Search PubMed⌕ Search

Biomedical subjects

H Fiebig

Publications and source records attributed to H Fiebig.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Secondary follicles in the thymus. Immunohistologic characterization of B lymphocytes using monoclonal antibodies].

Studies were conducted into the incidence of secondary follicles in individuals without autoimmune disease. Thymic tissue specimens were obtained from 20 children, aged between 6 months and 14 years who had undergone cardiac surgery and had been chosen at random. These specimens were immunohistologically investigated, using monoclonal anti-B cell antibodies (CD19 to CD23, CD37) and anti-immunoglobulin antibodies. Follicular structures were found in 7 cases. They were localized in thymic medullary regions. Immunohistologically, the secondary follicles in the thymus exhibited staining patterns similar to those recordable from follicles in other lymphatic tissues, such as tonsils. Formation of follicular structures from the potential of normally detectable scattered B cells in the thymus appears to be quite common also in cases without autoimmune diseases.

Adolescent↗
PubMed1989

[Detection of an early activation-dependent cell surface antigen on human T-lymphocytes].

The binding properties of a monoclonal antibody to an early activation marker of human lymphocytes are described. The monoclonal antibody BL-Ac/p26 binds to an antigen which is expressed on activated lymphocytes. This antigen is not detectable on resting lymphocytes or other blood cells. The surface radioiodinated antigen of activated T cells isolated by the monoclonal antibody BL-Ac/p26 is separated by SDS-PAGE in a major 26k Da component and a minor band (32 kDa) under reducing conditions. These polypeptide chains form disulphide linked dimers on the cell surface (Mr 55-77 kDa). This 26 kDa antigen is a very early activation marker of T lymphocytes. Human T lymphocytes stimulated by mitogens (PHA, ConA or PWM), anti-TCR/CD3 monoclonal antibodies or allogeneic leucocytes express this 26 kDa antigen after 2-4 hours.

Antibodies, Monoclonal↗
PubMed1988

Direct immunogold staining technique based on monoclonal antibodies: an immediate approach to the immunostaining of lymphocytes.

The report provides a procedure for labelling of monoclonal antibodies (moab's) with colloidal gold particles (mean diameter 30 or 40 nm). This procedure was exemplified for the moab's BL-T2, BL-Ig-L/1, and BL-Ia/1, which label mature T (and some populations of B) lymphocytes, B lymphocytes, and HLA class II antigen bearing lymphocytes, respectively. Each moab was characterized by an individual pH optimum for stabilization of the gold sol. The pH optima were +/- 5 (BL-T2), +/- 7 (BL-Ia/1), and +/- 9 (BL-Ig-L/1). The immunogold staining reagents were used for a direct immunostaining protocol of lymphocytes, which needs less than 100 min. The intensity of this direct immunolabelling was comparable with this one resulting from the indirect IGS. Furthermore, the comparison of the direct IGS with the immunofluorescence technique does not revealed any significant difference in the mean cell counts. The presented immunolabelling method offers a straight cell tagging, which can be advantageously used for a double staining procedure.

Adult↗
PubMed1988

[Bronchoalveolar lavage in patients with sarcoidosis--methodologic aspects of the collection, immunologic characterization of lymphocytes and studies of immunoglobulin content].

The activity of alveolitis in 25 patients with pulmonary sarcoidosis was determined by analysis of T-Lymphocytes and their subpopulations collected by broncho-alveolar lavage. The characterization of the lymphocytes was performed with monoclonal antibodies (BL-series). An amount of T-lymphocytes higher than 28% of all cells and a proportion of T4/T8-lymphocytes of 8:1 and over are signs of the activity of the alveolitis and an indication for corticoid therapy.

Antibodies, Monoclonal↗
PubMed1988

[Production and characterization of monoclonal antibodies to the secretory components of human IgA].

The monoclonal antibodies BL-HSC/1-3 are characterized by means of indirect radioimmunotechnique with regard to their binding pattern to a set of human proteins. The results suggest a binding specificity of the three monoclonals for A-determinants of the human secretory component. However, we could not point out a different binding pattern to the immunoglobulin-bound and the free molecule, respectively. By use of appropriate immunoassays, the monoclonal antibody BL-HSC/3 is the most suitable one for the detection of the secretory component and secretory IgA in body fluids. The protein band labeled by BL-HSC/3 in the immunoblotting analysis corresponds to a molar mass of 79,000 D according to the data known for the human secretory component.

Antibodies, Monoclonal↗
PubMed1987

T-helper cell activation in bullous pemphigoid.

In 10 untreated patients suffering from acute bullous pemphigoid the number of peripheral blood T cells (CD 3), T suppressor (CD 8) and T helper cells (CD 4) as well as activation antigens (DR and Tac) bearing lymphocytes was evaluated by monoclonal antibodies. While the pan-T cell population (CD 3) and T suppressor subpopulation (CD 8) were normal, the T helper subpopulation (CD 4) and the number of DR and Tac positive lymphocytes were significantly increased in the acute stage of bullous pemphigoid when compared to the age- and sex-matched controls. Phenotypically those DR positive cells belonged to the pan-T cell population (CD 3) at 66% and to the T helper subpopulation (CD 4) at 53% respectively. Under treatment with immunosuppressants the cell counts returned to normal suggesting a T helper cell activation to be involved in the acute stage of bullous pemphigoid.

Antigens, Surface↗
PubMed1987

[Importance of secretory IgA in human body fluids. I. Development of an enzyme immunoassay for secretory IgA].

This paper describes an enzyme-immunoassay for the quantitative estimation of secretory IgA(S-IgA). As solid phase a monoclonal antibody against human secretory component was used, a polyclonal peroxidase labeled anti-IgA serum as conjugate. Thus, the method was specific for S-IgA. The test was done in microtiter plates, the upper limit was 0.5 ng S-IgA/ml. The standards of our test system ran in normal ranges, the coefficients of variation were 6.9% in the within-day-test and 12.2% in the day-to-day-test. The described test system is effective and sensitive. It is suitable for clinical use.

Antibodies, Monoclonal↗
PubMed1986

Separation of human lymphoid cells by affinity chromatography and cell surface labelling by hydroxyethyl methacrylate particles using monoclonal antibodies.

The hydroxyalkyl methacrylate gel Separon, Sepharose 6MB and polystyrene dishes with bound antibodies were used for affinity chromatography of cells isolated from human tonsils and peripheral blood. Enrichment of T cells by filtration through anti-human immunoglobulin Separon or Sepharose 6MB columns was comparable to that achieved by "panning" on dishes or by Nylon wool column fractionation. High enrichment of B cells was obtained when cells pretreated with monoclonal anti-T cell antibodies were fractionated on columns or dishes where anti-mouse antibody was bound. Hydroxyethyl methacrylate copolymer microspheres were conjugated with monoclonal antibodies directed against surface markers of human lymphocytes or with anti-mouse immunoglobulin antibodies and used for surface labelling of cells. The results obtained by immunofluorescence were in good correlation with labelling by hydroxyethyl methacrylate immunobeads.

Animals↗
PubMed1986

[Detection of thymocyte antigens by monoclonal antibodies of the BL series].

The reactivity of 4 monoclonal pan T cell antibodies and 6 pan leukocyte antibodies was detected with human thymocytes. The study was performed with single cell suspensions and cryostat sections using immunofluorescence and immunoperoxidase techniques. Monoclonal antibodies with T cell specificity react with different percentages of thymocytes. The antibody BL-T1, which is directed against the sheep erythrocyte receptor, reacts with 90% of thymocytes. These cells were found uniform in the thymus cortex and medulla. On the other hand, the antibodies e.g. BL-T2 and T3 react only with 20% of the thymocytes, identified mainly in the medulla. Pan leukocyte antibodies are also suitable for the detection of different thymocyte membrane antigens. In single cell suspensions, it was found a reactivity of the used antibodies with 20, or 40, or 95% of the cells. The immunohistological findings are described.

Antibodies, Monoclonal↗
PubMed1986

Serum-mediated inhibition of the interferon-gamma-induced HLA-DR expression on monocytes in patients with psoriasis.

Psoriatic patients have a decreased proportion of monocytes expressing class II major histocompatibility complex antigens (DR+ monocytes) in their peripheral blood. The expression of the DR antigen on monocytes after culture in the presence of either autologous lymphocytes (endogenous interferon-gamma, IFN-gamma) or exogenous IFN-gamma was investigated. In normal AB serum the lymphocytes of the majority of the patients showed a spontaneous IFN-gamma production which was sufficient for DR antigen induction, while the monocytes displayed approximate normal susceptibility to exogenous IFN-gamma as judged by DR antigen expression. However, the sera of psoriatic patients contained one or more factors that interfered with the IFN-gamma-mediated DR antigen expression on cultured monocytes of the same patients. Restoration of IFN-gamma-induced DR antigen expression on monocytes in the presence of the patient's sera was achieved by the addition of superoxide dismutase, 2-mercaptoethanol, or indomethacin. The clinical significance of these observations is discussed.

Antigens, Surface↗
PubMed1986

Correlation between the phenotype and the functional capacity of activated T cells in patients with active systemic lupus erythematosus.

Activated T cells in the peripheral blood of patients with systemic lupus erythematosus (SLE) were determined using monoclonal antibodies against activation antigens. Elevated percentages of HLA-DR+ T cells were found in association with active disease. In contrast, we observed an increase in IL-2 receptor-bearing T cells in only six out of 16 patients with active disease. In vitro assays, like spontaneous proliferation, response to IL-2, production of IL-2, and immunoglobulin synthesis have shown that the different patterns of activation antigens are related to different functional stages of T-cell activation. The possible therapeutic consequences are discussed.

Antigens, Surface↗
PubMed1986

Drug design: nitrosoureas.

Attempts to develop more effective and less toxic antineoplastic nitrosoureas are summarized. Previous research resulted in the synthesis and extensive preclinical testing of new, short-chain, water-soluble, but lipophilic compounds--1-(2-chloroethyl)-1-nitroso-3-(2-hydroxyethyl)urea (HECNU) and 1-(2-chloroethyl)-1-nitroso-3-(methylene carboxamido)urea. Molecular mechanisms of reactions with biomolecules are discussed with regard to DNA alkylation and cross-linking, carbamoylation of glutathione and glutathione reductase inhibition. Results of a clinical phase-II study show that HECNU, as predicted from preclinical tests, exhibits outstanding activity in brain tumours. Future development concentrates on the use of carrier molecules for nitrosoureas. Results of an extensive structure-activity study with oestradiol-linked analogues show that an oestradiol-17 ester derivative is much more active than other analogues.

Alkylating Agents↗
PubMed1985

Decrease of HLA-DR antigen expression by human monocytes during cultivation in absence of exogenous or endogenous interferon-gamma.

The kinetics of HLA-DR antigen expression by human peripheral blood monocytes during cultivation in vitro was studied. Immediately after separation by glass adherence, about 60% of monocytes expressed DR antigens as judged by indirect fluorescence staining with a monoclonal antibody (BL-DR/1). Monocytes carefully depleted of lymphocytes, gradually lost their DR antigens during cultivation in the absence of exogenous interferon-gamma (IFN-gamma). However, addition of a few lymphocytes to the adherent cells prevented the decrease of DR antigen expression. Furthermore, it was shown that doses as low as 1 IU/ml of IFN-gamma are sufficient to induce DR antigen expression by cultured monocytes. Experiments with cyclosporin A suggest that lymphocytes contaminating the monocyte preparations can produce spontaneously sufficient amounts of IFN-gamma for maintenance of the DR antigens on monocytes.

Cells, Cultured↗
PubMed1985

Comparison of different markers on blood lymphocytes of chronic lymphocytic leukemia.

Mononuclear cells (MNC) of 17 patients suffering from B chronic lymphocytic leukemia (B-CLL) were analysed by various immunological methods. The B cell nature of CLL cell was determined by classical tests (MRBC-rosette-test, immunofluorescence test for detection of membrane bound immunoglobulins). The cytochemical detection of the new T-cell marker dipeptidyl peptidase IV (DP IV) was found to be suitable for the characterization of B-CLL. The B-CLL cells showed granular pattern of alpha-naphthylacetate esterase (ANAE) reaction and binding of the monoclonal pan T antibody BL-T2. These non typical reactions for normal B lymphocytes can be used for differential diagnosis of B-CLL in combination with other reliable T cell markers. Avoiding the separation of T cells, the mixed rosette assay was used to enumerate Fc-IgG-receptor bearing T(TG) and non T cells. Both cell populations were found to be significantly elevated in MNC of B-CLL.

Aged↗