PubMed Health⌕ Search

Biomedical subjects

L Döhner

Publications and source records attributed to L Döhner.

At least 19 recordsLinked to original sources
PubMed1998

Rapid identification of subgenera of human adenovirus by serological and PCR assays.

Bacterially expressed recombinant protein IX (pIX) of human adenovirus serotype 2 (Ad2) and 3 (Ad3) was evaluated for use as a subgenus-specific antigen by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Patients sera positive by ELISA for the genus-specific adenovirus hexon antigen recognized the recombinant pIX of Ad2 and Ad3 in a subgenus-specific manner by both assays. Polyclonal rabbit serum raised against the recombinant Ad2pIX reacted strongly by indirect immunofluorescence assay, with Adl, 2 and 5 (subgenus C) but not with serotypes representing other subgenera. In a similar way, anti-Ad3pIX reacted with Ad3, 7, 11 and 14 (subgenus B), but not with serotypes representing other subgenera. A polymerase chain reaction showed that the complete pIX gene could be amplified in a subgenus specific fashion using primers specific for Ad3 (subgenus B), Ad2 (subgenus C), or Ad40/41 (subgenus F). The pIX gene from the available isolates of subgenus A, D and E was not amplified with these primers. The use of pIX-based serological assays is useful for subgenotyping as a primary screen of anti-Ad sera. It is much more rapid than the currently used neutralization assay or hemagglutination inhibition test. The application of anti-pIX sera by immunofluorescence and a pIX gene-based PCR are rapid methods which will improve subgenus identification of adenoviruses.

Adenovirus Infections, Human↗
PubMed1997

Adenovirus-receptor interaction with human lymphocytes.

Lymphocytes play a key role in cell-mediated immunity and are host cells for several viral and bacterial pathogens. Their importance in adenovirus (Ad) infections is not yet fully understood. The initial event, the attachment of Ad to lymphocytes and their subsets, was examined using flow cytometry. The study included analysis of stimulated T cells in binding assays with FITC-labeled Ad fiber. The results confirm that native peripheral lymphocytes express very small amounts of Ad receptors. Stimulation with PHA and interleukin 2 induced the expression. The presence of Ad DNA as a sign of internalization in stimulated cells was demonstrated using the polymerase chain reaction. The findings suggest that lymphocytes after stimulation can turn into target cells for Ad. This is particularly important if there are indications for persistence of Ad, and in the case of immunocompromised patients severe, life-threatening diseases can develop.

Adenoviruses, Human↗
PubMed1996

Inhibition of cell adhesion to the virus by synthetic peptides of fiber knob of human adenovirus serotypes 2 and 3 and virus neutralisation by anti-peptide antibodies.

The fiber knob of adenovirus (Ad) causes the first step in the interaction of adenovirus with cell membrane receptors. To obtain information on the receptor binding site(s) several synthetic peptides derived from Ad2 and Ad3 fiber head sequences and their antisera were tested for interference with virus attachment to HeLa and FL cells and cell adhesion to viruses. The anti-peptide sera were also evaluated in ELISA and virus neutralisation test. Ad2 (of subgroup C) and Ad3 (of subgroup B) attachment was not significantly inhibited by peptides corresponding to the amino acid residues 535-554, 555-573, 562-582 of Ad2 fiber or 210-225, 267-283, 291-306 and 300-319 of Ad3 fiber. However, microplate pre-adsorbed Ad3 fiber residues 210-225 and 267-283 could bind FL and HeLa cells, and 1 mg/ml of Ad3 fiber residues 267-283 inhibited the cell adhesion to Ad3 virus to approximately 90%. This peptide may participate in the receptor binding site of Ad3 fiber. ELISA reactive anti-peptide antibodies against the homologous peptide and virus did not significantly reduce the cell adhesion to the immobilised virus or the virus attachment to cells, but in the neutralisation assay antibodies raised to Ad2 fiber residues 555-573 and 562-582 and Ad3 fiber residues 210-225 caused neutralisation of the homologous virus at serum dilutions of 1:500 and 1:32, respectively. The corresponding peptides and one further peptide of Ad2 fiber and two of Ad3 fiber seem to contain neutralisation epitopes.

Adenoviruses, Human↗
PubMed1992

Antigenic and molecular analysis of influenza A(H3N2) virus strains isolated in 1985 in open and closed communities of northern Germany.

Antigenic and molecular analyses of influenza A(H3N2) virus strains isolated in 1985 during outbreaks in open and closed communities of North Germany were carried out. The data obtained have shown that 11 strains isolated in a closed orphanage were antigenically similar to each other. The electrophoretic mobilities of either HA, NP, M1 and NS1 polypeptides or of double stranded RNA segments were indistinguishable. Analysis of viruses isolated at the same time from open communities has revealed that they contained at least three groups of strains differing in homology of 3-5 RNA segments. These data support the idea that an outbreak of influenza in a community is caused by single virus strain, from which their slightly different variants of the virus arise during circulation among sensitive persons.

Adolescent↗
PubMed1991

Intraepidemic variants of influenza virus H3 hemagglutinin differing in the number of carbohydrate side chains.

During the epidemic outbreak in the region of Greifswald in the winter 1974/75, we found influenza virus variants which showed differences in the electrophoretic mobility of HA. Among the 25 isolates 13 were of slower and 12 of higher mobility. HA1 of 6 isolates was studied by determining the number of the carbohydrate side chains and by direct sequencing of vRNA. Evidence is presented that variants showing a slower electrophoretic mobility of HA1 had consistently acquired a seventh carbohydrate side chain at Asn 126 in epitope A. All the isolates differed from the reference strain A/Port Chalmers/1/73 by the loss of the oligosaccharide at Asn 81. The field strain A/Dresden/3/71 possessed only 5 oligosaccharides in HA1. These results suggest that changes in glycosylation are an important mechanism in the structural variation underlying antigenic drift of HA.

Antigenic Variation↗
PubMed1991

Further studies on cold adapted variants of human influenza virus A/Krasnodar/101/59 (H2N2) with special reference to genetic stability of attenuation markers.

A previously described cold adapted (ca) attenuated virus, K/25, derived from parent strain A/Krasnodar/101/59 (H2N2), was further modified by 35 additional passages in chick embryos at suboptimal temperature. The virus obtained had retained a distinct ts and ca phenotype and some other markers of attenuation but differed from formerly isolated ca variants by its higher genetic stability connected with an increased growth capacity in chick embryos.

Animals↗
PubMed1989

Antigenic reactivity of matrix protein and nucleoprotein of influenza virus as detected by EIA after dissociation with different detergents.

Solid phase enzyme-immunoassay (EIA) was employed to assess the antigenic reactivity of matrix protein (M) and nucleoprotein (NP) of influenza A virus adsorbed to polystyrene in the presence of different detergents such as beta-octaglucoside (OG), Triton X-100, Tween-20, sodium dodecylsulphate (SDS), sodium deoxycholate (Doch-Na), Nonidet P-40 (NP-40), and sarcosyl at concentrations ranging from 0 to 2%. The antigenic reactivity of NP was the highest in the absence of detergents. For M protein, Doch-Na, SDS, NP-40 and sarcosyl of 0.05-0.1% enhanced the chromatophoric response in EIA 1.5-2 times. In contrast, the antigenic reactivity of M protein remained unchanged after OG or Triton X-100 treatments, and it decreased in the presence of Tween-20.

Adsorption↗
PubMed1989

Effects of norakin on respiratory syncytial virus in tissue culture and in mice.

Norakin at 1 microgram/ml inhibits the reproduction of respiratory syncytial virus (RSV) in Vero cells to 50% and at 5 micrograms/ml to 90%. The development of lung lesions in RSV-infected BALB/c mice was suppressed by 70% when the animals were treated with two doses (25 mg/kg each) of norakin, 30 min before and 4 hr post infection. (p.i.), respectively.

Animals↗
PubMed1986

Differences of nucleoproteins of human and avian influenza A virus strains shown by polyacrylamide gel electrophoresis and by the peptide mapping technique.

Electrophoretic mobility differences in polyacrylamide gels were detected between (35S)-methionine-labelled nucleoproteins (NPs) induced in monolayer cells by 15 human and 4 avian reference strains of influenza viruses. The (35S)-methionine-labelled tryptic peptides of nucleoproteins of these strains were also analyzed by peptide mapping technique. Based on several detectable hydrophilic peptides the NPs could be arranged in 7 clearly differentiable groups. After radioiodination of NPs from 4 human and 3 avian reference strains the tryptic peptide patterns showed one clear difference between human and avian strains.

Electrophoresis, Polyacrylamide Gel↗
PubMed1986

Variation of influenza A (H3N2) viruses isolated in the G.D.R. during 1969-1980 epidemics.

A collection of 39 influenza A virus strains of the subtype H3N2 isolated in G.D.R. and of six reference strains were analysed with regard to the antigenic structure of their surface proteins haemagglutinin (HA) and neuraminidase (NA) as well as regarding their polypeptide variations. For the field strains during the drift period from spring 1969 to spring 1980 seven main variations resulted from eight polyclonal sera with the haemagglutination inhibition test, and five main variations from six polyclonal sera with the neuraminidase inhibition test. Using the polyacrylamide gel electrophoresis polypeptide variations in HA, nonstructural proteins NS1, NS2 and nucleoprotein (NP) were detected. It could be shown that, even during one epidemic, strains circulated with different polypeptide composition. With the help of peptide mapping further variations of NP and NS1 were registered. The mechanisms leading to the emergence of new epidemic strains are discussed.

Animals↗
PubMed1985

The variability of genes of influenza A (H3N2) virus strains isolated in the G.D.R. during the 1970-1978 epidemic seasons.

Gene variability of all influenza A virus strains (H3N2) isolated in the G.D.R. during the epidemic seasons of 1970-1978 was investigated by cRNA:vRNA hybridization. From 1970 through 1975 a gradual smooth variability of the majority of genes and moderate heterogeneity in gene homology of the isolates were observed. From 1975 through 1977 the genome variability was more profound and the isolates differed from one another in gene homology. In 1978 the variability became less pronounced again. Quantitative evaluation of the variability for individual genes gave the following results: 0.4% nucleotides per year for genes, 1, 2, 3 (P proteins), 1.4% for gene 4 (HA), 0.1% for gene 5 (NP), 1.0% for gene 6 (NA), 0.1% for gene 7 (M) and 0.4 for gene 8 (NS).

Disease Outbreaks↗
PubMed1985

Hyperglycemia in BALB/c mice after pretreatment with one subdiabetogenic dose of streptozotocin and subsequent infection with a Coxsackie B4 strain.

Male BALB/c mice were injected with one subdiabetogenic dose of streptozotocin followed by Coxsackie B4 virus infection 7 days later. The animals developed a transient hyperglycemia after streptozotocin-pretreatment and infection with a human Coxsackie B4 isolate. Frozen sections of pancreata stained with FITC-labeled antibodies showed an intensive infection of the exocrine tissue. Immunofluorescence studies with isolated islets obtained from streptozotocin-treated or untreated animals demonstrated virus antigen in about 20% of the islets 5 days after in vivo virus infection. It is supposed that the hyperglycemia measured in our experiments was caused by a cumulative effect of streptozotocin and virus infection.

Animals↗