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Biomedical subjects

E Norrby

Publications and source records attributed to E Norrby.

At least 91 records · Page 5Linked to original sources
PubMed1990

Hemagglutinin-neuraminidase (HN) amino acid alterations in neutralization escape mutants of Kilham mumps virus.

The hemagglutinin-neuraminidase genes of the Kilham strain of mumps virus and three neutralization escape mutants (M11, M12 and M13) of this strain (Löve et al., 1985a) were sequenced using their genomes as template. The predicted amino acid sequences were compared. While one mutant had only one amino acid substitution the other two mutants had four and five respectively. A putative region for the epitope of the selected neutralizing monoclonal antibody was identified in a hydrophilic region encompassing amino acids 352-360, since the single amino acid substitution of one mutant occurred in this region and the other two mutants showed non-conserved amino acid changes in this part of the protein. The previously sequenced prototype strain RW, which lacks capacity to react with the selected neutralizing monoclonal antibody also has one non-conserved amino acid change in the region of the proposed neutralizing epitope. The three mutants showed different biological characteristics. These particular characteristics were therefore interpreted to be primarily associated with strain-specific amino acid changes outside the region of the presumed neutralizing epitope. The decrease in molecular weight in one mutant (M11) was shown to be due to a substitution in position 329 of an asparagine for an aspartic acid, leading to abolishment of a potential N-linked glycosylation site. In the other mutants, one substitution in position 239 of a lysine for a methionine was correlated with an increased neuraminidase activity of strain M12, while a substitution in position 360 of an arginine for a cysteine appeared to represent the most likely explanation for the reduced neurovirulence of strain M13.

Amino Acid Sequence↗
PubMed1990

Behavioural deficits and serotonin depletion in adult rats after transient infant nasal viral infection.

Dysfunction of subcortical serotoninergic neurons has been implicated in some behaviour disturbances. The serotoninergic neurons in the dorsal and median raphe project widely in the brain. They innervate the olfactory bulbs and can be targets for exogenous agents attacking the olfactory epithelium and bulbs. We report here an injury to the serotoninergic neurons after intranasal infection in 12-day-old rats with a temperature-sensitive mutant of vesicular stomatitis virus. The brain infection was focal and transient. Viral antigens could no longer be detected 13-15 days after infection. In spite of this the animals, as adults, had a severe serotonin depletion in the cerebral cortex and hippocampus, and showed abnormal locomotor and explorative behaviour as well as learning deficits. The neocortex was histologically intact and parameters related to other neurotransmitters such as dopamine, noradrenaline, GABA and acetylcholine showed no marked changes. A relatively selective damage to serotoninergic nuclei as a result of virus neuroinvasion through a natural portal of entry, may constitute a new pathogenetic mechanism for cortical dysfunction and behavioural deficits.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

Infection of cynomolgus monkeys with HIV-2 protects against pathogenic consequences of a subsequent simian immunodeficiency virus infection.

Simian immunodeficiency virus (SIV) infection in cynomolgus macaques leads to severe immunodeficiency with a fatal outcome. In contrast, HIV-2 infects these primates without apparently causing any immunological abnormalities. In this study three cynomolgus monkeys were experimentally infected with HIV-2 strain SBL-K135 and 168 days later challenged with 10-100 animal infectious doses of the closely related SIV strain SM to study protective immunity. At the time of SIV challenge the HIV-2-infected monkeys had neutralizing antibodies against HIV-2, but virus could no longer be recovered from their peripheral blood mononuclear cells (PBMCs) and no clinical symptoms or decrease in CD4+ lymphocytes were observed. Follow-up for 9 months after challenge with SIV showed that the HIV-2-infected monkeys were protected against SIV-induced immunodeficiency (no decrease of CD4+ lymphocytes) and lymphadenopathy. However, they were not resistant to SIV infection since virus could be recovered from their PBMCs and they developed anamnestic antibody responses. Four naive control monkeys which were inoculated with the same dose of SIV became persistently infected and developed a decrease of the absolute numbers of CD4+ cells and showed a marked lymphadenopathy. Two out of four control animals died 58-265 days postinfection with an immunosuppressive disease. Immunohistochemical examination showed abundant viral antigen in lymph-node biopsies from the SIV-infected control monkeys but absence of SIV or HIV-2 antigens in the biopsies from the three HIV-2-preinfected and SIV-superinfected monkeys. The present study demonstrates possibilities for induction of immunity against immunodeficiency induced by a primate lentivirus, a concept with application also to HIV infection and AIDS in man.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Antigenic variation of human and bovine parainfluenza virus type 3 strains.

Three human and six bovine parainfluenza virus type 3 (PIV3) strains were examined by the use of 60 monoclonal antibodies (MAbs). Fifty-three MAbs to the human C243 strain were directed against six, four, nine and seven epitopes of the haemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (N) and matrix proteins, respectively. Seven MAbs to the bovine strain were directed against three epitopes of the HN protein and three epitopes of the F protein. Each strain was characterized in ELISA and immunofluorescence tests with all MAbs and in a haemagglutination inhibition assay with the anti-HN MAbs. There were marked differences between human and bovine viruses, primarily in the HN protein where five epitopes differed. One epitope of the F and one of the N protein also differed. Bovine PIV3 was found to be a homogeneous subtype and distinct from human PIV3.

Animals↗
PubMed1990

Strain variation in parainfluenza virus type 4.

Variations in epitopes on structural proteins of four isolates of parainfluenza virus type 4 (PIV-4) and the Mr of polypeptides in these isolates were determined by radioimmune precipitation assay with monoclonal antibodies to parainfluenza virus type 4A (PIV-4A) and type 4B (PIV-4B). Three isolates antigenically resembled the prototype PIV-4A and the sizes of their structural proteins were 72K (HN protein), 61K (F0 protein), 61K (NP protein) and 40K (M protein). However, one virus isolate showed marked antigenic differences from both the 4A and 4B prototype viruses, particularly with regard to properties of the HN and F proteins. In addition, both the NP and F0 proteins of this isolate had a slightly increased Mr of 63K.

Animals↗
PubMed1990

Aberrant IgG subclass distribution to measles in healthy seropositive individuals, in patients with SSPE and in immunoglobulin-deficient patients.

Sera from healthy seropositive donors, patients with acute measles, subacute sclerosing panencephalitis, common variable immunodeficiency, and CH gene deletions were analysed for anti-measles IgG1-4. Compared with other anti-viral immune responses of IgG1 and IgG3, an unusual predominance of specific IgG1 prevailed; only four out of a total of 68 patients showed anti-measles IgG3. Of the 17 healthy, measles seropositive serum donors, all showed specific IgG1, none showed IgG3 and six had IgG4. Eight out of 10 patients with SSPE showed an anti-measles IgG1 and IgG4 response while IgG3 was not seen. The IgG1 and IgG4 subclass patterns had some exceptions. Anti-measles IgG3 was found in five out of five patients with deletion of the gamma-1 encoding gene segments and in four out of 15 patients with recent measles antigen stimulation. The subclass pattern was suggested to reflect the immunological compromise associated with measles infections.

Adolescent↗
PubMed1990

A subgroup-specific antigenic site in the G protein of respiratory syncytial virus forms a disulfide-bonded loop.

An antigenic site (represented by 15 amino acids, residues 174 to 188, designated peptide 12) of the large glycoprotein G of respiratory syncytial virus was demonstrated to be subgroup specific in peptide enzyme-linked immunosorbent assay tests with murine monoclonal antibodies and human postinfection sera. The role of individual amino acids in this subgroup-specific site was determined by use of single-amino-acid-deletion sets of peptides. When monoclonal antibodies were reacted with the deletion sets, a broad amino acid dependence of 11 or 12 residues, Cys-176 (Ile-175 in subgroup B) to Cys-186, was found. Human postinfection sera exhibited a narrower reaction profile (for subgroup A, Cys-182 to Trp-183; for subgroup B, Cys-176 to Lys-183). Reduction of peptides on microtiter plates by treatment with dithiothreitol completely destroyed their antigenic activity in tests with monoclonal antibodies and human postinfection sera of subgroup B. A variant of peptide 12 containing all four cysteines of the G protein (represented by 16 amino acids, residues 172 to 187, designated peptide 12var) also was subgroup specific. We concluded that the activity of the antigenic site in tests with monoclonal antibodies for subgroups A and B appears to depend on intrapeptide disulfide bonds. Reactions with postinfection sera of subgroup B also may depend on a disulfide bond. In contrast, postinfection sera of subgroup A appeared to have the capacity to identify a subgroup-specific site in a linear form of the selected 15-amino-acid-long peptide. Treatment of peptides with dithiothreitol had no effect on their antigenic activity in tests with human postinfection sera of subgroup A. These findings have relevance for molecular engineering of peptide antigens for use in respiratory syncytial virus subgroup-specific site-directed serology.

Amino Acid Sequence↗
PubMed1990

A monoclonal antibody to human immunodeficiency virus type 1 which mediates cellular cytotoxicity and neutralization.

Monoclonal antibodies (MAbs) were raised against human immunodeficiency virus type 1 gp120. One MAb, P4/D10, was found to mediate highly efficient antibody-dependent cellular cytotoxicity and virus neutralization. The reactivity was located to a major neutralizing region (amino acids 304 to 323) on gp120. Five other MAbs with a similar epitopic reactivity did not show any antibody-dependent cellulan cytotoxicity activity but had a virus-neutralizing capacity.

Amino Acid Sequence↗
PubMed1990

Envelope cross-reactivity between human immunodeficiency virus types 1 and 2 detected by different serological methods: correlation between cross-neutralization and reactivity against the main neutralizing site.

A total of 70 human immunodeficiency virus type 1 (HIV-1) and 42 HIV-2 antibody-positive serum samples, collected from groups of individuals in which only one type of HIV prevails, were tested for cross-reactivity against HIV-2 and HIV-1 proteins by Western blot (WB) (immunoblot), radioimmunoprecipitation assay (RIPA), neutralization analysis, and enzyme-linked immunosorbent assay with as antigen synthetic peptides representing selected parts of the envelope (env) glycoproteins. Cross-reactions against the env glycoproteins were observed by WB in 10% (7 of 70) and by RIPA in 40% (28 of 70) of the HIV-1 antibody-positive serum samples and by WB in 29% (12 of 42) and by RIPA in 48% (20 of 42) of the HIV-2 antibody-positive serum samples. Testing by enzyme-linked immunosorbent assay against a 36-amino-acid peptide (Cys-301-Cys-336) of the external glycoprotein of strain HTLV-IIIB of HIV-1 (HIV-1HTLV-IIIB) (known to represent a dominating, linear neutralizing site) showed type-specific reactions in 67% (38 of 57) of HIV-1 antibody-positive serum samples. Type-specific reactions against a homologous 35-amino-acid peptide of strain SBL-6669 of HIV-2 (HIV-2SBL-6669) were found in 75% (30 of 40) of HIV-2 antibody-positive serum samples, and these reactions were correlated to neutralization against HIV-2SBL-6669. Cross-reactions against these peptides were seen in 23% (13 of 57) and 33% (13 of 40) of the HIV-1 and HIV-2 antibody-positive serum samples, respectively. These cross-reactions were correlated to cross-neutralization against HIV-1HTLV-IIIB and HIV-2SBL-6669. Cross-neutralization against one heterotypic virus strain was demonstrated in 16% (9 of 57) of HIV-1 antibody-positive serum samples and in 22% (5 of 22) of HIV-2 antibody-positive serum samples, but no correlation was found between cross-neutralization and env cross-reactivity in WB or RIPA.

Blotting, Western↗
PubMed1990

Human immunodeficiency virus antibody responses determined by site-directed serology.

In this brief review, the use of synthetic peptides representing linear antigenic sites in human immunodeficiency virus (HIV) structural proteins for detection of antibodies in sera from HIV-infected individuals is discussed. It has been demonstrated that peptide antigens offer unique advantages for determination of HIV-specific antibodies. In particular, various peptides representing the region of amino acids 580-620 in the transmembranous glycoprotein have been effectively used. Of primary importance is the fact that properly designed site-specific serological tests allow a distinction between type-specific antibodies, a quality not provided by any other currently available test. Furthermore, synthetic peptide antigens allow the design of highly simplified and effectively standardized assays. Hereby, they lend themselves to use for screening purposes or confirmatory testings not only in industrialized countries, but also in developing countries. It is also possible that tests with selected peptides may measure antibodies which have value in predicting the risk for infection in children born to seropositive mothers and for progression of disease in infected individuals.

Amino Acid Sequence↗
PubMed1989

Immunochemistry of the dominating antigenic region Ala582 to Cys604 in the transmembranous protein of simian and human immunodeficiency virus.

The immunochemistry of two homologous uniquely antigenic peptides representing Ala582 to Cys604 in the transmembrane proteins of simian immunodeficiency virus of rhesus macaque origin, SIVmac (closely related to HIV-2) and HIV-1 (strain HTLV-IIIB) was characterized at the resolution of single amino acids. Five different antigenic sites were identified in the SIVmac peptide by use of 34 mAb against this peptide and two different sites were similarly demonstrated in the HIV-1 peptide by use of 10 peptide-specific mAb. Within some sites the mAb could be subgrouped to show a progressively more narrow epitopic dependence on amino acids in the central part of the site. Three SIVmac peptide mAbs had a remarkably narrow amino acid dependence, Glu584 and Tyr586. Anti-peptide mAbs reacting with the site Trp596 to Gln602 effectively blocked the capacity of the peptide to react with human postinfection HIV-2 antibodies previously demonstrated to have a restricted reactivity involving this site. No similar blocking was seen when mAb specific for Leu587 to Gln590 were used except with a single broadly reacting HIV-2 serum, which depended on an amino acid at a distance of only 6 residues, Trp596. A cross-reacting site involving amino acids Ala582 to Glu588/Lys588 was identified with mAb and rabbit hyperimmune sera against the two peptides. This site was not accessible in the intact transmembrane proteins as determined by ELISA and Western blot tests. Antipeptide mAb against other sites as well as rabbit sera reacted strongly in these tests and can be used as type-specific, component-unique reagents.

Alanine↗
PubMed1989

IgG subclass responses to a transmembrane protein (gp41) peptide in HIV infection.

The IgG subclass distribution to the E34/E32 peptides, derived from the HIV-1 glycoprotein 41 transmembrane protein, was analyzed in ELISA. Sera from individuals at different stages of the disease were assayed. A restricted subclass response of mainly IgG1 and IgG2 was found. The subclass response was of a different type than the one observed to HIV whole Ag and to a synthetic peptide from the C'-terminal part of the HIV-1 p24 core protein. An increased subclass restriction was observed in progressed stages of the disease.

Amino Acid Sequence↗
PubMed1989

Paramyxovirus SV5 and multiple sclerosis.

Multiple sclerosis is commonly associated with a local humoral immune response within the central nervous system. A hallmark of this intrathecal response is the presence of electrophoretically demonstrable oligoclonal bands of IgG in the cerebrospinal fluid (CSF) of up to 95% of patients. Observations indicating that a major part of the CSF IgG in some patients may represent antibodies to SV5, a simian virus closely related to human parainfluenza type 2 virus, were recently reported by Goswami et al. We have studied thirty patients with multiple sclerosis, but although we find intrathecal synthesis of IgG antibodies reacting with SV5 in seven of these, the antibodies were not associated with oligoclonal CSF IgG bands and could in each case be explained as potentially cross-reacting antibodies to other paramyxoviruses known to be human pathogens. We have therefore been unable to confirm that SV5 may be a major intrathecal immunogen in multiple sclerosis.

Adsorption↗
PubMed1989

Screening of African sera stored for more than 17 years for HIV antibodies by site-directed serology.

Antibodies to Human Immunodeficiency Virus type 1 (HIV-1) and type 2 (HIV-2) were investigated, using site-directed enzyme immunoassay (ELISA), in 320 specimens obtained from three remote, African tribes during 1969-1971. Using HIV-1 E34/E32 ELISA and HIV-2 149 ELISA, assay were conducted on 101 serum specimens from the Korekore tribe of Zimbabwe, 93 specimens from the Mano tribe of Liberia, and 126 specimens from the Turkana tribe of Kenya; specimens which tested positive in ELISA were further tested by radioimmunoprecipitation assay (RIPA) and Western blot (WB). Two serum specimens from the Mano tribe of Liberia gave OD 492 nm values greater than 0.2 in HIV E34/E32 ELISA in all three runs. These two specimens reacted with HIV-1 envelope proteins gp160 and gp120 and the internal protein p24 in RIPA and WB; however, the reactivity was uncostant. All other serum specimens were negative for HIV-1 and HIV-2 antibodies. Site directed ELISA serology for HIV-1 and HIV-2 gave very low rates of false positive reactivity. Thus, reaction with HIV-1 antigen was identified in two persons of one tribe in Liberia in 1971, but HIV-2 antibodies were not detected in this tribe; HIV-1 and HIV-2 antibodies were absent during the late 1960's and early 1970's from two African tribes resident in Zimbabwe and Kenya.

AIDS Serodiagnosis↗
PubMed1989

Total, anti-viral, and anti-myelin IgG subclass reactivity in inflammatory diseases of the central nervous system.

Total IgG subclass levels, anti-viral, anti-myelin basic protein (anti-MBP), and anti-ganglioside 1 (anti-GM1) IgG subclass levels were measured in 6 patients with herpes simplex virus encephalitis (HSVE), 16 with borreliosis, 8 with other bacterial infections, 12 with multiple sclerosis (MS), 13 with subacute sclerosing panencephalitis (SSPE), 5 with glioblastoma and 12 controls. Total IgG1 levels were elevated in cerebrospinal fluid (CSF) from all patient groups (but not in the controls), IgG2 in bacterial infections, IgG3 in HSVE and borreliosis and IgG4 in some SSPE patients. The anti-viral (anti-measles, varicella zoster virus and rubella) IgG antibodies in MS were restricted to IgG1, anti-measles IgG to IgG1 and sometimes IgG4 in SSPE, anti-borrelia IgG to IgG1, IgG2 and IgG3. In contrast to anti-viral antibodies, anti-MBP and GM1 antibodies belonged to IgG1, IgG3 or IgG4 in MS. The nature of the immunological activation appears to be reflected in the subclass patterns elicited in the central nervous system. Different IgG subclass patterns in infectious diseases and MS suggest a difference between antigen-specific and non-specific B-cell activation.

Antibodies↗
PubMed1989

Sequence analysis of the mumps virus mRNA encoding the P protein.

The nucleotide sequence of the mumps virus phospho- or polymerase-associated (P) protein mRNA has been determined by sequencing a full-length cDNA clone and confirmed by partially sequencing the mRNA and the genome. The mRNA contains 1311 nucleotides excluding the poly(A) and encodes a protein of 390 amino acids with a calculated molecular weight of 41,574. Three small polypeptides were seen in in vitro translation of viral mRNA and hybrid-selected P mRNA, possibly representing internal initiation in the same reading frame of the P protein. A second overlapping reading frame is predicted from the sequence which has a capacity to code for two polypeptides of 56 and 34 amino acids, respectively. Whether these two polypeptides are expressed in infected cells is not known. Comparison of the P protein sequence with that of Sendai virus, measles virus, parainfluenza virus type 3, and canine distemper virus (CDV) showed no distinct homology but comparison with the P protein of Newcastle disease virus (NDV) showed 25.6% homology.

Amino Acid Sequence↗