initiation factor, eif-3. the role of eif-3 in this cleavage reaction, however, is not known. an antiserum was raised against human eif-3 and used to analyze the eif-3 subunit composition in poliovirus-infected and uninfected hela cells and after incubation of eif-3 in vitro with viral 2a protease. no evidence for 2apr ... | 1992 | 1313911 |
| infection of hela cells with poliovirus results in modification of a complex that binds to the rrna promoter. | in hela cells, rna polymerase i (pol i)-mediated transcription is severely inhibited soon after infection with poliovirus. we have developed a gel retardation assay to analyze dna-protein complexes formed at the pol i promoter. we show here that two complexes (a and c) formed by nuclear extracts from uninfected cells disappear after infection of cells with poliovirus. in contrast, a new, rapidly migrating complex (d) is formed in virus-infected cell extract. this change in the mobility of gel-re ... | 1992 | 1313918 |
| specific interactions of hela cell proteins with proposed translation domains of the poliovirus 5' noncoding region. | to determine which sequences or structures in the poliovirus 5' noncoding region (5'ncr) are involved in binding proteins used for internal ribosome binding and protein synthesis initiation, translation competition assays were performed in rabbit reticulocyte lysates in the presence and absence of hela cell extract. the results revealed two functional domains in the poliovirus 5'ncr. one, requiring nucleotides (nts) 457 to 626, binds proteins that are required for translation of all mrnas and th ... | 1992 | 1313920 |
| a mutation present in the amino terminus of sabin 3 poliovirus vp1 protein is attenuating. | the attenuated phenotype of sabin 3 poliovirus compared with its neurovirulent progenitor strain has been largely accounted for by mutations in the genome at positions 472 and 2034 (g. d. westrop, k. a. wareham, d. m. a. evans, g. dunn, p. d. minor, d. i. magrath, f. taffs, s. marsden, m. a. skinner, g. c. schild, and j. w. almond, j. virol. 63:1338-1344, 1989). by sequencing vaccine virus rna, we recently identified another sabin 3-specific mutation at position 2493 (u----c), which predicts an ... | 1992 | 1313923 |
| retroviral vectors containing putative internal ribosome entry sites: development of a polycistronic gene transfer system and applications to human gene therapy. | recombinant retroviral vectors producing multicistronic mrnas were constructed. picornavirus putative internal ribosome entry sites (ires) were used to confer cap-independent translation of an internal cistron. internal cistrons were engineered by ligation of various lengths of the ires of encephalomyocarditis (emc) virus or polio virus to the e. coli chloramphenicol acetyltransferase (cat) gene. the ires/cat fusions were introduced into retroviral vectors 3' to the translation stop codon of the ... | 1992 | 1313966 |
| immunogenicity and antigenicity of chimeric picornaviruses which express hepatitis a virus (hav) peptide sequences: evidence for a neutralization domain near the amino terminus of vp1 of hav. | we evaluated the antigenic characteristics of chimeric picornaviruses created by inserting peptide sequences from hepatitis a virus (hav) capsid proteins into the b-c loop of vp1 of sabin strain type 1 poliovirus (pv-1). fifteen viable chimeras were generated. each retained the ability to be neutralized by polyclonal pv-1 antisera. two chimeras (h15 and h2) stimulated production of low levels of hav neutralizing antibodies in immunized rabbits or mice, although in both cases only a small fractio ... | 1992 | 1314456 |
| antigenic n to h conversion of poliovirus by a monoclonal antibody at low ionic strength. | monoclonal antibody 35-1f4 at low ionic strength converted native virions (n antigen) to noninfectious h-antigenic, empty capsids. the reaction was stoichiometric, as the amount of n antigen that could be converted to h was limited to an average of 2 virions per molecule of antibody. the antibody remained associated with virus aggregates after antigenic conversion. using antibody immobilized onto protein a-bearing staphylococci, it could be shown that the loss of antigen-converting power was con ... | 1992 | 1314469 |
| poliomyelitis case confirmation: characteristics for use by national eradication programmes. | highly sensitive case definitions were first introduced by national poliomyelitis eradication programmes to avoid missing true cases of the disease, though false-positive diagnostic errors could still occur owing to low specificity. extensive data from all 1620 cases of acute, flaccid paralysis reported in brazil during 1987-88 provided an opportunity to study the characteristics of confirmed poliomyelitis cases and epidemiologically to evaluate potential case definitions that maximized both sen ... | 1992 | 1314710 |
| early immunization of neonates with trivalent oral poliovirus vaccine. | described is the evaluation in brazil of the immune response of early immunization with trivalent oral poliovirus vaccine (topv). a total of 85 normal neonates from são paulo were assigned one of the following immunization schedules: group a--one dose of topv at birth and subsequent doses at 2, 4, and 9 months of age; or group b--one dose of topv at 2, 4 and 6 months of age. blood samples were collected sequentially from the mother at delivery, from the umbilical cord, and from the child at 2, 4 ... | 1992 | 1314711 |
| towards identification of cis-acting elements involved in the replication of enterovirus and rhinovirus rnas: a proposal for the existence of trna-like terminal structures. | on the basis of a comparative analysis of published sequences, models for the secondary structure of the 3'-terminal [poly(a)-preceding] untranslated region of the entero- and rhinovirus rnas were worked out. the models for all these viruses share a common core element, but there are an extra enterovirus-specific element and still an additional element characteristic of a subset of enterovirus rnas. the two latter models were verified for poliovirus and coxsackievirus b genomes by testing with s ... | 1992 | 1315956 |
| determinants of substrate recognition by poliovirus 2a proteinase. | poliovirus proteinase 2a (2apro) is autocatalytically released from the viral polyprotein by cleavage in cis of a tyr-gly dipeptide at its own amino terminus, resulting in separation of the p1 structural and p2-p3 nonstructural protein precursors. a second ty-gly dipeptide within 3d polymerase is cleaved by 2apro in trans, but this is not essential for viral proliferation. the mechanism which limits cleavage to only 2 of the 10 tyr-gly dipeptides within the poliovirus polyprotein has not been ch ... | 1992 | 1316450 |
| determination of the poliovirus rna polymerase error frequency at eight sites in the viral genome. | the poliovirus rna polymerase error frequency was measured in vivo at eight sites in the poliovirus genome. the frequency at which specific g residues in poliovirion rna changed to another base during one round of viral rna replication was determined. poliovirion rna uniformly labeled with 32pi was hybridized to a synthetic dna oligonucleotide that was complementary to a sequence in the viral genome that contained a single internal g residue. the nonhybridized viral rna was digested with rnase t ... | 1992 | 1316481 |
| immunocytochemical localization of capsid-related particles in subcellular fractions of poliovirus-infected cells. | the structural proteins of poliovirus can assemble into a series of different configurations (capsid-related particles, crp). only some seem to be true capsid precursors and the role of most crp in morphogenesis is unclear. we used electron microscopic immunocytochemistry with monoclonal antibodies recognizing different crp [protomers, pentamers, 65s empty capsids (ec), 74s-ec, and virions] to locate crp in subcellular fractions containing virus-induced vesicles associated with the viral replica ... | 1992 | 1316678 |
| genetic diversity and rapid evolution of poliovirus in human hosts. | | 1992 | 1318186 |
| myristylation of poliovirus capsid precursor p1 is required for assembly of subviral particles. | the poliovirus capsid precursor polyprotein, p1, is cotranslationally modified by the addition of myristic acid. we have examined the importance of myristylation of the p1 capsid precursor during the poliovirus assembly process by using a recently described recombinant vaccinia virus expression system which allows the independent production of the poliovirus p1 protein and the poliovirus 3cd proteinase (d. c. ansardi, d. c. porter, and c. d. morrow, j. virol. 65:2088-2092, 1991). we constructed ... | 1992 | 1318418 |
| genetic characterization of sabin types 1 and 3 poliovaccine virus following serial passage in the human intestinal tract. | poliovirus isolates types 1 and 3 were obtained from five and seven successive passages respectively, in infants who had been fed monovalent opv in two separate clinical trials conducted in 1960. the purpose of these trials was to answer the question how much the vaccine virus would revert to its original neurovirulent phenotype following multiplication in the intestinal tract. human passages were performed either by contact exposure or by feeding the excreted virus while the infants were mainta ... | 1992 | 1319179 |
| possible influence of measles virus infection of cynomolgus monkeys on the outcome of the neurovirulence test for oral poliovirus vaccine. | macaque monkeys are susceptible to measles infection which triggers temporary immuno-depression similar to the well known phenomenon in humans. it is known that feral monkeys become infected with measles virus when they are exposed to humans. since macaca mulatta and m. fascicularis are species used to assay the neurovirulence of oral poliovirus vaccine, the immunodepression caused by measles infection of the test monkeys could significantly alter the results of the neurovirulence test. the seru ... | 1992 | 1319180 |
| ulnar nerve inoculation of poliovirus in bonnet monkey: a new primate model to investigate neurovirulence. | a new monkey model of poliovirus neurovirulence has been developed avoiding the currently used intraspinal injection route which traumatizes the spinal cord. poliovirus type 1 (0.1 ml) was inoculated into the ulnar nerve of bonnet monkeys (macaca radiata) at the right elbow. five monkeys were inoculated with 10(7) tcid of lsc/2ab (sabin vaccine strain); none developed any illness. limb paralysis, clinically resembling spinal poliomyelitis in children, developed in all four monkeys given greater ... | 1992 | 1320307 |
| inactivation of poliovirus type 1 in mixed human and swine wastes and by bacteria from swine manure. | the persistence of poliovirus type 1 (po1) in mixed septic tank effluent and swine manure slurry was determined, and the antiviral effects of several bacterial cultures isolated from swine manure slurry were demonstrated. in two field experiments, po1 was consistently inactivated more rapidly in the mixed waste than in the control dulbecco's phosphate-buffered saline (d-pbs). d values (time [in days] for a 90% reduction of virus titer) were 18.7 and 29.9 for the mixed waste and 56.5 and 51.8 for ... | 1992 | 1320368 |
| identification of candidate sequences that determine virulence in coxsackievirus b4. | we have previously shown that a major determinant of virulence for coxsackievirus b4 mapped to the 5' end of the viral genome. comparison of the corresponding cdna sequences of a virulent and a non-virulent virus has allowed the identification of candidate determinants of virulence in the 5' untranslated region and the capsid proteins vp1, vp2 and vp4. thirteen nucleotide substitutions were observed in a region spanning 3298 nucleotides. four mutations were detected in the non-coding region. of ... | 1992 | 1320798 |
| a poliovirus replicon containing the chloramphenicol acetyltransferase gene can be used to study the replication and encapsidation of poliovirus rna. | a poliovirus replicon, flc/rep, which incorporates the reporter gene chloramphenicol acetyltransferase (cat) in place of the region encoding the capsid proteins vp4, vp2, and part of vp3 in the genome of poliovirus type 3, has been constructed. transfection of cells indicates that the flc/rep replicon replicates efficiently and that active cat enzyme is produced as a cat-vp3 fusion protein. the level of cat activity in transfected cells broadly reflects the level of flc/rep rna. a series of muta ... | 1992 | 1321286 |
| linker scanning mutagenesis of the internal ribosome entry site of poliovirus rna. | the initiation of cap-independent translation of poliovirus mrna occurs as a result of ribosome entry at an internal site(s) within the 5' noncoding region. a series of linker scanning mutations was constructed to define the genetic determinants of rna-protein interactions that lead to high-fidelity translation of this unusual viral mrna. the mutations are located within two distinct stem-loop structures in the 5' noncoding region of poliovirus rna that constitute a major portion of a putative i ... | 1992 | 1321289 |
| postinfection treatment with antiviral serum results in survival of neural cells productively infected with virulent poliovirus. | the death of human neuroblastoma cells undergoing productive infection with virulent poliovirus was prevented by addition of antiserum against the virus a few hours after the onset of infection; this treatment, however, did not prevent reproduction of the virus. despite the presence of the viral antigen, the cells retained the ability to divide. upon further cultivation in the absence of antiserum, the cells developed specific postinfection immunity or resistance to superinfection with polioviru ... | 1992 | 1321295 |
| [seroepidemiology of poliomyelitis in mexico]. | with the massive vaccination campaigns with the inactivated poliomyelitis vaccine starting in 1955 and its oral presentation in 1961, this disease has been controlled in many countries. however, wild polio virus is still transmitted in many developing countries. the study reported in this article had the objectives of estimating the prevalence of antibodies against polio for three types of virus (1, 2 and 3) in the population from 12 to 59 months of age in mexico and determining the factors asso ... | 1992 | 1321508 |
| dependence of the adenovirus tripartite leader on the p220 subunit of eukaryotic initiation factor 4f during in vitro translation. effect of p220 cleavage by foot-and-mouth-disease-virus l-protease on in vitro translation. | the adenovirus tripartite leader (tpt) 5' untranslated region (5'utr) allows translation in poliovirus-infected cells, in which the p220 subunit of eukaryotic initiation factor 4f is degraded. this p220-independent translation was investigated by measuring in vitro translation in a reticulocyte lysate of a reporter gene, chloramphenicol acetyltransferase, coupled to the tpt 5'utr. the p220 subunit was degraded by translation of a foot-and-mouth-disease l-protease construct. surprisingly, the tpt ... | 1992 | 1321714 |
| paralytic poliomyelitis in england and wales, 1985-91. | to ascertain all cases of paralytic poliomyelitis in england and wales during 1985-91 and to determine the source of infection in each case. | 1992 | 1322218 |
| cloning and inducible synthesis of poliovirus nonstructural proteins. | the poliovirus nonstructural protein-encoding genes have been cloned and expressed in escherichia coli using the inducible system described by studier and moffat [j. mol. biol. 189 (1986) 113-130] and studier [j. mol. biol. 219 (1991) 37-44]. the two genes encoding the poliovirus proteases, 2apro and 3cpro, were cloned together with their flanking regions in order to test the ability of the polyprotein precursors synthesized to cause proteolytic cleavage and generate mature forms. both proteases ... | 1992 | 1322344 |
| expression of poliovirus nonstructural proteins in escherichia coli cells. modification of membrane permeability induced by 2b and 3a. | the poliovirus nonstructural proteins 2b, 2c, 2c3a, 2c3ab, 3a, and 3ab have been cloned and efficiently expressed in escherichia coli cells. each individual protein, or combinations of some of them, were cloned using polymerase chain reaction techniques and correspond to the genuine poliovirus protein plus an additional methionine. the system used to express them uses pet vectors containing the promoter of gene 10 of phage t7. expression of protein 2c in bl21 (de3) plyss cells, which express the ... | 1992 | 1322409 |
| isolation of polioviruses from sewage and their characteristics: experience over two decades in sweden. | indigenous polio ceased in sweden in 1962 after 5 years' use of killed polio vaccine. in 1967, it was considered of interest to investigate whether poliovirus was present in the sewage. a method for selective isolation of poliovirus from sewage was developed. the method appeared to increase the yield. the studies were carried out at intervals up to 1990. in 1989-90, the virus isolates were characterized by the use of monoclonal antibodies differentiating between vaccine-like (sabin-like) and non ... | 1992 | 1322558 |
| genetic analysis of an ntp-binding motif in poliovirus polypeptide 2c. | poliovirus polypeptide 2c is a nonstructural protein involved in replication of the viral genome. analysis of the primary amino acid sequence of 2c shows homology to a family of proteins which contain a nucleoside-triphosphate (ntp)-binding motif. this motif consists of elements "a" (2/5 hydrophobic stretch) g/axxgxgks/t, where x stands for any amino acid, and "b" (3/5 hydrophobic stretch) d or dd/e. to assess the significance of the consensus sequence in 2c, we have engineered point mutations i ... | 1992 | 1322588 |
| temperature-sensitive polioviruses containing mutations in rna polymerase. | site-directed mutagenesis was performed to change the wild-type residue (asparagine) to aspartate, histidine, or tyrosine at amino acid 424 of the poliovirus rna polymerase, 3dpol. the mutations were introduced into plasmids containing full-length viral cdna and plasmids which direct the expression of 3dpol in escherichia coli. mutant viruses, recovered after transfection of hela cells with rna transcripts of the full-length clones, produced small plaques at 32 degrees. in addition, the plaquing ... | 1992 | 1322590 |
| inactivation of coliphage ms-2 and poliovirus by copper, silver, and chlorine. | the efficacy of electrolytically generated copper and silver ions (400 and 40 micrograms/l, respectively) was evaluated separately and in combination with free chlorine (0.2 and 0.3 mg/l) for the inactivation of coliphage ms-2 and poliovirus type 1 in water at ph 7.3. the inactivation rate was calculated as log10 reduction/min: k = -(log10 ct/c0)/t. the inactivation of both viruses was at least 100 times slower in water containing 400 and 40 micrograms/l copper and silver, respectively (k = 0.02 ... | 1992 | 1322762 |
| poliovirus induces indoleamine-2,3-dioxygenase and quinolinic acid synthesis in macaque brain. | accumulation of the neurotoxin quinolinic acid within the brain occurs in a broad spectrum of patients with inflammatory neurologic disease and may be of neuropathologic significance. the production of quinolinic acid was postulated to reflect local induction of indoleamine 2,3-dioxygenase by cytokines in reactive cells and inflammatory cell infiltrates within the central nervous system. to test this hypothesis, macaques received an intraspinal injection of poliovirus as a model of localized inf ... | 1992 | 1322853 |
| analysis of the functional significance of amino acid residues in the putative ntp-binding pattern of the poliovirus 2c protein. | the amino acid sequence of the poliovirus 2c protein contains two highly conserved stretches, gspgtgks136 and mdd177, which correspond to the consensus 'a' and 'b' motifs (gxxxxgks/t and dd/e, respectively) found in nucleoside triphosphate-binding proteins. to assess the functional importance of these amino acid sequences, we changed conserved and non-conserved amino acids. the replacement of the non-conserved thr133 residue with ser or ala did not markedly change the virus phenotype. similarly, ... | 1992 | 1322957 |
| role of amino acid residue 187 of poliovirus polypeptide 2c in determining the guanidine trait. | although mutations in codons 164 and 179 of poliovirus polypeptide 2c can establish guanidine resistance, the majority of guanidine-resistant and guanidine-dependent viruses contain an m----l change at amino residue 187 along with other critical mutations. the change at residue 187 probably contributes to the guanidine phenotype along with a variety of other modifications in polypeptide 2c, possibly altering conformation of the polypeptide during the initiation step of viral rna synthesis. | 1992 | 1323552 |
| genetic variation in vivo and proposed functional domains of the 5' noncoding region of poliovirus rna. | poliovirus has a single-stranded rna genome of about 7,440 nucleotides (nt) with an unusually long 750-nt noncoding region in the 5' end (5'ncr). several regulatory functions have been assigned to the 5'ncr. we sequenced the 5'ncrs of 33 wild-type 3 poliovirus strains to study the range and distribution of naturally occurring sequence variations. in this regard, the 5'ncr can be divided into a conserved part (nt 1 to 650) and a hypervariable part (nt 651 to 750). in the conserved part, altogethe ... | 1992 | 1323698 |
| [non-radioactive diagnosis of viral infections using "dna-peroxidase" probes]. | dna-peroxidase probes were synthesized according to a modified method (renzetal) for the detection of lambda phage dna (model system), polio, potato x and m, tobacco mosaic viral rnas by spot hybridization onto nitrocellulose membranes. cdnas (300-1400 bases) complementary to the viral rnas were cloned in m13 phage dna or ptz19. efficacy of each step of the probe construction and the diagnostic procedure were thoroughly examined. peroxidase activity manifested with non-toxic stain (nts) was 3-5 ... | 1992 | 1324402 |
| presence of non-maternal antibodies in newborns of mothers with antibody deficiencies. | to explain the mechanism for induction and production of specific antibodies found in the newborn already at birth, without previous known exposure to the antigen, we chose a model that presumably excluded the possibility of specific antibodies being transferred from the mother to the fetus. specific igg, iga, and igm antibodies against escherichia coli and poliovirus antigens were determined with elisa in serum, saliva, and amniotic fluid from hypogammaglobulinemic and iga-deficient mothers as ... | 1992 | 1324463 |
| using the virus challenge dose in the analysis of virus neutralization assays. | we propose a new basis for adjusting the results of virus neutralization assays. these assays consist of two separate experiments performed in parallel: a virus titration experiment and a serum dilution assay. in the virus titration experiment, one estimates the amount of virus used in the assay (the virus challenge dose). in a typical virus neutralization assay, the virus challenge dose may range over an order of magnitude. in the serial dilution assay, one measures the serum neutralizing activ ... | 1992 | 1324519 |
| detection of enteroviruses in faeces by polymerase chain reaction. | a polymerase chain reaction (pcr) technique for the detection of human enteroviruses in stool specimens was developed. the test was based on the synthesis of cdna, followed by pcr and slot blot hybridization. the primers used were selected from a highly conserved sequence in the 5'non-coding region of the enteroviral genome. by this method 27 different enterovirus serotypes (15 echo, 6 coxsackie a, 4 coxsackie b, poliovirus type 2 and enterovirus 71) from 89 patients could be detected. using pos ... | 1992 | 1324520 |
| nucleotide binding by the poliovirus rna polymerase. | cross-linking of ribonucleoside triphosphates (ntps) to specific binding sites on the poliovirus rna-dependent rna polymerase has been performed by ultraviolet irradiation and by reduction of oxidized nucleotide-protein complexes. the latter method approached a cross-linking efficiency of 1 ntp/molecule of enzyme. nucleotide competition experiments suggested that the same binding site is occupied by all ntps. analysis of peptides produced by proteinase glu-c and trypsin digestion and labeled wit ... | 1992 | 1324924 |
| proteolytic processing of the cardioviral p2 region: primary 2a/2b cleavage in clone-derived precursors. | the primary 2a/2b cleavage within cardiovirus polyprotein was examined by construction of cdna plasmids which linked fragments from the p2 region of encephalomyocarditis virus (emcv) and mengovirus genomes to the emcv 5' nontranslated region. when rna transcripts from these clones were tested in reticulocyte extracts, the synthesized proteins were cotranslationally processed at the 2a/2b site. no viral segments outside of the p2 region were required for this activity. engineered deletions which ... | 1992 | 1325705 |
| poliovirus spreads from muscle to the central nervous system by neural pathways. | a transgenic mouse model was used to address an unsolved question in the pathogenesis of poliomyelitis: how poliovirus invades the central nervous system (cns). ld50 values for intramuscular and intracerebral inoculation of poliovirus in transgenic mice expressing poliovirus receptors (tgpvr mice) were similar. after intramuscular inoculation with poliovirus, paralysis was observed first in the inoculated limb. in contrast, localization of initial paralysis to the inoculated limb was not observe ... | 1992 | 1326581 |
| poliovirus infection results in structural alteration of a microtubule-associated protein. | poliovirus infection results in profound changes in cellular metabolism and architecture. to identify alterations in cellular proteins following poliovirus infection which might account for these changes, monoclonal antibodies were prepared by screening for differences in antigen pattern in infected and uninfected cell lysates. further characterization of the antigen of one such antibody (25 c c1) is described in this report. the 25 c c1 antigen is a cytoskeleton-associated protein which decreas ... | 1992 | 1326643 |
| mutational analysis of the proposed fg loop of poliovirus proteinase 3c identifies amino acids that are necessary for 3cd cleavage and might be determinants of a function distinct from proteolytic activity. | mutations were introduced into a cdna clone of poliovirus resulting in single-amino-acid substitutions within the region of the proposed fg loop of proteinase 3c. rnas were made by in vitro transcription with t7 rna polymerase and used to transfect hela cells. virus viability was assessed as indicated by cell lysis. in parallel, rnas were translated in vitro by using a hela cell lysate, and the patterns of the processed poly-proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel ele ... | 1992 | 1326654 |
| cis-acting lesions targeted to the hydrophobic domain of a poliovirus membrane protein involved in rna replication. | the structural requirements of the hydrophobic domain contained in poliovirus polypeptide 3ab were studied by using a molecular genetic approach in combination with an in vitro biochemical analysis. we report here the generation and analysis of deletion, insertion, and amino acid replacement mutations aimed at decreasing the hydrophobic character of the domain. our results indicated that the hydrophobicity of this region of 3ab is necessary to maintain normal viral rna synthesis. however, in vit ... | 1992 | 1326655 |
| international workshop: 'poliovirus attenuation: molecular mechanisms and practical aspects'. 9-10 december 1991, holiday inn, bethesda, md, u.s.a. | | 1992 | 1327006 |
| [insertional mutagenesis of protease 2a of the poliomyelitis virus and its substrate, simultaneously expressed in escherichia coli cells]. | in order to clarify the structural features of protein substrates which determine their sensitivity towards poliovirus 2a protease, a high-efficiency bacterial expression system for cdna of the poliovirus genome fragment has been developed. the expressed protein encompasses the c-end half of the vp1 capsid protein. 2a protease, and a large portion of the 2b protein. virus-specific products were found in the insoluble fraction of bacterial cell lysates which were mainly represented by two protein ... | 1992 | 1327188 |
| motor neuron diseases and viruses: poliovirus, retroviruses, and lymphomas. | the viral theory of motor neuron disease (mnd) has been rejuvenated in the last 5 years for several reasons. first, it is now recognized that enteroviruses and picornaviruses similar to poliovirus can persist and induce immune-mediated diseases. in some picornavirus animal models, the immune-mediated disease can occur and continue long after the infectious virus has been cleared, and in some cases of human mnd an immune-mediated disease may occur. second, the human retroviruses human immunodefic ... | 1992 | 1327304 |
| replication of poliovirus rna and subgenomic rna transcripts in transfected cells. | full-length and subgenomic poliovirus rnas were transcribed in vitro and transfected into hela cells to study viral rna replication in vivo. rnas with deletion mutations were analyzed for the ability to replicate in either the absence or the presence of helper rna by using a cotransfection procedure and northern (rna) blot analysis. an advantage of this approach was that viral rna replication and genetic complementation could be characterized without first isolating conditional-lethal mutants. a ... | 1992 | 1328676 |
| involvement of membrane traffic in the replication of poliovirus genomes: effects of brefeldin a. | brefeldin a (bfa) is a macrolide antibiotic that has multiple targets in vesicular transport and blocks membrane traffic between the cis- and trans-golgi compartments, leading to the disruption of the trans-golgi apparatus (for a review see pelham, 1991, cell 67, 449-451). consequently, bfa interferes with the maturation of viral glycoproteins and suppresses the formation of infectious viruses that contain a lipid envelope. we report that this antibiotic strongly inhibits poliovirus replication ... | 1992 | 1329315 |
| genotype-specific in vitro amplification of sequences of the wild type 3 polioviruses from mexico and guatemala. | the extensive nucleotide sequence heterogeneity among independent genotypes of wild polioviruses permits the systematic design of genotype-specific molecular reagents. we have prepared two sets of polymerase chain reaction (pcr) primer pairs specific for the genotype of wild poliovirus type 3 recently endemic to mexico and guatemala. nucleotide sequences of a representative wild type 3 virus isolated in mexico in 1989 differed from the corresponding sabin 3 (leon 12 a1b) sequences at 167 of 900 ... | 1992 | 1329370 |
| the soluble form of two n-terminal domains of the poliovirus receptor is sufficient for blocking viral infection. | by means of deleting a c-terminal portion of the open reading frame of the poliovirus receptor cdna, and by vaccinia virus-mediated overexpression we have produced a protein corresponding to the first two n-terminal ig-like domains of the poliovirus receptor. this protein that lacked the third ig-like domain, the transmembrane region and most of the intracellular c-terminal tail was detected in the medium of vaccinia virus infected cells. the properties of the truncated pvr cdna were further cha ... | 1992 | 1329376 |
| cleavage specificity on synthetic peptide substrates of human rhinovirus 2 proteinase 2a. | proteinase 2a of human rhinovirus serotype 2 (hrv2 2a) was expressed in escherichia coli and partially purified; the preparation was used to study various enzymatic parameters. using a 16-amino acid peptide representing the native cleavage region of hrv2 2a, an apparent km value of 5.4 x 10(-4) mol/liter was determined. a minimum of 9 amino acids (comprising residues p8 to p1') was necessary for cleavage to occur. proteolysis of substituted peptides was highly tolerant toward changes at p1, p2', ... | 1992 | 1331062 |
| processing procedures for recovering enteric viruses from wastewater sludges. | a powdered beef extract specially formulated for recovering viruses from environmental samples and designated as beef extract v was evaluated using indigenous and viral seeded wastewater sludge samples. when beef extract v was used to process activated and aerobically digested sludge solids, virus recoveries were shown to be similar to other methods that used commercially available supplemented beef extract. when used to process other sludge solids (primary and activated without primary clarific ... | 1992 | 1331161 |
| inhibition of rotavirus in vitro transcription by optimal concentrations of monoclonal antibodies specific for rotavirus vp6. | three monoclonal antibodies (mabs) obtained from inoculation of mice with either a serotype 1 human rotavirus or rotavirus sa11 (serotype 3) inhibited the in vitro transcription of rotavirus sa11. two of the mabs exhibited a biphasic inhibitory response. removal of antibody from mab preparations by adsorption with sepharose-protein g reduced the inhibitory activity completely for all three mab preparations. analysis by radioimmunoprecipitation and western blotting indicated that all three mabs r ... | 1992 | 1331302 |
| accumulation and persistence of hepatitis a virus in mussels. | accumulation and persistence of hepatitis a virus (hav) in the mussel mytilus chilensis was evaluated. under optimal filtration activity of mussels (temperature 12 degrees c, salinity 3%, feeding twice a day with dunaliella marina), hav was concentrated 100-fold from the surrounding water. similar concentrations of hav were reached in the filtration apparatus and in the digestive system (hepatopancreas). hav persisted for about 7 days in mussels. elimination of hav from mussels was slower than e ... | 1992 | 1331305 |
| identification of precursors of structural proteins vp1 and vp2 of hepatitis a virus. | the morphogenetic pathway of hepatitis a virus (hav), classified as a member of the enteroviruses within the picornaviridae, still remains obscure and seems to differ considerably from that of poliovirus, the most studied representative of this genus. in order to elucidate the precursor/product relationship of hav structural proteins, subviral particles, which represent more than 50% of the viral antigen produced in infected cells, were separated from mature virions and their polypeptide pattern ... | 1992 | 1331311 |
| myristate-protein interactions in poliovirus: interactions of vp4 threonine 28 contribute to the structural conformation of assembly intermediates and the stability of assembled virions. | the vp4 capsid protein of poliovirus is n-terminally modified with myristic acid. within the poliovirus structure, a hydrogen bond is observed between the myristate carbonyl and the hydroxyl side chain of threonine 28 of vp4. this interaction is between two fivefold symmetry-related copies of vp4 and is one of several myristoyl-mediated interactions that appears to structurally link the promoters within the pentamer subunit of the virus particle. site-specific substitutions of the threonine resi ... | 1992 | 1331497 |
| a second gene for the african green monkey poliovirus receptor that has no putative n-glycosylation site in the functional n-terminal immunoglobulin-like domain. | using cdna of the human poliovirus receptor (pvr) as a probe, two types of cdna clones of the monkey homologs were isolated from a cdna library prepared from an african green monkey kidney cell line. either type of cdna clone rendered mouse l cells permissive for poliovirus infection. homologies of the amino acid sequences deduced from these cdna sequences with that of human pvr were 90.2 and 86.4%, respectively. these two monkey pvrs were found to be encoded in two different loci of the genome. ... | 1992 | 1331508 |
| n glycosylation of the virus binding domain is not essential for function of the human poliovirus receptor. | the human poliovirus receptor (hpvr) is a glycoprotein with three immunoglobulin-like extracellular domains, of which the n-terminal domain (v-type domain) is necessary and sufficient for virus binding and uptake. the effect of n glycosylation of the v domain of hpvr on binding and entry of poliovirus was studied. stable mouse l-cell lines were generated that express pvr-specific cdna. one of the cell lines expressed a mutant of hpvr, in which both asparagine residues of the two n-glycosylation ... | 1992 | 1331527 |
| purification and characterization of poliovirus polypeptide 3cd, a proteinase and a precursor for rna polymerase. | a cdna clone encoding the 3cd proteinase (3cdpro) of poliovirus type 2 (sabin), the precursor to proteinase 3cpro and rna polymerase 3dpol, was expressed in bacteria by using a t7 expression system. site-specific mutagenesis of the 3c/3d cleavage site was performed to generate active proteolytic precursors impaired in their ability to process themselves to 3cpro and 3dpol. of these mutations, the exchange of the thr residue at the p4 position of the 3c/3d cleavage site for a lys residue (3cdpro ... | 1992 | 1331532 |
| evaluation of three methods for the concentration of poliovirus from oysters. | three methods for the concentration of poliovirus from oyster homogenates were compared. the adsorption-elution-precipitation method gave the lowest average virus recovery (24.1%), while the beef extract elution-acid precipitation method and the non-fat dry milk elution-acid precipitation methods gave recoveries of 47.2% and 39.6%, respectively. although the overall recovery rates with these methods were lower than those reported in previous studies, recoveries of 40-47% obtained with the elutio ... | 1992 | 1331717 |
| translational enhancement of the poliovirus 5' noncoding region mediated by virus-encoded polypeptide 2a. | genetic and biochemical studies have revealed that the 5' noncoding region of poliovirus mediates translation of the viral mrna by an unusual mechanism involving entry of ribosomes in internal sequences of mrna molecules. we have found that mrnas bearing the 5' noncoding region of poliovirus were translated at an enhanced rate in poliovirus-infected mammalian cells at a time when translation of cellular mrnas was not yet inhibited. this translational enhancement of the polioviral 5' noncoding re ... | 1992 | 1332040 |
| in vitro antiviral activity of four isothiazole derivatives against poliovirus type 1. | the in vitro effects of four isothiazoles [5,5'-diphenyl-3,3'-diisothiazole disulfide, 5-phenyl-3-mercapto-isothiazole, 5,5'-(4-chlorophenyl)-3,3'- diisothiazole disulfide, and 5-(4-chlorophenyl)-3-mercapto-isothiazole] on poliovirus type 1 were studied. the derivatives tested demonstrated remarkable viral inhibition, with a higher selectivity index than the previously studied iminodithiole precursors. under one-step growth conditions, all the isothiazole derivatives caused the greatest activity ... | 1992 | 1332598 |
| inducible expression of a toxic poliovirus membrane protein in escherichia coli: comparative studies using different expression systems based on t7 promoters. | the poliovirus 3ab gene has been cloned and overproduced in t7 expression vectors using different approaches to allow reduction of basal levels of expression. expression of the poliovirus 3ab gene is highly toxic for e. coli cells, due to drastic changes induced in membrane permeability of the bacteria that lead to cell lysis when the t7 lysozyme is present. the best production of 3ab was achieved with the t7/lac system in cells lacking t7 lysozyme, where this toxic protein was synthesized to hi ... | 1992 | 1332717 |
| intracellular localization of poliovirus rna by in situ hybridization at the ultrastructural level using single-stranded riboprobes. | polioviral rna was localized by electron microscopic in situ hybridization on sections of poliovirus-infected hep-2 cells. viral plus-strand rna was found accumulated in the close surroundings of the membrane-bound replication complex. two different regions of the viral genome were detected with the same frequency, which indicates the predominant presence of full-length genomic rna. viral proteins of the p2 and the p3 genomic region were detected mainly over the core of the replication complex, ... | 1992 | 1333118 |
| deletion and insertion mutants of hbsag particles. | we have found previously that hybrid 22-nm hbsag particles can be created by insertion of short antigenic sequences into the hbv major envelope protein. we have now performed a detailed deletion mutagenesis of the s gene of hbv encoding hbsag. deletion of the 51 c-terminal amino acids including most of the third and all of the fourth hydrophobic domain of the s protein did not affect particle assembly and secretion. however, secretion of 22-nm particles was abolished by minor deletions in the n- ... | 1992 | 1333319 |
| isolation of enteroviruses and adenoviruses in continuous simian cell lines. | the ability of five simian cell lines--bgm, llc-mk2, ma104, vero and bsc-1--to isolate enteroviruses and adenoviruses from faeces was assessed and compared with that of primary or secondary rhesus monkey kidney (rhmk) and hep2 cultures. for enteroviruses, llc-mk2 and bgm were best of the five lines, detecting 77% and 73% respectively of 88 strains isolated, but neither was as good as rhmk, which detected 88%. both vero and bsc-1 detected less than 50%. all cell types were good at isolating polio ... | 1992 | 1333563 |
| seroimmunity to poliomyelitis in an albanian immigrant population. | the immunity against poliomyelitis in a representative sample of the albanian population recently immigrant to italy was evaluated. a significant number of the subjects examined lacked protective antibodies against one or more polioviruses. the most prevalent seronegativity related to poliovirus type 3 (41.3%), followed by poliovirus type 1 (21.5%). this result was more consistent in the younger age groups. our data suggest the hypothesis that this problem arises from the use of a vaccine of dis ... | 1992 | 1333689 |
| the second international standard for anti-poliovirus sera types 1, 2 and 3. | the second international standard for anti-poliovirus sera types 1, 2 and 3 was established by the who expert committee on biological standardization in 1991 on the basis of an extensive collaborative study. nine laboratories from eight countries participated and all used neutralizing antibody assays. the standard is a human serum pool which contains antibodies to all three poliovirus types and replaces the three previously established monovalent standards which were all hyperimmune monkey sera. ... | 1992 | 1333776 |
| [vaccination against measles at 6 months of age]. | measles immunization with the edmonston zagreb stain was carried out in 71 six-month-old infants. proportions of subjects with immunity were 91% among the 47 subjects retested before one year of age and 100% among the 28 subjects retested between two and three years of age. these results support the who recommendation that measles immunization should be given at the age of six months. the concerns expressed by some about possible adverse effects of early measles immunization (decreased immune de ... | 1992 | 1334394 |
| preparative separation of foreign antigens for highly efficient presentation to t cells in vitro. | a method is described for the separation and purification of proteins from complex mixtures of foreign antigens in a form suitable for stimulating t cells in vitro. the technique involves electrophoretic separation of proteins followed by elution, concentration and adsorption of the polypeptide subunits to latex microspheres. alternatively, where a specific antibody is available, proteins may be affinity-purified from a heterogeneous mixture of antigens, using antibody-coated latex microspheres. ... | 1992 | 1335464 |
| possible approaches to develop vaccines against hepatitis a. | more than a decade ago, successful replication of hepatitis a virus (hav) in cell culture opened the way to the development of live attenuated and inactivated vaccine candidates. serial passages of hav in cell culture led to attenuation as demonstrated by experiments in non-human primates. several live vaccine candidates obtained through serial passages have been evaluated in volunteers. significant improvements in the yield of viral antigen from infected cell cultures stimulated the development ... | 1992 | 1335659 |
| antibody response of children immunized with poliovaccines: an evaluation using two strains of poliovirus type 1. | neutralizing antibody response of children immunized with either opv (3 doses), or ipv (2 doses) was evaluated against poliovirus type 1 sabin vaccine strain and a local neurovirulent isolate. both vaccines elicited significantly better antibody response against the vaccine strain than against the neurovirulent isolate. moreover, approximately 35 per cent of sera contained very low levels of antibody against the virulent virus in spite of good antibody titre against the vaccine strain. the obser ... | 1992 | 1335965 |
| activity of glutaraldehyde at low concentrations against capsid proteins of poliovirus type 1 and echovirus type 25. | the activity of glutaraldehyde (gta) against capsid proteins of poliovirus type 1 and echovirus type 25 was studied to understand the mode of action of this reagent against enteroviruses. the viruses were treated with gta concentrations ranging from 0.005 to 0.10%. in the poliovirus particles, high-molecular-weight products were formed by 0.05% gta, whereas in the echovirus particles, they were formed at 0.005% gta. these products consist of complexes composed essentially of vp1 and vp3. there s ... | 1992 | 1336351 |
| poliovirus surveillance: isolation of polioviruses in japan, 1980-1991. a report of the national epidemiological surveillance of infectious agents in japan. | this report presents an overall distribution of poliovirus isolations in japan, where poliomyelitis has been under control over two decades as a result of legal administration of two doses of the trivalent live oral poliovirus vaccine of the sabin strains (opv) to children under 48 months of age. during the past 12 years from 1980 through 1991, a total of 1,126 poliovirus isolations from humans and 268 isolations from sewage/river water were reported by respectively 49 and nine of the participat ... | 1992 | 1338392 |
| comparability of poliovirus neutralizing antibody tests. | a serology panel was used to assess the comparability of results of poliovirus neutralizing antibody assays. five laboratories from three countries provided results with seven in-house methods. a high degree of within-laboratory reproducibility was seen for all laboratories and methods, with 94% of results for repeat titrations within plus or minus one twofold dilution. considerable differences in sensitivity between methods were, however, observed. the period of serum/virus incubation prior to ... | 1992 | 1339040 |
| disinfection of irreversible hydrocolloid impressions: a comparative study. | this paper demonstrates the potential for cross contamination with bacteria and viruses from impression materials and evaluates the efficacy of four disinfection systems on irreversible hydrocolloid impressions contaminated with streptococcus sanguis or poliovirus. an irreversible hydrocolloid impression was made of a contaminated acrylic resin template. the impression was disinfected and residual microorganisms were harvested by sonication, cultured, and counted. the results showed that the imp ... | 1992 | 1339136 |
| lack of in vitro interference between sa-11 rotavirus and attenuated poliovirus type 1. | to determine if rotavirus interferes with the multiplication of poliovirus, and hence the efficiency of the polio vaccine, the effect of timing and concentration of simian rotavirus (ssa-11) on polio-1 infection in ma-104 cells was studied in vitro by evaluating the cytopathic effect, the reduction of the infectivity titers and the visualization of viral particles by electron microscopy. we found that poliovirus 1 was able to replicate when the challenge dose was administered within the first 8 ... | 1992 | 1339225 |
| origins of hiv. | | 1992 | 1350845 |
| effect of enterovirus infection on susceptibility of hela cells to shigella flexneri invasivity. | invasiveness of shigella flexneri m90t in hela cells was significantly increased when cells were preinfected with poliovirus 1, coxsackievirus b3 and echovirus 6. this effect was dependent on the dose of virus used, evident at early stages of viral infection and lasted hours before the appearance of a cytopathic effect. an increase of bacterial invasion ability was also noticed when hela cells were incubated with uv-inactivated enteroviruses. this enhancing effect obtained with both viable and u ... | 1992 | 1364020 |
| growth of poliovirus using alginate entrapped-anchorage dependent vero cells. | obligatory anchorage dependant vero cells were successfully grown in gelatinous-like macrocarriers made of calcium alginate. entrapped single cells were immobilized within the polymerized alginate matrix divide to form large spherical clumps of cells. a cell density of 17 x 10(6) cells/ml of alginate with over 95% viability was obtained after 14 days in spinner flasks. when subjected to poliovirus type i infection, spherical masses of vero cells progressively showed extensive cytopathic effect b ... | 1990 | 1369301 |
| viral proteases as targets for chemotherapeutic intervention. | many viruses encode proteinases that are essential for infectivity, and are consequently attractive chemotherapeutic targets. the biochemistry and structure of the human immunodeficiency virus proteinase have been characterized extensively, and potent peptide-mimetic inhibitors have been developed. techniques and strategies used to improve the efficiency of these compounds are likely to be applicable to other viral proteinases. | 1992 | 1369416 |
| human poliovirus receptor gene expression and poliovirus tissue tropism in transgenic mice. | expression of the human poliovirus receptor (pvr) in transgenic mice results in susceptibility to poliovirus infection. in the primate host, poliovirus infection is characterized by restricted tissue tropism. to determine the pattern of poliovirus tissue tropism in pvr transgenic mice, pvr gene expression and susceptibility to poliovirus infection were examined by in situ hybridization. pvr rna is expressed in transgenic mice at high levels in neurons of the central and peripheral nervous system ... | 1992 | 1370085 |
| interaction between viruses and monoclonal antibodies studied by surface plasmon resonance. | an automated biosensor system designed for measuring molecular interactions in real time and without any labelling of the reactants has been used to study the interaction of two animal viruses (vaccinia virus and poliovirus) and two plant viruses (cowpea mosaic virus and tobacco mosaic virus) with monoclonal antibodies. using monoclonal antibodies specific for different conformational states of viral protein, it was found that the virus particles retained their conformational integrity when immo ... | 1992 | 1372280 |
| identification of t-helper epitopes in the vp1 capsid protein of poliovirus. | poliovirus-specific t lymphocytes were isolated from virus-immunized mice of different h-2 haplotypes. immunological characterization of this population indicates that the effector population involved in the observed poliovirus-specific proliferative response was that of cd4-positive t-helper cells. proliferative responses also were induced within these t-lymphocyte populations upon stimulation with either purified vp1 capsid protein or vp1 synthetic peptides. by using these synthetic peptides, ... | 1992 | 1373200 |
| poliovirus chimeras expressing sequences from the principal neutralization domain of human immunodeficiency virus type 1. | sequences from the principal neutralization domain of human immunodeficiency virus type 1 (hiv-1) strain lai or rf have been expressed in antigenic site 1 of the capsid of the sabin strain of poliovirus type 1. a number of the resulting chimeras were viable. viable variants bearing mutations within the insertion site spontaneously arose from several nonviable chimeras. in general, these mutations result in a decrease in positive charge in the substituted antigenic site 1. two of the chimeras wer ... | 1992 | 1373205 |
| expression of heterologous peptides at two permissive sites of the male protein: antigenicity and immunogenicity of foreign b-cell and t-cell epitopes. | we previously determined a number of 'permissive' sites in the periplasmic maltose-binding protein (male) from escherichia coli. these sites accept the insertion of heterologous peptides without major deleterious consequences for the activities, structure and cellular location of the protein. this study explores the versatility of two such permissive sites for the synthesis of foreign peptides, and examines the antigenicity and the immunogenicity of the inserts. one site is located after amino a ... | 1992 | 1373395 |
| monoclonal antibodies to the c4 region of human immunodeficiency virus type 1 gp120: use in topological analysis of a cd4 binding site. | we have raised antisera and monoclonal antibodies (mabs) to the c4 region of hiv-1 gp120, using an antigen chimaera of poliovirus as immunogen. these mabs and sera, together with mabs to the same region raised by other methods, fall into three groups defined by their abilities to bind to recombinant gp120 and/or the immunogenic peptide. in some cases, the amino acids recognized by the mabs have been identified by pep-scan and by solution phase peptide inhibition of binding to recombinant gp120. ... | 1992 | 1376134 |