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O J Iversen

Publications and source records attributed to O J Iversen.

At least 37 records · Page 2Linked to original sources
PubMed1993

Surprisingly high levels of anaphylatoxin C5a des Arg are extractable from psoriatic scales.

Water-soluble extracts from psoriatic scales and normal human skin were prepared using either phosphate-buffered saline, pH 7.2, or 0.1 M carbonate buffer, pH 10.8. Anaphylatoxin C5a des Arg was quantified using a novel sandwich enzyme-linked immunosorbent assay (ELISA) using neoepitope-specific monoclonal antibodies. Alkali was about five to eight times more efficient than PBS in extracting C5a des Arg from scales, probably via dissociation of bound C5a des Arg. C5a des Arg concentration in scales from three patients suffering from psoriasis vulgaris varied between 2.5 and 4.6 ng/mg scale. No C5a des Arg was detectable in normal skin extracts. The biological activity of alkali-extractable C5a des Arg, i.e. chemotaxis, was preserved. The concentration of C5a des Arg relative to the concentration of albumin was taken as a parameter of the degree of complement activation in the psoriatic lesions, and was found to be more than six times higher than values attained in serum after maximum complement activation by zymosan. We conclude that complement activation may play a quantitatively important role in the inflammatory process in psoriasis.

Antibodies, Monoclonal↗
PubMed1993

Variability over time of complement activation induced by air bubbles in human and rabbit sera.

Complement activation induced by air bubbles in rabbit and human sera was studied by measuring the generation of anaphylatoxin des-Arg-C5a. des-Arg-C5a was quantified by sandwich enzyme-linked immunosorbent assays based on neoepitope-specific anti-des-Arg-C5a monoclonal antibodies. Air bubbles were continuously introduced to serum via a calibrated microflowmeter, and the serum was incubated at 37 degrees C for 30 min. Air bubbles clearly generated increased amounts of des-Arg-C5a compared with corresponding levels in control serum, and a dose-dependent effect was also noted. Strong positive correlations between des-Arg-C5a concentrations in control sera and sera incubated with air bubbles at a flow of 0.5 ml/min were found. To study variation over time, serum was obtained at regular intervals from six rabbits and from six healthy humans during 66- and 196-day periods, respectively. A pronounced intraindividual variability over time was thus observed. The reason for the large variability is at present unknown. We conclude that the sensitivity of complement to activation by air bubbles is not an inherent, static feature of the complement system of an individual. Therefore single-point analysis of complement activation by air bubbles appears to be an inappropriate parameter by which to differentiate a "sensitive" or "insensitive" complement system between individuals.

Air↗
PubMed1993

Use of scale antibodies for the detection of antigens in psoriatic lesions.

Extractable IgG from psoriatic scale was purified, labelled with biotin and used in ELISA and immunofluorescence (IF) in an attempt to detect and localize prominent antigens in psoriatic scale extracts and in psoriatic lesions, respectively. Biotinylated immunoglobulins isolated from psoriatic scale from each of 5 patients were used. Scale extracts were fractionated on a Sephacryl S-300 column, and antigens detected by scale IgG were eluted in the void volume and at a Kav 0.55. The profile was very similar for each antibody preparation. Antigens recognized by serum IgGs from both healthy controls and psoriatic patients were detected in the void volume only. Antigens recognized by a rabbit antiserum against the psoriasis-associated antigen, pso p27 (6), were restricted to the fractions eluted at a Kav 0.55. Furthermore, the binding of scale IgG to the antigens eluted at Kav 0.55 was inhibited by purified pso p27 antigen. Two of the scale antibody preparations gave rise to a distinct fluorescence on skin biopsies from psoriatic lesions in indirect immunofluorescence. The antigens recognized were localized to a subfraction of dermal cells and in the endothelial lining of some of the dermal vessels. Double labelling with these scale antibodies and a rabbit anti-pso p27 antiserum showed that both antibody preparations bound to the same cells in the psoriatic lesions, while only a minority of these cells were recognized by a murine monoclonal antibody against human IgG. The observations described indicate that the pso p27 is a major antigen in the immune reactions in psoriasis.

Animals↗
PubMed1992

Production of monoclonal antibodies against the human anaphylatoxin C5a des Arg and their application in the neoepitope-specific sandwich-ELISA for the quantification of C5a des Arg in plasma.

A panel of ten murine monoclonal antibodies (MAbs) was raised against the human anaphylatoxin C5a des Arg. The MAbs were shown to abrogate or significantly inhibit the chemotactic activity in zymosan activated serum. MAb 4A2E10E2 and MAb 3G3C4 were used as capture and detecting antibody, respectively, in a sandwich enzyme-linked immunosorbent assay (ELISA) for the quantification of C5a des Arg. This ELISA was shown to be very sensitive (detection limit 20 pg/ml) and could be applied directly to plasma/serum samples. The lack of interference by plasma components, in particular C5, suggested specificity for an epitope on C5a (des Arg) which is concealed in native C5 and exposed on the activation fragment only, i.e., a 'neoepitope'. The mean C5a des Arg level in EDTA-plasma from 25 healthy individuals assessed at a 1/20 dilution was 11.2 ng/ml (SD 3.4; range 6.4-16.8 ng/ml). The applicability of the assay was investigated in patients treated with haemodialysis using different membranes. Markedly elevated plasma levels of C5a des Arg were found in blood returning from the dialyzer following contact with cuprophane membranes.

Animals↗
PubMed1992

Characterization of the alpha antigen of the c proteins of group B streptococci (GBS) using a murine monoclonal antibody.

A murine monoclonal antibody raised against the alpha antigen of the group B streptococcal c proteins was analysed by immunofluorescence and whole-cell ELISA against a collection of 22 c protein-producing GBS. All the strains showing fluorescence and reactivity in ELISA turned out to be alpha antigen-carrying strains as defined by polyclonal rabbit antisera, while none of the strains producing only the beta antigen was positive. Western blot analyses of the alpha antigen released into the culture medium of growing bacteria suggest that the alpha antigen is present as distinct proteins of variable molecular weights. The upper limit of the molecular weights varies considerably from one strain to another, from approximately 200 kD to 70 kD. With all strains, the bands seen by the MAb occurred at regularly spaced intervals of about 10 kD throughout the gel. Some strains gave rise to 15-16 bands, while others gave rise to only one or two bands. The present investigation suggests that alpha antigens include several, probably identical, repeating subunits of approximately 10 kD. The epitope recognized by the MAb seems to be located on a 10-kD fragment, and in addition, it appears to be surface located, making the MAb a suitable tool in serodiagnostic work.

Antibodies, Bacterial↗
PubMed1992

Binding of human IgA to HCl-extracted c protein from group B streptococci (GBS).

The c beta protein of group B streptococci obtained by HCl extraction appears as a ladder-like pattern in SDS-PAGE when detected by a rabbit anti-c beta serum, and a similar picture is seen when the crude extract is incubated with human IgA and an anti-human IgA conjugate. Affinity-purified c beta antigen and IgA receptors from GBS gave identical pictures in Western blots using rabbit anti-c beta serum. Both the c beta antigen and the IgA receptor are exposed on the surface of GBS as demonstrated by immunofluorescence.

Antigens, Bacterial↗
PubMed1991

Complement activation and pulmonary dysfunction in experimental Escherichia coli septicaemia.

Septicaemia was induced in anaesthetized and artificially ventilated rabbits. Three groups receiving different doses of Escherichia coli 055:B5 and a control group were studied. The animals were followed for 240 min after the start of the bacterial infusion. One animal in the high-dose and one in the medium-dose group died. Septic shock developed in the high-dose group. The infusion of E. coli led to a severe, sustained neutropenia and a dose-dependent thrombocytopenia. A severe arterial hypoxaemia developed during the infusion of bacteria in three of four animals, and in one of three animals in the high- and medium-dose groups, respectively. Both the levels of C5a in plasma and the accumulation of granulocytes in the lung tissue, as assessed by a morphometric method, were dependent on the dose of bacteria. A strong positive correlation was found between levels of C5a and endotoxin. The levels of both C5a and endotoxin correlated positively to the degree of accumulation of granulocytes in the lung tissue. The results from the present study suggest that the magnitude of bacteraemia and the degree of complement activation are probably important factors determining the course and the severity of septicaemia.

Animals↗
PubMed1991

Evaluation of monoclonal antibodies in serovar classification of group B streptococci (GBS). Brief report.

We have produced murine MAbs against the c protein from GBS and selected one anti-c alpha and one anti-c beta MAb for serovar classification of c-protein-producing strains. A total of 61 GBS isolates, classified by serotype-specific rabbit antisera, were tested in an immunofluorescent assay and whole-cell ELISA. The MAbs permitted classification of the isolates into 13 serovars. A total of 34 strains contained the c alpha antigen, seven strains the c beta antigen, and 20 strains both the c alpha and the c beta antigen. The distribution of GBS with regard to c-protein serovars was identical to that recorded when rabbit anti-c alpha and -c beta sera were used. The results show that the MAbs are directed against common epitopes on c alpha and beta, respectively. The MAbs will be useful in the serovar determination of clinical GBS isolates and in the study of the structure and immunobiology of c proteins.

Animals↗
PubMed1991

An antigenic determinant is shared by psoriasis-associated p27 antigen and the Fc part of human IgG.

Rabbit antisera against the major internal protein, p27, of retrovirus-like particles from psoriatic urine, and against the serologically cross-reacting antigen, pso p27, from psoriatic scale, reacted with the Fc part of human IgG. Evidence indicating that the p27 antigen and the pso p27 antigen are identical has been presented in previous reports. A commercial antiserum against human IgG recognized a component in the pso p27-containing solution used as the source of antigen for immunization of the rabbits. By means of monoclonal antibodies against the pso p27 antigen, it was demonstrated that the Fc-reacting antibodies, and the antiserum against human IgG, recognized an epitope on the pso p27 antigen. The data indicated that an antigenic determinant is shared by the p27 antigen(s) and human IgG, suggesting that p27 antigen(s) may act as antigen(s) eliciting the production of antibodies with rheumatoid factor activity in psoriatic patients.

Animals↗
PubMed1991

Interference by anti-C5a monoclonal antibodies with the binding of C5a to cellular receptors and the induction of enzyme release from granulocytes.

A sandwich ELISA based on monoclonal antibodies (MAb) for the quantification of rabbit C5a is only modestly influenced by the presence of MAb 4A3A9, which reacts with an epitope on C5a different from those of MAbs used in the sandwich ELISA. Incubation of rabbit or human granulocytes with C5a in the presence of MAb 4A3A9 results in a less pronounced decrease of the C5a concentration as compared to the concentration measured in the absence of MAb. We interpret the results to indicate an interference of MAb 4A3A9 with the binding of C5a to and/or the dissociation of C5a from its cellular receptor. MAb 4A3A9 is the least effective (25.4% inhibition) among anti-C5a MAbs in inhibiting C5a-induced beta-glucuronidase release from neutrophils. Together, these findings may indicate that a C5a-MAb complex is still able to induce a C5a effect even if MAb does interfere with the binding of ligand to the receptor.

Animals↗
PubMed1990

The expression of retrovirus-like particles in psoriasis.

Retrovirus-like particles have been isolated from patients with psoriasis. Antigens crossreacting with the major internal proteins pso p27, of these particles have been demonstrated in the wall of dermal vessels and in a subfraction of cells in psoriatic lesions. The antigen has also been observed in blood lymphocytes from psoriatic patients. Pso p27 antigen and anti-pso p27 antibodies are present as complement-activating immune complexes in psoriatic scale and in the blood of patients with psoriasis and psoriatic arthritis. The potential contribution of the circulating immune complexes to the inflammatory process in psoriasis is discussed.

Antigens↗
PubMed1990

The psoriasis-associated antigen, pso p27, participates in the formation of complement activating immune-complexes in psoriatic scale.

The psoriasis-associated antigen, pso p27, and antibodies recognizing this antigen were demonstrated in extracts from psoriatic scales. It was demonstrated that the antigen was present in complexes containing IgG as well as complement factor C1q. The complexes were studied with respect to complement-activating potential. This was measured as the ability of the complexes to induce the generation of the complement factor C5a using rabbit serum as the source of complement. The data obtained showed that the pso p27-containing complexes were able to activate the complement system, indicating that the pso p27 antigen may contribute to the inflammatory process in psoriasis.

Animals↗
PubMed1989

Measurement of complement activation in rabbit plasma or serum using monoclonal antibodies against C5a.

Eight murine monoclonal antibodies (MoAb) raised against the major zymosan-induced chemotactic factor in rabbit serum were found to neutralize the chemotactic activity induced by lipopolysaccharides (LPS) and antigen-antibody complexes. A 15 kDa antigen was identified in plasma incubated with LPS by immunoblot analysis with MoAb. This is similar to the molecular weight of the major zymosan-induced chemotactic factor. Both the generation of this 15 kDa antigen and chemotactic activity were abrogated in a heat-inactivated plasma. A cross-reaction to human C5a was demonstrated for three MoAb (5H8B9, 4B1C11, and 2A5E3) in an indirect enzyme-linked immunosorbent assay (ELISA) of partially purified C5a and by the isolation of zymosan-induced chemotactic activity by affinity chromatography. MoAb 5H8B9 and 4B1C11 were able to neutralize the chemotactic activity in human zymosan-activated serum. MoAb 2A5E3 was able to bind 125I-labelled human C5a des Arg. We conclude that these MoAb are directed against rabbit C5a. MoAb 5B2C5 and 2B1A2, which are directed to different antigenic binding sites on C5a, may be applied in a sandwich ELISA for the detection and quantification of C5a des Arg in rabbit serum or plasma. The sandwich ELISA can be performed directly on serum or plasma samples without having to precipitate native C5. Complement activation is demonstrated by measuring the increased generation of C5a des Arg in rabbit plasma or serum activated with LPS, zymosan, antigen-antibody complexes, or cobra venom factor.

Animals↗
PubMed1988

Monoclonal antibodies against the major zymosan-induced chemotactic factor in rabbit serum.

The major zymosan-induced chemotactic factor in rabbit serum was purified by a two-step ion exchange chromatography procedure. The purified chemoattractant was used as antigen for production of murine monoclonal antibodies against the major chemotactic factor. The primary screening of the hybridoma cultures was an indirect ELISA using purified chemotactic factor as antigen. The final selection among ELISA-positive clones was performed according to the results obtained in a chemotactic inhibition assay. Six monoclonal antibodies were raised. These antibodies completely abrogated or substantially reduced the chemotactic activity in crude zymosan-activated serum. The chemotactic factor(s) could be absorbed onto an immunosorbent column containing monoclonal antibody and subsequently be specifically eluted with acid. By Western blot analysis the molecular weight of the major chemotactic factor was estimated to be approximately 15,000, and isoelectric focusing indicated a pI of about 9.4.

Animals↗
PubMed1988

Monoclonal antibodies against the major internal protein, p27, of a psoriasis-associated retrovirus-like particle.

Four murine monoclonal antibodies (MoAb) were raised against p27 isolated from psoriatic scale. The MoAb recognized the antigen on a subfraction (0.1-1%) of psoriatic lymphocytes as well as in skin biopsies from psoriatic patients. In contrast, the antigen could not be detected on lymphocytes or in skin biopsies from healthy controls. A sandwich ELISA assay using the MoAb for detection of p27 is described. This method, together with a competition antibody-binding assay for distinction of epitopes, demonstrates that the MoAb recognize four different antigenic determinants on p27.

Animals↗
PubMed1988

Participation of antigens related to the psoriasis associated antigen, pso p27, in immune complex formation in patients with ankylosing spondylitis.

Analysis of five serum samples and three synovial fluids from patients with ankylosing spondylitis (AS) and five serum samples from healthy blood donors for the presence of antibodies cross reacting with the Fc part of rabbit IgG (rheumatoid factors (RFs] using an isotype specific, enzyme linked immunosorbent assay (ELISA) showed only insignificant amounts of free RFs, while IgG RFs were observed in alkaline dissociated circulating immune complexes (CICs). Only insignificant amounts of free antibodies reacting with the psoriasis associated antigen pso p27 could be detected in the samples, while extensive amounts of IgG antibodies and moderate amounts of IgM antibodies reacting with pso p27 were detected in alkaline dissociated CICs from the patients. Pso p27 has been reported to share a common determinant with the Fc part of human IgG. Removal of the RF activity from the CICs of patients with AS by absorption with IgG resulted in a decrease of the anti-pso p27 activity. Monoclonal anti-pso p27 antibodies in a sandwich ELISA were used to detect antigens cross reacting with pso p27. A positive reaction was observed in all serum CICs and in one of the synovial fluid CICs. The data indicate that antigens related to pso p27 participate in CIC formation in AS and may also be responsible for the elicitation of rheumatoid factors in patients with AS.

Antibodies↗