Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Staphylococcus aureus toxic shock syndrome toxin 1 (TSST-1) is involved in the pathogenesis of toxic shock syndrome and perhaps other staphylococcal diseases. Recently, the C-terminal part of the TSST-1 toxin has been shown to be responsible for mitogenic activity in animal models. We studied the role of the C-terminal structural unit of TSST-1 with regard to proliferation, cytokine release (tumor necrosis factor alpha [TNF-alpha], interleukin-6 [IL-6], and IL-8), mRNA expression for IL-6, IL-8, IL-10, TNF-alpha, and CD40 ligand (CD40L), synthesis of immunoglobulin E (IgE), IgA, IgG, and IgM, CD23 expression, and soluble CD23 (sCD23) release from human peripheral blood mononuclear cells (PBMC). For this purpose, we used the recombinant wild-type TSST-1 (p17) mutant toxin Y115A (tyrosine residue modified to alanine) and toxin H135A (histidine residue modified to alanine). Unmodified toxin p17 and mutant toxin Y115A, at a concentration below 5 ng, to a lesser degree, induced a strong proliferation. Toxin p17 followed by toxin Y115A was the most pronounced inducer for mRNA expression for IL-10 and CD40L and cytokine generation (mRNA and protein) for TNF-alpha, IL-6, and IL-8. Mutant protein H135A failed to activate human PBMC. Both toxins p17 and, to a lesser degree, Y115A significantly suppressed IL-4- and anti-CD40-induced synthesis of all four Igs as well as IL-4-induced CD23 expression and sCD23 release. Mutant toxin H135A failed to do so. Thus, our data show that a region in the C terminus of TSST-1 is responsible not only for mitogenic activity but also for additional immunomodulating biological activities of TSST-1. More specifically, histidine residue H135A of the 194-amino-acid toxin appears to be critical for the expression of biological activities in a human in vitro model.
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PMID:Role of a carboxy-terminal site of toxic shock syndrome toxin 1 in eliciting immune responses of human peripheral blood mononuclear cells. 753 24

Previous studies have suggested that interleukin-6 (IL-6) may mediate growth of multiple myeloma (MM) in either an autocrine or paracrine growth mechanism. However, those molecules which can trigger IL-6 secretion either by tumor cells or non-MM marrow cells are not well characterized. In the present study, we have examined the expression and functional significance of CD40 on MM and plasma cell leukemia (PCL) cells and derived cell lines, as well as long-term bone marrow stromal cells (BMSCs) and derived cell lines. CD40 was expressed on the majority of MM cells (> 90%) and BMSCs (> 70%). Triggering via CD40 using NIH3T3 CD40 ligand transfectant (CD40LT) cells increased (> 30%) cell surface CD80, CD18, CD11a, CD11b, and CD11c expression on MM cell lines. Culture with either fresh or paraformaldehyde fixed NIH3T3 CD40LT cells upregulates IL-6 secretion in MM cells and MM-derived cell lines, as well as normal and MM bone marrow mononuclear cells (BMMCs), BMSCs, and BMSC lines; this effect can be specifically blocked by anti-CD40 monoclonal antibody (MoAb). BMMCs and BMSCs from patients with MM secreted significantly more IL-6 than those from healthy donors (n = 3, P < .001); moreover, after stimulation using CD40L, IL-6 secretion was fourfold greater (n = 3, P < .001) from MM BMMCs and BMSCs than from normal BMMCs and BMSCs. Myeloma (CD38+CD45RA-) cells and non-MM (CD38+CD45RA+, CD38-CD45RA+, and CD38-CD45RA-) BMMCs were separated by dual fluorescence cell sorting. The latter secreted fourfold more IL-6 than the former (n = 2, P < .001). Increased IL-6 secretion (up to 28-fold) and proliferation (Stimulation index 10) by CD38+CD45RA-MM cells was triggered by culture with NIH3T3 CD40LT cells. Finally, anti-CD40MoAb partially (30%) blocked tumor cell to BMSC adhesion-induced IL-6 secretion. These studies support the view that CD40L may trigger IL-6 secretion by both MM cells and BMSCs and that IL-6-mediated autocrine and paracrine growth mechanisms may be possible in MM.
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PMID:CD40 ligand triggered interleukin-6 secretion in multiple myeloma. 753 94

Interleukin-6 (IL-6), a product of bone marrow stromal cells (BMSCs), is a growth factor for multiple myeloma (MM) cells. Transforming growth factor-beta1 (TGF-beta1) is also produced by BMSCs and can regulate IL-6 secretion by several tissues, including BMSCs. The present study was designed to characterize in vitro tumor growth regulation by TGF-beta1 in MM. Sorted CD38+CD45RA- MM cells secreted significantly more TGF-beta1 (8.2 +/- 2.0 ng/mL) than peripheral blood mononuclear cells (P < .001), splenic B cells (P < .001), and CD40 ligand (CD40L) pretreated B cells (P < .05). TGF-beta1 secretion by MM-BMMCs (3.8 +/- 0.9 ng/mL) was significantly greater than by N-BMMCs (1.2 +/- 0.1 ng/mL, P < .001). MM-BMSCs also secreted significantly more TGF-beta1 (6.6 +/- 2.5 ng/mL, n = 11) than N-BMSCs (4.4 +/- 0.6 ng/mL, P < .02, n = 10) and N-BMSC lines (3.9 +/- 0.2 ng/mL, P < .02, n = 6). TGF-beta1 secretion was correlated with IL-6 secretion in MM-BMSCs. Anti-TGF-beta1 monoclonal antibody both blocked IL-6 secretion by BMSCs and inhibited the increments in IL-6 secretion by BMSCs induced by MM cell adhesion. Moreover, exogenous TGF-beta1 upregulated IL-6 secretion by MM-BMSCs, normal BMSCs, and CD38+ CD45RA- MM cells, as well as tumor cell proliferation. This is in contrast to the inhibitory effect of TGF-beta1 on proliferation and Ig secretion of normal splenic B cells. Finally, retinoblastoma proteins (pRB) are constitutively phosphorylated in MM cells; TGF-beta1 either did not alter or increased pRB phosphorylation. pRB are dephosphorylated in splenic B cells and phosphorylated in CD40L triggered B cells in contrast to its effects on MM cells, TGF-beta1 decreased phosphorylation of pRB in CD40L treated B cells. These results suggest that TGF-beta1 is produced in MM by both tumor cells and BMSCs, with related tumore cell growth. Moreover, MM cell growth may be enhanced by resistance of tumor cells to the inhibitory effects of TGF-beta1 on normal B-cell proliferation and Ig secretion.
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PMID:Transforming growth factor-beta1: differential effects on multiple myeloma versus normal B cells. 863 41

Although the expression and function of CD40 on B lymphocytes has been well studied, the significance of CD40 on non-lymphoid cells such as keratinocytes (KC) is not as well characterized. We demonstrate in this report that CD40 is expressed by virtually all human KC, and that it functions as an important signaling molecule. Flow cytometry of undifferentiated and terminally differentiated KC indicated that both cell types expressed CD40, as determined by binding to monoclonal antibodies and a recombinant CD40 ligand fusion protein; interferon-gamma (IFN-gamma) treatment of KC increased CD40 expression. Cultured KC also expressed 1.5-kb CD40 transcripts. Activation of KC cell surface CD40 using the monoclonal antibody G28.5 resulted in the rapid generation of a 50-kDa tyrosine phosphorylated polypeptide, as well as a dose-dependent increase in the secretion of interleukin-6, a cytokine that has been linked to KC proliferation. KC also co-stimulated a significant T lymphocyte proliferative response to the mitogen phytohemagglutinin that was CD40 dependent. These data indicate that KC constitutively express a low level of functional CD40 and regulate their expression in response to IFN-gamma. These data support the concept that KC, via their expression of CD40, have the capacity to amplify inflammation in the skin by interacting with CD40 ligand-bearing T cells.
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PMID:Human epidermal keratinocytes are induced to secrete interleukin-6 and co-stimulate T lymphocyte proliferation by a CD40-dependent mechanism. 864 19

Interleukin-6 (IL-6) is the major cytokine to date mediating antigen (Ag)- or mitogen-driven B cell differentiation. Recently, CD40 ligand (CD40L), with the co-stimulatory cytokines IL-4 and IL-10, has been shown to trigger immunoglobulin (Ig) secretion and class switching. In the present report, we have examined the role of IL-6 in mediating B cell differentiation and Ig secretion triggered with CD40L and/or these cytokines. Culture of splenic B cells with CD40L triggered (1) significant (5.4-fold) increases in IL-6 secretion; (2) differentiation, evidenced by sequential loss of B cell (CD20, CD21) and acquisition of plasma cell (CD38, PCA-1) surface antigens (Ags); and (3) Ig secretion. Interleukin-4 increased both IL-6 and IgG secretion stimulated by CD40L. Interleukin-10+ CD40L triggered 100-fold increments in IgG, IgA and IgM secretion, but IL-10 suppressed IL-6 secretion triggered with CD40L +/- IL-4. Exogenous IL-6 can further increase IgG secretion induced by CD40L + IL-10; moreover, the anti-IL-6 monoclonal antibody partially blocked IgG secretion triggered by CD40L +/- IL-4 or IL-10. Finally, IL-10 suppressed differentiation of B cells induced by CD40L. These studies suggest that CD40L augments Ig secretion in at least two mechanisms: by triggering IL-6 secretion and related differentiation, and by priming B cells for responsiveness to IL-10.
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PMID:CD40 ligand triggers interleukin-6 mediated B cell differentiation. 870 23

Interleukin-6 (IL-6) mediates autocrine and paracrine growth of multiple myeloma (MM) cells and inhibits tumor cell apoptosis. Abnormalities of retinoblastoma protein (pRB) and mutations of RB gene have been reported in up to 70% of MM patients and 80% of MM-derived cell lines. Because dephosphorylated (activated) pRB blocks transition from G1 to S phase of the cell cycle whereas phosphorylated (inactivated) pRB releases this growth arrest, we characterized the role of pRB in IL-6-mediated MM cell growth. Both phosphorylated and dephosphorylated pRB were expressed in all serum-starved MM patient cells and MM-derived cell lines, but pRB was predominantly in its phosphorylated form. In MM cells that proliferated in response to IL-6, exogenous IL-6 downregulated dephosphorylated pRB and decreased dephosphorylated pRB-E2F complexes. Importantly, culture of MM cells with RB antisense, but not RB sense, oligonucleotide (ODN) triggered IL-6 secretion and proliferation in MM cells; however, proliferation was only partially inhibited by neutralizing anti-IL-6 monoclonal antibody (MoAb). In contrast to MM cells, normal splenic B cells express dephosphorylated pRB. Although CD40 ligand (CD40L) triggers a shift from dephosphorylated to phosphorylated pRB and proliferation of B cells, the addition of exogenous IL-6 to CD40L-treated B cells does not alter either pRB or proliferation, as observed in MM cells. These results suggest that phosphorylated pRB is constitutively expressed in MM cells and that IL-6 further shifts pRB from its dephosphorylated to its phosphorylated form, thereby promoting MM cell growth via two mechanisms; by decreasing the amount of E2F bound by dephosphorylated pRB due to reduced dephosphorylated pRB, thereby releasing growth arrest; and by upregulating IL-6 secretion by MM cells and related IL-6-mediated autocrine tumor cell growth.
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PMID:Interleukin-6 promotes multiple myeloma cell growth via phosphorylation of retinoblastoma protein. 882 42

CD40 is an important signaling and activation antigen found on certain bone marrow-derived cells. Recently, CD40 has also been shown to be expressed by nonhematopoietic cells, including certain human fibroblasts, but not others. Little is known about the function of CD40 on fibroblasts. The current study investigates the hypothesis that CD40 is expressed on orbital fibroblasts and represents a pathway for interaction between these fibroblasts and CD40 ligand-expressing cells, such as T lymphocytes and mast cells. We report here that orbital connective tissue fibroblasts, obtained from normal donors and from patients with severe thyroid-associated ophthalmopathy (TAO), express functional CD40. CD40 is upregulated approximately 10-fold by interferon-gamma (500 U/ml) treatment for 72 h. These fibroblasts become activated through triggering of CD40 with CD40 ligand (CD40L). This is evidenced by nuclear translocation of nuclear factor-kappa B and induction of the proinflammatory and chemoattractant cytokines interleukin-6 and interleukin-8, respectively. These data support the concept that cognate interactions between orbital fibroblasts and infiltrating T lymphocytes, via the CD40-CD40L pathway, may promote the tissue remodeling observed in TAO and other inflammatory diseases of the orbit. Disruption of the CD40-CD40L interaction may represent a therapeutic intervention to reduce the inflammatory components of TAO, which remains a vexing clinical problem.
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PMID:Human orbital fibroblasts are activated through CD40 to induce proinflammatory cytokine production. 953 Jan 2

CD40-CD40 ligand (CD40L) interaction was originally defined as important molecules for the development of humoral immunity. Thereafter, some investigations have focused on its essential roles for the induction of cell-mediated immunity in host defenses. Here we investigated the antitumor activity of murine alveolar macrophages through CD40-CD40L interaction. The CD40L gene was transfected into murine lung cancer cells (3LLSA), and CD40L-expressing clones (3LLSA-CD40L) were established. Stimulation of CD40 molecules on the surface of alveolar macrophages with 3LLSA-CD40L cells induced the production of nitric oxide, tumor necrosis factor-alpha, and interleukin-12 and the tumoricidal activity of alveolar macrophages in the presence of interferon-gamma, which increased the surface expression of CD40 molecules on alveolar macrophages. These findings were not observed when alveolar macrophages were obtained from CD40-deficient mice. On the other hand, interleukin-6 production by alveolar macrophages did not depend on CD40-CD40L interaction. We also established a murine melanoma cell line expressing CD40L (B16 4A5-CD40L) that could induce tumoricidal activity of alveolar macrophages. Furthermore, when spleen cells were cocultivated with 3LLSA-CD40L cells, specific cytotoxic T lymphocytes for wild-type 3LLSA cells could be induced. These results suggest that CD40L gene transfer into tumor cells may induce antitumor immunity in a tumor-bearing host and may offer a new strategy for cancer gene therapy.
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PMID:Enhancement of tumoricidal activity of alveolar macrophages via CD40-CD40 ligand interaction. 1040 30

The onset of cerebral ischaemia triggers a cascade of proinflammatory molecular and cellular events. Clinical studies suggest that the strength of this acute response is important in early and late clinical outcomes, early clinical worsening, and extent of brain damage. Variables that are predictors of adverse stroke outcome include erythrocyte sedimentation rate, and levels of C-reactive protein (CRP), interleukin-6, tumour necrosis factor-alpha and intercellular adhesion molecule-1. Current data indicate that inflammation serves to fuel atherosclerosis and can act as the link between atherosclerosis and atherothrombosis. Growing evidence indicates that platelets act as prominent players in the inflammatory component of these disease processes. Thus, upon activation, platelets release a series of cytokines and growth factors and express CD40 ligand, which interacts with the CD40 receptor on other major cell types involved in atherosclerosis/atherothrombosis. In healthy volunteers, CD40L expression in platelets is not significantly inhibited by acetylsalicylic acid (ASA) alone, but is inhibited after treatment with the ADP-receptor antagonist clopidogrel or with clopidogrel plus ASA. Of a range of potential inflammatory biomarkers that have been reported in the literature, the best studied is CRP. Such biomarkers may have clinical utility for refined identification of patients at high risk for atherothrombosis in different arterial beds and for monitoring of therapeutic agents in clinical trials.
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PMID:Role of inflammation in stroke and atherothrombosis. 1473 Feb 51

Platelets play an important role in the inflammatory response. In a nonrandomized comparison, we examined the effect of clopidogrel pretreatment on platelet inflammatory marker expression in patients undergoing percutaneous coronary intervention (PCI). Platelet expression of the inflammatory markers CD40 ligand (L) and CD62 P-selectin (P) and serum levels of interleukin-6 and CD40L were compared in patients pretreated (>24 hours before PCI) or not pretreated with clopidogrel. Blood samples were obtained before and after the procedure, and from 18 to 24 hours later. Marker expression in resting and adenosine diphosphate (ADP) (50 micromol/L) and thrombin receptor activating peptide (TRAP) (10 micromol/L) activated samples was quantified by flow cytometry. Serum CD40L and interleukin (IL)-6 levels were determined by enzyme-linked immunosorbent assay. Seventy-nine patients were recruited into the study. Forty-two percent were pretreated with clopidogrel for a median of 5 days (range 1 to 1,325). Clopidogrel pretreatment was associated with lower ADP-activated platelet CD40L expression in baseline and postprocedural samples. Similarly, platelet CD62P expression at all time points in ADP-activated and in baseline and postprocedural TRAP-activated samples was lower in patients pretreated with clopidogrel. These differences remained after multivariate adjustment between the groups. Serum CD40L levels increased from 2.13 +/- 2.37 ng/ml at baseline to 4.77 +/- 3.86 ng/ml at 18 to 24 hours after the procedure (p <0.0001). Similarly, serum IL-6 levels increased at 18 to 24 hours after the procedure (14.8 +/- 42.0 pg/ml before vs 25.5 +/- 36.0 pg/ml at 18 to 24 hours after the procedure, p <0.0001). Clopidogrel pretreatment did not affect serum IL-6 or CD40L levels. Thus, clopidogrel pretreatment reduces platelet inflammatory marker expression in patients undergoing PCI.
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PMID:Effect of clopidogrel pretreatment on inflammatory marker expression in patients undergoing percutaneous coronary intervention. 1501 68


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