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H Fiebig

Publications and source records attributed to H Fiebig.

At least 37 records · Page 2Linked to original sources
PubMed1998

Mapping of T-cell epitopes of Phl p 5: evidence for crossreacting and non-crossreacting T-cell epitopes within Phl p 5 isoallergens.

BACKGROUND: Group 5 allergens represent major grass pollen allergens because of their high sensitization indices. The identification of T-cell epitopes of these allergens is a prerequisite for the design of immunotherapeutic strategies based on peptide vaccination or modified allergens with conserved T-cell epitopes. OBJECTIVE: This study was undertaken to determine T-cell epitopes on Phl p 5 major pollen allergen of timothy grass (Phleumn pratense). METHODS: T-cell lines (TCLs) and T-cell clones (TCCs), specific to Phl p 5, were established from the peripheral blood of 18 patients allergic to grass pollen. All TCCs were mapped for epitope specificities using 178 overlapping dodecapeptides representing the primary structures of two isoforms of Phl p 5 (Phl p 5a and Phl p 5b). Phenotype and cytokine production profiles of TCCs were tested. Selected TCCs were analysed for HLA class II restriction. RESULTS: A total of 82 TCCs were isolated. All TCCs displayed the helper cell (TH) phenotype. Their reactivity with two recombinant expressed isoforms of Phl p 5a and Phl p 5b was heterogeneous. The epitope specificity of the TCCs was then revealed. Nineteen T-cell epitopes could be identified on Phl p 5. Eighty-one percent of mapped TCCs recognized three T-cell reactive regions on the Phl p 5 allergen. Some TCCs were reactive with isoepitopes presenting on Phl p 5a as well as Phl p 5b. Allergen-specific stimulation induced a TH0-like type of cytokine production in 25 of 50 TCCs. Almost all TCCs secreted high concentrations of interleukin-13. CONCLUSION: Phl p 5, a major grass pollen allergen, contains several T-cell epitopes. Some epitope regions were recognized by several patients. Epitope recognition pattern could not be correlated with special HLA class II haplotypes. T-cell stimulating isoepitopes were found at corresponding regions of Phl p 5a and Phl p 5b isoforms.

Adult↗
PubMed1996

Conformational changes in CD45 upon monoclonal antibody crosslinking.

The CD45 protein tyrosine phosphatase is expressed in different isoforms that result from alternative splicing of three exons (A, B, and C) encoding regions near the N-terminus of the extracellular part of the molecule. We describe here a novel epitope on the N-terminal end of CD45 that is recognized by the MAb BL-TSub/2. Crossblocking studies showed that BL-TSub/2 and UCHL1 (CD45RO) binding sites are partially overlapping. However, in marked contrast to the CD45RO epitope, protease treatment of cells strongly diminished BL-TSub/2 binding. Similar to the UCHL1 epitope, the BL-TSub/2 binding site involves carbohydrate moieties, since neuraminidase treatment abrogated the reactivity of the MAb. Markedly, preincubation of cells with both CD45 common and CD45RA MAb induced a pronounced increase of BL-TSub/2 binding. This latter finding suggests that crosslinking of the CD45 molecule leads to conformational changes that could influence association of the molecule with putative ligands.

Animals↗
PubMed1996

Characterization of major allergens of Parietaria officinalis.

The major allergens of Parietaria officinalis were characterized with a panel of nine monoclonal antibodies (mAbs). The binding of mAbs and patients' IgE in Western blots revealed two proteins with similar molecular weights in the range of 8-10 kD. Analysis of the mAb-binding patterns in Western blots of P. officinalis extract under reducing and nonreducing conditions allows the mAbs to be divided into three different groups. mAbs of group I recognize the higher-molecular-weight component (9.4 kD), mAbs of group II recognize the lower component (8.8 kD) and mAbs of group III recognize both proteins. A comparable mAb-binding pattern was observed with Western blots of Parietaria judaica. The mAbs were used for affinity purification of the corresponding proteins from a P. officinalis extract. The purified proteins obtained with mAbs of group I-III inhibit the binding of patients' IgE (serum pool) to a high degree, indicating that they posses the major IgE-reactive epitopes. The affinity-purified proteins were subjected to SDS-PAGE, blotted and immunologically stained by mAb binding. The results confirmed those obtained with the complete extracts. The N-terminal amino acid sequences of the blotted proteins were analyzed. The sequences of all the proteins contained highly conserved regions: GGVV (positions 4-7) and MPPLL (positions 11-15), alternating with highly variable regions (positions 1-3 for group II and 8-10 for group I). A specific group I sequence appears to be at position 1-3 with the amino acids APA and a specific group II sequence appears to be at position 8-10 with the amino acids GAL. It is possible that the two similar proteins are isoforms of Par o 1.

Allergens↗
PubMed1995

In vitro production of monoclonal antibodies in high concentration in a new and easy to handle modular minifermenter.

This paper describes a new and easy to handle reusable minifermenter for high-density culture of hybridoma and other cells. The culture apparatus is composed of two modules: a 40 ml disposable cell culture and antibody production chamber (the 'production module') and a 550 ml medium reservoir (the 'supply module'). The two modules are separated from each other by a dialysis membrane allowing passage of low molecular mass nutrients and metabolites. The monoclonal antibodies are produced and enriched in the production module. The outer part of this module is made from a thin gas-permeable silicone rubber membrane allowing exchange of gases (oxygen and carbon dioxide). To start the culture, the cells are injected into the production module through ports in the silicone rubber which are equipped with Luer Lock connectors. Samples can be removed in the same way. For culturing, the minifermenter is rolled on a roller apparatus in a carbon dioxide-supplied incubator. Depending on the individual properties of the hybridoma cells cultured, cell densities of more than 10 x 10(6) (in some cases up to 35 x 10(6)) cells per ml and monoclonal antibody concentrations of several mg per ml can be obtained in the new minifermenter. On average, 61 mg (range: 9-159 mg) could be produced within 1-4 weeks. In terms of their properties the monoclonal antibodies produced in the new modular minifermenter were indistinguishable from antibodies prepared from ascitic fluid or from the supernatant of conventional stationary culture. The culture method is a useful alternative to the in vivo production method in mice. In addition, it represents a completely new, inexpensive and easy to handle general solution to the problem of culturing cells in high density and obtaining cellular products in high concentrations.

Antibodies, Monoclonal↗
PubMed1993

Expression cloning of the early activation antigen CD69, a type II integral membrane protein with a C-type lectin domain.

CD69 is a very early activation Ag of T lymphocytes. It is a cell surface glycoprotein that can only be detected after stimulation of lymphocytes. Despite extensive studies on its biologic activities, little is known about its molecular function. To investigate the latter in more detail, we have cloned a cDNA encoding CD69 on the basis of its expression in COS cells. The nucleotide sequence of clone CD69.13 is 1676 bp in length and contains a single open reading frame of 600 bp encoding a protein of 199 amino acids. The predicted molecular mass of 22,559 Da could be confirmed by in vitro translation. The protein contains a hydrophobic transmembrane region between amino acids 41 and 61 but no N-terminal signal peptide, which suggests that it is a type II membrane protein. It has one potential N-glycosylation site at amino acid 166. Two glycosylated forms of 26 to 28 kDa and 32 to 34 kDa were detected both in transfected COS cells and in in vitro translation in the presence of canine microsomes. Proteinase K degradation of the N-terminal part after in vitro protein synthesis supports the view of CD69 being a type II integral membrane protein with the N-terminal 40 amino acids in the cytoplasm, a transmembrane domain of 21 amino acids, and C-terminal 138 amino acids as the extracellular domain. Homology searches revealed sequence similarity with members of a supergene family of type II integral membrane proteins with a C-type lectin domain, indicating that CD69 is involved in signal transduction.

Amino Acid Sequence↗
PubMed1993

Regional sublocalization of the human CD69 gene to chromosome bands 12p12.3-p13.2, the predicted region of the human natural killer cell gene complex.

The early activation antigen CD69 is a member of a supergene family of type II integral membrane proteins with a C-type lectin domain. In recent reports the genes encoding the natural killer (NK) cell-related molecules of this supergene family, NKR-P1, NK1.1 and Ly-49, were shown to be clustered in a chromosomal region in mouse, termed the NK gene complex. The human homologue of this complex is likely to reside on chromosome 12 near the PRP locus (12p13.2). By analyzing T cell hybrids, the CD69 gene was previously mapped to human chromosome 12. Here we report the regional sublocalization of the human CD69 gene to chromosome bands 12p12.3-p13.2, suggesting that CD69 belongs to one linkage group together with different cell surface molecules on NK cells.

Animals↗
PubMed1991

[Characterization of a T-cell subpopulation with a new monoclonal antibody BL-TSub/2].

The mab BL-TSub/2 binds to a majority (80%) of thymocytes. The antigen isolated from these cells has an apparent molecular weight of about 170 kDa. The mab BL-TSub/2 recognized antigen is expressed on approximately 50% of mature T cells in peripheral blood. The mab BL-TSub/2 does not bind to monocytes, granulocytes, platelets and CD16+NK cells. The antigen is possibly present on a part of peripheral B cells in very low density. Double labelling experiments showed that about 30% of CD4+ and 60% of CD8+ cells react with the mab BL-TSub/2. This BL-TSub/2+ subset is not identical with T-cell subpopulations till now defined. Within the CD4+ subset the majority of BL-TSub/2+ cells is included in the CD45RO+ subset while only a small proportion is CD45RA+. However, the CD8+ BL-TSub/2+ cells are mostly CD45RA+ with only few cells belonging to the CD45RO+ subset.

Antibodies, Monoclonal↗
PubMed1991

[Epitope analysis of CD68 antigens].

Different epitopes of CD68 antigen are detectable by three new generated monoclonal antibodies (MABs) BL-M68/1-3 (all mouse IgM). The MAB BL-M68/3 reacts with an epitope, which is stable also in formalin-fixed paraffin-embedded tissues. In immunohistochemical blocking experiments using the own biotinylated MABs and six CD68 MABs from the IV. Workshop on Human Leucocyte Differentiation Antigens two new epitopes could be defined. The number of known CD68 epitopes increases at least up to seven.

Antibodies, Monoclonal↗
PubMed1991

[Characterization of a monoclonal antibody against a differentiation antigen of human natural killer cells (NK cells)].

The new murine monoclonal antibody BL-(H5) reacts with a novel surface molecule which is mainly expressed on human NK and B cells. The antigen is not expressed on peripheral T lymphocytes, thymocytes and different human T-cell lines. BL-(H5) does not bind to erythrocytes and platelets. The monoclonal antibody reacts in western blotting experiments with an antigen of 78kDa.

Antibodies, Monoclonal↗
PubMed1991

[Circulating lymphocyte subpopulations in patients with Crohn's disease].

Circulating lymphocytes were enumerated in 25 patients with Crohn's disease and in 43 healthy donors by immunofluorescent staining using monoclonal antibodies for T cell surface phenotypic markers (CD 3, CD 4, CD 8) or for surface immunoglobulin of B cells (mu-chain). Proportions of peripheral T cells and percentages of T cell subsets in Crohn's disease were not significantly different from those in controls. For analyzing the lymphocytes for the expression of activation associated antigens (HLA-DR, CD 25) we found increased numbers of activated lymphocytes during acute exacerbation, whereas, in remission, the population of activated lymphocytes was in the upper normal range. The results leads to the conclusion that the assessment of activated lymphocytes may serve as a parameter in the evaluation of the activity of Crohn's disease.

Adolescent↗
PubMed1990

[Monoclonal antibodies against determinants on human MHC class II antigens].

Monoclonal antibodies against different non-polymorphic determinants of HLA class II antigens are described. The epitopes are present on HLA-DR and HLA-DQ gene products as detected by monoclonal antibody BL-Ia/l, and at HLA-DR and HLA-DP gene products which are recognized by monoclonal antibody BL-Ia/4. Another epitope recognized by the monoclonal antibody BL-Ia/DQ is only found on DQ molecules. The monoclonal antibodies BL-Ia/1, BL-Ia/4, and BL-Ia/5 are directed against the beta-subunit of 29 kDa/35 kDa class II heterodimer molecules. The recognized epitopes are shown to be not dependent on the association of the alpha- and beta-chains.

Antibodies, Monoclonal↗
PubMed1990

T-cell depletion and haematological side effects of two cytotoxic monoclonal antibodies.

We investigated two cytotoxic monoclonal antibodies of BL-series (BL-IIIB4 and BL-IIG2) according to T-lymphocyte depletion from bone marrow. Both antibodies work together with human complement similar Campath-1, which was tested parallelly. The extent of T-cell depletion is about 95% for all three antibodies. On the other hand the haemopoietic side effects tested by CFU-GM recovery and LTBMC are for the BL-antibodies not as strong as for Campath-1, especially in view of LTBMC. T-cell regeneration could be shown in long term cultures. Our results indicate a possible suitability of the two investigated antibodies for T-cell depletion of bone marrow.

Antibodies, Monoclonal↗
PubMed1990

[Immunoenzyme assay of parasite-specific IgG4 antibodies in schistosomiasis using the monoclonal antibody BL-IgG4/1].

Sera from 251 children living in endemic areas (Schistosoma mansoni or Schistosoma haematobium) and from 188 hospital outpatients in Ethiopia were evaluated for specific IgG4 antibodies reacting with Schistosoma mansoni adult worm antigen employing an enzyme-immunoassay. Patients with schistosomiasis (n = 140) possessed a significantly higher mean value of specific IgG4 antibodies than normal controls (n = 30) and individuals from different countries who had no schistosomiasis but are infected with other parasites (n = 114). Blood samples dried on filter paper were also acceptable in these test. The use of the test in diagnosis is compared and assessed with parasitological methods.

Animals↗
PubMed1990

[Enzyme immunoassay of the level of parasite-specific IgE antibodies in schistosomiasis using the monoclonal antibody BL-IgE 9].

Sera from patients with chronic schistosomiasis (Schistosoma mansoni or Schistosoma haematobium) were examined for the presence of parasite specific IgE antibodies by means of ELISA technique using tegument antigen prepared from adult worms of Schistosoma mansoni and using the monoclonal antibody BL-IgE 9. Individuals from tropical countries who had no schistosomiasis and blood donors from GDR were studied for comparison. Significantly higher levels of specific IgE antibody were given by sera from patients with schistosomiasis than by the controls. These differential responses serologically differentiated between patients with chronic schistosome infections and noninfected individuals.

Antibodies, Helminth↗
PubMed1990

[Characterization of murine monoclonal antibodies against the common acute leukemia antigen (CALLA)].

This study presents two murine monoclonal antibodies which react with the Common Acute Lymphoblastic Leukemia Antigen (CALLA). Both antibodies can be used for the diagnosis of common ALL (cALL). Indirect immunofluorescence studies (FACS-analysis) showed that the antibodies react with granulocytes and different human cell lines (Nalm-6, Reh, Raji, CCRF-CEM). The monoclonal antibodies BL-CALLA/1 and BL-CALLA/2 identify a single polypeptide chain of 95 kD. Both antibodies recognize the same or closely related epitope of the CALLA-molecule and are able to modulate in vitro the antigen on the CALLA-positive cell line Reh.

Animals↗
PubMed1989

The phospholipid- and calcium-dependent protein kinase as a target in tumor chemotherapy.

Evidence for a constitutive activation of protein kinase C (EC 2.7.1.37) in Ha-ras transformed 3T3 cells is presented. Several compounds which inhibit protein kinase C in vitro have been studied with regard to their antiproliferative activity in cultured tumor cells. The following agents were investigated: 3-hexadecyl-mercapto-2-methoxy-methyl-propyl-1- phosphocholine (BM 41440); 1-octadecyl-2-methyl-sn-glycero-3-phosphocholine (ET-18-OCH3); quercetin, tamoxifen and staurosporine. All compounds decrease protein kinase C activity in vitro as well as in intact cells and inhibit cell multiplication within the same dose range. The results suggest a causal relation between the antiproliferative effects and the inhibition of protein kinase C. All inhibitors of protein kinase C synergistically enhance the antiproliferative activity of cis-diamminedichloroplatinum(II). Available data suggest that the effects of protein kinase C inhibitors should be exploitable for tumor chemotherapy.

Animals↗
PubMed1989

[Prognostic factors in diffuse malignant mesothelioma of the pleura].

Diffuse malignant pleural mesothelioma (DMM) is associated with a very poor prognosis and is only partially accessible to treatment. On the basis of a retrospective analysis, we made an attempt to identify possible factors that influence the prognosis. Between 1964 and 1986, 84 evaluable patients were treated: the ratio of male to female patients was 4.3:1, their average age being 58.5 +/- 11.9 (range: 21-82 years). The tumour types included 50% epithelial, 38% biphasic, and 12% mesenchymal tumours. The classification in accordance with the suggestions of Butchart revealed: I 10%, II 89%, III 0%, IV 1%. In 32% of the patients, treatment was purely symptomatic, in 42% a palliative surgical procedure with decortication of the tumour and tumour-pleurectomy was performed, while in 26% the palliative procedure was followed by adjuvant chemotherapy using doxorubicin and cisplatin. The median survival for the patients overall was 253 days. Parameters that were found not to correlate with the prognosis were: age, sex, exposure to asbestos, use of tobacco, pleural effusion, and growth behaviour in the thymus aplastic nude mouse. A significant influence was found for the histological type of the tumour and therapy administered, epithelial and biphasic tumour forms, as also surgical and combined surgical/chemotherapeutic treatment resulting in a more prolonged survival. On the basis of these results, surgical therapy should always be employed, despite the fact that there is almost always no curative option; postoperative adjuvant therapy is capable of further improving the prognosis.

Adult↗