Search results for "Lymphokine"
showing 10 items of 82 documents
Granulocyte-macrophage colony-stimulating factor induces cytokine secretion by human polymorphonuclear leukocytes.
1989
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is known as an inducer of proliferation and functional activation of myeloid cells. This study was carried out to characterize the effects of GM-CSF on polymorphonuclear leukocytes (PMN) more extensively. Using Northern blot analysis, we show that PMN are able to accumulate mRNAs for different cytokines, including tumor necrosis factor-alpha (TNF-alpha); G-CSF, and M-CSF, all of which are involved in inflammation and hematopoiesis. Biological assays and immunoassays demonstrate that PMN translate these mRNAs, except TNF-alpha, into secretory proteins. However, the expression of these cytokines is dependent on stimulation by exogenous…
Colon Cancer Stem Cells Dictate Tumor Growth and Resist Cell Death by Production of Interleukin-4
2007
A novel paradigm in tumor biology suggests that cancer growth is driven by stem-like cells within a tumor. Here, we describe the identification and characterization of such cells from colon carcinomas using the stem cell marker CD133 that accounts around 2% of the cells in human colon cancer. The CD133(+) cells grow in vitro as undifferentiated tumor spheroids, and they are both necessary and sufficient to initiate tumor growth in immunodeficient mice. Xenografts resemble the original human tumor maintaining the rare subpopulation of tumorigenic CD133(+) cells. Further analysis revealed that the CD133(+) cells produce and utilize IL-4 to protect themselves from apoptosis. Consistently, trea…
In vivo and in vitro induction of natural killer cells by cloned human tumor necrosis factor
1988
The natural killer (NK) cell activity of mice in the peritoneal cavity is very low or undetectable and testing peritoneal NK cells is a useful model for studying the influence of activating substances upon local injection. Injection of tumor necrosis factor (TNF) at doses of 10-200 ng caused a marked activation of NK cell activity which was maximal after 24 h and declined rapidly on day 2. A similar effect was observed when interferons alpha and beta were injected, and there were additive results when interferon was injected together with TNF. The NK cell nature of the effector cells activated by TNF was substantiated by the finding that previous injection with anti-asialo GM 1 antibody pre…
Biochemical properties of MHC class II molecules endogenously synthesized and expressed by mouse Langerhans cells
1991
The cell surface expression and biosynthesis of Langerhans cells (LC)-derived major histocompatibility complex (MHC) class II molecules from epidermal cells (EC) prepared freshly and cultured for up to 3 days was investigated. Based on the constitutive expression of MHC class II determinants by LC, a panning and magnetic bead selection procedure was employed, yielding 65% and 86% of I-A+ cells, respectively. Phenotypical and cytochemical examinations revealed that the two LC preparations were free of contaminating macrophages as well as B and T cells. Freshly prepared enriched LC were highly efficient in the stimulation of protein antigen-specific T cell clones, while LC purified from short…
Production of T suppressor factor specific for the hapten picryl chloride requires both T suppressor cells and an antigen-specific, genetically restr…
1987
Summary We investigated the requirement for activation of T suppressor cells specific for the hapten picryl chloride and the release of hapten-specific T suppressor factor. Using an in vivo experimental system, we report that activation of T suppressor cells and the consequent release of T suppressor factor required two signals: one was provided by primed T suppressor cells, i.e. spleen cells from mice injected with the tolerogen picrylsulphonic acid, and the other was provided by the specific antigen in the context of H-2 gene products. Mechanisms by which the interaction between these two signals led to activation of T suppressor cells and the production of T suppressor factor, as well as…
Role of Natural Killer Activity in Development of Spontaneous Metastases in Murine Renal Cancer
1985
Abstract We have studied the role of natural killer activity during the growth and dissemination of a transplantable renal adenocarcinoma (Renca) of spontaneous origin in BALB/c mice. The pattern of growth of this tumor accurately mimics that of adult human renal cell carcinoma in terms of clinical stages I–IV, particularly with regard to spontaneous metastasis to lung and liver. Renca is moderately sensitive to lysis by natural killer cells from normal mice and is more efficiently lysed by natural killer cells from mice treated with the biological response modifier maleic anhydride divinyl ether, a pyran copolymer. Our studies demonstrate that selective depression of natural killer activit…
Macrophage inhibiting activity in serum and central lymph of Listeria-immune mice.
1975
Serum and central lymph from mice immunized with live Listeria monocytogenes six days previously and boostered four hours before collection exerted significant inhibition of macrophage migration in vitro. It is concluded that lymphokines or lymphokine-like products of the cellular immune reaction are released in vivo and are possibly instrumental in the generation of acquired cellular antibacterial immunity.
Characterization of a T-cell-derived mast cell costimulatory activity (MCA) that acts synergistically with interleukin 3 and interleukin 4 on the gro…
1990
The proliferation of mucosal mast cells (MMC) depends on the presence of interleukin 3 (IL 3) and can be further enhanced by interleukin 4 (IL 4). The supernatant of a TH2 cell clone (ST2/K.9) stimulated by concanavalin A was found to contain a factor, provisionally termed mast cell costimulatory activity (MCA), that substantially enhances the proliferation of MMC promoted by a combination of IL 3 and IL 4. In comparison to other lymphokines MCA is rather resistant to tryptic digestion but is very sensitive to pH values lower than 6.0 and to organic solvents. Chromatographic fractionation of MCA revealed that activity is associated with protein(s) or glycoprotein(s) of 35 to 40 kDa. Partial…
The role of accessory cells in polyclonal T cell activation. I. Both induction of interleukin 2 production and of interleukin 2 responsiveness by con…
1983
Recent studies from other laboratories have shown that concanavalin A (Con A) acts at two separate steps in polyclonal T cell activation: interleukin 2 (IL2) production, and induction of responsiveness to IL2. Using a combination of techniques for the depletion of accessory cells from lymph node T cells, we have investigated which of these steps, if not both, is responsible for the known requirement for accessory cells in the Con A response. It was found that with increasing T cell purification, first the ability is lost to produce sufficient levels of endogenous IL2, whereas induction of IL2 responsiveness can still take place. Further removal of accessory cells however yields a population…
NFAT1 deficit and NFAT2 deficit attenuate EAE via different mechanisms
2015
EAE serves as an animal model for multiple sclerosis and is initiated by autoreactive T cells that infiltrate the CNS. Recognition of myelin-associated Ags within the CNS leads to activation of the transcription factor family NFAT. Here, we demonstrate an essential role for NFAT in disease induction, as the combined lack of NFAT1 (NFATc2) and NFAT2 (NFATc1) completely protected mice. Single deficiency of either NFAT1 or NFAT2 ameliorated the course of EAE, and NFAT2 ablation resulted in an obstructed proinflammatory reaction. However, NFAT1 deficit led to an anti-inflammatory response with nonpathogenic Th17 and Th2 cells concurrently secreting IL-17, IL-4, and IL-10. Both IL-4 and IL-10 co…