Biomedical subjects

E Norrby

Publications and source records attributed to E Norrby.

At least 145 records · Page 8Linked to original sources

PubMed1987

Serum antibody responses to individual viral polypeptides in human rotavirus infections.

A radioimmunoprecipitation assay (RIPA) was used to study the serum antibody responses to individual polypeptides that developed after infection with viruses from human rotavirus subgroups I and II. Paired sera from eight children (1 to 8.5 years of age) were used in the study. Although all of the eight acute sera were negative by the complement fixation test, four of them were positive by RIPA, indicating a previous infection by rotavirus. A significant difference in the number of polypeptides immunoprecipitated was seen among the convalescent sera. The number of polypeptides immunoprecipitated was found to be related to previous infection experience. At most, ten different polypeptides were immunoprecipitated: seven structural polypeptides VP1 to VP7 and three non-structural polypeptides, NS1, NS2 and NS3. No sera immunoprecipitated VP8 or VP9. Acute sera positive by RIPA immunoprecipitated up to five polypeptides, VP1, VP2, VP3, VP4 and VP6. One of the non-structural proteins (NS2) was found to be particularly immunogenic, since antibodies to this polypeptide were detected in several convalescent sera. Among the structural proteins VP2 and VP6 were found to be the two immunodominant polypeptides which were recognized by all convalescent sera. Only three convalescent sera immunoprecipitated VP7, the major type-specific antigen responsible for inducing neutralizing antibodies. Three of four originally seronegative children with no reactivity in the convalescent sera to VP7 developed neutralizing antibodies to a single serotype. One child developed antibodies to two serotypes.

Antibodies, Viral↗

PubMed1987

Mumps virus infection of dissociated rodent spinal ganglia in vitro. Expression and disappearance of viral structural proteins from neurons.

Cultured spinal ganglia and cord from mice and hamsters were infected with mumps virus or Sendai virus. Expression of five structural proteins, the haemagglutinin-neuraminidase, fusion, nucleocapsid (NP), phospho (P) and matrix proteins was examined with monoclonal antibodies to each protein. In Sendai virus-infected mouse neurons all five viral proteins were detected. In hamster neurons infected with mumps virus all viral proteins were also expressed, but in mouse neurons only the NP and P proteins were seen. This suggests a species-specific cellular restriction of viral protein synthesis in mumps virus-infected mouse neurons. There was no, or only a slight, reduction in the number of neurons between days 4 and 20 after infection of mouse cultures with mumps virus, but the proportion of infected neurons diminished from 68% to 15% during this time.

Animals↗

PubMed1987

Immune response to rotavirus polypeptides after vaccination with heterologous rotavirus vaccines (RIT 4237, RRV-1).

The antibody response to individual rotavirus polypeptides after vaccination with live attenuated heterologous rotavirus vaccines was studied with a radioimmunoprecipitation assay (RIPA). Following vaccination with bovine rotavirus strain RIT 4237 and rhesus monkey rotavirus strain RRV-1, an antibody response was demonstrated mainly against the inner capsid polypeptides VP2 and VP6 and to a lesser extent against VP3/VP4. There was no qualitative difference between the vaccines in the antibody response; both vaccines induced antibodies against the same polypeptides. Quantitatively the antibody response to RRV-1 was somewhat stronger. All prevaccination sera contained by RIPA low levels of rotavirus antibodies. The effect of these antibodies on the 'take' of the vaccines is discussed.

Antibodies, Viral↗

PubMed1987

Antigenic analysis of human and bovine parainfluenza virus type 3 strains with monoclonal antibodies.

The antigenic characteristics of eight human strains and two bovine strains, one of which is represented by two plaque variants, of parainfluenza virus type 3 were analysed. The strains and variants were compared using 52 monoclonal antibodies against five, two, six and six epitopes of the haemagglutinin-neuraminidase (HN), fusion, nucleocapsid and matrix viral proteins respectively, employing radioimmuno-precipitation and immunofluorescence assays. The human strains, seven of which were isolated over 6 years at different geographical locations and the eighth one representing an older prototype strain, showed very little antigenic variation. Extensive differences were detected in all four proteins examined between the human strains and the two strains of bovine origin. Two bovine variants were less effectively neutralized than the prototype human strain with a series of monoclonal antibodies against the HN protein.

Animals↗

PubMed1987

In vitro and in vivo stimulation of murine lymphocytes by human respiratory syncytial virus strains.

Respiratory syncytial virus (RSV) strains of subtype A (A2, WV9894, and WV12138) and of subtype B (WV1293, WV4843, and WV6873) are mitogenic in vitro for unprimed BALB/c spleen cells. The virus also triggered splenocytes in vitro to secrete immunoglobulins. Plaque-purified and UV-irradiated materials of both RSV subtypes produced comparable levels of DNA synthesis. Infectious materials of both subtypes also induced pronounced responses. Lymphocyte activation with UV-inactivated RSV strain A2 was dose-dependent and maximal responses occurred after 4-5 days of incubation. The virus preparations were mitogenic for spleen cells depleted of T lymphocytes by treatment with anti-Thy 1.2 and complement and for lymphocytes of congenitally athymic mice (nu-nu). They were also mitogenic for highly purified T lymphocytes separated by panning of spleen cells on anti-mouse Ig-coated Petri dishes, suggesting that both B and T lymphocytes respond to the mitogenic activity of RSV. Moreover, mice infected intranasally with RSV strain A2 generated local as well as peripheral cellular and humoral responses.

Animals↗

PubMed1987

Viral IgM antibodies in serum and cerebrospinal fluid in patients with multiple sclerosis and controls.

Serum and cerebrospinal fluid (CSF) from 28 patients with multiple sclerosis (MS), 14 with other neurological diseases (OND) and 31 control subjects with tension headache were analysed for presence of IgM antibodies against measles, mumps and varicellae zoster by a specific enzyme-linked immunosorbent assay (ELISA). This technique excluded false positive reaction due to possible presence of rheumatoid factor. Twelve of the 28 patients with MS had IgM antibodies in serum and 4 in CSF, the latter always being accompanied by presence of corresponding IgM antibodies in serum. Six patients had mumps specific IgM, 5 had measles specific IgM and 3 varicellae specific IgM. In 2 patients, viral IgM antibodies were demonstrated in serum against 2 different viruses. Among the 14 OND patients, one with Wilson's disease had demonstrable serum IgM varicellae antibodies and one with radicultis had elevated serum and CSF measles and varicellae IgM antibodies. Among 31 controls, 2 had IgM antibodies in serum, one against varicellae and one against mumps. No correlations were found between viral IgM antibodies and CSF IgM index, serum IgM levels or blood-brain barrier state. Our data show that MS may be accompanied by a systemic IgM response against the 3 viruses tested, occasionally against 2 of the 3 different viruses simultaneously. The occurrence in MS of virus-specific IgM may be a reflection of viral reactivation and/or polyclonal B cell activation.

Adult↗

PubMed1987

Subgroup characteristics of respiratory syncytial virus strains recovered from children with two consecutive infections.

Respiratory syncytial virus strains from 13 children who had repeat infections at least 1 year apart were identified as either subgroup A or subgroup B according to reaction patterns with several monoclonal antibodies directed against the large surface glycoprotein (G), fusion protein (F), nucleoprotein (NP), and matrix protein (M). The virus strains were characterized by enzyme immunoassay, polyacrylamide gel electrophoresis, and immunofluorescence procedures. During the first infection, 10 children had subgroup A strains and 3 had subgroup B strains. Of the 10 children with subgroup A strains during their first infection, 6 had subgroup B and 4 had subgroup A strains during the second infection. Of the three children with subgroup B strains during their first infection, one had subgroup A and two had subgroup B strains during their second infection. No child experienced unusually severe respiratory tract illnesses during second infections with respiratory syncytial virus. Fourfold or greater rises in serum antibody as determined by enzyme immunoassay were as common after the first infection as after the second infection among the seven children tested. Thus, second infections with strains of either subgroup of respiratory syncytial virus did not potentiate respiratory illness, and infection with subgroup A strains of respiratory syncytial virus provided some protection from a second infection with the homologous, but not the heterologous, subgroup of the virus.

Acute Disease↗

PubMed1987

Protection against lethal measles virus infection in mice by immune-stimulating complexes containing the hemagglutinin or fusion protein.

The importance of each of the two surface glycoproteins of measles virus in active and passive immunization was examined in mice. Infected-cell lysates were depleted of either the hemagglutinin (H) or fusion (F) glycoprotein by using multiple cycles of immunoaffinity chromatography. The products were used to prepare immune-stimulating complexes (iscoms) containing either F or H glycoprotein. Such complexes are highly immunogenic, possibly as a result of effective presentation of viral proteins to the immune system [B. Morein, B. Sundquist, S. Höglund, K. Dalsgaard, and A. Osterhaus, Nature (London) 308:457-460, 1984]. Groups of 3-week-old BALB/c mice were inoculated with the iscom preparations. All animals developed hemolysis-inhibiting antibodies, whereas only sera of animals immunized with the iscoms containing the H glycoprotein had hemagglutination-inhibiting antibodies. Sera from animals immunized with the H or F preparation only precipitated the homologous glycoprotein in radioimmune precipitation assays. The immunized animals were challenged with a lethal dose of the hamster neurotropic variant of measles virus. Of the 7-week-old animals in the nonimmunized control group, 50% died within 10 days after challenge. No animals in the immunized groups showed symptoms of disease throughout the observation period of 3 months. Passive administration of anti-H monoclonal antibodies gave full protection against the 100% lethal acute infection with the hamster neurotropic variant of measles virus in newborn mice, whereas anti-F monoclonal antibodies failed to protect the animals. This study emphasizes that both H and F glycoproteins need to be considered in the development of measles virus subunit vaccines.

Animals↗

PubMed1987

Prospects for new viral vaccines.

The records of virus vaccinology are impressive. Smallpox has been subjected to global eradication and diseases like poliomyelitis and measles have been extensively reduced in many industrialized countries. The prospects for development of new vaccines are good, and new fields of knowledge have opened up as a consequence of the introduction of revolutionary technology such as recombinant-DNA technology and the hybridoma and synthetic peptide methodology. Thus, the way ahead will involve both implementation of the effective use of available products and logistic decisions about the most appropriate technology for new immunogen products.

HIV↗

PubMed1986

Characterization of epitopes on the measles virus hemagglutinin.

Measles virus hemagglutinin epitopes were analyzed using nine monoclonal antibodies (MAbs) in competitive binding assays (CBA) and by in vitro selection of antigenic variants. In CBA the nine MAbs formed four different but partially overlapping binding groups. In vitro selected variants were analyzed by radioimmune precipitation assay, hemagglutination inhibition (HI), and neutralization assays. Seven operationally distinct MAb antigenic sites could be delineated: two sites were defined by two MAbs to each and five sites by single MAbs. Variants which had lost reactivity to different combinations of MAbs were generated by a branched sequential selection procedure. The most epitopically modified variants had lost reactivity in all assays to eight MAbs. None of these variants showed any major changes in hemagglutination nor neurotropism per se. Only minor changes were detected by HI in reactivity of these variants with human measles antiserum indicating that the epitopic changes were not of major epidemiological significance at least in terms of HI.

Antibodies, Monoclonal↗

PubMed1986

Measles virus hemagglutinin. Removal of the initiator methionine in the mature protein, and evidence for further processing to produce a 'ragged' end.

Measles virus hemagglutinin has been isolated by immunoadsorption. The total composition of the protein and its N-terminal amino acid sequence give data matching the structure indirectly deduced from cDNA. However, direct analysis of the hemagglutinin also shows that the mature protein is proteolytically processed and has a partly heterogeneous N-terminus. The initiator Met is removed, and non-stoichiometrically also the second residue.

Amino Acid Sequence↗

PubMed1986

Measles IgM antibodies in cerebrospinal fluid and serum in subacute sclerosing panencephalitis.

Using a direct enzyme-linked immunosorbent assay (ELISA), we examined serum and cerebrospinal fluid (CSF) from six patients with subacute sclerosing panencephalitis (SSPE) and control subjects for presence of measles-virus-specific IgM antibodies. All samples from the SSPE patients contained demonstrable titers of measles antibodies. The levels of measles IgM antibodies were higher in CSF diluted 1:5 than in serum diluted 1:50, reflecting a local production of IgM antibodies in the central nervous system. Antibody titers remained constant over the course of SSPE in three of the patients followed for three to six months. The IgM ELISA had high sensitivity as well as specificity and was not complicated by false-positive reactions owing to the presence of rheumatoid factor.

Antibodies, Viral↗

PubMed1986

Occurrence of respiratory syncytial virus subtypes A and B strains in Sweden.

The subtype characteristics of 22 strains of respiratory syncytial (RS) virus isolated in Sweden were determined by the use of monoclonal antibodies. Eleven antibodies specific for distinct epitopes on five different structural proteins were used in immunofluorescence and radioimmune precipitation assays. One group of 12 isolates were derived from a three-month epidemic during 1984, whereas the other ten virus isolates were recovered during a time period of 13 years (1971-1983). All isolates could be allocated to the previously defined groups of subtype A and B strains of RS virus. During the single epidemic season, five subtype A and seven subtype B strains were found. During the 13-year period a randomly alternating appearance of six subtype A and four subtype B strains was observed. Thus RS virus strains of different subtype characteristics may occur alternately or concomitantly. The possible significance of consecutive infections with RS virus subtypes for immunopathological events deserves further studies.

Aged↗

PubMed1986

Detection of antigen in immune precipitates by silver staining of SDS-polyacrylamide gels.

The silver staining technique of Merril et al. (1981) was used to identify antigens separated by SDS-PAGE after dissociation of immune complexes purified by absorption with staphylococcus A protein. The five and four dominating structural components of measles and RS virus (Mr range 28,000 to 79,000) respectively precipitated with monoclonal antibodies were readily identified, except when the Mr of the virus-specific antigen was in the same range as immunoglobulin heavy and light chains. Specific antigens were identified less effectively after precipitation with polyclonal sera because of a larger background of stainable proteins. This method, which combines the sensitivity and high resolution of silver staining and the specificity of immune complexing with monoclonal antibodies, is rapid and inexpensive.

Antibodies, Monoclonal↗

PubMed1986

Selection of mutants of mumps virus with altered structure and pathogenicity by passage in vivo.

The neurotropic Kilham strain of mumps virus was serially passaged in newborn hamster brains in order to assess possible changes in viral characteristics. Two modes of passage were employed, one with a 4-5 day interval between inoculation and harvest and the other with a 10-12 day interval. After 10 and 8 passages, respectively, two viral variants were isolated which differed in antigen characteristics and in pathogenicity. In Vero cell cultures the variant derived from the short-term passage, designated as RK, showed much greater fusion capacity than the other, designated as SK. The highly fusing variant was highly lethal and caused much more extensive necrosis and grew to higher titers in the brain. With a series of monoclonal antibodies directed against the structural proteins of mumps virus marked differences between the variants could be detected in the nucleocapsid (NP) protein and also slight changes in the hemagglutinin-neuraminidase (HN) and phospho- (P) proteins. Differences were found in the preference of the viral variants to infect various regions of the brain. The RK variant heavily infected the caudate nucleus whereas the SK variant did not. This study demonstrates that different modes of passage can affect characteristics of virion components and disease pattern.

Animals↗

PubMed1986

Augmented antibody response to live attenuated measles vaccine in children with Plasmodium falciparum parasitaemia.

The impact of malarial infection on the humoral immunological response to measles virus antigen was studied in 184 children aged 8-19 months in Guinea-Bissau. Pre- and post-immunization measles serology was performed using dried blood on absorbent paper and the ELISA technique. Blood smears obtained at the time of vaccination and 2 and 4 weeks afterwards were examined for malaria parasites. Pre-vaccination antibodies to measles were found in 44 out of 184 children (24%). Plasmodium falciparum was identified in 62 of the 132 initially non-immune children who completed the study. The rate of seroconversion was 127 out of 132 (96%). Post-immunization measles antibody titres were significantly higher in the vaccinees with P. falciparum than in those without malaria parasites in the blood.

Antibodies, Viral↗

PubMed1986

Nuclear accumulation of measles virus nucleoprotein associated with a temperature-sensitive mutant.

A measles virus (MV) Lec strain conditional-lethal (temperature-sensitive) mutant, designated MV ts38, has been isolated from 5-fluorouracil-mutagenized stock. The mutant has been characterized with regard to growth characteristics at 32 degrees C (permissive temperature) and 39 degrees C (non-permissive temperature). Virus-specific RNA transcription and/or translation appeared to be blocked at the non-permissive temperature as no virus-specific products could be detected by biochemical or immunological procedures. Following initiation of viral replication at 32 degrees C, with subsequent shift-up to 39 degrees C, presynthesized nucleoprotein (NP) was transported to, and accumulated in the cell nucleus whereas other viral proteins could not be detected there. A corresponding accumulation of NP in the nucleus is most often seen in association with MV neurotropic subacute sclerosing panencephalitis isolates in vivo and in vitro.

Animals↗

PubMed1986

Structural differences between subtype A and B strains of respiratory syncytial virus.

Differences in the properties of homologous intracellular structural components of eight strains of subtype A and eight strains of subtype B of human respiratory syncytial (RS) virus were examined. The size of the fusion (F) protein cleavage products and the phosphoprotein (P) showed systematic differences between virus strains representing the two subtypes. The apparent mol. wt. in SDS-polyacrylamide gels under reducing conditions was 48,000 (48K) and 46K to 47K for the cleavage product F1 in subtype A and B strains, respectively. The size of the F2 protein was 18K to 20K. The subtype B strains showed a slightly higher mol. wt. of this protein compared to the subtype A strains. The size of the P protein was 36K in subtype A strains, but only 34K in subtype B strains. Variations also occurred in the size of the glycoprotein (G) and the 22K to 24K structural protein. These variations did not correlate with the virus subtypes, but were strain-specific. The size of non-glycosylated forms of the F protein cleavage products was determined by use of material from tunicamycin-treated cells. A 44K to 45K non-glycosylated form of the F1 protein was detected with subtype A virus strains, but the corresponding protein of subtype B strains was not reproducibly identified, presumably due to instability in the absence of glycosylation or altered antigenicity. Monoclonal antibody immunosorbent-bound viral glycoproteins were partially digested with proteases. The pattern of breakdown products of the F1 protein was distinctly different between subtype A and B strains, but it was similar among strains of the same subtype. No subtype-specific pattern was seen in proteolytic digests of monoclonal antibody-bound G protein.

Electrophoresis, Polyacrylamide Gel↗