Fluorescence-activated cytometry cell sorting based on immunological recognition.
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Cell Separation↗
Biomedical subjects
M Assenmacher
Publications and source records attributed to M Assenmacher.
Induction of interleukin 4 (IL-4) expression in T helper (Th) cells is not dependent on IL-4 from non-Th cells.
Interleukin 4 (IL-4) is essential for the induction of immunoglobulin E (IgE) responses in mice. Recent in vitro studies have suggested that IL-4 derived from non T helper (Th) cells, in particular from mast cells and basophils, may be essential for triggering of IL-4 expression in Th cells and may directly contribute to IgE isotype switch induction. Here, we have generated mice carrying a functional IL-4 gene only in Th cells or non-Th cells, respectively, by reconstitution of IL-4-deficient mice (IL-4T mice) with CD4+ or CD4- spleen cells from congenic wild-type animals. In mice in which only CD4+ cells are able to express IL-4, antigen-specific IgE is produced in a T cell-dependent immune response. Thus, induction of IL-4 expression in Th cells can occur in the absence of IL-4 from non-Th cells, which suggests that at least some Th cells can express IL-4 in response to another signal which has yet to be identified. No IgE is detectable, however, in mice in which only CD4- cells can express IL-4, suggesting that Th cells are the primary, if not the only source of IL-4 for initial induction of IgE synthesis.
Animals↗
Flow cytometric determination of cytokines in activated murine T helper lymphocytes: expression of interleukin-10 in interferon-gamma and in interleukin-4-expressing cells.
In an immune response, effector functions are controlled by T helper (Th) 1 cytokines [interferon-gamma (IFN-gamma), interleukin (IL)-2 and tumor necrosis factor-beta] and Th2 cytokines (IL-4, IL-5 and IL-10). Here we analyze by multiparameter immunofluorescence to what extent IL-2, IL-4, IL-5, IL-10 and IFN-gamma are co-expressed in individual normal murine Th cells upon activation in vitro with the bacterial superantigen Staphylococcus aureus enterotoxin B, presented in the context of major histocompatibility complex class II. IL-2 and IFN-gamma are co-expressed by some, but not by other Th cells. Expression of IL-4 and IFN-gamma is exclusive. IL-10 is co-expressed in individual cells either with IL-4 or with IFN-gamma. No IL-5-expressing cells are detected. While IL-10- and IL-4-co-expressing Th cells correspond to classical Th 2 cells, cells co-expressing IL-10 and IFN-gamma could be involved in negative-feedback regulation of a Th1 response. Apart from such functional implications, our results show that IL-2, IL-4, IL-5, IL-10 and IFN-gamma are expressed independently of each other in individual murine Th cells.
Animals↗
Regulation of T helper cell cytokine expression: functional dichotomy of antigen-presenting cells.
A bias to either cell-mediated or antibody-mediated effector mechanisms is induced in an immune response against a pathogen, if activated T helper cells (Th) predominantly express Th1 [interleukin (IL)-2, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-beta] or Th2 (IL-4, IL-5, IL-6 and IL-10) cytokines. Here we provide evidence that, due to the capability to secrete IL-1, macrophages, but not B cells, as antigen-presenting cells (APC) induce production of IFN-gamma in resting Th cells. Normal murine splenic Th cells were activated in vitro with the superantigen Staphylococcus aureus enterotoxin B (SEB) presented by macrophages as compared to other APC from murine spleen. As determined by immunofluorescence, Th cells producing IL-2 but almost none producing IL-4 and IL-5 are generated, irrespective of the type of APC. Generation of IFN-gamma-producing Th cells is largely dependent on presentation of SEB by macrophages. The requirement for macrophages, however, is overcome if IL-1 is provided. Expression of IFN-gamma by Th cells is not induced, if production of IL-1 by macrophages is inhibited by IL-10. Our results suggest a functional dichotomy of APC: normal resting Th cells differentiate into IL-2 and IFN-gamma secreting cells (Th1 cells) if antigen is presented by macrophages, whereas presentation by B cells generates Th cells secreting IL-2, which might differentiate into Th2 cells upon re-stimulation.
Animals↗