Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cytokine preparation from rat peritoneal exudate cells was studied. The preparation was pronase sensitive and heat labile, but was insensitive to trypsin treatment. Administration to rats resulted in elevated serum levels of alpha 1-acid glycoprotein, sialyltransferase activities and cortisol, but depressed serum albumin levels; in addition, hepatic sialyltransferase activities were increased and hepatic beta-galactosidase and beta-N-acetylhexosaminidase activities were depressed.
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PMID:Studies on rat cytokines as mediators of the acute phase response. 634 Jun 81

Glucocorticosteroids (GCS) added to otherwise unstimulated cultures of human peripheral blood mononuclear cells (PBMC) induce the synthesis and secretion of all classes of immunoglobulin. The magnitude of this response is similar to that seen with other polyclonal B cell activators such as pokeweed mitogen (PWM), and like that of PWM, the steroid effect is dependent on both T cells and monocytes. To determine the cellular target for GCS in these cultures, separated populations of T cells and non-T cells were preincubated with steroids and then recombined. No immunoglobulin was produced in any of these preincubation experiments. As a different approach to this question, supernatants were collected from various cell populations following stimulation with PWM, concanavalin A (Con A), phytohemagglutinin (PHA), alloantigens, or GCS. These supernatants were tested for their effects on GCS-induced Ig production by B cells. Supernatants from 3-d cultures of unstimulated, as well as GCS-treated, PBMC contained a T cell-replacing factor that permitted T-depleted PBMC to produce Ig upon steroid stimulation. This supernatant factor (TRF-S) could be produced in the absence of steroid stimulation, but both the factor and GCS were necessary for the induction of Ig synthesis. Production of the TRF-S required the presence of both T cells and adherent cells in culture and was found in the highest concentrations at 3-4 d of culture. Supernatants from cultures stimulated with PWM, PHA, Con A, and alloantigens did not contain detectable TRF-S activity, and TRF-S was unable to replace helper T cells for PWM-induced Ig production. TRF-S required the presence of adherent cells in the T cell-depleted responder population for its action. Further, it was effective in inducing Ig production along with GCS in the presence of a sufficient concentration of cyclosporin A to block all T cell helper activity for primary responses of PBMC to PWM or GCS. TRF-S was inactivated by trypsin treatment, heating to 56 degrees C, freezing, lyophilization, and storage at 4 degrees C for greater than 3 wk. Its molecular weight is probably 10,000 daltons or more, since TRF-S activity is not rapidly dialyzable. These experiments indicate that GCS-induced Ig production by human B cells does not require the presence of intact T cells in the cultures and therefore the steroids are not exerting their influence directly on T suppressor or T helper cells. Furthermore, they demonstrate a previously unrecognized cytokine that induces the differentiation of human B cells to Ig production in the presence of GCS.
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PMID:T cell-replacing factor for glucocorticosteroid-induced immunoglobulin production. A unique steroid-dependent cytokine. 660 6

Human alpha 2-macroglobulin (alpha 2M), which irreversibly entraps proteinases through a drastic conformational change, has also been reported to bind various cytokines. The meaning of cytokine binding to native and/or transformed alpha 2M molecules is, however, not understood. In an attempt to elucidate this question, we have studied the interaction of radioiodinated recombinant human interleukin-2 (125I-rhIL-2) with native and chymotrypsin (alpha 2M-C)- or methylamine-transformed (alpha 2M-MA) alpha 2M. Our results show that native and alpha 2M-MA are able to bind 125I-rhIL-2, with binding occurring only with the latter in a covalent manner, whereas the labeled cytokine is proteolyzed when incubated with alpha 2M-entrapped chymotrypsin. The degradation of uncomplexed 125I-rhIL-2 has also been observed in the presence of trypsin, whereas 125I-rhIL-2 bound to alpha 2M-MA is protected. Moreover, the proliferative activity of this cytokine on responsive cells is still maintained either with native alpha 2M- or alpha 2M-MA-complexed rhIL-2 in comparison with that observed with the cytokine alone. Our results, which lead us to consider alpha 2M molecules as IL-2-binding proteins, emphasize the possible role of these molecules as immune response regulators.
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PMID:Evidence for the binding of a biologically active interleukin-2 to human alpha 2-macroglobulin. 753 36

Alpha 2-Macroglobulin (alpha 2M) is a multifunctional secreted glycoprotein that serves as a ubiquitous proteinase inhibitor and as a binding protein for platelet-derived growth factor (PDGF) BB and homologues of PDGF-BB secreted in culture by macrophages. The interaction of alpha 2M with PDGF-A chain molecules has not been addressed. This is a potentially important issue because fibroblasts and smooth muscle cells produce PDGF-AA, whereas macrophages produce mainly PDGF-BB. Recombinant human 125I-PDGF-B chain molecules (AB and BB) bound to plasma-derived, native human, or bovine alpha 2M and trypsin-activated alpha 2M on Superose 6 fast protein liquid chromatography gel filtration and on nondenaturing polyacrylamide gel electrophoresis, whereas 125I-PDGF-AA did not. Similar results were obtained with 125I-PDGF isoforms binding to immobilized bovine alpha 2M and alpha 2M-methylamine. The same differential pattern of unlabeled PDGF isoforms binding to alpha 2M was observed by Western blotting of PDGF. Human lung fibroblasts secreted alpha 2M as measured by Western blotting, and fibroblast-derived alpha 2M possessed the same differential binding pattern for PDGF isoforms as did plasma-derived alpha 2M. The specific binding of PDGF-AB and -BB to these fibroblasts was inhibited by native bovine alpha 2M, although PDGF-AA binding was not affected. Native alpha 2M preferentially blocked fibroblast chemotaxis to the PDGF-B chain dimers. These data suggest that only PDGF-B chain dimers, such as those produced by macrophages or released from platelets, are regulated by alpha 2M and that PDGF-AA produced by fibroblasts and smooth muscle cells is not controlled by this cytokine-binding protein.
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PMID:Differential binding and regulation of platelet-derived growth factor A and B chain isoforms by alpha 2-macroglobulin. 754 96

Allergic mucosal inflammation is characterized by tissue infiltration with eosinophils, and associated activation of mast cells and T lymphocytes. Tumour necrosis factor (TNF) alpha/cachectin is a candidate cytokine relevant to the pathogenesis of these events through its capacity to upregulate the expression of endothelial cell adhesion molecules, mediate granulocyte chemoattraction, and activate eosinophils, mast cells and T cells. To investigate the presence and localization of TNF alpha in the nasal mucosa in allergic rhinitis, nasal biopsies from perennial rhinitic (n = 13) and non-rhinitic volunteers (n = 11) were embedded in glycol methacrylate and immunostained with a monoclonal antibody directed against TNF alpha, and adjacent 2 microns sections stained for tryptase, CD3 and eosinophil cationic protein. This identified positive immunostaining for TNF alpha in the submucosa of both the rhinitic and normal subjects (median cell counts 13 and 23 cells/mm2 respectively, P = 0.24) with cellular localization to mast cells but not to T-lymphocytes or eosinophils. In a subsequent study of seven atopic subjects, nasal allergen challenge produced increases in lavage levels of histamine and albumin, which was associated with significant release of TNF alpha as early as 2 min post-allergen when compared with the saline control day (P = 0.05). This difference was also apparent when studying the area under the curve both at 30 and 60 min post-challenge t-test (P = 0.015 and 0.02 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:TNF alpha is localized to nasal mucosal mast cells and is released in acute allergic rhinitis. 755 43

Mast cells are granule-containing secretory cells which are distributed preferentially about the microvascular bed in oral mucosa. This work examined the contribution of mast cell mediators to inflammation in the oral cavity. Mast cells in oral tissues expressed the serine proteases, tryptase and chymase, with a minor subpopulation being chymase-negative. Mast cells contained the cytokine tumour necrosis factor-alpha (TNF) in their granules. Degranulation of mast cells was a consistent feature of inflammatory lesions (lichen planus, gingivitis, pulpitis, periapical inflammation). In lichen planus, intracellular stores of TNF were depleted, and expression of mRNA for TNF was upregulated, indicating ongoing production and release of the cytokine. The density of mast cells in tissue compartments was related to the level of expression of E-selectin, an endothelial adhesion molecule which is known to be induced in skin by TNF derived from degranulating mast cells. Further attention should be directed toward the role of mast cell products, particularly TNF, in inflammation in the oral cavity.
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PMID:Relationship between mast cell degranulation and inflammation in the oral cavity. 756 63

Chemokines are considered important mediators of various inflammatory processes. In human basophils, different CC chemokines are known to stimulate release of histamine and generation of leukotriene (LT)C4. In the present study, we have evaluated the effect of RANTES (regulated upon activation, normal T cell expressed and secreted), monocyte chemotactic protein (MCP)-1, MCP-2, MCP-3, macrophage inflammatory protein (MIP)-1 alpha and MIP-1 beta on mast cell activation. Whereas all these CC chemokines caused dose-dependent release of histamine from basophils in mixed human leukocyte suspensions, none of them was able to induce release of histamine as well as tryptase or prostaglandin (PG)D2 from human skin mast cells, nor did priming with these substances enhance IgE-mediated mediator release. In addition, all chemokines failed to promote changes in the cytosolic free calcium level in the human mast cell line HMC-1. These results add further evidence for the differences between human mast cells and basophils regarding cytokine-dependent activation.
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PMID:Effect of CC chemokines on mediator release from human skin mast cells and basophils. 758 Feb 86

Human mast cells can be divided into two distinct phenotypes based on their content of neutral serine proteases, suggesting that they serve differing biologic and pathologic roles. Recently, it has been demonstrated that human mast cells are a source of several pleiotropic cytokines including IL-4, IL-5, IL-6, IL-8, and TNF-alpha, but not all mast cells contain all of these cytokines, suggesting that there is also functional heterogeneity with respect to cytokine expression. In this study, we have examined the relationship between mast cell neutral protease expression and cytokine content using immunohistochemistry. Bronchial mucosal biopsies from five normal subjects and five patients with allergic asthma, and nasal mucosal biopsies from five normal subjects and three patients with allergic rhinitis were embedded in glycol methacrylate. Sections (2 microns) were stained for IL-4, IL-5, and IL-6, adjacent to serial sections stained for tryptase and chymase. The distribution of cytokines among the tryptase+ chymase- mast cells (MCT) and tryptase+ chymase+ mast cells (MCTC) was examined by co-localization of cytokines to MCTC or MCT in serial sections using the camera-lucida. Although IL-4 was distributed among both mast cell phenotypes, it was expressed preferentially by the MCTC subset (overall 85% MCTC:15% MCT). In contrast, IL-5 and IL-6 were restricted almost exclusively to the MCT subset. Immunostaining of isolated skin mast cells (> 99% MCTC) supported these findings, with strong immunoreactivity present for IL-4 but very little for IL-5 or IL-6. These results indicate that in addition to exhibiting heterogeneity with respect to neutral protease content of the secretory granules, human mast cells are also heterogeneous with respect to cytokine content. This suggests that the biologic functions of MCTC and MCT cells differ as a result of their capacity to generate and release different cytokine profiles.
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PMID:Heterogeneity of human mast cells based on cytokine content. 760 7

alpha-Thrombin is a multifunctional serine protease that has an important role in the coagulation cascade, wound healing, and inflammatory response. In this study, we show that thrombin induces IL-6 production in human epithelial cells and fibroblasts. ELISA and Northern blot analyses showed that physiologic concentrations of thrombin (0.1-1 micrograms/ml) induced IL-6 production in human lung fibroblasts, skin fibroblasts, and epithelial cells. Hirudin, a thrombin inhibitor, completely blocked IL-6 induction by thrombin. Treatment of fibroblasts with inactivated diisopropylphosphofluoridate (DIP)-alpha-thrombin, gamma-thrombin, or trypsin had no effect on IL-6 production. In contrast, treatment with the thrombin-tethered ligand receptor peptide TRP-7 (SFLLRNP) induced IL-6 production, but at lower levels than that induced by native alpha-thrombin. Finally, IL-6 pretreatment of lung or skin fibroblasts resulted in the enhanced production of IL-6 following exposure to thrombin. These results suggest that fibroblasts and epithelial cells may represent a significant source of IL-6 in the inflammatory response to tissue injury, and that cytokine production is an important biologic consequence of thrombin's interaction with its seven-transmembrane domain (STD) receptor.
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PMID:Thrombin induces IL-6 production in fibroblasts and epithelial cells. Evidence for the involvement of the seven-transmembrane domain (STD) receptor for alpha-thrombin. 760 66

Clinical studies of vernal keratoconjunctivitis (VKC) patients show that total IgE serum levels are increased even in the absence of IgE antibodies to common allergens. Activated eosinophils are also a constant feature of VKC at both the circulation (cytofluorimetry) and tissue (tear cytology and conjunctival scrapings) levels. Moreover, allergen challenge induces a prolonged inflammatory reaction with a prevalent participation of eosinophils, lymphocytes and possibly basophils. Immunohistochemical studies of VKC biopsies show a multicellular inflammatory infiltrate with prevalence of activated eosinophils, mast cells and CD4 lymphocytes in both epithelium and subepithelium. Mediator studies indicate that eosinophil products (eosinophil peroxidase, eosinophinal cationic protein and eosinophil-derived neurotoxin/eosinophil protein X) are increased in both serum and tears, where tryptase and interleukin (IL)-5 are also detectable in higher amounts than in controls. On the basis of these findings, we postulate that VKC can represent a phenotypic model of up-regulation of the cytokine gene cluster on chromosome 5q which through its products (IL-3, IL-4, IL-5 and granulocyte/macrophage-colony-stimulating factor) regulates Th2 prevalence, IgE production as well as mast cell and eosinophil growth and function in VKC.
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PMID:Vernal keratoconjunctivitis: a model of 5q cytokine gene cluster disease. 761 25


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