Biomedical subjects

O Scheiner

Publications and source records attributed to O Scheiner.

At least 145 records · Page 8Linked to original sources

PubMed1993

Pathogenic Entamoeba histolytica: cDNA cloning of a histone H3 with a divergent primary structure.

Entamoeba histolytica has an unusual nuclear structure characterized by a low degree of chromatin condensation and the absence of stainable metaphase chromosomes. Although nucleosome-like particles were observed, no information about histones was available so far. In this paper we describe a cDNA clone with significant homology to H3 histones that was isolated from a library of pathogenic E. histolytica. The complete cDNA encodes a 15-kDa polypeptide, which like the histone sequence from Volvox carteri is shorter by one residue than the human homologue. The amino acid sequence has only 69% identity with human H3.3 histone and 67% identity with the human H3.1 histone. This is the highest degree of sequence divergence observed for any eukaryote H3 histone sequence. Our results indicate that this divergence may contribute to the unusual chromatin structure of E. histolytica.

Amino Acid Sequence↗

PubMed1993

Allergens from birch pollen and pollen of the European chestnut share common epitopes.

Type I allergy to pollen of the European chestnut (Castanea sativa) represents a major cause of pollinosis in (sub) Mediterranean areas. Using sera from 14 patients with established allergy to pollen of the European chestnut, 13/14 sera (92%) showed IgE-binding to a 22 kD protein, 2/14 (14%) displayed additional binding to a 14 kD protein and 1/14 (7%) bound only to the 14 kD protein of European chestnut pollen extract. Two monoclonal mouse antibodies, BIP 1 and BIP 4, directed against different epitopes of Bet v I (the major birch pollen allergen), and a rabbit antibody to recombinant birch profilin (rBet v II) were used to characterize the proteins of the European chestnut pollen. The recombinant birch pollen allergens, rBet v I and rBet v II (profilin) were employed to show common allergenic structures on proteins from both birch and European chestnut pollen by IgE-inhibition experiments. Despite the fact that the 22 kD protein displayed a higher molecular weight in comparison to the 17 kD major birch pollen allergen, Bet v I, we could demonstrate reactivity of both monoclonal antibodies, BIP 1 and BIP 4, with this protein. A complete inhibiton of IgE-binding to this 22 kD protein was shown by pre-incubating sera with purified recombinant Bet v I. In addition, the 14 kD protein could be identified by IgE-inhibition studies with recombinant Bet v II and by using a rabbit anti-profilin antibody as the profilin from pollen of the European chestnut.

Allergens↗

PubMed1993

Characterisation of dog allergens by means of immunoblotting.

Sera from 75 patients with clinical type I allergy against dogs were investigated by means of immunoblotting using extracts prepared from dog hair/dander (CAN XI D) and saliva. In addition, selected sera were tested on extracts made of hair, skin, salivary glands (parotis and submandibularis), serum and liver. A 69-kD IgE-binding protein was identified in all extracts tested with an incidence of approximately 40% and shown to be dog albumin by means of inhibition experiments. In 96% of patients' sera IgE antibodies reactive with a 19-kD and/or a 23-kD protein of the hair/dander extract (CAN XI D) were observed. IgE binding to a 23-kD band was also detected in the hair and saliva extracts, but not in skin, salivary gland, serum and liver extracts. A 19-kD IgE-binding protein was strongly expressed in skin and to a lesser degree in saliva, but not in hair, serum and liver. Preincubation of patients sera with the hair extract and subsequent probing with the hair/dander extract (CAN XI D) inhibited IgE binding to the 23 kD protein whereas preincubation with the skin extract abolished IgE binding to the 19-kD protein. Using the hair/dander extract as inhibitor, IgE binding to the 19- and 23-kD proteins of saliva was abrogated. Thus it is concluded that the 23-kD protein is preferentially expressed in hair and saliva whereas the 19-kD protein is found in saliva and skin. Furthermore these two proteins are likely to represent immunologically independent major allergens.

Adolescent↗

PubMed1993

Detection of IgE antibodies specific for allergens in cow milk and cow dander.

Sera from patients with cow milk protein allergy (n = 6) and cow dander allergy (n = 5) were analyzed for reactivity of IgE antibodies specific for allergens derived from milk and cow dander. The cow milk- and cow dander-allergic patients exhibited elevated specific IgE levels to milk and to cow dander, respectively, as determined by RAST. IgE immunoblot analysis revealed that cow milk-allergic patients exhibited IgE binding to the milk allergens casein, beta-lactoglobulin, alpha-lactalbumin and bovine serum albumin. Four of six cow milk-reactive patients also exhibited IgE binding to cow dander proteins with molecular weights of 20, 22, 36, 50 and > 200 kD. IgE from the sera of cow dander-allergic patients reacted with the major allergens of cow dander (20 and 22 kD) and with other proteins with molecular weights of 24, 36, 42, 50 and 70 kD. Only one out of five of these sera displayed IgE reactivity with cow milk proteins with molecular weights of 69, 92 and > 200 kD. Inhibition studies revealed the cross-reactive nature of the IgE antibodies. Preincubation of cow milk-positive sera with cow milk and subsequent immunoblotting led to complete blocking of IgE binding to cow dander proteins and to cow milk proteins. Preincubation of cow milk-positive sera with cow dander extract led to blocking of IgE binding only to defined cow milk proteins: these could be identified in 2 cases as casein and in 1 case as beta-lactoglobulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Properties of tree and grass pollen allergens: reinvestigation of the linkage between solubility and allergenicity.

In this study we reinvestigated the kinetics of allergen release from birch pollen (Betula verrucosa) and timothy grass pollen (Phleum pratense) using different protein extraction procedures, immunoblotting with specific antibodies and immune electron microscopy. Pollen allergens such as the major birch pollen allergen, Bet v I, the major timothy grass pollen allergens, Phl p I and Phl p V, group-II/III allergens from timothy grass and profilins were released rapidly and in large amounts from hydrated pollen. Within a few minutes pollen allergens could be detected in aqueous supernatants prepared from birch and grass pollen with serum IgE or specific antibodies. In parallel the allergen content in the pollen pellet fractions decreased. A nonallergenic protein such as heat shock protein 70 can be extracted in sufficient amounts only with harsh extraction procedures. Immune electron microscopy of dry and rehydrated birch pollens showed that after short hydration, the major birch pollen allergen, Bet v I, migrated into the exine and to the surface of intact pollen grains, whereas profilin, against which a lower percentage of patients is sensitized, was retained in the pollen grain. Comparing the amino acid composition and hydrophilicity of the tested allergens with a nonallergenic protein such as heat shock protein 70, no significant difference was noted. In agreement with earlier observations we conclude that the allergenic properties of proteins are rather linked to the amount and speed of solubility from airborne particles than to intrinsic properties.

Allergens↗

PubMed1993

[Molecular and functional characterization of allergens: fundamental and practical aspects].

Well-defined allergens are a prerequisite for the exact diagnosis and immunotherapy of Type I (IgE-mediated) allergic diseases. The allergens have to be available in highly purified form and in sufficient quantities. By applying molecular cloning methods this goal can be achieved with respect to both characterization and reproducibility of allergen preparations. Moreover, this technique leads to the deduction of primary structures of allergens, which allows computer-aided comparisons with already known amino acid sequences. Significant sequence similarities with well-described proteins may point to a biological and biochemical function of the cloned allergen. The major allergen of white birch, Bet v 1, and its close relatives from alder, hazel, and hornbeam belong to a family of pathogenesis-related proteins ubiquitous in angiosperms. Based on these results, a percentage of food intolerance can now be regarded as Type I allergy due to Bet v 1-related proteins. By sequence comparisons, Bet v 2, another birch pollen allergen, was identified as the ubiquitous cytoskeleton-associated protein, profilin. For its high sequence conservation and its ubiquitous appearance in allergenic sources of plant origin, profilin was shown to represent a pan-allergen. Recombinant non-fusion Bet v 1 revealed identical immunological properties with respect to interaction with both antibodies and Bet v 1-specific T cell clones when compared with natural Bet v 1 purified from birch pollen.

Allergens↗

PubMed1993

[Effector cells in allergy: biological principles and new pharmacologic concepts].

The clinical symptoms of allergy are caused by cellular (IgE-triggered) responses to an allergen. Effector cells of allergy include eosinophil and basophil granulocytes, as well as tissue mast cells. Growth and accumulation, as well as IgE-dependent and independent functions of these cells are regulated by distinct proteohormones and peptides. The hemopoietic cytokines IL-3 (interleukin-3), IL-5 and GM-CSF (granulocyte-macrophage colony-stimulating factor) are involved in the regulation of basophils (and eosinophils), whereas the ligand for c-kit, SCF (stem cell factor) is a mast cell-specific agonist. Basophils and mast cells express high-affinity IgE-binding sites. Allergen binding to IgE on mast cells and basophils, and consecutive cross-linking of IgE receptors is followed by production and/or secretion of inflammatory mediator substances. Specific activation and deactivation of mast cells/basophils in vitro has been demonstrated by use of recombinant cytokines and allergens, and specific haptens or by use of novel drugs, and should lead to epitope-specific diagnosis and better management of allergic diseases in the future.

Allergens↗

PubMed1993

[New concepts in therapy of type I allergic diseases].

The molecular characterization of allergens with recombinant DNA techniques allowed cDNA sequences to be obtained and, hence, information regarding the primary structure of allergens. It is now possible to express well-defined recombinant allergens in heterologous expression systems and to obtain large amounts of highly pure recombinant allergens for the improvement of current diagnosis and therapy of type I allergic diseases. Due to extensive cross-reactivities and structural similarities of the relevant allergens it is possible to define a limited number of allergens, which is a prerequisite for allergen-specific therapeutic concepts. Specific concepts of active immunotherapy and strategies of passive therapeutic interference based on recombinant techniques are discussed.

Allergens↗

PubMed1993

Tumor necrosis factor alpha and interleukin-1 beta mRNA expression in HMC-1 cells: differential regulation of gene product expression by recombinant interleukin-4.

Cytokine-activation pathways in mast cells are supposed to play a significant role in host defense mechanisms and allergic reactions. Interleukin-4 (IL-4) is a well-characterized regulator of growth and function of mast cells. The human mast cell line HMC-1 was established from a patient suffering from mast cell leukemia and was shown to expose IL-4 binding sites. In the present study, the effects of recombinant human (rh) IL-4 and other rh cytokines (IL-2, IL-3, IL-6, IL-8) on expression of cytokine mRNA in HMC-1 cells were examined by Northern blot analysis using oligonucleotide probes. Tumor necrosis factor alpha (TNF-alpha) and IL-1 beta transcripts were found to be expressed constitutively in HMC-1 cells, whereas transcripts for IL-3, IL-4, IL-5, IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF) could not be detected. Of all cytokines tested, rhIL-4 was found to down-regulate IL-1 beta mRNA expression and formation of immunoreactive IL-1 beta protein in HMC-1 cells. The effect of IL-4 on IL-1 beta gene product expression was time- and dose-dependent (maximum effects obtained with 100 U/mL of rhIL-4). No effect of IL-4 on expression of TNF-alpha mRNA in HMC-1 cells was observed. These results raise the possibility that human mast cells are a source of both TNF-alpha and IL-1 beta. Furthermore, our study provides evidence that IL-4 regulates IL-1 beta gene product expression in HMC-1 cells. The HMC-1 cell line should be a useful tool for studying cytokine activation pathways in human mast cells.

Base Sequence↗

PubMed1992

Expression of leucocyte adhesion molecules at the human blood-brain barrier (BBB).

The expression of leucocyte adhesion molecules was studied on cerebral endothelia by immunocytochemistry. In peritumoral "normal" brain tissue we found low endothelial expression of ICAM1, LFA3, CD44, and CD9, whereas VLA1 was present on vessels in high incidence and density. LFA1, CD2, and CR3 were found on intraluminal and parenchymal leucocytes, but were absent on brain vessels. In brain tumors and inflammatory brain lesions, we observed an up-regulation of endothelial ICAM1 and LFA3 expression, whereas other adhesion molecules on endothelial cells remained unchanged. Within the brain parenchyma, ICAM1 and LFA3 were found on astrocytes and tumor cells; on the contrary, LFA1 was expressed on microglial cells similar to CR3. CD44 and CD9 showed a diffuse neuropil expression in normal and tumoral tissue, whereas VLA1 was not expressed on any parenchymal cells. Our data show that multiple different adhesion molecules are present on blood-brain barrier endothelium (BBB) under normal conditions and some adhesion molecules are up-regulated in brain tumors and under inflammatory conditions. The presence of adhesion molecules in the vessel walls as well as on parenchymal cells like astrocytes and microglia may guide inflammatory cells into and through the brain in the course of immune surveillance and inflammation.

Antibodies, Monoclonal↗

PubMed1992

Complementary DNA cloning and expression in Escherichia coli of Aln g I, the major allergen in pollen of alder (Alnus glutinosa).

Previous data showed that the major pollen allergens from trees of the order Fagales, in particular alder, birch, hazel, and hornbeam, are highly interrelated. As only the complete amino acid sequence of Bet v I, the major allergen from birch, has been known, it was of interest to obtain the primary structure of other major allergens of this group, to attribute IgE-binding properties to certain features of the amino acid sequences of those allergens. cDNA was synthesized from alder pollen mRNA, sequence-specifically amplified by polymerase chain reaction and cloned into plasmid bluescript. Comparison of the deduced amino acid sequences of Aln g I and Bet v I revealed a 86.8% homology. The Aln g I encoding cDNA was subcloned into pKK223-3 and expressed in Escherichia coli as a full-length nonfusion protein. The recombinant Aln g I bound IgE from tree pollen-allergic patients and was shown to share IgE-epitopes with Bet v I by inhibition studies with recombinant Bet v I. Computer-aided calculations predicted epitopes in both Aln g I and Bet v I at the same position; the Bet v I molecule was predicted to possess two additional epitopes near the N-terminus of the molecule.

Allergens↗

PubMed1992

Identification of common allergenic structures in hazel pollen and hazelnuts: a possible explanation for sensitivity to hazelnuts in patients allergic to tree pollen.

It is known that most patients with type I allergy to tree pollens also suffer from intolerance to nuts. To identify allergenic structures common to hazel pollen and hazelnuts, cross-reactivity of patients' IgE was investigated. With use of immunoblotting,.serum IgE from 25 patients displaying type I allergic reactions to tree pollens and intolerance to hazelnuts (group I) bound to the 17 kd major hazel pollen allergen Cor a I (100%) and to the 14 kd hazel pollen profilin (16%). IgE binding to proteins of comparable molecular weights in hazelnut extracts was found (18 kd and 14 kd), suggesting that proteins similar to Cor a I and hazel profilin might be also expressed in hazelnuts. In contrast, only four sera (22%) from 18 patients (group II) with tree pollen allergy but without any case history of nut hypersensitivity showed IgE binding to the 18 kd protein of hazelnut extract, and none of these sera exhibited IgE reactivity to the hazelnut profilin. To characterize the hazel pollen and hazelnut allergens, purified recombinant Bet v I (major birch pollen allergen) and purified recombinant Bet v II (birch profilin), respectively, were used for IgE-inhibition experiments. Binding of IgE from patients (with nut allergy) to the blotted hazelnut allergens could be blocked by preincubation of patients' sera with the recombinant proteins. Furthermore, the 18 kd protein of hazelnut extract was purified and induced specific release of histamine from basophils of a patient suffering nut hypersensitivity but not from a healthy control donor. A rabbit antibody raised against celery profilin identified the 14 kd proteins in hazel pollen and hazelnuts as profilin. Our experiments suggest a protein with IgE binding properties similar to the major allergens from pollens of hazel, Cor a I, and of birch, Bet v I, as predominant allergens in hazelnuts, and show that the plant pan-allergen profilin can be detected in both hazel pollen and hazelnut extracts.

Allergens↗

PubMed1992

Distribution of allergens and allergen-coding mRNAs in various tissues of white birch.

The distribution of allergenic proteins was investigated in various tissues of white birch, Betula verrucosa (pollen, leaves and male inflorescences containing immature pollen). In addition, callus and suspension culture cells were investigated for expression of IgE-binding proteins. Furthermore, RNA was extracted from all these tissues and subjected to in vitro translation in a cell-free wheat germ system. Bet v I, the major birch pollen allergen, could be extracted easily from pollen, and in low amounts from callus and leaves. No Bet v I could be extracted from immature male inflorescences. Minor allergens were expressed in high concentrations in pollen and in low concentrations in immature male inflorescences. No minor allergens could be detected in callus and leaves. In contrast to these observations, RNA from all the tissues as well as from callus could be translated in vitro into Bet v I as well as into minor allergens, in particular birch profilin (Bet v II), an important minor allergen. These data suggest that IgE-binding proteins of B. verrucosa, especially Bet v I, under certain circumstances can readily be synthesized in tissues other than pollen. This concept is corroborated by the recent observation that Bet v I reveals high homology with disease resistance response gene products from other plants, suggesting a similar function of Bet v I for the birch.

Allergens↗

PubMed1992

Humoral immune response against a 70-kilodalton heat shock protein of Entamoeba histolytica in a group of patients with invasive amoebiasis.

In order to investigate the humoral immune response against Entamoeba histolytica a lambda ZapII cDNA library was constructed from trophozoites of the pathogenic E. histolytica strain SFL-3. The library was screened with serum IgG from a patient with invasive amoebiasis. Forty-nine immunopositive lambda clones were isolated and partial sequences from the inserts were obtained. By comparison of the sequences with the merged database MIPSX from the Martinsried Institute for Protein Sequences we were able to identify homologous proteins for 36 of the clones. Twenty-six of the clones encoded intracellular proteins, among these, the major part (16 clones) were highly homologous to the eukaryotic 70-kDa heat shock proteins (Hsps). The open reading frame of one complete clone encodes a protein of 656 amino acid residues of 71.5 kDa which has 69.8% sequence identity with the human Hsp70 protein. In a larger screening experiment only 3 out of 12 patients detected with their IgG the phage which expressed the 70-kDa heat shock protein(s).

Amino Acid Sequence↗

PubMed1992

Association between IgE response against Bet v I, the major allergen of birch pollen, and HLA-DRB alleles.

The association of the human IgE response against Bet v I, the major allergen of birch pollen, and the HLA-DR and DQ phenotype was studied. Birch pollen allergic patients showed a typical case history, positive skin-prick test, and positive RAST with birch pollen extracts. They were divided into two groups. Group I (n = 37) consisted of individuals generating IgE antibodies that selectively reacted with Bet v I. Their serum IgE did not react with minor allergens from birch pollen as tested by immunoblot analysis, nor did they show a response against allergens from a panel of grass and other tree pollen or perennial allergens from animals and fungi as determined by skin-prick test. Patients belonging to group II (n = 34) possessed IgE reacting with Bet v I plus one or more additional allergens. The control group consisted of 637 healthy blood donors. Comparison of the frequencies of RFLP-defined HLA-DR and DQ alleles in patients and the control group revealed that the distribution of DRB3 alleles in group I patients differed significantly from that in the control group: A higher frequency of the DRw52a/c alleles in comparison to the control group (pcorr less than 0.02) was observed. In addition, alleles defined by nucleotide sequences coding for the amino acid sequence tyrosine-phenylalanine-histidine at positions 30-32 of the beta chain of DR molecules were found with a higher frequency in patient group I (pcorr less than 0.02), too. These alleles comprise DRw52a/c and some DRB1 alleles.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

PubMed1992

Autotransplanted jejunum in patients with carcinomas of the head and neck: transport of immunosurveillance against tumor cells?

Autologous jejunum, transplanted as a functional replacement immediately after radical dissection of advanced stages of squamous cell carcinomas of the head and neck and subsequently irradiated, was examined by immunohistochemistry (APAAP/PAP-technique). Biopsies from 9 patients were taken at the time of transplantation and up to 24 months thereafter (group 1) and from 5 patients only once after transplantation (group 2). Twenty-six monoclonal antibodies (mAbs) were used as surface markers to give an overview about phenotypical changes with respect to T-, B- and M phi-antigens. 1) B cells: a general increase of CR2+ (CD21, p less than 0.01) could be noticed after transplantation, immunoglobulin positive cells remained unchanged expect for a significant decrease of IgM+ (p less than 0.01) and IgA1+ (p less than 0.01) cells. 2) The number of T cells (CD3+) showed no significant differences although TcR gamma/delta+ cells decreased (p less than 0.01) in the autotransplant. ICAM-1 (CD54) and IL-2R (CD25) were found on a significant (p less than 0.01) higher number of cells after transplantation. 3) Cells with M/M phi morphology showed increased expression of the Fc gamma receptors (CD64, p less than 0.001; CD32, n.s.; CD16, p less than 0.001), of the complement receptors CR1 (CD35, (p less than 0.001) and CR3 (CD11b, p less than 0.02), of HLA-DQ (p less than 0.01), and of the antigens 25F9 (mature M phi; p less than 0.01) and CD4 (p less than 0.02). Correlation analyses of data obtained from the biopsies of the 14 autotransplanted jejunum cases revealed a CD35+ and a 25F9+ subpopulation of M/M phi. Our findings indicate that despite irradiation autotransplanted jejunum contained cells with immunological capacities. Therefore, the replacement of larynx by autologous jejunum may facilitate not only mechanical but also immunological functions.

Adult↗

PubMed1992

Histological and immunohistochemical investigations of hydroxyethyl-starch deposits in rat tissues.

Tissue storage of hydroxyethyl starch (HES), a widely used artificial colloid, has been reported. In order to clarify whether storage of HES can be detected in tissues by immunohistochemical methods, use was made of a polyclonal rabbit anti-HES antiserum. Thirteen days after a single intravenous injection of HES rats were sacrificed and liver, spleen, lymph node, lung, kidney and skin were removed. On paraffin sections in all organs the anti-HES antiserum stained mainly cells which could be attributed to the mononuclear phagocyte system, as confirmed by the use of the antimacrophage monoclonal antibody ED1. The use of a polyclonal anti-HES antiserum may allow analysis of long-term storage and possible side effects in various tissues of man.

Animals↗

PubMed1992

No evidence for the existence of preformed antibodies against hydroxyethyl starch in man.

Using the highly sensitive ELISA technique for detecting anti-hydroxyethyl starch (HES) antibodies in man sera from 1,056 patients were analyzed. Patients of both sex, who had never had any prior contact with HES, were included in the study. In none of the cases could any titer of HES-reactive antibodies be detected. These data suggest that in man preformed HES-reactive antibodies do not exist or are extremely rare. In any case, unlike dextran-reactive antibodies, they should not have a high clinical importance. The mechanism behind the very rarely observed anaphylactoid reactions after HES application is still unknown.

Adult↗