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C Orvell

Publications and source records attributed to C Orvell.

At least 109 records · Page 6Linked to original sources
PubMed1985

Hemagglutinin-neuraminidase glycoprotein as a determinant of pathogenicity in mumps virus hamster encephalitis: analysis of mutants selected with monoclonal antibodies.

With the aid of monoclonal antibodies directed against a specific site on the hemagglutinin-neuraminidase surface glycoprotein, four mutants of the Kilham neurotropic strain of mumps virus were isolated. All four mutants had increased neuraminidase activity. Two mutants (M10 and M12) lost their hemagglutination capacity with human O erythrocytes but retained their ability to agglutinate guinea pig erythrocytes at 4 degrees C. A third mutant (M11) showed a change in the molecular weight of the hemagglutinin-neuraminidase glycoprotein. These three mutants (M10, M11, and M12) showed unaltered capacity to infect tissue cultures and to cause encephalitis in newborn hamsters. A fourth mutant (M13) retained its hemagglutination activity and capacity to infect Vero cell cultures but showed significantly lower neurovirulence in the suckling hamster brain than did the parental Kilham strain and the other three mutants. Both the number of infected neurons and the amount of infectious virus in the brain was reduced. On the other hand, there were no apparent differences in the occurrence of viral antigen in ependymal cells, indicating a selective change in affinity for neurons in the brain. These results suggest that certain changes in the hemagglutinin-neuraminidase glycoprotein may lead to an alteration of the neuropathogenicity of the Kilham strain of mumps virus.

Animals↗
PubMed1985

Is rinderpest virus the archevirus of the Morbillivirus genus?

Groups of 6-39 monoclonal antibodies identifying 3-18 distinct epitopes on the nucleoprotein (NP), polymerase (P), hemagglutinin (H; equivalent in canine distemper and rinderpest viruses), and fusion (F) components of measles and canine distemper viruses were characterized in immunofluorescence tests with fixed Vero cell cultures infected with measles, canine distemper and rinderpest viruses. The majority of NP-specific monoclonal antibodies reacted with all three viruses, but one-third of the antibodies only reacted with the homologous virus. A few antibodies detected epitopes uniquely shared between either measles and rinderpest viruses or canine distemper and rinderpest viruses. Of the P-specific antibodies, two-thirds only reacted with the homologous virus, one antibody detected an epitope shared between canine distemper and rinderpest viruses, and the rest reacted with all three viruses. Also, the majority of antibodies against the H component were type-specific, but four antibodies reacted both with measles and rinderpest viruses. In contrast, the F component was antigenically highly conserved. 17 of 21 antibodies against this component reacted with all three viruses; one antibody reacted only with measles and rinderpest virus F components, and three antibodies reacted only with the homologous virus. No monoclonal antibody of any specificity selectively reacted with only measles and canine distemper viruses. Furthermore, the measles virus H component appeared to be more closely related to the equivalent rinderpest virus component than to the canine distemper virus component. Thus, it is proposed that rinderpest virus is the archevirus of the morbillivirus group from which canine distemper virus was first to evolve and, more recently (perhaps about 5,000 years ago), measles virus.

Antibodies, Monoclonal↗
PubMed1984

A novel approach to the study of glycolipid receptors for viruses. Binding of Sendai virus to thin-layer chromatograms.

A method for the binding of virus to a silica gel thin-layer chromatogram is presented. After development the chromatogram is overlayed with the 125I-labelled virus and the bound virus is autoradiographed. Alternatively, the unlabelled virus may be detected after exposure to monoclonal antibody and labelled anti-antibody. The Sendai virus strain used did not bind to brain gangliosides earlier proposed to be receptors, but bound to human erythrocyte gangliosides. This finding may be explained by the existence of Sendai virus variants with different receptor specificities.

Animals↗
PubMed1984

Mumps virus infection of the developing mouse brain--appearance of structural virus proteins demonstrated with monoclonal antibodies.

Newborn mice and hamsters were inoculated intracerebrally with mumps virus strains of high and low neurovirulence, Kilham and RW, respectively and with an egg-adapted patient isolate. The presence of viral antigen in brain tissue was analyzed with the immunofluorescence technique employing monoclonal antibodies against nucleoprotein (NP), polymerase (P), matrix (M), hemagglutinin-neuraminidase (HN) and fusion (F) mumps virus components. As expected, hamsters developed a fatal encephalitis eight to nine days after infection with the Kilham strain and synthesis of all five structural viral antigens was identified. In contrast, mice infected with any of the virus strains did not develop signs of disease, but in brain material collected on days nine and 12 after infection viral antigen was present in many neurons. However, only NP and P antigens were demonstrable and no infectious virus was present. The antibody response in mice developed later than in hamsters. Neurons in the mouse brain may exert a host cell restriction on the virus maturation, and mice offer a suitable host for the establishment of defective, persistent mumps virus infections.

Animals↗
PubMed1984

The role of viral glycoproteins in mumps virus-mediated antibody-dependent cellular cytotoxity in vitro.

Treatment of human peripheral blood lymphocytes with live or UV-inactivated mumps virions enhances antibody-mediated cellular cytotoxicity (ADCC), reflected by increased target cell lysis in a 51Cr-release assay or an increased number of plaque-forming cells on monolayers of bovine erythrocytes (Eb) in the presence of anti-Eb antibodies. Virus treatment of the Eb targets causes a similar enhancement. The role of viral glycoproteins in ADCC enhancement was investigated by using a panel of monoclonal antibodies raised in mice against mumps virions. Most of the lymphocytes bound mumps virions, as ascertained by indirect immunofluorescence. A high proportion of virus-treated lymphocytes also formed rosettes with Eb. Anti-HN antibodies inhibited rosetting to various degrees. Although antibodies with high haemagglutination inhibition titres were most efficient inhibitors, antibodies without this serological activity were also inhibitory. Anti-F antibodies were only weakly inhibitory, and anti-NP antibodies had no effect. Anti-HN antibodies also abrogated target cell lysis in the 51Cr-release assay and effector cell recruitment in the ADCC plaque assay by inhibiting virus-mediated Eb-lymphocyte interactions both at the target cell and at the effector cell level. Anti-F or anti-NP antibodies were only weakly or not at all inhibitory. The results suggest that virus-mediated enhancement of ADCC is caused by the HN glycoprotein, primarily (although perhaps not exclusively) by its improvement of the effector cell-target cell contacts necessary for the efficient execution of target cell lysis.

Antibodies, Monoclonal↗
PubMed1984

The reactions of monoclonal antibodies with structural proteins of mumps virus.

Mouse hybridomas producing antibodies against structural proteins of mumps virus were established by fusion of FO or SP 2/0 myeloma cells with spleen cells from BALB/c mice immunized with purified preparations of egg-grown mumps virus. Ascites fluids collected after i.p. inoculation of mice were characterized by different serologic tests. By immune precipitation tests with [35S]methionine-labeled mumps virus polypeptides, 17 clones were found to produce antibodies against the nucleocapsid protein (NP), 11 against the polymerase (P) protein, 10 against the membrane (M) protein, 12 against the fusion (F) protein, and 24 against the hemagglutinin-neuraminidase (HN) protein. Competitive binding enzyme-linked immunosorbent assay (ELISA) tests were performed to determine the reactivity of the monoclonal antibodies with different antigenic sites of each structural component. The monoclonal antibodies directed against the NP, P, and M proteins identified a minimum of 10, 10, and 9 separate antigenic sites, respectively. The 12 clones directed against F were directed against a minimum of eight separate antigenic determinants. These antibodies did not neutralize the infectivity of the virus either in the absence or presence of anti-gamma-globulin. Only low capacity to block hemolysis (HL) activity of the virus was detected in clones directed against three of the eight antigenic sites. Based on their serologic reactivity, the 24 clones directed against the HN protein could be divided into four groups. The first group of clones could not inhibit any biologic activity of the protein. The second group consisted of two clones that blocked HL but did not block hemagglutination (HA) or neuraminidase (NA) activity. The third group, which included five clones, blocked HA, NA, and HL activity of the virus and had high neutralizing capacity. These clones were directed against three distinct antigenic sites. Two of the clones directed against one antigenic site could block NA activity only when a large substrate, fetuin, was used, but not when a small substrate, neuraminlactose, was used in the test. The fourth group included five clones that could block NA but not HA activity of the virus. These clones could neutralize the infectivity of the virus and had high capacity to block HL activity. In blocking experiments, all these antibodies reacted with one antigenic site. The reaction of all clones was tested in ELISA with four different strains of mumps virus. Each strain had unique antigenic sites. Variations were found in four, three, and three different antigenic sites of the NP, P, and HN proteins, respectively.

Animals↗
PubMed1983

Monoclonal antibodies to epitopes shared by actin and vimentin obtained by paramyxovirus immunization.

Three hybridoma clones producing IgM antibodies against actin were obtained from mice immunized with purified virions of paramyxoviruses. When tested on growing lung fibroblasts, ascites fluids of all clones stained in immunofluorescence cytoplasmic bundles of microfilaments, but also fibrillar networks. On colchicine-treated cells, perinuclear coils were seen in addition to microfilament bundles. In addition, one clone gave a pronounced speckled staining to the nuclei. Absorption of the ascites fluids with purified actin abolished all staining patterns. Using the Western blotting technique the antibodies reacted with both actin and vimentin polypeptides. DNase I abolished the staining of the actin filaments and of the nuclei, but left the vimentin pattern unimpaired. Thus, the monoclonal antibodies evidently reacted with epitopes common to actin and vimentin.

Actins↗
PubMed1983

Sendai virus infection in the brains of mice: distribution of viral antigens studied with monoclonal antibodies.

Newborn and 12- and 21-day-old mice were inoculated intracerebrally with Sendai virus. Titers of infectious virus peaked on days 1-2 after infection and had disappeared after three days in 12- and 21-day-old mice and six days in newborn mice. The levels of infectious virus in the brain declined before the appearance of serum antibodies, which in newborn mice was delayed until day 12. Immunofluorescence analysis showed viral antigens in neurons and their dendritic processes 12 and 24 days after infection in newborn animals but not in older ones. Immunofluorescent staining with monoclonal antibodies to five major structural components of Sendai virus--the nucleocapsid, polymerase, matrix, fusion, and hemagglutinin-neuraminidase proteins--showed that all were present in choroid plexus epithelial cells and ependymal cells during acute infection. However, during acute and persistent infections in neurons, the first three antigens were found, but the last two--surface glycoproteins--were lacking or found at low levels.

Animals↗
PubMed1983

Cellular localization of five structural proteins of Sendai virus studied with peroxidase-labelled Fab fragments of monoclonal antibodies.

By the use of horseradish peroxidase-labelled Fab fragments of monoclonal antibodies, five major structural components of Sendai virus, namely the nucleocapsid (NP), polymerase (P), matrix (M), fusion (F), and haemagglutinin-neuraminidase (HN) proteins were localized in infected Vero cells. The P and NP proteins were found in association with large clusters of ribosome-like particles and nucleocapsids in the cell cytoplasm. They were not concentrated at the cytoplasmic membrane, except in nucleocapsids within budding viral particles. F and HN proteins, on the other hand, were found in connection with ribosomes and endoplasmic reticulum in the cell cytoplasm, but not in nucleocapsids. Both proteins were evenly distributed on the outer cytoplasmic membrane and appeared on the surface clearly before budding of viral particles. The M protein was seen in connection with both nucleocapsids and ribosomes. It was not found at the cell surface except in budding viral particles.

Animals↗
PubMed1983

Sendai-virus-induced cell-mediated cytotoxicity in vitro. The role of viral glycoproteins in cell-mediated cytotoxicity.

Treatment of peripheral blood lymphocytes from normal donors with small amounts of purified Sendai virions results in enhanced cellular cytotoxicity in vitro to uninfected tissue culture target cells (virus-dependent cellular cytotoxicity (VDCC)), without any obvious correlation to the natural cytotoxicity (NK) displayed by the lymphocytes in the absence of virus. Removal from the virions of the two surface components present in the viral envelope, the HN glycoprotein (gp 71), carrying haemagglutinating and neuraminidase activity, and the F glycoprotein (gp 49), carrying fusion activity, by treatment with pronase abrogated their capacity to induce VDCC. Similar results were obtained when virions lacking the HN glycoprotein after treatment with chymotrypsin were added to the lymphocytes. In contrast, treatment of the virus particles with trypsin, which removed the F glycoprotein, did not affect their capacity to induce VDCC. When the solubilized and separated peplomers were used for lymphocyte treatment, either alone or in combination, the purified HN glycoprotein had full capacity to induce VDCC, whereas the F glycoprotein was inactive. These results suggest that the HM peplomer is solely or primarily responsible for the cytolytic activity arising in non-sensitized lymphocytes when confronted with certain viruses.

Adult↗
PubMed1981

Antibodies against measles virus polypeptides in different disease conditions.

The occurrence of antibodies to the nucleoprotein and matrix (M) antigens of measles virus was determined in early and late measles convalescent sera and in sera from patients with multiple sclerosis, subacute sclerosing panencephalitis, chronic active hepatitis, and atypical measles. Antibodies to the two components were identified separately in serially diluted samples both by radioimmune precipitation assays and by complement fixation tests employing purified nucleoprotein and M components as antigens. The antibody response to M antigen in connection with acute infections was weak, and with time titers of antibodies to M antigen were reduced below detectable levels in most cases. A different situation was seen in patients with atypical measles. A pronounced antibody response to M antigen was shown to be a part of the generally accentuated immune response in these patients. Confirming results of others, it was shown that in spite of the increased antibody titers against most measles components in sera from patients with subacute sclerosing panencephalitis, no or only low titers of antibodies to M antigen were present. However, a similar representation of antibodies to measles virus components was also seen in sera from patients with active chronic hepatitis. The significance of this finding for the interpretation of a weak antibody response to M antigen in the presence of a pronounced antibody response to other components is discussed.

Antibodies, Viral↗
PubMed1980

Structural polypeptides of canine distemper virus.

The structural polypeptides of two strains of canine distemper virus and the Lec strain of measles virus were analysed by SDS-polyacrylamide-slab-gel electrophoresis. One strain of canine distemper virus derived from a live vaccine (Convac, Dumex), contained six major structural polypeptides with mol.wt. of 85, 78, 59, 43, 41 and 34 x 10(3). The 85K polypeptide was glycosylated. It was interpreted to be equivalent ot the 79K glycoprotein of the measles hemagglutinin. The second strain, a rapidly growing variant of the Onderstepoort strain of canine distemper virus characterized by extensive syncytium forming cytopathic effects in tissue culture, contained the 5, 43, 41 and 34K polypeptides, but the 85 and 78K polypeptides were not present in detectable amounts. The 43K polypeptide was identified as cellular actin by limited proteolysis. By use of monospecific rabbit hyperimmune sera against each of the major structural polypeptides of measles virus, the 59, 41 and 34K structural polypeptides could be identified as nucleocapsid protein (NP), fusion (F) polypeptide, and the membrane (M) polypeptide, respectively. In neutralization tests with rabbit hyperimmune sera against each of the two strains, this Onderstepoort strain, which contained reduced amounts of the hemagglutinin glycoprotein, gave higher neutralization titers than the vaccine strain.

Actins↗
PubMed1980

Immunological relationships between homologous structural polypeptides of measles and canine distemper virus.

The major structural polypeptides of measles and canine distemper virus (CDV) were isolated by SDS-polyacrylamide slab gel electrophoresis. Rabbit hyperimmune sera directed against the isolated HA, P, NP, F and M polypeptides were prepared. In addition, rabbit hyperimmune sera directed against purified native internal components of measles virus and against purified virions of measles and CDV, untreated or treated with trypsin, were prepared. These sera were used to study the immunological relationships between measles and CDV in immune precipitation tests with 35S-methionine-labelled extracellular virions and intracellular virus polypeptides and by use of component fixation and mixed haemadsorption tests. An immunological relationship between the M polypeptides was demonstrated with sera against both native partially denatured antigens. A reciprocal immunological cross-reactivity between the NP polypeptides was demonstrated by the use of sera directed against native antigens. However, antisera directed against the NP polypeptides isolated from gels did not show any cross-reaction, indicating that they lacked antibodies against the shared antigenic determinants. The immunological cross-reactivity between envelope components of the two viruses was analysed. A close reciprocal immunological relationship between the F polypeptides was demonstrated by immune precipitation of labelled polypeptides. Immunological cross-reactivity between the HA polypeptides of the two viruses could not be demonstrated by use of the same technique neither with sera directed against denatured antigen nor with sera against native antigen when extracellular denatured 35S-methionine-labelled purified virions were used in immune precipitation. A slight cross-reactivity could, however, be demonstrated with sera against native antigens in immune precipitation tests with 35S-methionine-labelled intracellular antigens. It is concluded that all the major structural polypeptides of measles and CDV show varying degrees of reciprocal immunological cross-reactions. The M polypeptides of the two viruses appear most closely related, whereas the HA polypeptides show the most pronounced differences.

Cross Reactions↗
PubMed1980

Isolation and immunological characterization of the nucleocapsid and membrane proteins of measles virus.

Measles virus nucleoprotein (NP) and matrix (M) components were purified by two different procedures. Antigens were prepared by sedimenting material from 1% Cutscum extracts of infected cells into the interphase between 65 and 40% sucrose and further fractionation of the interphase material in a linear CsCl gradient, density range 1.20 to 1.33 g/ml. NP components contaminated with some M material and cellular actin banded at 1.30 to 1.32 g/ml, but at the low density range of 1.20 to 1.22 g/ml pure M component was demonstrable. Partially denatured antigens were obtained by elution of the 60K NP and 36K M polypeptides after SDS-polyacrylamide slab gel electrophoresis. Rabbit hyperimmune sera were prepared against both purified antigens and isolated polypeptides. All sera reacted only with homologous antigen except the antiserum against NP components isolated from CsCl gradients, which also contained antibodies to the M component. Antibodies against NP antigen stained both intranuclear inclusions and cytoplasmic material in immune fluorescence tests. In contrast, antisera against M antigen only stained the cytoplasm. Since intranuclear nucleocapsids are smooth, whereas intracytoplasmic nucleocapsids are 'fuzzy', this may infer that the fuzziness, at least in part, is caused by M antigen adhering to nucleocapsid components.

Capsid↗
PubMed1980

The role of viral glycoproteins in mumps-virus-dependent lymphocyte-mediated cytotoxicity in vitro.

Human peripheral blood lymphocytes (PBL) from healthy donors express enhanced natural cytotoxicity to target cells after a brief exposure to mumps virus in vitro. We describe here experiments aiming at elucidating the mechanism of this virus-dependent cytotoxicity. Treatment with proteolytic enzymes resulted in virus particles depleted of one or both kinds of their glycoproteins spikes. Removal of both of these components frrom the virion abrogated their ability to enhance cytotoxicity. This virus-dependent cytotoxicity was significantly but not completely reduced when one of the spike glycoproteins (gp 75, HANA) was removed selectively. Similarly, nucleic-acid-free preparations of the spikes, obtained by detergent treatment of mumps virions, also elicited enhanced cytotoxicity. However, the activity of these preparations was lower than that of untreated virions. Further evidence for the importance of HANA was provided by the use of (F(ab')2 fragments of anti-HANA-specific rabbit antibodies. When these fragments were allowed to react with virus before addition of the virus to PBL, no augmentation of cytolysis was observed. Antibody fragments specific for the other spike protein (gp 61, F) failed to inhibit the virus-dependent enhancement of PBL-mediated cytotoxicity. However, anti-HANA and anti-F blocked this reaction when added directly to the mixture of virus-treated PBL and target cells. The results are compatible with the hypothesis that virus-dependent cytotoxicity requires HANA for anchoring the virus to PBL receptors (and perhaps to bring effector and target cells into closer contact), whereas F may be involved in subsequent events increasing effector cell function.

Antigens, Viral↗