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S Jahn

Publications and source records attributed to S Jahn.

At least 91 records · Page 5Linked to original sources
PubMed1987

Functional properties of lectin-induced thermostable SE rosette (TSER)-forming cells derived from human peripheral blood.

Mitogens are able to stimulate T cells in human peripheral blood lymphocyte cultures to form thermostable rosettes with sheep erythrocytes (TSER). Previously we characterized TSER-forming cells as BL/T2-, DR- and 4F2-positive, e.g. activated T lymphocytes. In this study the evidence is presented that mitogen-induced TSER-forming cells are the responding, proliferating lymphocytes. We studied the sequential activation of human lymphocytes by various mitogens. PHA-induced TSER-forming cells could not been further activated neither by PWM nor by Con A. DNA synthesis rate in Con A-preactivated lymphocytes was enhanced by PHA but not by PWM. PWM-induced TSER-forming cells, however, were further activated as well by PHA as by Con A. These data suggest the heterogeneity of the pathways by which different mitogens activate human immune cells. PWM- and PHA-induced TSER-forming cells could support B lymphocyte differentiation, when PWM was added to the cultures, whereas Con A-preactivated cells failed, indicating different functional activities induced by mitogenic lectins.

Concanavalin A↗
PubMed1987

[In vitro immunization for the production of antibodies to tetanus toxin and toxoid. 1. Systems for the detection of in vitro synthetized specific immunoglobulins. Strategies of test development].

By means of semipurified tetanus toxin for solid phase coating in an enzyme immunoassay (ELISA) for detection of specific IgG and IgM antibodies a detection limit of 0.02 IU per litre was achieved. The addition of serum from animals like horses or goats as inert protein to the dilution medium was omitted to prevent a displacement of human antibodies by antitetanus antibodies present in the animals sera. The specificity of the ELISA was demonstrated by inhibition experiments with soluble antigen and in an ELISA for detection of anti-tetanus toxin antibodies from mice immunized with the toxoid from the different purification steps.

Antibodies, Bacterial↗
PubMed1987

[In vitro immunization for the production of antibodies to tetanus toxin and toxoid. 2. Antibody production in lymphocyte cultures].

The aim of this work was to optimize the antigen-specific prestimulation of human lymphocytes for further hybridization to produce human monoclonal antibodies. In vitro stimulation of human peripheral blood lymphocytes with purified Tetanus Toxoid (TT) resulted both in an increased amount of secreted specific antibodies and in an enhancement of the portion of anti-TT antibodies in the level of total immunoglobulin secretion. Both IgG and IgM antibodies were found. Donors who had not been boostered in vivo with TT for more than 10 years also showed an antibody response to the antigen in vitro. Five days after in vivo boostering we found in lymphocyte cultures derived from 3 donors an enhanced antibody synthesis in the response to TT and also an increased portion of specific antibodies in the spontaneously secreted immunoglobulin in unstimulated control cultures.

Antibodies, Bacterial↗
PubMed1987

In vitro immunization for antibody production against tetanus toxin and toxoid. 3. Recombinant gamma interferon and indomethacin support specific antibody production induced by antigen-pulsed immobilized monocytes.

Specific antibody production against Tetanus Toxin by in vitro cultured human peripheral blood lymphocytes may be enhanced, when monocytes were immobilized onto FCS-coated culture plates and then pulsed with Tetanus Toxoid. Using this model several immunomodulators were tested for their influence on in vitro immunization efficiency. A combination of recombinant gamma interferon and indomethacin added during antigen presentation to lymphocytes, was able to potentiate specific antibody response.

Antibody Formation↗
PubMed1987

Influence of hydroxyurea on lectin-induced early and late events in peripheral blood lymphocyte cultures.

Activation events induced by lectins in human lymphocyte cultures differed not only in time kinetics of their appearance but were also in a different manner inhibited by hydroxyurea (HU). 4F2 and Tac expression, thermostable sheep erythrocyte rosette formation, cell volume distribution changes and the enhancement of the purine metabolic rate [( 3H]adenine incorporation) induced by PHA, Con A or PWM were not influenced by HU treatment, suggesting G1-phase dependency of these markers. The decrease in the mitogen-induced marker expression after 48 h of incubation with HU can be explained by the unability of activated cells to process the cell cycle, to divide and to become newly positive cells. Mitogen-induced RNA synthesis was partially, DNA synthesis, PWM-induced Ig synthesis and lectin-mediated HLA class II antigen expression were totally inhibited by HU. It holds especially for the DR antigen that its appearance in a polyclonal model of lymphocyte activation occurs in a later (postmitotic G1) phase of the cell cycle. The inhibitory effect of HU on late activation parameters could be removed after washing the cells. Mitogen-activated, HU-treated PBL cultures after removing HU continued cell cycle progression without requirement for further addition of lectin.

Adenine↗
PubMed1986

[Production of human monoclonal antibodies by heterohybridization of human B lymphocytes of the spleen with mouse myeloma cells].

Human lymphocytes were derived from the spleen of a 15-year-old female patient after partial splenectomy. High cell yield and percentage of human B-lymphocytes (over 30%) gave useful conditions for their fusion to mouse myeloma cells (P3 X63/Ag8/653). Fusion efficiency (cultures with growth) was 96%. From 288 initially seeded cultures 176 showed IgM and only one IgG production as determined by enzyme immunoassays. Twenty primary cell lines were cloned with differing results and 17 heterohybridoma cell clones with high IgM production rates could be established for more than 6 months in vitro. The present results show the possibility to produce human monoclonal antibodies in heterohybrids derived from human spleen lymphocytes.

Adolescent↗
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

[Histamine receptor-bearing lymphocytes. VI. Influence of histamine on the Go-G1 transition of activated lymphocytes].

Histamine (10(-4) M) suppressed the PHA-induced activation of lymphocytes in vitro. This was shown by inhibition of the expression of DR- and 4F2-antigens, of the blast transformation, DNA- and RNA-synthesis, and the formation of thermostable sheep erythrocyte rosettes. Histamine affect these phenomenons only when added to the culture during the first hours. Already 6 hrs after addition of PHA, it exerted no significant suppression. The target of the inhibiting effect of histamine is the G0-G1-transition of the lymphocytes. Cells that already had entered the G1-phase were no more susceptible to histamine.

Animals↗
PubMed1986

Dipeptidyl peptidase IV in human T lymphocytes. An approach to the role of a membrane peptidase in the immune system.

Dipeptidyl peptidase IV (DP IV), an ectoenzyme in the cell membrane of human T lymphocytes, is an important constituent in the process of lymphocyte activation and proliferation. In the presence of specific inhibitors and antibodies against DP IV several in vitro functions of activated lymphocytes were found to be impaired. These include mitogen induced DNA synthesis, immunoglobulin secretion and production of interferon-gamma. The functional importance of DP IV during activation of lymphocytes is underlined by an increase in cellular DP IV activity upon mitogenic stimulation.

B-Lymphocytes↗
PubMed1986

[Chemiluminescence, formation of thermostable E-rosettes and DNA synthesis of human mononuclear cells induced by various lectins].

Various plant lectins differentiate in their ability to induce early (chemiluminescence and thermostable rosette formation) and later (DNA synthesis) activation events of human mononuclear cells. Both phytohaemagglutinin and concanavalin A induced a cell activation detectable by the three investigated parameters. Wheat germ agglutinin was characterized as an efficient stimulator in both assays of early events whereas the induction of DNA synthesis measured by [3H]-thymidine incorporation was low. In contrast, pokeweek mitogen did evoke only a weak chemiluminescence signal, but induced a small number of thermostable rosettes and a high [3H]-thymidine incorporation. The results obtained from experiments with mononuclear cells of twelve healthy donors did not show a firm correlation between the investigated three parameters of cell activation.

Adult↗
PubMed1986

[Influence on the immune response of C-reactive protein (CRP)].

The influence of C-reactive protein (CRP) on early and late parameters of mitogen-induced lymphocyte activation in vitro has been tested. Early activation markers (increase of cell size and formation of thermostable SE rosettes) and the lymphocyte proliferation (3H-thymidine incorporation) were changed by CRP (10-50 micrograms/ml), whereas PWM-induced stimulation was inhibited and PHA-induced activation was enhanced. Production of human immunoglobulins in vitro in culture from 12 healthy donors was influenced by CRP in a different manner. Modulation of mitogenic responses of lymphocytes by CRP occurs in an early stage of the cell cycle. Responsible for this phenomenon can be soluble factors, which were removed from the culture by washing the cells after 24 hrs. We discuss here the unspecific modulatory role of CRP in various immune-mediated diseases.

Adult↗
PubMed1986

A sensitive and class specific solid phase enzyme immunoassay for anti-DNA autoantibodies in supernatants of lymphocyte cultures and human hybridomas.

A solid phase enzyme immunoassay using methylated bovine serum albumin (BSA)-precoated and DNA-coated microtiter plates was developed for the detection of IgG and IgM anti-DNA autoantibodies in the supernatants of lymphocyte cultures and hybridomas. In patients with systemic lupus erythematosus (SLE) the significantly raised IgG anti-DNA antibody synthesis indicates that preactivated anti-DNA clones circulate in the peripheral blood. This was associated with the detection of anti-DNA antibodies in the sera. The screening of 53 supernatants from human x mouse hybridomas showed an antibody to denatured DNA in 16 supernatants.

Antibodies, Monoclonal↗
PubMed1986

Pokeweed mitogen induced synthesis of human IgG and IgM in vitro. Technical aspects and the role of adherent cells.

The Pokeweed mitogen (PWM)-inducing in vitro synthesis of human IgG and IgM was determined by enzyme immunoassay (EIA) in culture supernatants of PWM-stimulated peripheral blood lymphocytes (PBL) from 83 healthy donors ranging from 24-46 years. Seventy five per cent were characterized as normal responders (200-2000 ng/ml IgG and IgM), 10% classified as high responders (2000-3000 ng/ml), and another 10% had a very high response (more than 5000 ng/ml of both IgG and IgM). One of 83 donors was shown to be a PWM non-responder. In 83 unstimulated cultures from the same donors 660 +/- 75 ng/ml IgG and 60 +/- 10 ng/ml IgM were measured after 8 days of incubation. Ten donors exhibited similar dose dependence of PWM-induced Ig synthesis but differed in time kinetics (optimum between 8 and 12 days of culture). Regression analysis of IgG and IgM production in 83 PWM-stimulated lymphocyte cultures from different healthy donors showed a correlation coefficient of r = 0.627. Intracellular Ig in PWM-stimulated cells was quantified by EIA technique after cell lysis in time kinetic experiments. Reproducibility and accuracy of the test system are described in detail. An excess of monocytes of more than 20% in the culture caused an inhibition of the Ig synthesis (calculated on constant numbers of B cells). Monocytes were further immobilized in FCS-coated culture plates and pulsed with PWM for 2 h. Adding unstimulated, nonadherent cells to the plates after removing the mitogen resulted in an Ig production comparable to that with the classical method.

Adult↗
PubMed1985

The influence of haematoporphyrin derivative and visible light on murine skin graft survival, epidermal Langerhans cells and stimulation of the allogeneic mixed leucocyte reaction.

The influence of combined photochemical treatment with a haematoporphyrin derivative and visible light on antigen-presenting cells was evaluated. Treatment of murine skin grafts with this procedure prolonged their subsequent survival on allogeneic recipients. The haematoporphyrin derivative and light decreased the ATPase activity of epidermal Langerhans cells in murine skin. When stimulator cells in a human allogeneic mixed leucocyte reaction were treated with the haematoporphyrin derivative and light, they lost their stimulatory capacity. It is proposed that the haematoporphyrin derivative and visible light interfere, on analogy with ultraviolet radiation, with the function of antigen-presenting cells.

Adenosine Triphosphatases↗
PubMed1985

Lectin-induced thermostable SE-rosette (TSER) formation by human peripheral blood lymphocytes.

Lectin-activated human peripheral blood lymphocytes were able to form thermostable rosettes with sheep red blood cells (SRBC). Capability to form thermostable rosettes (TSER) after lectin treatment was comparable in time kinetics and dose dependence to cell size distribution changes. Enhancement of TSER formation by human lymphocytes exposed to PHA and Con A, however, occurred before 3H-Thymidine incorporation could been registered. Lectin treatment of lymphocytes from 20 healthy donors for 48 hrs induced 49 +/- 4% (PHA), 33 +/- 5% (Con A), and 20 +/- 2% (PWM) thermostable rosette forming cells, whereas in unstimulated cultures were found 4 +/- 1%. Furthermore, thermostable rosette forming cells were enriched by gradient centrifugation and characterized as activated lymphocytes of T-origin by SE rosetting and binding studies with various monoclonal antibodies. It was shown that preparation of TSER forming cells after lectin activation makes it possible to enrich the fraction of lectin-stimulated T lymphocytes.

Animals↗
PubMed1984

Platelet prostanoids in interaction of platelets with collagen substrates. I. Activation of platelets by surfaces coated with different types of human collagen.

We have studied the interaction of human platelets with surfaces coated with human type I, III, IV, and V collagen (CI, CIII, CIV, and CV). It was established using scanning electron microscopy that the reactivity of the collagen substrates for platelets varies widely. On CV, only the initial attachment of platelets takes place; spreading actively goes on CIV while on CI and CIII, along with spreading, the formation of multilayer thrombi-like platelet aggregates occurs. The production of malondialdehyde induced by the interaction of platelets with CI and CIII substantially exceeds that stimulated by CIV and CV. Indomethacin practically completely inhibits the formation of thrombi-like aggregates but only by 25% inhibits platelet spreading. An ADP-scavenger creatine phosphate/creatine phosphokinase inhibits the formation of thrombi-like aggregates and platelet spreading by 25-30%. The obtained data demonstrate that: (i) the formation of thrombi-like aggregates on CI and CIII is mediated mainly by the synthesis of platelet prostanoids, and not by the ADP release; (ii) the spreading of platelets on CIV, CIII, and CI is only partially mediated by prostanoid synthesis and ADP release which suggests a participation of other mechanisms in this process.

Blood Platelets↗