Biomedical subjects

D Kraft

Publications and source records attributed to D Kraft.

At least 199 records · Page 11Linked to original sources

PubMed1993

[Regulation of IgE synthesis].

IgE synthesis results from a complex interaction between T cells, B cells, and allergen presenting cells under the control of T cell and mast cell-/basophil-derived cytokines (IL-4, IL-5, and IL-6). IL-4 provides a first and crucial signal, which does not, however, suffice for the induction of IgE synthesis by human B cells. A second signal is required, which then leads to B cell activation and production of IgE+ B cells. Cognate as well as non-cognate T/B cell interactions or stimulation by Epstein-Barr (EB) virus infection, the ligand for CD40, ACTH, hydrocortisone etc. can provide this signal. Based on this concept of a multicomponent network new approaches may lead to the development of more effective strategies for the treatment of IgE-mediated allergic diseases.

Anaphylaxis↗

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

Profilins constitute a novel family of functional plant pan-allergens.

Type I allergy is a major health problem in industrialized countries where up to 15% of the population suffer from allergic symptoms (rhinitis, conjunctivitis, and asthma). Previously, we identified a cDNA clone that encoded a birch pollen allergen as profilin. Profilins constitute a ubiquitous family of proteins that control actin polymerization in eukaryotic cells; in particular, profilin participates in the acrosomal reaction of animal sperm cells. Although profilins had been unknown in plants so far, our finding led to the assumption that profilins might have similar functions in pollens during plant fertilization and therefore represent allergenic components in almost all pollens. We show that profilins are prominent allergens that can be isolated from tree pollens (Betula verrucosa, birch), from pollens of grasses (Phleum pratense, timothy grass), and weeds (Artemisia vulgaris, mugwort). About 20% of all pollen allergic patients tested (n = 65) displayed immunoglobulin E (IgE) reactivity to recombinant birch profilin that was expressed in pKK223-3. An IgE inhibition experiment performed with recombinant birch profilin and purified natural profilins from timothy grass and mugwort indicates common IgE epitopes. Moreover, all pollen profilins purified from these far distantly related plant species, and likewise the purified recombinant birch profilin, are able to elicit dose-dependent histamine release via high affinity Fc epsilon receptor of blood basophils from profilin allergic patients. The presence of profilin and possibly related proteins as crossreacting allergenic components in various plants therefore provides an explanation as to why certain allergic patients display type I allergic reactions with pollens and even food from distantly related plants. A functional pan-allergen, like profilin, available as purified recombinant protein, may be a useful diagnostic and probably therapeutic reagent.

Allergens↗

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

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

Type I allergy induced by Limulus Amoebocyte Lysate (LAL).

During the last few years Limulus Amoebocyte Lysate (LAL) has been extensively used to detect minimal amounts of endotoxins of Gram-negative bacteria in products of the pharmaceutical industry, in food stuff, body fluids, house dust and room air. LAL is produced from cells of the haemolymph (amoebocytes) of the horseshoe crab (Limulus polyphemus), which respond with an extremely sensitive clotting system upon contact with endotoxins. In this study we demonstrate by typical case history, positive skin test and ELISA the occurrence of Type I allergy to LAL in a patient suffering from conjunctivitis and rhinitis at work.

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↗

PubMed1992

Diagnosis of grass pollen allergy with recombinant timothy grass (Phleum pratense) pollen allergens.

In order to establish a test system for grass pollen allergy based on the use of recombinant allergens we chose timothy grass (Phleum pratense), a widely spread grass, as a model. From a lambda gt11 cDNA expression library that we had constructed from pollen RNA of timothy grass (P. pratense), we had obtained with serum IgE from a grass pollen-allergic individual 60 IgE-binding clones. By differential testing with sera from different grass pollen-allergic patients, we selected three distinct clones encoding Phl p I (group I), Phl p V (group V) and profilin from timothy grass, which when used together allowed the diagnosis of grass pollen allergy in 97 out of 98 tested grass pollen-allergic patients employing a simple plaque lift technique. This recombinant test based on plaque lifts containing allergen-beta-galactosidase fusion proteins was compared with IgE immunoblots using crude pollen protein extracts from timothy grass. Both methods were in good agreement with RAST scores and clinical data, and proofed to be useful for the diagnosis of grass pollen allergy. Our results further indicate that a limited panel of only two recombinant grass pollen allergens, Phl p I and Phl p V, together with the plant panallergen profilin could be sufficient for the diagnosis and possibly immunotherapy of grass pollen allergy.

Adolescent↗

PubMed1992

Molecular characterization of IgG and IgE antigens of Entamoeba histolytica.

Several surface IgG antigens of E. histolytica have been characterized. We isolated two novel cDNAs by screening a library of pathogenic E. histolytica with rabbit antiserum against a membrane preparation of pathogenic amebas. cDNA K15 encodes a large protein > 220 kDa with sequence homology to myosins and K18 encodes a protein of around 40 kDa. Serum IgG from patients suffering from amebiasis binds to both antigens. Some IgE antibodies are able to recognize homologous proteins in all eukaryotes investigated. We demonstrate that IgE antibodies from pollen allergic patients bind to plant, human, as well as E. histolytica profilins.

Allergens↗

PubMed1992

[Quality control in the allergy laboratory--4 years "Allergy Ring Trial" in Austria].

In 1988 the Austrian Society for Allergology and Immunology initiated an external quality control program for the in vitro allergy diagnosis. In 12 mailings, 62 sera from allergic patients were sent to selected laboratories in order to determine total and antigen specific IgE according to the laboratory-specific methods. The values for total IgE varied considerably (73.9% were within +/- 1 SD, 94.3% within +/- 2 SD and 99.1% within +/- 2 SD, but only 0.9% beyond that). Sources of error were mainly attributable to inappropriate equipment and low quality reagents, but also bad test performance, with respect to personnel and the routines. In contrast, antigen specific IgE against pollen, mites, moulds, insect venoms, animal danders, drugs, parasites, environmental and food antigens revealed quite homogeneous results. Out of 1492 data, only 46 (3.1%) had to be declared as "wrong", and the variability of the RAST-classes was low. Whereas the quality of the reagents from all the different suppliers was not absolutely reliable at the beginning of the study, it improved considerably with time, as consequence of our complaints. The comparability of the methods for detecting total-IgE were non-satisfactory, whereas those for antigen specific IgE were generally good. The variety of methods employed (radio- and enzyme immunologic, fluoro- and nephelometric methods, etc.) should entail appropriate consequences, especially critical comparisons within one and the same laboratory; in addition, international standardization of the "normal" values should replace company-standards, and quality control programs for each test system before it is marketed should be mandatory. Our results confirm, that external control should be obligatory for any laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗

PubMed1991

Identification of profilin as a novel pollen allergen; IgE autoreactivity in sensitized individuals.

A complementary DNA encoding a pollen allergen from white birch (Betula verrucosa) that was isolated from a pollen complementary DNA library with serum immunoglobulin E from a birch pollen-allergic individual revealed significant sequence homology to profilins. The recombinant protein showed high affinity to poly-L-proline. Immunoglobulin E antibodies from allergic individuals bound to natural and recombinant birch profilin and also to human profilin. In addition, birch and human profilin induced histamine release from blood basophils of profilin-allergic individuals, but not of individuals sensitized to other plant allergens. The structural similarity of conserved proteins might therefore be responsible for maintaining immunoglobulin E antibody titers in type I allergy.

Amino Acid Sequence↗

PubMed1991

Common epitopes of birch pollen and apples--studies by western and northern blot.

Eighty-three sera from patients with birch-pollen allergy were investigated for IgE antibodies against apple allergens by means of immunoblotting. In immunoblots, 81 patients (97.6%) exhibited IgE directed against the major allergen of birch, Bet v I (17 kd), and these patients also demonstrated IgE binding to apple allergens in the molecular weight range 17 to 18 kd. Inhibition studies by preincubation of sera with birch-pollen extract led to complete blocking of IgE binding to this 17 to 18 kd protein, whereas preincubation with apple extract could not diminish IgE binding to Bet V I. Furthermore, a 17 kd protein in apple extract could be detected by immunoblotting with a Bet v I-specific monoclonal antibody. Northern blotting with a Bet v I cDNA clone as a probe revealed cross-hybridization of birch and apple allergen coding nucleic acids under conditions of high stringency, suggesting significant homology of the nucleic acid level. Our results support the concept that antigens in birch pollen and apples share allergenic epitopes leading to IgE cross-reactivities that may cause clinical manifestations when a special threshold level of specific IgE antibodies is reached.

Adolescent↗

PubMed1991

Recombinant allergens for immunoblot diagnosis of tree-pollen allergy.

Diagnosis of type I allergy essentially depends on the availability of defined allergens, which can be provided by recombinant deoxyribonucleic acid (DNA) technology. We have previously isolated the c(complementary)DNAs encoding the major birch-pollen allergen, Bet v I, and another allergen with a molecular weight of 14 kd that was identified as birch profilin and designated Bet v II. These cDNAs were isolated from a lambda gt11 expression library by screening with the serum IgE from allergic patients. To obtain expression in Escherichia coli of recombinant allergens without additional fused polypeptides, both cDNAs were inserted into the plasmid pKK223-3. E. coli cells expressing Bet v I and birch profilin (Bet v II) were used for the preparation of recombinant proteins. These proteins were tested for their IgE-binding properties on immunoblots with sera from 100 different birch pollen-allergic patients. All patients' sera, which reacted with the natural allergens, Bet v I and Bet v II, demonstrated an identical IgE-binding pattern to recombinant birch-pollen allergens. Recombinant allergens may therefore be useful for the setup of diagnostic tests that allow the discrimination of different IgE-binding patterns as well as for patient-tailored immunotherapy.

Allergens↗