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Biomedical subjects

K J Wiegers

Publications and source records attributed to K J Wiegers.

At least 19 recordsLinked to original sources
PubMed1990

Molecular basis for linkage of a continuous and discontinuous neutralization epitope on the structural polypeptide VP2 of poliovirus type 1.

We obtained neutralizing monoclonal antibodies against a continuous neutralization epitope on VP2 of poliovirus type 1 strain Mahoney by using a combined in vivo-in vitro immunization procedure. The antibody-binding site was mapped to amino acid residues within the peptide segment (residues 164 through 170) of VP2 by competition with synthetic peptide and sequencing of resistant mutants. Cross-neutralization of these mutants with another neutralizing monoclonal antibody revealed a linkage of the continuous epitope and a discontinuous neutralization epitope involving both loops of the double-loop structure of VP2 at the twofold axis on the surface of the virion.

Amino Acid Sequence↗
PubMed1987

Binding site of neutralizing monoclonal antibodies obtained after in vivo priming with purified VP1 of poliovirus type 1 is located between amino acid residues 93 and 104 of VP1.

Three hybridomas obtained after in vitro stimulation of spleen cells of mice primed in vivo with purified VP1 of poliovirus type 1 (Mahoney) with the homologous virus produced antibodies which reacted with VP1 and immunoprecipitated and neutralized only the homologous virus. Evidence for the location of their binding sites was obtained by inhibition of virus neutralization and virus binding by a synthetic peptide comprising the amino acid sequence 93-104 of VP1 of poliovirus type 1 (Mahoney).

Animals↗
PubMed1986

In vitro stimulation of presensitized mouse spleen cells with poliovirus type 1, Mahoney, and enhancement of poliovirus-specific hybridomas.

In vivo immunization of BALB/c mice with poliovirus type 1, strain Mahoney, or with its purified polypeptides resulted in 0.2 to 0.5 antigen-specific hybridoma microcultures per 10(6) spleen cells. Stimulation of spleen cells from mice immunized with poliovirus or with its polypeptides in vitro with poliovirus 6 days prior to fusion with the myeloma cells led to a six- to 20-fold increase in the number of positive microcultures, i.e. after stimulation the yield of poliovirus-specific hybridomas was up to 3.8 antigen-specific microcultures per 10(6) spleen cells. The in vitro stimulation of spleen cells primed in vivo was demonstrated by the detection of poliovirus-specific antibody-producing cells 6 days after in vitro cultivation in the presence of poliovirus as antigen. Only spleen cells stimulated under these conditions in vitro gave rise to specific antibody-producing cells and yielded antigen-specific hybridomas after somatic hybridization.

Animals↗
PubMed1985

Evidence for conformational changes of poliovirus precursor particles during virus morphogenesis.

Antisera raised against isolated structural polypeptides VP1, VP2 and VP3 of poliovirus type 1, strain Mahoney, reveal a differential reaction against mature virus and its precursor particles. During virus morphogenesis antigenic sites recognized by VP1 and VP2 antisera are lost stepwise from the surface of precursor particles. These sites are cross-reacting between serotypes and are also lost from precursor particles of type 2 (MEF-1) and type 3 (Saukett). They are absent on the surface of mature virus of all three serotypes. In contrast, the VP3 antiserum recognizes sites expressed maximally on the surface of infectious virus of type 1 (Mahoney). This antiserum did not show significant intertypic cross-reactions with virus particles, empty capsids or 14S particles of poliovirus types 2 and 3. However, it does recognize intertypic cross-reacting sites, like the VP1 and VP2 antisera, on denatured polypeptides and 5S particles of each serotype.

Cross Reactions↗
PubMed1983

Monospecific antisera against capsid polypeptides of poliovirus type 1 distinguish antigenic structures of poliovirus proteins.

Pure poliovirus polypeptides, namely VP1, VP2, VP3 and VP4, have been isolated by isoelectric focusing after dissociation of poliovirus by urea. When injected into rabbits, all four polypeptides produced monospecific antisera which were used for the characterization of poliovirus particles and poliovirus-infected cells. The specificity of these antisera was determined by immunoprecipitation of polypeptides obtained by dissociation of poliovirus with SDS, followed by characterization by polyacrylamide gel electrophoresis. The antisera revealed differences in the antigenic sites of native poliovirus particles, heated poliovirus particles and naturally occurring empty capsids. Only VP3 antiserum reacted with native poliovirus and showed some neutralization, whereas all antisera precipitated heated virus and empty capsids. These antisera reacted also with the appropriate precursors of the capsid polypeptides demonstrating their usefulness for an analysis of the cleavage pathway by monospecific antibodies and revealed a second protomer (90 kilodalton) polypeptide for the capsid proteins of poliovirus particles.

Antibodies, Viral↗
PubMed1983

[Mechanism of virus inactivation by peracids].

Peracids are a class of substances inactivating the largest spectrum of viruses in comparison to the other known disinfectants. The mode of action is unknown however. For the detection of the reaction mechanism we studied the inactivating kinetics of poliovirus and polio-RNA as well as the virus- and RNA-inactivation in dependence on the peracid concentration. In addition the sedimentation of the virus and the virus-RNA were determined. The inactivation curves of virus particles and virus-RNA respectively showed a similar, not linear course. The sedimentation of the virion and the RNA were altered after treatment with peracid and showed a disrupted capsid and a fragmented RNA as a result of incubation with the disinfectant.

Antiviral Agents↗
PubMed1981

Poliovirus-specific polypeptides in infected HeLa cells analysed by isoelectric focusing and 2D-analysis.

Analysis of poliovirus-infected cells by isoelectric focusing in urea resolves at least 25 bands. Combination of isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) in a two-dimensional analysis (2D-analysis) revealed a much better resolution than each method separately. By 2D-analysis most of the bands could be correlated with the known poliovirus-specific polypeptides generated in the infected cell. With this technique it was possible to determine the apparent isoelectric point (pI) of the identified poliovirus polypeptides. They are in the range from pH 5.6 for polypeptide 7d to pH 8.8 for polypeptide X, which is the most basic found so far.

Electrophoresis, Polyacrylamide Gel↗
PubMed1981

[The virus inactivating efficacy of peracids and peracidous disinfectants (author's transl)].

It has always been an aim to develop chemicals able to kill a broad spectrum of microorganisms. Research in this field led to peracids inactivating vegetative bacterial forms, spores, fungi and viruses. Since liquid peracids are very unstable, powders were developed which dissolved in water, formed peracids. In this paper the inactivating efficacy of peracids derived from powders as well as of pure peracids is presented. It is shown that both inactivate the following viruses: poliomyelitisvirus type 1, coxsackievirus B3, adenovirus type 5 and SV40. The most resistant viruses were the picornaviruses, especially coxsackievirus B3. But in all cases, inactivation is in accordance with the guidelines of the Deutsche Vereinigung zur Bekämpfung der Viruskrankheiten (DVV) (15). Furthermore, it is shown that pure peracids are more reactive than peracids formed from powders. But with all peracids there remains residual infectivity, which may be due to inhomogenic virus populations.

Adenoviridae↗
PubMed1980

Preparative isoelectric focusing of poliovirus polypeptides in urea-sucrose gradients.

Isoelectric focusing in urea using small density gradient columns for dissociated poliovirus resulted in a complete separation of the four virus polypeptides. Identification and purity of VP1, 2, 3 and 4 was shown by SDS-polyacrylamide gel electrophoresis. The isoelectric points were determined and compared with the values obtained in gels. The recovery of the individual polypeptides was about 80%. Up to 500 microgram of poliovirus per tube could thus be separated in a one-step procedure giving pure and SDS-free poliovirus polypeptides.

Electrophoresis, Polyacrylamide Gel↗
PubMed1978

Isoelectric points of polypeptides of standard poliovirus particles of different serological types and of empty capsids and dense particles of poliovirus type 1.

The isoelectric points of polypeptides of standard and dense poliovirus particles and of empty capsids have been determined by isoelectric focusing in urea and by two-dimensional analysis. Comparing virus strains belonging to the three serological types of poliovirus, differences in the pI of some, but not all of the structural polypeptides are found. The pI of polypeptides of dense particles and of empty capsids are identical with those of standard particles. Polypeptide VPo present in empty capsids has a pI between those of VP4 and VP2.

Capsid↗
PubMed1978

The effect of cesium salts on dense poliovirus particles.

The buoyant density of dense poliovirus particles has been examined in density gradients other than cesium chloride in order to determine the dependence of this property on the nature of the solvent. In Urografin (sodium and methylglucamine amidotrizoate), dense poliovirus particles banded at two densities--1.33 and 1.39 g/cm(3)--whereas in cesium metrizoate they banded only at 1.39 g/cm(3) and in cesium sulfate at 1.38 g/cm(3). The presence of cesium ions gives rise to the occurrence of dense particles, which are indistinguishable in their buoyant density and sedimentation coefficient from standard poliovirus particles when prepared in the absence of Cs+. In their physical properties dense poliovirus particles are more closely related to rhinoviruses and foot-and-mouth-disease virus, i.e., to members of the genus Rhinovirus, than to standard poliovirus particles belonging to the genus Enterovirus.

Capsid↗
PubMed1977

Differences in the physical properties of dense and standard poliovirus particles.

Dense poliovirus particles (DP) differ in buoyant density, sedimentation coefficient and lability from standard poliovirus particles. Dense particles band at a density of 1-44 g/ml in isopycnic CsCl gradients and sediment in sucrose gradients at 220S. However, when DP are centrifuged in sucrose gradients containing 1-5 M-KCl, NaCl or LiCl, two types of particles are observed, one sedimenting at 220S and the other at 160S. Particles sedimenting at 220S are converted into particles sedimenting at 160S by incubation at 37 degrees C in 1-5 M-KCl. The high buoyant density seems to be correlated with the high lability of DP. Dense particles are extremely labile in isotonic phosphate-buffered saline. Their degradation proceeds through an RNA-containing particle lacking polypeptide VP4, to RNA and empty capsids.

Capsid↗
PubMed1975

Effect of DEAE-dextran on protein synthesis in HeLa cells.

Concentrations of DEAE-dextran which are currently used to stimulate the interaction between animal cells and natural or synthetic polynucleotides, inhibit protein synthesis in HeLa cells. This inhibition results from the blocking of more than one of the steps in protein synthesis, including transport of amino acids. The results support the hypothesis that enhancement of cellular competence for infection by viral RNA involves interference with initiation of cellular protein synthesis.

Amino Acids↗
PubMed1975

Isolation and characterization of 'dense particles' from poliovirus-infected HeLa cells.

Dense poliovirus particles (buoyant density 1.44 g/ml in CsCl) isolated from infected HeLa cells contain the normal four structural polypeptides VP1 to VP4, and 35S poliovirus RNA. In addition, small amounts of VPo and single-stranded RNA sedimenting slower than the poliovirus genome are present. Dense particles have a low specific infectivity, are neutralized by type-specific poliovirus antisera, and are detected during growth as early as normal virus but disappear when virus production stops. They appear to represent a different, more open, conformation of the normal virus capsid.

Amino Acids↗