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Biomedical subjects

B Wahren

Publications and source records attributed to B Wahren.

At least 235 records · Page 13Linked to original sources
PubMed1989

Human immunodeficiency virus type 1 p24 production and antigenic variation in tissue culture of isolates with various growth characteristics.

Two monoclonal antibodies (Mabs) reacting with different epitopes of the human immunodeficiency virus type 1 core protein p24 (HIV p24) were used either singly or in combination as tracers in enzyme-linked immunosorbent assays. The culture supernatant of 215 samples of peripheral blood mononuclear cells from 112 patients were measured for HIV p24 and reverse transcriptase (RT) activity during cultivation. One hundred forty-one cultures were positive for HIV p24 and 122 for RT after 32 days of cultivation. After 8-9 days, HIV p24 was detected in 50.4% and RT in 27.8% of the cultures later judged as HIV positive. Two patients seemed to have substrains of HIV-1 not reactive with one of the Mabs.

Acquired Immunodeficiency Syndrome↗
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

Properties of IgG subclasses to human cytomegalovirus.

The IgG subclass of antiviral antibodies to human cytomegalovirus (CMV) is mainly of IgG1 type. Most CMV seropositive sera also have virus-specific IgG3, but of a lower titre as measured by enzyme-linked immunosorbent assay (ELISA). We studied the reactivity pattern of these two IgG subclasses to CMV structural polypeptides in order to define how virus-specific IgG1 and IgG3 contribute to the neutralization of CMV. Neutralization of CMV was performed with CMV IgG1 and IgG3 separated from CMV seropositive human sera on a protein A Sepharose gel. Both IgG1 and IgG3 have a neutralizing capacity. IgG3 had a 10-fold better neutralizing effect than IgG1 when related to the ELISA titre. In order to analyse the specific reactivities, CMV Towne virion polypeptides were separated by electrophoresis and transferred to nitrocellulose. Using mouse monoclonals to human IgG1 and IgG3 in combination with a biotin-streptavidin system, the reactivities of the subclasses were examined. IgG1 and IgG3 appeared to react with the same structural polypeptides. The strongest IgG1 reactivities were obtained with CMV polypeptides of apparent molecular weights of 145, 80, 64, 56, 52 and 27.5 kDa. The CMV IgG3 reactivity was restricted compared to IgG1, the strongest and most frequent reactivities occurring to polypeptides of 145 and 80 kDa.

Antibodies, Viral↗
PubMed1989

Detection of antibodies against myelin basic protein and increased levels of HIV-IgG antibodies and HIV antigen after solubilization of immune complexes in sera and CSF of HIV infected patients.

Fifteen HIV seropositive patients were studied. It was possible to enhance detection of HIV antigen and HIV and myelin basic protein (MBP) antibodies after dissociation of immune complexes by acid hydrolysis. HIV p24 antigen was then detected in four patients, three of whom were previously antigen negative. In 14 patients the treatment resulted in increased anti-HIV IgG subclass levels. Anti-MBP IgG was detected in 12 patients. Intrathecal synthesis of anti-MBP IgG subclasses was found in eight patients, five of whom had symptoms from the central nervous system.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Efficacy and safety of vaccination of marrow transplant recipients with a live attenuated measles, mumps, and rubella vaccine.

Long-term immunity to measles, mumps, and rubella viruses was studied in 57 patients after allogeneic bone marrow transplantation. Among patients who were seropositive at the time of transplant, 51% had retained antibodies to measles, 42% had retained antibodies to mumps, and 76% had retained antibodies to rubella 2 y later. There was no difference in the ability to retain antibodies to these viruses between patients with and those without chronic graft-versus-host disease (GVHD). Twenty seronegative patients without active chronic GVHD or ongoing immunosuppressive treatment were vaccinated with a live attenuated trivalent vaccine against measles, mumps, and rubella. No early or late side effects were detected after the vaccinations. The percentages of patients who seroconverted after vaccination were 77%, 64%, and 75% for measles, mumps, and rubella, respectively. Vaccination of transplant recipients with a live attenuated vaccine against measles, mumps, and rubella is safe and usually effective 2 y after transplant if the patients do not have active chronic GVHD or ongoing immunosuppressive treatment at the time of vaccination.

Adolescent↗
PubMed1989

Diagnostic implication of specific immunoglobulin G patterns of children born to HIV-infected mothers.

We analysed HIV-specific immunoglobulin G (IgG) responses to gag and env peptides in infants born to HIV-positive mothers. Questions of interest were whether there are early specific markers for prognosis, and whether any specific IgG is related to the prevention of vertical transmission of infection. Fifty-three children, 0-24 months old and born to HIV-1-infected mothers, were retrospectively divided into two groups based on HIV seroreactivity or non-reactivity at 15 months of age. Their sera were used to find reactivities important in diagnosis and/or prediction of the putative HIV disease. Three important findings emerged. First, a low IgG titer against the very immunodominant penv9 in newborns was found to be associated with rapid progression to AIDS. This difference was clearly reflected in the reactivity to a small peptide representing amino acid (aa) 598-606. The second interesting finding was the putative hypervariable loop on gp120 (especially aa 324-338), reactivity to which was found only in the uninfected group, and was seen in six out of 19 uninfected children under 6 months of age. This specific response was not caused by a generally high total anti-HIV reactivity, and may indicate a role of protective antibodies against vertical transmission. The response to this region in the infected group, on the other hand, was directed to the amino terminal half of the putative loop, in particular peptide 53, aa 304-318. Finally, response to a part of the amino terminal end of P17 was seen in seven out of eight infected children over 6 months of age.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS Serodiagnosis↗
PubMed1989

Structure-activity relationships of fluorinated nucleoside analogs and their synergistic effect in combination with phosphonoformate against human immunodeficiency virus type 1.

One hundred nucleoside analogs with fluorine substitutions at various positions on the pentose ring were evaluated for inhibitory activity against human immunodeficiency virus type 1 (HIV-1). Nine compounds emerged as inhibitors of HIV-1 replication, with various degrees of selectivity; the most active of these was 3'-fluoro-3'-deoxythymidine, followed by 5'-amino-3'-fluoro-3'-deoxyadenosine. Substitution of fluorine at the 2'-deoxy or 3'-deoxy position resulted in increased antiviral activity of the thymidine analogs, whereas the activity of adenosine or cytidine analogs was not increased by fluorination at either position. The most potent inhibitor, 3'-fluoro-3'-deoxythymidine, was shown to give synergistic inhibition of HIV-1 replication in combination with the PPi analog phosphonoformate.

Antiviral Agents↗
PubMed1989

Inhibition of human immunodeficiency virus in vitro by combinations of 3'-azido-3'-deoxythymidine and foscarnet.

We describe a synergistic effect of combinations of foscarnet and 3'-azido-3'-deoxythymidine against human immunodeficiency virus type 1 multiplication in cell culture, an additive effect of foscarnet and 3'-azido-3'-deoxythymidine triphosphate against human immunodeficiency virus type 1 reverse transcriptase, and a low toxicity in cell culture of combinations of the two drugs.

Antiviral Agents↗
PubMed1989

Epitope mapping of monoclonal antibodies against human immunodeficiency virus type 1 structural proteins by using peptides.

Murine monoclonal antibodies directed against the structural proteins p17 and p24 of human immunodeficiency virus type 1 were investigated in an epitope mapping system. Overlapping peptides consisting of 15 amino acids of the p17 and p24 protein, respectively, were used as competitors in an enzyme-linked immunosorbent assay. Three different immunogenic regions (A, B, and C) could be defined, one on p17 and two on p24. Twenty monoclonal antibodies reacted with the human immunodeficiency virus type 1 peptides of region B, although differences in the reactivity of these antibodies with human immunodeficiency virus type 2 and simian immunodeficiency virus strain mac were detectable. Recognized epitopes were characterized by computer analysis as described by T.P. Hopp and K.R. Woods (Proc. Natl. Acad. Sci. USA 78:3824-3828, 1981) and P.Y. Chou and G.D. Fasman (Biochemistry 13:222-245, 1974).

Amino Acid Sequence↗
PubMed1989

Antiviral IgM and IgG subclasses in varicella zoster associated neurological syndromes.

The varicella zoster virus (VZV) and herpes simplex virus (HSV) IgGl-4 subclasses were compared in serum and cerebrospinal fluid (CSF) of 22 patients with VZV-associated neurological symptoms, 12 patients with HSV-associated neurological symptoms and 14 controls. The clinical syndromes of the VZV-associated diseases comprised meningo-encephalitis, myelitis, myelopathies and polyneuropathies, mostly with a favourable outcome. A characteristic finding was an intrathecal synthesis of VZV IgG1 and HSV-3. Commonly also IgG2 and 4 were seen in CSF of VZV patients. Their intrathecally synthesised HSV IgG was restricted to IgG1. VZV IgG3 occurred in serum and/or CFS together with VZV IgM in 14 cases and may be a marker of recent VZV replication. In patients with HSV-associated neurological disease, a multi-IgG subclass HSV response and concomitant VZV antibodies restricted to IgG1 was found. Intrathecal synthesis of both HSV and VZV IgG occurred in 20 patients. Detection of two or more VZV or HSV specific IgG subclasses synthesised intrathecally identified the aetiological agent in 19 of these 20 cases.

Adult↗
PubMed1989

Hydrophobicity and lectin affinity of alkaline phosphatase isozymes in seminoma and normal testis.

Isozymes of alkaline phosphatases (ALP) in seminoma and normal testis were separated by use of high-performance liquid chromatography and a TSK-gel phenyl-5PW column. The tissue-nonspecific (liver) ALP (LAP) was the dominating isozyme, consisting of more than 90% ALP activity. The placental ALP (PLAP)-like enzyme contributed to 4-8% of the total ALP activity. The intestinal isozyme (IAP) could not be identified. The glycosylation patterns of the isozymes were studied using concanavalin A (Con A) affinity chromatography and batch elution with competing sugar. All PLAP activity in placental extracts and LAP activity in liver extracts was bound to Con A-Sepharose. In the tumor extracts, only 50-70% of the PLAP-like enzyme and 20-50% of the LAP activity from seminomas were bound to Con A-Sepharose. A similar binding pattern of the PLAP-like enzyme and LAP was also seen in the normal testes. This variability in Con A reactivity with PLAP or the PLAP-like enzyme was also reflected in serum of seminoma patients and of pregnant women. Thus, ALP expressed in seminoma has different lectin affinity characteristics compared with the same isozyme from placenta and liver, but almost identical to ALP in the normal testes. These findings imply that the PLAP-like enzyme and LAP in the testis can be discriminated from PLAP of placenta and LAP of liver by carbohydrate lectin affinity. It also supports the concept that the increased amounts of ALP in seminomas result from the enhanced eutopic expression of enzymes normally expressed in the testis.

Alkaline Phosphatase↗
PubMed1989

Electrophoretic heterogeneity of alkaline phosphatase isozymes in seminoma and normal testis.

Electrophoretic patterns of seminoma- and normal-testis-derived alkaline phosphatase isozymes, the placental alkaline phosphatase (PLAP)-like enzyme and the tissue-nonspecific (liver) alkaline phosphatase (LAP), were studied on starch gel and isoelectric focusing (IEF). Different migration patterns of the PLAP-like enzyme were observed with respect to both seminomas and normal testes on starch gel electrophoresis. On IEF, seminomas showed different staining patterns among different tumors; however, a common main activity was focused at pIs of 4.3-4.6, corresponding to pIs of PLAP. Normal testes showed two enzyme-staining regions, at pIs of 4.1 and 5.0-5.2, which were discriminated from pIs of PLAP and the PLAP-like enzyme in seminoma. The PLAP-like enzyme in seminoma was differentiated from PLAP by digestion with neuraminidase. Neuraminidase treatment simplified the distribution patterns of the PLAP-like enzyme in normal testis, but did not alter the pattern of microheterogeneity in seminoma. Two factors other than sialylation, namely structural modification of the carbohydrate moiety and variation of hydrophobicity, were shown to contribute to the microheterogeneity of the PLAP-like enzyme in seminoma. LAP in seminoma and in normal testis also showed marked electrophoretic heterogeneity and differences in pI distributions from LAP of liver. However, the migration patterns after desialylation were very similar to each other. The findings imply that electrophoretic heterogeneity demonstrated in LAP in seminoma and in normal testis is caused by a difference in sialic acid content in the molecule, and the heterogeneity of the PLAP-like enzyme in seminoma is considerable.

Alkaline Phosphatase↗
PubMed1989

Significance of alkaline phosphatase isozymes in the monitoring of patients with colorectal carcinoma.

The clinical course of colorectal carcinoma may be monitored by tumor markers such as carcinoembryonic antigen (CEA), carcinoma antigen (CA) 19-9 and CA-50. Alkaline phosphatase isozymes were previously used to study the clinical course of testicular and gynecologic tumors. In this study we investigated 8 patients with advanced colorectal carcinoma. Their sera were analyzed for the tumor markers CEA, CA 19-9, CA-50 and three alkaline phosphatase isozymes: the nonspecific liver isozyme LAP, the intestinal isozyme IAP and the placental isozyme PLAP. Rising levels of CEA, CA 19-9 and CA-50 were seen as expected, and PLAP also showed rising levels during tumor progression. LAP remained elevated. This indicates an association between progression of colorectal carcinoma and a raised serum content of alkaline phosphatase isozymes.

Adult↗
PubMed1989

A new peptide for human parvovirus B19 antibody detection.

A serological assay for human parvovirus B19 was developed. Linear overlapping synthetic peptides were synthesised according to parts of open reading frames 1 and 2. A region at the N-terminus of viral protein VP2 detected serological reactivity in indirect enzyme-linked immunosorbent assays for IgG and IgM with known seropositive human sera. A cyclized peptide taken from this region, amino acids 284-307, gave the best selective reactivity with seropositive and seronegative sera. The peptide assay appears suitable for further studies of B19 infections and their complications.

Adult↗
PubMed1989

Analysis of a subclass-restricted HIV-1 gp41 epitope by omission peptides.

To define the amino acids involved in IgG subclass reactivity to two overlapping HIV-1 gp41 (E34/32; amino acid positions 582-613) peptides, sera from 18 HIV-infected individuals were studied. Peptides mimicking E34 but with single amino acid deletions or glycine substitutions were used to define the amino acid residues necessary for antibody binding. Two dominating immunogenic epitopes, containing highly hydrophilic amino acids, were found on the original peptide. Further analysis was undertaken with two corresponding omission sets of dodecapeptides representing halves of the complete E34 plus a terminal cystein peptide. The subclass reactivities usually differed between the patients with regard to the epitopes with which the different IgG subclasses reacted and also to the importance of different amino acids in antibody binding. The 600 glycine and the 601 lysine were involved in the binding of all IgG1, 2 and 4 and most IgG3. The development of E34/32-reactive IgM and IgG subclasses showed different patterns in four patients with primary HIV infections, contradicting the existence of a general pattern for the development of IgG subclasses to this peptide. The findings suggest that different progenitor clones are selected for synthesis of the different subclasses.

Amino Acid Sequence↗
PubMed1989

Mapping of IgG subclass and T-cell epitopes on HIV proteins by synthetic peptides.

Fifteen amino acid peptides, sequentially overlapping by 10 amino acids, were synthesized on the basis of the HTLV-III sequences of the gag and env proteins. They were used as antigens in IgG subclass ELISAs and T-cell stimulation assays. Sera and cells were obtained from 30 asymptomatic, HIV-infected homosexuals. In all subclasses reactivity was found to parts of the gag protein, while IgG1 dominated anti-env peptide responses. It was possible to delineate peptides showing restricted IgG subclass responses that were dominated by either IgG1, 2, 3 or 4. A negative correlation was generally observed between B-cell and T-cell reactivity, but a T-cell and B-cell co-operation was suggested by the response to two IgG1-restricted peptides. The IgG3-dominated epitopes were present in peptides previously known to be amphipathic and capable of T-cell stimulation. The analysis of subclass-restricted responses on the peptide level will assist the understanding of the subclass expression in vivo, since the peptide mapping approximates the delineation of a subclass-restricted response at the level of single epitopes.

Epitopes↗
PubMed1989

Human monoclonal antibodies against a recombinant HIV envelope antigen produced by primary in vitro immunization. Characterization and epitope mapping.

Peripheral blood lymphocytes from healthy, HIV sero-negative blood donors have been in vitro immunized using penv9, a recombinant fragment of the envelope of HIV-1. This primary in vitro immunization followed by Epstein-Barr virus (EBV) transformation and somatic cell fusion subsequently gave rise to several specific anti-penv9 monoclonal antibodies (MO28, MO30 and MO43) of mu isotype. The hybridomas have been kept in culture for over 6 months and the antibody productivity for MO30 was measured to 18 micrograms x (24 hr x 10(6) cells)-1. The fine specificity of the antibodies was mapped by a peptide inhibition enzyme immunoassay, using overlapping synthetic pentadeca peptides covering the whole penv9. These human monoclonal antibodies exhibited a similar epitope specificity directed against a non-sequential determinant, including the amino acids 632-646, 677-681 and 687-691. This specificity is very rarely found in immune sera from seropositive patients and presently not reported in human monoclonal antibodies derived from in vivo immunized individuals, indicating that different antibody specificities can be obtained by the in vitro immunization technology. These human monoclonal antibodies did not neutralize HIV. The results presented here demonstrate the feasability of generating human monoclonal antibodies against HIV by primary in vitro immunizations, thereby avoiding the use of lymphocytes derived from infected patients when human monoclonal antibodies for therapeutic purposes are to be produced.

Antibodies, Monoclonal↗