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Biomedical subjects

U Desselberger

Publications and source records attributed to U Desselberger.

At least 127 records · Page 7Linked to original sources
PubMed1984

The genomes of rotaviruses isolated from chronically infected immunodeficient children.

Abnormal RNA migration profiles were found in numerous rotavirus samples from two chronically infected children suffering from severe combined immunodeficiency. In both cases additional bands consisting of dsRNA were found migrating between RNA segments 1 and 7, and in one case RNA segment 11 was lost from the profile. Hybridization studies using segment-specific cloned cDNA probes indicated that some of the additional bands had sequence homologies with normal rotavirus dsRNA segments. In most cases these sequences were derived from genome segments of lower molecular weight by the formation of covalently linked concatemers.

Child, Preschool↗
PubMed1983

Cocirculation of different rotavirus strains in a local outbreak of infantile gastroenteritis: monitoring by rapid and sensitive nucleic acid analysis.

Rotaviruses isolated from 22 patients during a local outbreak of infantile gastroenteritis in October/November 1981 were genotyped by establishing their RNA migration patterns on polyacrylamide gels. A highly sensitive silver staining procedure was used to visualize the RNAs. It was found that strains with at least four different RNA patterns cocirculated and also showed serological differences.

Child, Preschool↗
PubMed1983

Silver staining of nucleic acids. Applications in virus research and in diagnostic virology.

The rapid and sensitive method of silver staining of nucleic acids in polyacrylamide gels is used to visualise double-stranded (ds) and single-stranded (ss) molecules of both DNA and RNA. The binding of silver ions to nucleic acids in gels is stoichiometric and independent of the GC content of ds DNA. Silver staining can be applied to problems in virus research and to the analysis of clinical virus isolates.

DNA, Viral↗
PubMed1983

Efficient expression of influenza virus NS1 nonstructural proteins in Escherichia coli.

RNA segment 8 of the influenza A virus genome codes for two nonstructural proteins, NS1 and NS2, for which the functions are unknown. Cloned cDNA copies of this gene from three different influenza A virus strains were inserted into an Escherichia coli plasmid expression vector, pAS1, carrying the strong regulatable lambda phage promoter, PL. After induction, the NS1 proteins were overproduced to levels of 20-25% of total cellular protein. This was surprising in that the codon composition for these eukaryotic genes is similar to that for weakly expressed proteins in E. coli. Thus, under the appropriate conditions, it appears that high level expression of genes containing a relatively large proportion of minor codons can be obtained. The NS1 protein produced in bacteria from a cloned cDNA copy of the A/PR/8/34 virus NS gene was purified to apparent homogeneity and used to generate a high-titer monospecific rabbit antiserum. Immunoprecipitation studies showed this antibody to be crossreactive against the NS1 proteins produced by several different influenza A virus strains. Immunofluorescence experiments in Madin-Darby canine kidney cells showed the NS1 proteins to be located in the nucleoplasm early in infection for all strains examined. With some of the strains, NS1-specific immunofluorescence was observed predominantly in the nucleoli later in infection. This technology can be used to obtain other viral proteins in pure form for structural, functional, and immunological studies.

Animals↗
PubMed1980

Genetic structure and genetic variation of influenza viruses.

The following contribution summarizes our most recent results concerning analysis of the influenza A, B and C virus genomes. In addition, we present data on the extent of genetic variation of H1N1 influenza viruses isolated during the months following the 1977 outbreak of H1N1 influenza in China and Russia. A detailed description of these results is published elsewhere.

Base Sequence↗
PubMed1980

Antineuraminidase antibody response to vaccination of chickens with intact virus and different submit preparations of the influenza virus strains A/Sing/1/57 (H2N2), A/Hong Kong/1/68 (H3N2) and A/Port Chalmers/1/73 (H3N2).

The antineuraminidase (AN) antibody response to vaccination of chickens with intact virus and different subunit preparations of the influenza virus strains A/Sing/1/57 (H2N2), A/Hong Kong/1/68 (H3N2) and A/Pt. Chalmers/1/73 (H3N2) was tested comparatively. Using a photometric method capable of analysing mixtures of AN antibodies against antigenically different N2 neuraminidases, it was concluded that vaccination with subunits produced by treatment with bromelain and Sarkosyl can yield AN antibody response against heterologous neuraminidase. By contrast, vaccination with intact and ether-treated virus gave AN antibody response against homologous neuraminidases. The conclusion was reached that the NA's of the strains A/Sing/1/57 and A/Pt. Chalmers/1/73 share antigenic determinants and that the NA of the strain A/Hong Kong/1/68 shares antigenic determinants with that of the strains A/Sing/1/57 and A/Pt. Chalmers/1/73.

Animals↗
PubMed1980

The 3' and 5'-terminal sequences of influenza A, B and C virus RNA segments are highly conserved and show partial inverted complementarity.

The 3'- and 5'-terminal nucleotides of the genome segments of an influenza A, B, and C virus were identified by directly sequencing viral RNA using two different sequencing techniques. A high degree of conservation at the 3' ends as well as at the 5' ends was observed among the genome segments of each virus and among the segments of the three different virus types. A uridine-rich region was observed from positions 17 through 22 at the 5' end of each segment. Moreover, the conserved 3' and 5'-terminal sequences showed partial and inverted complementarity. This feature results in very similar sequences at the 3' ends of the plus and minus strand RNAs and may also enable single-strand RNAs of influenza virus to form "panhandle" structures. Inverted complementary repeats may play an important role in initiation of viral RNA replication.

Base Sequence↗
PubMed1979

Evolution of human influenza A viruses in nature: sequential mutations in the genomes of new H1N1.

The genetic variation of the new pandemic H1N1 influenza A viruses isolated in 1977 was analyzed by two-dimensional oligonucleotide fingerprinting and RNA sequencing. Differences were observed in the fingerprints of the RNAs of these viruses, and analysis of the changes suggested that sequential mutations occurred in their genomes. Based on these data, a scheme is presented which proposes divergent evolution of strains from a common ancestry. Furthermore, it was found that mutations were not restricted to the genes coding for the hemagglutinin and the neuraminidase, but were scattered throughout the genome, suggesting that selective antibody pressure is not solely responsible for the emergence of genetic variants. Our data also strengthen the hypothesis that the new H1N1 influenza virus strains are derived from strains circulating in 1950.

Antigens, Viral↗
PubMed1978

[Changes in the antigenicity of influenza virus neuraminidases due to various methods of preparation].

The influenza virus strains A/Sing/1/57 (H2N2), A/Bel/42 (HoN1) and A/Bel/42 (Ho)-A/Sing/1/57 (N2) were treated with bromelain under reducing conditions and with reducing agent alone, and the antigenicity of the neuraminidase (NA) of intact virus and of the split products was tested comparatively. It was found that the antigenicity of NA was influenced quantitatively and qualitatively by the preparation procedure. Antineuraminidase (AN) antibodies obtained after vaccination of guinea pigs with intact virus and with split products differed in their cross-reactivity with heterologous neuraminidases. AN antibodies directed against N2 NA on the recombinant differed qualitatively from those directed against N2 NA of parent virus. The results warrant the conclusion that the antigenicity of isolated NA or of NA on recombinant virus can differ from that of the NA on intact homologous virus and that such alterations could influence the determination of antigenic relationship between neuraminidases.

Antibodies, Viral↗
PubMed1978

Biochemical evidence that "new" influenza virus strains in nature may arise by recombination (reassortment).

Oligonucleotide analysis of two avian influenza A viruses (Hav6N2 and Hav6Nav4) isolated in nature showed identical or almost identical patterns for the corresponding M and HA genes; 24 of 25 and 13 of 13 large oligonucleotides were indistinguishable by two-dimensional gel analysis. On the other hand, remarkable differences in the oligonucleotide patterns of the remaining genes were observed. Only 2 of 11 oligonucleotide spots of the NS gene, 10 of 27 spots of the NA/NP genes, and 22 of 49 spots of the P genes were indistinguishable between the two strains. On the basis of this observation that at least two genes of these viruses are virtually identical whereas others show easily detectable differences, we conclude that the two avian strains are related to each other by a recombinational event. In addition, it was found that animals in nature can be doubly infected with influenza viruses. Both lines of evidence strongly suggest that recombination is at least one mechanism by which "new" influenza virus strains emerge in nature.

Genes, Viral↗
PubMed1978

Further investigations on the antioncogenic activity of A/PR8/34 (HON1)- influenza virus on polyoma virus induced tumors in newborn Wistar rats.

The oncogenic activity of polyoma virus in newborn Wistar rats can be significantly reduced by simultaneous vaccination with the A/PR8/34 (HON1) strain of influenza virus. The antioncogenic activity (AOA) of influenza virus suspensions was neutralized by the addition of homologous influenza antibodies, indicating that AOA was due to influenza virus and not to any non-viral material possibly present. The AOA of influenza virus was found to decline with storage at 4 degrees C and to depend critically on the relative doses of influenza virus and polyoma virus inoculated per animal. Simultaneous inoculation of animals with influenza and polyoma virus reduced significantly the antibody response to polyoma virus in all experiments, suggesting that influenza virus reduced the multiplication of polyoma virus. By contrast, the antibody response to influenza virus was significantly enhanced by inoculation with polyoma virus in some experiments, only. Influenza virus was found to reduce markedly the adsorption of polyoma virus on rat embryo fibroblast cells, suggesting that AOA could be at least partially due to interference of influenza virus with polyoma virus adsorption on target cells.

Animals↗
PubMed1977

Preparation-conditioned changes of the antigenicity of influenza virus neuraminidases.

The influenza virus strains A/Sing/1/57 (H2N2), A/Bel/42 (H0N1) and A/Bel/42 (HO)-A/Sing/1/57 (N2) were treated with bromelain under reducing conditions and with reducing agent alone, and the antigenicity of the neuraminidase (NA) of intact virus and of the split products was tested comparatively. It was found that the antigenicity of NA was influenced quantitatively and qualitatively by the preparation procedure. Antineuraminidase (AN) antibodies obtained after vaccination of guinea pigs with intact virus and with split products differed in their cross-reactivity with heterologous neuraminidases. In several cases, the quantity of AN antibody formation depended on the hemagglutinin (HA) dose present in the vaccines. The N2 NA on the recombinant virus was significantly more sensitive to treatment with reducing agent than was the N2 NA on the parent virus. AN antibodies directed against N2 NA on the recombinant differed qualitatively from that directed against N2 NA of parent virus. The results warrant the conclusion that the antigenicity of isolated NA or of NA on recombinant virus can differ from that of the NA on intact homologous virus and that such alterations could influence the determination of antigenic relationship between neuraminidases.

Animals↗
PubMed1976

[Immunologic status in Hodgkin patients: correlation with Epstein-Barr virus titers].

1. In Hodgkin's disease patient's immunological in vitro and in vivo parameters are of prognostic importance. 2. Skin test reactivity correlates to peripheral T-lymphocyte counts and Con A induced lymphoblastogenesis. 3. Con A is the most sensitive in vitro indicator for detecting latent immunodeficiency. 4. Hodgkin patients in long term remission after tumor reductive therapy exhibit a qualitative and quantitative lymphocyte defect. 5. In Hodgkin patients Herpes virus related antibody titers are elevated against Epstein Barr virus (EBV). The elevation coincides with a decreased T-cell number and function. Antibodies against other Herpes viruses (HSV, CMV, VZV) are in the normal range, when tested by the complement fixation method.

Antibodies, Viral↗
PubMed1976

Kinetics of reactions of antihemagglutinin and antineuraminidase antibodies with H2N2 and H3N2 influenza virus strains and description of a modification of the photometric ACU method for titration of antineuraminidase antibodies.

The isotherms describing the reactions of selected H2N2 and H3N2 virus strains with antihemagglutinin (AH) and antineuraminidase (AN) antibodies were established by use of a photometric hemagglutination inhibition test [antibody concentration unit (ACU) method]. It was found that the AN antibody isotherms had significantly higher values of the constant 1/N than did the AH antibody isotherms. This finding confirms for further virus strains the conclusion that the photometric ACU method can discriminate objectively between AN and AH antibodies. The results obtained when determining by use of the photometric ACU method the kinetics of reactions of AN antibodies oriented to A/Bel (HO)-A/Sing (N2) virus with the neuraminidases of H2N2 and H3N2 strains, and vice versa, indicated that the N2 neuraminidases of the test strains could be divided into the following groups: One group comprising the strains A/Sing/1/57 and A/AA/1/65, a second comprising the strains A/Hong Kong/1/68 and A/England/42/72 and a third represented by A/Port Chalmers/1/73. This finding indicated progressive antigenic variation of the neuraminidases of the strains tested. A modification of the photometric ACU method for the titration of AN antibodies oriented to N2 strains has been developed. The modified technique was found to be more sensitive and accurate than was AN antibody titration by means of enzyme inhibition and HI pattern test.

Animals↗
PubMed1976

Influence of vaccination with A/PR 8/34 (HO-N1) influenza virus on the oncogenic activity of polyoma virus in newborn Wistar rats.

Vaccination with the A/PR 8/34 (HO N1) strain of influenza virus can decrease significantly the oncogenic activity of polyomavirus in newborn Wistar rats. This effect was regularly observed when animals were vaccinated with 24 hr after birth, whereas vaccinations performed on Days 3 and 10 failed to influence the oncogenic potential of polyoma virus. In 3 series of experiments, influenza virus vaccination resulted in sigificantly decreased tumor rates, and, in a 4th series, in reduced tumor growth only. Heat inactivation of influenza virus failed to abolish its influence on the oncogenicity of polyoma virus. In most of the experiments, the antibody response to influenza virus was enhanced by inoculation of animals with polyoma virus. In contrast, polyoma virus antibody titers were, in some experiments, decreased, and, in others, not influenced by vaccination with influenza virus.

Animals↗