Biomedical subjects

O Scheiner

Publications and source records attributed to O Scheiner.

At least 181 records · Page 10Linked to original sources

PubMed1989

The gene coding for the major birch pollen allergen Betv1, is highly homologous to a pea disease resistance response gene.

Pollen of the white birch (Betula verrucosa) is one of the main causes of Type I allergic reactions (allergic rhinoconjunctivitis, allergic bronchial asthma) in Middle and Northern Europe, North America and the USSR. Type I allergies are a major threat to public health in these countries, since 10-15% of the population suffer from these diseases. BetvI, an allergenic protein with an Mr of 17 kd is a constituent of the pollen of white birch and is responsible for IgE binding in more than 95% of birch pollen allergic patients. Here, we report the complete nucleotide sequence and deduced amino acid sequence of a cDNA clone coding for the major pollen allergen (BetvI) of white birch. It is similar to the N-terminal peptide sequences of the allergens of hazel, alder and hornbeam (close relatives) but it has no significant sequence homology to any other known allergens. However, it shows 55% sequence identity with a pea disease resistance response gene, indicating that BetvI may be involved in pathogen resistance of pollen.

Allergens↗

PubMed1989

Interaction of different strains of Entamoeba histolytica with target cells: characterization of electrophysiological and morphological features.

Two strains of Entamoeba histolytica with pathogenic zymodemes (SFL3, HK9), one strain with non-pathogenic zymodeme ("Bru") and one non-pathogenic Entamoeba sp. strain ("cold strain"), were investigated with respect to their interaction with target cells. Three test systems were used: 1) direct microscopical observation and qualitative as well as quantitative evaluation of contact and binding events with MDCK cells as targets, 2) kinetics of cytotoxic activity as measured by means of chromium release from 51Cr-labelled K562 cells, and 3) electrophysiological observations with freshly prepared mouse liver cells. We observed that the non-pathogenic cold strain interacted only shortly with target cells (statistical events, interaction type "I"), but did not induce morphological changes, chromium release or depolarization of targets. Non-pathogenic and avirulent strain "Bru" showed, apart from type "I"-binding, the ability to establish tight (type "II") and long-lasting contact (type "III") with targets, but again without cytotoxic effects. The pathogenic but avirulent strain HK9 tightly interacted (type "II") and sometimes long-lasting with target cells, but morphological changes and chromium release were of a moderate degree during the first 20 min, and depolarization was only a rare event. In contrast, strain SFL3 produced tight and long-lasting contacts (type "III" binding), leading to cell death in 83% (type "IV" interaction) within 20 min, substantial chromium release within 10 min and rapid depolarization ("electric collapse") of target cells.

Animals↗

PubMed1989

Characterization of Micropolyspora faeni antigens by human antibodies and immunoblot analysis.

IgG, IgM and IgA antibody responses against Micropolyspora faeni (Mf) antigens were studied by means of immunoblotting experiments using 70 sera derived from three groups of farmers, namely patients with extrinsic allergic alveolitis (EAA) due to thermophilic actinomycetes (n = 25), patients without EAA but with hay exposure (n = 14), and patients suspected to have EAA (n = 31), and 27 sera from two groups of control persons (healthy laboratory workers, n = 13; healthy farmers, n = 14). Patients with EAA showed IgG, IgM and IgA antibody responses mainly against the antigens with molecular weights (MW) of 11, 12, 25, 35 and 60 kD ("major antigens"), and in addition, but less often, against six antigens with MW in the range of 15 to 62.5 kD ("minor antigens"). The other two groups of patients and also the exposed control persons showed very similar results; however, the antibody response in healthy farmers was substantially weaker in comparison to the three groups of patients and was almost limited to the major antigens with MW 11, 25 and 60 kD. Although patients with proven EAA had higher amounts of antibodies, there was no correlation between this antibody response and the onset of disease. The results indicate the necessity of including at least the major antigens with MW of 11, 25 and 60 kD in all extracts used for in vitro diagnosis of Mf-induced EAA.

Adult↗

PubMed1989

IgE and IgG antibodies of patients with allergy to birch pollen as tools to define the allergen profile of Betula verrucosa.

IgE and IgG antibody response to birch pollen antigens were studied by means of immunoblotting experiments testing 58 sera from patients with Type I allergy to birch pollen. 56/58 patients showed IgE antibodies reactive with Bet v I, a 17 kilodalton (kD) pollen protein. 2D-electrophoresis/immunoblot revealed a heterogeneity of that protein. Ten spots (pH 4.9-5.9) could be detected, presumably representing differentially glycosylated isoallergens. In 33/58 patients, there was no evidence of IgE antibodies directed against allergens other than Bet v I. However, in 25/58 of patients' sera, 11 minor allergens (13, 15, 18, 27, 29, 32, 39, 44, 57, and 68 kD) with individual incidences from 1.7% to 17.2% were identified. All proteins were also recognized by the patients' IgG antibodies: in the case of Bet v I recognition was weak, whereas the IgG response to the minor allergens was pronounced. Sera from healthy individuals showed similar IgG antibody responses, but no IgG to the 15, 27, and 29 kD proteins. Our results suggest that IgG directed against minor allergens may function as trapping antibodies in healthy individuals. Too low or lacking amounts of anti-Bet v I IgG may facilitate an allergic reaction.

Adolescent↗

PubMed1989

Specificities of IgE and IgG antibodies in patients with birch pollen allergy.

58 sera from patients with established birch pollen allergy showed characteristic antibody-binding patterns in immunoblotting experiments. Regarding IgE, 56/58 patients recognized a protein of molecular weight (MW) 17 kilodaltons (kD), previously defined as Bet v I. 23/58 patients in addition reacted with a variety of 11 minor allergens with MWs ranging from 13 to 68 kD. A 13-kD protein was proved to represent an independent minor allergen. IgG binding in patients and healthy individuals was more pronounced on the minor allergens than on Bet v I. 3 different allergens were not detected by IgG of healthy individuals. In two-dimensional electrophoresis/immunoblot, a monoclonal antibody and human IgE (in both cases directed against Bet v I) detected a very similar cluster of spots, probably representing isoallergens of Bet v I.

Allergens↗

PubMed1989

Monoclonal antibodies against birch pollen allergens: characterization by immunoblotting and use for single-step affinity purification of the major allergen Bet v I.

Two monoclonal antibodies against birch pollen proteins were produced by immunizing BALB/c mice with birch pollen extract. In immunoblotting experiments, antibody BIP 1 reacted with a 17-kilodalton (kD) protein considered to represent the major birch pollen allergen Bet v I. A second monoclonal antibody, BIP 3, reacted with 3 different birch pollen proteins of molecular weights 32, 36 and 68 kD of which the 36- and 68-kD proteins corresponded to minor allergens of birch pollen. Two-dimensional electrophoresis/immunoblotting experiments revealed that BIP 1 reacted with all Bet v I isoallergens, also identified by human IgE antibodies. Using BIP 1 coupled to Sepharose 4B as reverse immunosorbent, Bet v I was obtained in a single-step procedure and characterized as single band by SDS-PAGE.

Allergens↗

PubMed1988

Expression of the VEP13 antigen (CD16) on native human alveolar macrophages and cultured blood monocytes.

Human alveolar macrophages (AM phi) from thirteen patients, who were suffering from various lung diseases were harvested by bronchoalveolar lavage. Peripheral blood monocytes from eight healthy donors were isolated by Ficoll-Hypaque gradient centrifugation and adherence to plastic surface. To detect the VEP13 antigen (CD16) on these cells, a rosette assay employing ox erythrocytes coated by the CrCl3 method with purified VEP13 monoclonal antibody (Eo-VEP13) was used. A mean of 31.3% of freshly isolated AM phi and 3.9% of blood monocytes formed Eo-VEP13 rosettes. Monocytes cultured for 3 or 6 days in the presence of a supernatant from mouse L929 cells, which had been shown previously to improve long-term viability of human monocytes in culture, showed 12.5% and 25.3% Eo-VEP13 rosettes, respectively. No significant increase in VEP13 antigen expression was noted by culturing monocytes without L929 cell supernatant. The factor in L929 supernatant that induces VEP13 antigen expression has not been identified. Tunicamycin at 10 micrograms/ml inhibited significantly VEP13 antigen expression on monocytes. In contrast, IgG rosette formation was not reduced by tunicamycin. Our data show that subpopulations of native human AM phi and peripheral blood monocytes cultured in presence of a supernatant of L929 fibroblasts containing mainly murine CSF may express the CD16 antigen, which is normally found on large granular lymphocytes (LGL). Suppression by tunicamycin indicates that Fc receptor glycosylation takes place during a later differentiation step of mononuclear phagocytes.

Antibodies, Monoclonal↗

PubMed1988

Lack of induction of IgE and IgG antibodies to yeast in humans immunized with recombinant hepatitis B vaccines.

Yeast-derived hepatitis B vaccines (partially purified or highly purified) at different dosages and a plasma-derived hepatitis B vaccine (control) were injected into 50 young volunteers 3 times at monthly intervals. Before and 4 weeks after this series of immunizations, blood samples were drawn and tested for presence of IgE and IgG antibodies against yeast antigens. No rise in IgE antibodies against Saccharomyces cerevisiae antigens nor in IgG antibodies against Candida albicans antigens was found. Together with former clinical results this underlines the experience that type I and type III reactions against putative yeast contaminants apparently play no major role after immunization with recombinant hepatitis B vaccines.

Adult↗

PubMed1988

Isolation and characterization of messenger RNA from male inflorescences and pollen of the white birch (Betula verrucosa).

A glycoprotein with a molecular weight (MW) of 17 kilodaltons (kD), Bet v I, represents the major allergen of the white birch (Betula verrucosa, BV) and plays an important role in tree-pollen-induced type I allergic reactions. In order to characterize the major and also some minor allergens of BV, we investigated the IgE-binding properties of these allergens using immunoblot techniques. Normal and patients' sera were employed for this study. Furthermore, RNA from male inflorescences and from pollen of BV were isolated and purified by affinity chromatography on oligo-dT-cellulose. Poly(A)+-mRNA thus obtained was translated in vitro in a cell-free wheat germ system and the proteins synthesized were separated by SDS-PAGE and transferred to nitrocellulose. The blots were incubated with normal human sera and with sera from patients allergic to birch pollen. Bound IgE antibodies were detected with 125I-labeled anti-IgE. We observed major IgE binding to a protein of an MW of 12.5 kD, and little IgE binding to a 17-kD protein, presumably Bet v I. Comparing the products of in vitro translation from mRNA preparations of mature pollen and of male inflorescences collected in June, October and February, little seasonal variations could be observed. As the in vitro translation system does not glycosylate proteins, our results show that the majority of IgE in patients' sera is not directed against the carbohydrate moieties of these allergens.

Allergens↗

PubMed1987

Differentiation of rat bone marrow cells into macrophages under the influence of mouse L929 cell supernatant.

Bone marrow cells (BMC) flushed from femora of Lewis rats were cultured in Dulbecco's modification of Eagle's medium supplemented with mouse L929 cell supernatant as a source of colony-stimulating factor (CSF). Differentiation of macrophage progenitor cells into macrophages (M phi) and expression of various markers were kinetically assessed. The proportion of M phi increases from approximately 4% in freshly isolated BMC to 100% after 7-8 days of cell culture. These cells, termed bone marrow cell-derived macrophages (BMDM phi), adhere to and spread on plastic surface; exhibit M phi morphology; stain intensely for nonspecific esterase; are able to phagocytose latex particles, IgG-sensitized erythrocytes, and C3-coated red cells; and express receptors for IgG and C3. A subpopulation of BMDM phi expresses MHC class II antigens as demonstrated by immunofluorescence using MRC OX6 and MRC OX17 monoclonal antibodies which recognize antigens coded in the I-A or I-E subregion of the MHC, respectively. Collectively, our results show that supernatant from mouse L929 cells supports and is continuously required for proliferation and differentiation of rat BMC into typical M phi, and suggest that mouse CSF cross-reacts with the putative receptor on rat M phi.

Animals↗

PubMed1987

Molecular weight analysis of Entamoeba histolytica antigens recognized by IgG and IgM antibodies in the sera of patients with amoebiasis.

The sera of four patients with amoebic liver abscess and two patients with diarrhea caused by Entamoeba histolytica were tested on "Western blots" prepared from E. histolytica strains A3, SFL-3 and HK-9 separated by SDS-PAGE. IgG antibodies in the sera from patients with liver abscess were found to react with several "major" (i.e. strongly staining) band of approximate molecular weights 150-250 kD, 100 kD, 80 kD, 60 kD, 35 kD, 30 kD, 20 kD, and 5-15 kD and the 150-250 kD group of bands. A comparison of the patterns of reactivity obtained with these sera and strains A3, SFL-3 and HK-9 would indicate that some of these bands, especially the 5-15 kD groups of bands might carry antigenic determinants specific for individual strains of amoebae. This 5-15 kD group of bands is completely pelleted at 30.000 g and could therefore be associated with the cytoplasmic membrane. The 150-250 kD group of bands consists of smaller subunits of 40-65 kD molecular weight linked by disulfide bridges; the respective proteins are sensitive to digestion with elastase but not with trypsin, and seem to carry antigenic determinants containing sugar residues as evidenced by their sensitivity to treatment with NaJO4.

Amebiasis↗

PubMed1986

Interaction of serum components with the cytotoxic action of Entamoeba histolytica.

Native normal human serum is capable of inhibiting the cytotoxic action of Entamoeba histolytica against K562 tissue culture target cells assessed by a 51Cr-release test. It is suggested that a part of the inhibitory activity on amoebae's cytotoxic action is represented by the complement system which is known to lyze trophozoites by activation of the alternative pathway. For the rest of the serum's inhibitory activity on amoebic cytotoxic action molecule(s) is (are) responsible which act(s) independently of Mg2+ and Ca2+. The serum components have to act before the trophozoites have come in contact with the target cells. The opsonization of trophozoites with antiamoebic antibodies led to an inhibition of amoebae's cytotoxic action (ACA) in a dose-dependent manner. The inhibitory components of normal human serum and antiamoebic antibodies potentiated each other in their capacity to inhibit ACA. It is suggested that opsonization of amoebae with C3b via its metastable binding site leads to redistribution phenomena on the amoebae's surface similar to the effects observed with antiamoebic antibodies, both events leading to inhibition of ACA.

Animals↗

PubMed1984

Spaetlese lung.

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Agricultural Workers' Diseases↗

PubMed1984

Measurement of the respiratory burst in human monocytes and polymorphonuclear leukocytes by nitro blue tetrazolium reduction and chemiluminescence.

We compared measurements of chemiluminescence (CL) assessing the rate of production of oxygen intermediates at a given instance, and of nitro blue tetrazolium (NBT) reduction detecting total superoxide produced during the assay period, for the assessment of the respiratory burst of both human monocytes (M phi) and polymorphonuclear leukocytes (PMN). In the CL experiments, opsonized and non-opsonized zymosan was used to stimulate peripheral blood M phi and PMN. Opsonized zymosan yielded an earlier and 2-fold higher peak response than non-opsonized zymosan. The stimulatory action of zymosan in CL varied with the time of incubation and depended on the concentration of cells and zymosan. No light generation was observed in the absence of viable cells. In contrast to NBT reduction, incubation of PMN with dextran sulfate did not result in increased light generation but rather in a quenching of the response in CL. Opsonized zymosan also yielded a higher level of NBT reduction than non-opsonized zymosan. Comparing NBT reduction with CL in 21 healthy individuals, with 2 X 10(5) M phi and 2.5 X 10(5) PMN for NBT and 5 X 10(5) PMN for CL tests, we found that NBT brings about spontaneous oxidative metabolism, possibly reflecting the intracellular compartment, the chemiluminescent response of resting cells being only marginal. The data suggest higher sensitivity of the CL method. These results provide useful comparative data for 2 established methods used to document the respiratory burst in phagocytic cells.

Adolescent↗

PubMed1984

Use of monoclonal antibodies against factor H to investigate the role of a membrane-associated protein antigenically related to H in C3b-receptor function.

Three murine monoclonal IgG1 kappa-antibodies, MAH-1, MAH-2, and MAH-3, were raised against factor H purified from human plasma. In cross-inhibition studies MAH-3 did not compete with MAH-1 and MAH-2, and vice versa, for the binding to H, whereas MAH-1 and MAH-2 inhibited each other. MAH-1 and MAH-2 inhibited the binding of H to C3b attached to an ELISA plate as well as to C3b bound to sheep erythrocytes by means of the classical pathway convertase and of C3b to H attached to an ELISA plate. The determinant defined by MAH-1 and MAH-2 was no longer accessible on H bound to C3b. In contrast, MAH-3 interfere with the binding of H to C3b or vice versa only to a smaller extent but recognized a determinant still accessible on H bound to C3b and was able to agglutinate EAC14o23b-H in an indirect Coombs test. All three antibodies were shown to bind to tonsil cells and Raji cells in an indirect cell ELISA. The membrane-associated molecule detected by these antibodies had an apparent m.w. of 140,000 D in SDS-PAGE. All three antibodies partially inhibited the binding of EAC14o23b to tonsil lymphocytes and, in the presence of 0.1 mM DFP, to Raji cells; binding of EAC14o23bi and EAC14o23d to tonsil cells was not affected. We conclude that MAH-3 recognizes a determinant distinct from the ones recognized by MAH-1 and MAH-2, the latter possibly defining identical epitopes that are located close to the binding site for C3b. The fact that these two distinct epitopes could be detected on a 140,000-D membrane-associated protein from lymphoid cells strongly suggests that this molecule is at least antigenically related to serum H and shares with H a region carrying the binding site for C3b. The rosette inhibition studies imply that this structure is important for the binding of C3b-coated particles to lymphoid cells.

Animals↗

PubMed1984

[Entamoeba histolytica: II. Effect of humoral immune mechanisms on cytotoxic activity].

The time dependency of the cytotoxic action of E. histolytica against tissue culture cells of mammalian origin was assessed in a 51Cr-release assay. Obviously, the amebae-dependent cytotoxic activity within the first 30-60 min of the assay against K562 (an erythroleukemic cell line) and MH1C1 (a rat hepatoma cell line) correlated with the pathogenicity of the respective amebae in vivo as measured by the hamster liver infectivity test. The in vivo apathogenic strain of E. histolytica (HK9) exhibited a delayed cytotoxic action in comparison with the in vivo pathogenic strain (SFL3), which revealed approximately 50% of maximum 51Cr-release after 10 min of the assay. Peripheral blood lymphocytes and HeLa cells proved to be not suitable to discriminate between pathogenic and apathogenic strains in vitro. Human antibodies directed against E. histolytica were capable of inhibiting the cytotoxic action of pathogenic amebae against K562 and MH1C1 within the first 30-60 min of the assay, revealing a kinetic pattern nearly identical with that observed with apathogenic amebae against K562. Possibly, this antibody-mediated inhibition of the cytotoxic action of E. histolytica against target cells reflects one of the defence mechanisms of the host against invasive amebiasis.

Animals↗

PubMed1983

Coupling of C3b to erythrocytes by disulfide bond formation: preparation of EC3b for hemolytic and complement receptor assays.

We describe a new method of preparing C3-coated erythrocytes by coupling C3 to thiol-activated erythrocytes. The procedure involves three steps. Firstly, sheep erythrocytes were treated with N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) to introduce 3-(2-pyridyldithio) propionyl residues into membrane proteins. Secondly, C3 was cleaved with trypsin or CoVF, Bb enzyme to obtain C3b exposing the SH group (C3b-SH). Finally, the C3b-SH was coupled to the thiol-activated erythrocytes (TA-E) through thiol/disulfide exchange to form the TA-EC3b conjugate. E coated with C3d was prepared by treating TA-EC3b with KSCN inactivated serum and plasmin. Studying the rosette formation between TA-EC3b or TA-EC3d and cells expressing C3b (CR1) and C3d (CR2) receptors and the inhibition thereof with anti-CR1 and anti-CR2 antibodies as well as with C3-sheep E membrane protein complexes, we found that TA-EC3b and TA-EC3d bound exclusively to CR1 and CR2, respectively. In addition, TA-EC3b like EAC1423b bound factors B and H as tested by hemolytic and direct binding assays. The advantage of TA-EC3 for complement receptor and hemolytic assays are the simplicity of the preparation method and the general applicability of the TA-EC3.

Animals↗

PubMed1983

Importance of factors H and I for the adherence of C3b-coated erythrocytes to cells.

The role of cell membrane-associated human factor H for the binding of cell-bound C3b to complement receptor-carrying (CR+) cells was investigated. Pretreatment of CR+ cells with antibodies to factor H inhibited the adherence of C3b-coated red cells to human tonsil lymphocytes (TL) and peripheral blood monocytes (M phi). The C3b receptor reactivity of human polymorphonuclear leucocytes (PMN) was not influenced and the one of Raji lymphoblastoid cells only slightly influenced; iC3b and C3d receptor reactivity was in no case affected. When diisopropylfluorophosphate (DFP) in a concentration of 0.1 mM was present during pretreatment of the CR+ cells with anti H, the antibodies gained the capacity to inhibit the adherence of C3b-coated erythrocytes to Raji cells; this effect was dose-dependent with respect to DFP. In contrast, there was no influence of DFP on the inhibition pattern of anti H in the case of TL and M phi. The adherence of C3b-coated erythrocytes to PMN remained unaffected by anti-H antibodies in the presence of DFP. Polyclonal as well as monoclonal antibodies directed against human factor I inhibited the binding of C3b cells to Raji cells but not to TL. Additionally, when anti I and anti H antibodies were both present, C3b receptor reactivity of Raji cells was inhibited to a larger extent than with either antibody alone; again, TL remained unaffected. Results obtained by washing the Raji cells before and after treatment with anti H and anti I suggest that the respective antibodies act on factor H primarily on the level of the cell membrane and on factor I in the fluid phase.

Animals↗