Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
Materialart
Erscheinungszeitraum
  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 28 (1988), S. 0 
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Human peripheral blood lymphocytes (PBL) were activated with K46M, a mitogenic monoclonal antibody against La-reactive T lymphocyte surface structures. The cultures were expanded in the presence of interleukin 2 (IL-2). After 1 month of culture, the activated T cells were cloned by limiting dilution at 0.5 cells/well. Five clones with the CD3+CD4+ phenotype and one clone with the CD3+CD8+ phenotype wore obtained The CD3+CD8+ clone (K99) displayed a strong major histocompatibility complexe (MHC)-unrestricted cytolytic activity against MOLT-4 and a weaker reactivity against the bladder tumour cell lines T24 and RT4. The natural killer (NK)-susceptible K562 cells were not lysed. Two of the CD3+CD4+ clones (K91 and K914) showed a helper activity in pokeweed mitogen (PWM)-induced IgG production by B cells. These cells differed in the expression of CD45R and CDw29 antigens, as defined by the monoclonal antibodies 2H4 or D10D11 and 4B4. When stimulated with PWM for 48 or 72 h, clone K91 and an additional CD4-positive clone (K913) secreted a factor into the supernatants which helped B ceils to produce IgG. The K913 supernatant also induced some IgM production. The supernatant obtained after similar simulation of K914 cells was inactive. None of these supernatants induced B cells to proliferate when tested together with phorbol myristate acetate (PMA). However, when K91 and K914 cells were activated with phytohaemagglutinin (PHA) for 48 or 72 h, the supernatant from K91 was strongly helpful in B-cell proliferation, whereas the supernatant from K914 cultures was only moderately active In conclusion, we have established human T helper clones that release different factors supporting either B-cell proliferation or maturation when stimulated with PWM or PHA.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A murine monoclonal antibody, MoAb B1B6 (IgG1χ), which recognizes the large sialoglycoprotein (LSGP)on human peripheral blood lymphocytes (PBL) effectively enhanced the spontaneous cytotoxicity of these cells against She natural killer (NK)-sensitive target cells K562 and Molt-4. Whereas preincubation of she lymphocytes with MoAb B1B6 resulted in increased cytotoxicity, preincubation of the target cells had no effect, indicating that the MoAb amplified cytotoxicity at the effector cell level. Kinetic analysis of the data revealed no differences between the control and the MoAb-treated lymphocytes with regard to Vmax, usually considered to reflect the overall lytic potential of the cells. The slopes of the saturation curves, however, differed significantly for She two cell populations, indicating a substantial increment in the activity of the MoAb-treated cells. When studied lit the single cell level and with K562 as targets, treatment of PBL with the MoAb resulted in the recruitment of new effector lymphocytes from the pool of non-binding cells. In contrast, when Molt-4 cells were employed as targets, no additional effector cells were recruited. These results indicate that the enhanced cytotoxicity induced by MoAb B1B6 is the result of either recruitment of new effector lymphocytes or of an increased recycling capacity of preexisting effector cells. Together with previous observations, these findings support the conclusion that LSGP belongs to the set of surface molecules which regulate human lymphocyte activation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A monoclonal antibody, K46M (IgM x), obtained after immunization with leucoagglutinin (La)-reactive T-cell surface components, stimulated human lymphocytes to proliferate. It induced maximal proliferation at 〉20μg IgM/ml after 3–4 days of culture. Cells stimulated by K46M produced interleukin 2 (IL-2) and gamma interfeton (IFN-γ) and expressed receptors for IL-2 and transferrin. The majority of the activated cells were phenotypically T cells as defined by monoclonal antibodies against CD3 and CD2, and an increase in the K46M-positive cells was also observed during the activation period. K4GM-activated cells display major histocompatibility complex (MHC)-unrestricted cytotoxicity against several cultured target cells. The frequencies of the cytotoxic and of the proliferative precursor cells were determined using a limiting dilution assay. K46M seems to activate a larger fraction of cytotoxic precursor cells aganit Molt 4 than against K562, but the statistical significance of these observations requires further exploration. Both K46M or La activated 40% of PBL to proliferate, whereas 70% of PBL were induced by OKT3. However, the frequency of K46M-ativated cells was 40% only when the lymphocytes were plated at low cell densities, i.e. 〈0.5 cells per well. At higher densities an inhibition of proliferation was seen that resulted in a biphasic response curve, indicating that the activation of PBL by K46M was not a single hit event. This was not found with either La or 0KT3. Whether K46M, in contrast to OKT3 and La, activates a subpopulation with suppressor activity remains to be established.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Activation of human peripheral blood lymphocytes (PBL) with the mitogenic monoclonal antibody (MoAb) K46M, which recognizes 1-5% of PBL, resulted in the expansion of cells with cytolytic activity. Thus, after culture of the activated lymphocytes in medium containing interleukin 2 (IL-2), they lysed a variety of cultured cell lines. The majority of the activated lymphocytes reacted with MoAb to CD8, CD3, and to the T cell antigen receptor heterodimer (Ti) but not with antibodies to antigens expressed on natural killer (NK) cells. The cytotoxicity was not inhibited by MoAb to CD3 or Ti. However, the killing of K562, but not of other cell lines, was enhanced by three to four times in the presence of anti-Ti antibodies. Anti-CD3 or other control antibodies had no effect. Cold target inhibition experiments indicated that the cytolytic lymphocytes recognized closely related structures on the target cells. Phenotypically and functionally similar effector cells emerged after activation of PBL with the anti-CD3 MoAb OKT3. Taken together, the results indicate that activation of PBL with MoAb K46M induces cytotoxic cells that differ from classical NK cells but that resemble mature cytotoxic T lymphocytes (CTL). However, unlike CTL, cytotoxicity was not MHC-restricted and the conventional T-cell receptor complex (CD3/Ti) appeared not to be involved in target cell recognition and cytolysis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 39 (1994), S. 0 
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: CZ-1 is a novel sialic acid-dependent epitope of the murine CD45RB molecule which is expressed on cells that proliferate when cultured in IL-2. Because IL-2 appears to be Important in the differentiation of NK cells, the authors examined the expression of CZ-1 on immature NK-Iineage cells within the bone marrow. All mature NK1.1+ cells as well as their NK1. l− IL-2 responsive precursors were CZ-1+. Furthermore, IL-2 unresponsive transplantable NK progenitor cells expressed CZ-1 also. To examine expression of CZ-1 on other immature lymphoid progenitor cells. CZ-1+ and CZ-1 marrow cells were tratisplanted Into lightly irradiated scid mice. Transfer of CZ-1+ cells resulted iti rapid and sustained generation of thymocytes and splenic B cells, whereas CZ-1− cells caused delayed repopulation. This suggested that the slowly repoptilating pluripotent stem cells lacked CZ-1. Therefore, expression of CZ-1 on Ly66 Lin− c-kit+ cells, highly enriched for pluripotent stem cells, was examined. This population appeared lo be homogeneously CZ-1dull. Thus, it appears that expression of CZ-1 is developmentally regulated, with diflerentiation associated with increased expression. Since CZ-1 is expressed on a protein tyrosine phosphatase, it is likely that this molecule regulates differentiation of NK and other lymphoid cells.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...