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C Orvell

Publications and source records attributed to C Orvell.

123 records · Page 7Linked to original sources
PubMed1979

Characterization of the polypeptides synthesized in cells infected with a temperature-sensitive mutant derived from an HVJ (Sendai virus) carrier culture.

The intracellular synthesis of virus-specific polypeptides in cells infected with the wild-type virus of HVJ (HVJ-W) (haemagglutinating virus of Japan--the Sendai strain of parainfluenza 1 virus) and with a temperature-sensitive (ts) mutant (HVJ-pB) derived from an HVJ carrier culture has been analysed by polyacrylamide gel electrophoresis. At the permissive temperature (32 degrees C), all of the known virus structural polypeptides were identified in cells infected with each strain of virus and in addition to the non-structural polypeptides B and C, another polypeptide at the region with a molecular weight of 26,000 to 27,000 (26 to 27K) could be detected in infected cells. At the non-permissive temperature (38 degrees C), the synthesis of the polypeptide M was markedly restrained in cells infected with HVJ-pB, while other major virus polypeptides were present in approximately comparable amounts to cells infected with the wild-type virus. A non-structural polypeptide with a molecular weight of 105K was dominant in ts mutant infected cells at higher temperatures and disappeared after temperature-shift from 38 degrees to 32 degrees C. The production of the non-structural polypeptides B and 27K was also temperature-sensitive. The molecular weights of the polypeptides B, M and 27K in HVJ-pB infected cells were larger than those of the corresponding polypeptides in HVJ-W infected cells. The synthesis of the M protein in HVJ-prinfected cells started just after lowering the incubation temperature and the newly made M protein was successfully incorporated into virus particles.

Animals↗
PubMed1979

Assembly of viral structural proteins in cells infected with a temperature-sensitive mutant derived from an HVJ (Sendai virus) carrier culture. Brief report.

The processing of virus polypeptides synthesized in cells infected with HVJ (haemagglutinating virus of Japan--the Sendai strain of parainfluenza 1 virus) was studied. Maturation of a temperature-sensitive (ts) mutant (HVJ-pB) derived from an HVJ carrier culture was inhibited at 38 degrees C incubation. A considerable amount of viral components were made at the restrictive temperature. They were, with the exception of the polypeptide HN, well preserved without a great loss of their function and successfully incorporated into virus particles released after lowering the incubation temperature. The membrane (M) protein seems to be essential for virus morphogenesis.

Animals↗
PubMed1978

Structural polypeptides of mumps virus.

The structural polypeptides of egg grown mumps virus were analysed by SDS-polyacrylamide-slab-gel electrophoresis. Mumps virions contained eight major polypeptides with mol. wt. of 75, 73, 71, 61, 47, 44, 42 and 40 X 10(3). The 75 K and 61 K polypeptides were glycosylated. In virions treated with pronase and trypsin, the 75 K glycoprotein was removed more readily from the virus than the 61 K glycoprotein. The gradual removal of the 75 K glycoprotein was paralleled by a decrease of haemagglutinating activity. The large glycoprotein was cleaved into a 40 K glycoprotein by trypsin treatment. Pronase and trypsin treatment also removed the smallest 40 K non-glycosylated polypeptide. Thus this polypeptide appears to be located on the outside of the virion and probably represents a cleavage product of the large glycoprotein. Treatment of virions with 2% Triton-X 100 under alkaline conditions in the absence or presence of 2 M-KCl solubilized the two glycoproteins and a fraction of the 71 and 44 K polypeptides, but not the 73 and 47 K polypeptides. The two smallest polypeptides were solubilized by treatment with 2% Triton X-100 in the presence of 2 M-KCl. Since the 40 K polypeptide was interpreted to represent a cleavage product of the large surface glycoprotein the 42 K polypeptide was proposed to represent the membrane protein of mumps virus. The 44 K polypeptide co-migrated with Vero cell actin. The nature of the 47 K polypeptide could not be determined, but it is probably located in the central part of the virus. The 73 K polypeptide and in some experiments also the 71 K polypeptide were found in purified nucleocapsid preparations. It is concluded that mumps virus has a general polypeptide composition similar to other paramyxoviruses. However, the molecular weights of the different polypeptides of mumps virus differ markedly from the corresponding polypeptides in Newcastle disease virus and Sendai virus.

Glycoproteins↗
PubMed1977

New tests for characterization of mumps virus antibodies: hemolysis inhibition, single radial immunodiffusion with immobilized virions, and mixed hemadsorption.

Hemolysis inhibition (HLI), single radial immunodiffusion (SRID) with immobilized virions, and mixed hemadsorption tests were used for measuring antibodies against mumps virus. Rabbit hyperimmune sera against mumps and early and late human convalescent sera were analyzed. All three tests identified antibodies against both hemagglutinin and the second major envelope component, hemolysin (fusion factor). The sensitivity of the HLI test corresponded to that of the hemagglutination inhibition (HI) test, but in some sera HLI antibodies occurred in greater quantity than HI antibodies. The SRID test readily identified rises in antibody titers in connection with acute infection. Due to its simplicity and lack of sensitivity to nonspecific inhibitors, it is recommended for use in this context. The mixed hemadsorption test showed a high sensitivity for specific identification of mumps antibodies. It therefore may be suitable for use in screening for immunity to mumps.

Antibodies, Viral↗
PubMed1976

Identification of paramyxovirus-specific haemolysis-inhibiting antibodies separate from haemagglutinating-inhibiting and neuraminidase-inhibiting antibodies. 1. Sendai virus haemolysis-inhibiting antibodies.

Egg-grown Sendai virus was used for preparation of rabbit hyperimmune sera directed against purified whole virus and pronasetreated projectionless virus particles. These sera and convalescent sera after natural Sendai infection in guinea pigs were studied in haemolysis-inhibition (HLI), haemagglutination-inhibition (HI) and neuraminidase-inhibition (NI) tests both before and after absorption with Tween 80-ether (TE) treated virus preparations. In addition, neutralization tests using the different sera were carried out. HI and NI antibodies and the major population of neutralizing antibodies in convalescent sera were removed by absorption with TE treated virus material without changing the titre of non-HI HLI antibodies. Rabbit hyperimmune sera directed against projectionless virus particles exhibited HLI antibody titres in marked excess of HI and NI antibody titres, whereas this was not found in sera against purified whole virus. In contrast, absorption of sera against projectionless particles eliminated HI antibodies without changing the titre of non-HI HLI antibodies. The protein composition of antigenic preparations used in absorption experiments and for preparation of sera was investigated by SDS-polyacryladmie-gel electrophoresis. TH treatment had no significant effect on the polypeptide pattern of Sendai virus. Pronase-treatment predominantly affected the two glycosylated proteins of Sendai virus. The larger glycoprotein was not detectable in pronasetreated projectionless virus particles, whereas the smaller glycoprotein was present in reduced quantities.

Animals↗
PubMed1976

Identification of paramyxovirus-specific haemolysis-inhibiting antibodies separate from haemagglutinating-inhibiting and neuraminidase-inhibiting antibodies. 2. NDV and mumps virus haemolysis-inhibiting antibodies.

Egg-grown Newcastle disease (NDV) and mumps virus were used for preparation of rabbit hyperimmune sera against purified whole virus and projectionless virus particles. These sera and convalescent sera after natural NDV and mumps infections in chickens and human subjects, respectively, were studied in haemolysis-inhibition (HLI), haemagglutination-inhibition (HI) and neuraminidase-inhibition (NI) tests both before and after absorption with Tween 80-ether (TE) treated virus preparations. In addition, neutralization tests using the different sera were carried out. HI and NI antibodies and the major population of neutralizing antibodies in convalescent sera were removed by absorption with TE treated virus material without changing the titre of non-HI HLI antibodies. Rabbit hyperimmune sera directed against projectionless virus particles exhibited HLI antibody titres in marked excess of HI and NI antibody titres, whereas this was not found in sera against whole virus. Absorption with TE treated virus material resulted in removal of all demonstrable antibody activities in sera against whole virus. The corresponding absorption of sera against projectionless particles eliminated HI antibodies without changing the titre of non-Hi HLI antibodies. In rabbit hyperimmune sera, HI antibodies were of primary importance in neutralization tests. After addition of anti-gamma globulin to the test, an efficient neutralization was observed if mumps non-HI HLI antibodies were used whereas this was not found if NDV non-HI HLI antibodies were used.

Animals↗
PubMed1970

Morphogenesis of respiratory syncytial virus in a green monkey kidney cell line (Vero).

The structure and morphogenesis of respiratory syncytial (RS) virus particles in a green monkey kidney cell line (Vero) were examined. Infected cells contained dense intracytoplasmic inclusions composed of filamentous structures. In places where inclusion material was associated with membranes, structural modifications were induced. There was a thickening of the membrane and an addition of projections 12 to 15 nm in length. The same changes were most frequently observed after association of isolated filamentous structures with the cytoplasmic membrane. The budding-off process was clearly visualized. The diameter of mature virus particles varied between 90 and 130 nm and that of the internal component varied between 11 and 15 nm. The similarities between ultrastructural features of cells infected with RS virus and pneumonia virus of mice are pointed out. It is proposed that these two viruses should be classified together in a third subgroup of myxoviruses.

Animals↗
PubMedDate not supplied

Asymmetric budding of viruses in ependymal and choroid plexus epithelial cells.

Sendai virus injected intracerebrally into 3-week-old mice caused infection of ependymal and choroid plexus epithelial cells. Budding of mature viruses occurred only from the apical surfaces of these cells. The viral peplomere proteins, haemagglutinin-neuraminidase and fusion, were concentrated on the apical portion of the ependymal cells, while the nucleocapsid-associated polymerase protein was dispersed throughout the cytoplasm. This indicates that intracellular routing of the virus envelope glycoproteins to the cell surface may be one of the factors that determines the site of virus budding. Vesicular stomatitis and vaccinia viruses, on the other hand, budded or egressed predominantly from the baso-lateral cell surfaces.

Animals↗
PubMedDate not supplied

[Epitope analysis of mumps virus proteins in a persistent cell culture infection: changes in the hemagglutinin-neuraminidase polypeptide].

Monoclonal antibodies (MABs) against major structural mumps virus proteins were used for epitope analysis in primarily and persistently infected HEp-2 cells by means of immunofluorescence and radioimmunoprecipitation techniques. Qualitatively, no differences were found in MAB binding between corresponding proteins of the original and persistent viruses, whereas quantitative differences observed might be explained in terms of weakened viral protein synthesis in persistent infection. Limited proteolysis of MAB-bound antigen has revealed alterations in certain epitopes on persistent virus HN polypeptide. Despite the inability of HEp-2 infected cells for hemadsorption, HN protein was expressed on the surface of these cells to the same extent as in the hemadsorbing system of mumps virus-infected Vero cells.

Animals↗
PubMedDate not supplied

[Antigenic variants of the respiratory syncytial virus in Argentina and Uruguay].

The characterization of RSV antigenic variants was carried out on 160 nasopharyngeal aspirates from children under 5 years of age, from Argentina and Uruguay, with acute respiratory infection and a previously positive etiological diagnosis for RSV. Results for Argentina were: 20.9% of samples belonged to subtype A, 76.9% to subtype B and the remaining 2.2% to new subtypes as yet uncharacterized. Results for Uruguay were: 5.6% of samples belonged to subtype A, 81% to subtype B and 13.5% to other subtypes. Subtype B was predominant in both countries. The correlation of RSV antigenic variants with the clinical picture and epidemiological profile is currently underway.

Antigenic Variation↗