Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IgE binds to two types of Fc receptors, called Fc epsilon R1 (or high-affinity Fc epsilon R) and Fc epsilon R2 (or low-affinity Fc epsilon R). The Fc epsilon R1 is composed of four polypeptide chains, one alpha, one beta, and two gamma chains. The alpha chain contains the IgE binding site and is a member of the immunoglobulin supergene family. The Fc epsilon R2, also called CD23, consists of one polypeptide chain which shows homology to animal lectin receptors. Fc epsilon R1 are expressed on mast cells and basophils. Crosslinking of the Fc epsilon R1 induces immediate release of mediators of inflammation such as histamine and leukotrienes and delayed secretion of interleukins 4, 5, and 6. Fc epsilon R2 are expressed on resting mu delta + B cells, monocytes/macrophages (M phi), eosinophils, and platelets but rarely on T cells. Interleukin-4 upregulates Fc epsilon R2 expression on B cells and M phi. The functions of Fc epsilon R2 on the different cell types are not fully established and are controversial. Fc epsilon R2 on M phi, eosinophils, and platelets mediate cytotoxicity to schistosomules, enhance phagocytosis, and induce the release of granule enzymes. However, M phi from patients with atopic dermatitis expressing significantly more Fc epsilon R2 than M phi from normals do not release more leukotriene C4, prostaglandin E2, or beta-glucuronidase after incubation with aggregated IgE than normal monocytes. Furthermore, aggregated IgG1 is much more efficient than IgE in inducing mediator release from M phi and IgG1 antibodies are not known to induce immediate-type hypersensitivity reactions. Therefore, definitive proof that Fc epsilon R2 are involved in the pathogenesis of allergic disorders is still lacking. IL-4 appears to play a central role in immediate-type hypersensitivity. It induces human B cells to secrete IgE and IgG4, Ig isotypes typical for antibodies to helminthic parasites and allergens. IL-4 stimulates mast cell growth and upregulates Fc epsilon R2 expression. Interferon-gamma and IL-2 inhibit the IL-4-induced IgG4 and IgE secretion. Whether the abnormally high IgE antibody production in atopic patients is the result of overproduction of IL-4 or deficient IFN-gamma/IL-2 production is presently unknown.
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PMID:Fc receptors for IgE and interleukin-4 induced IgE and IgG4 secretion. 219 Oct 55

The functional properties of infiltrating macrophages (Mphi) must be tightly regulated to facilitate appropriate responses to complex conditions in an inflammatory focus. This study was designed to ascertain whether uncommitted Mphi that have been exposed to combinations of cytokines with opposing functions develop properties dictated by one cytokine or by cytokine mixtures. Uncommitted rat bone marrow-derived Mphi (BMDMs) were incubated with IFN-gamma, TNF-alpha, TGF-beta, IL-4, IL-6, and IL-10 alone or sequentially in combinations. After 48 h, function was assessed by nitric oxide (NO) generation, uptake of apoptotic neutrophils, and beta-glucuronidase expression. IFN-gamma followed 4 h later by TNF-induced NO generation. The pretreatment of BMDMs before IFN-gamma priming with TNF, TGF-beta, and IL-4 suppressed NO generation by 87%, 92%, and 85%, respectively; IL-10 had no effect. The same cytokines administered at 4 h after IFN priming had no effect on NO generation. The uptake of apoptotic polymorphonuclear leukocytes was augmented by TNF (40% vs 29% controls; p < 0.05) and decreased by IFN-gamma, IL-10, and IL-4. The TNF response was unaffected by subsequent treatment with IFN-gamma, IL-4, or IL-10. Similarly, the decreased polymorphonuclear leukocyte uptake induced by IFN-gamma, IL-4, or IL-10 was unaffected by the subsequent addition of TNF. Beta-glucuronidase expression was increased by TGF-beta and decreased by IFN-gamma. These responses were not modified by cytokines with the opposing function. Thus, the functional response of BMDMs to complex mixtures of cytokines was determined by the first cytokine to which they were exposed. Once activated, BMDMs become unresponsive to alternative activating signals, a finding which has obvious implications for Mphi function in vivo.
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PMID:Initial cytokine exposure determines function of macrophages and renders them unresponsive to other cytokines. 971 70

The anti-inflammatory activities of the isolated flavonoids, quercetin 3-O-methyl ether (1), kaempferol (2), and quercetin (3), of Rhamnus nakaharai, and anthraquinone, frangulin B (4), of Rhamnus formosana, were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells, neutrophils, macrophages, and microglial cells. Compounds 1 - 3 strongly inhibited the release of beta-glucuronidase and lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe/cytochalasin B (fMLP/CB). Compound 1 strongly inhibited superoxide anion formation in fMLP/CB or phorbol 12-myristate 13-acetate (PMA)-stimulated rat neutrophils. Compound 1 exhibited potent inhibitory effect on tumor-necrosis factor-alpha ( TNF-alpha) formation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells while 1 and 4 showed potent inhibitory effects on TNF-alpha formation in LPS/IFN-gamma (interferon-gamma)-stimulated murine microglial cell lines N9.
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PMID:In vitro anti-inflammatory effects of quercetin 3-O-methyl ether and other constituents from Rhamnus species. 1173 18

Salmonella enteritidis infection has received attention during recent years owing to its high prevalence worldwide. In the present study, the protective effect of probiotic dahi (curd) supplemented with Lactobacillus acidophilus and L. casei against Salmonella enteritidis infection in mice is investigated. Seven days pre-feeding with probiotic dahi significantly increased anti-S. enteritidis sIgA (secretary IgA) antibodies and lymphocyte proliferation in S. enteritidis infected mice. IL-2, IL-6 and IFN-gamma production were significantly increased in supernatant of cultured splenocytes collected from mice pre-fed with probiotic dahi, while IL-4 levels were not changed significantly. Moreover, activities of beta-galactosidase and beta-glucuronidase, and counts of S. enteritidis in intestine, liver and spleen were decreased, whereas total lactobacilli in faeces were increased in mice pre-fed with probiotic dahi. Pre-feeding of probiotic dahi for 7 days was more effective than 2 days pre-feeding. Thus, the results indicate that, pre-feeding with probiotic dahi ameliorated S. enteritidis infection by stimulating specific and non-specific immune response. Above all, it lowered colonization of gastrointestinal tract as well as translocation of S. enteritidis.
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PMID:Dahi containing probiotic Lactobacillus acidophilus and Lactobacillus casei has a protective effect against Salmonella enteritidis infection in mice. 1914 89

In the present study, effect of dahi containing probiotic Lactobacillus casei (probiotic dahi) was evaluated to modulate immune response against Salmonella enteritidis infection in mice. Animals were fed with milk products along with standard diet for 2 and 7 days prior to the S. enteritidis challenge and continued on the respective dairy food-supplemented diets during the postchallenge period. Translocation of S. enteritidis in spleen and liver, beta-galactosidase and beta-glucuronidase enzymatic activities and secretory IgA (sIgA) in intestinal fluid, lymphocyte proliferation, and cytokine (interleukin [IL]-2, IL-4, IL-6, and interferon-gamma [IFN-gamma]) production in cultured splenocytes were assessed on day 2, 5, and 8 of the postchallenge period. Colonization of S. enteritidis in liver and spleen was remarkably low in probiotic dahi-fed mice than mice fed milk and control dahi. The beta-galactosidase and beta-glucuronidase activities in intestinal fluid collected from mice prefed for 7 days with probiotic dahi were significantly lower at day 5 and 8 postchallenge than in mice fed milk and control dahi. Levels of sIgA and lymphocyte proliferation rate were also significantly increased in probiotic dahi-fed mice compared with the other groups. Production of IL-2, IL-6, and IFN-gamma increased, whereas IL-4 decreased in splenic lymphocytes collected from probiotic dahi-fed mice. Data showed that dahi prefed for 7 days before S. enteritidis challenge was more effective than when mice were prefed for 2 days with dahi. Moreover, probiotic dahi was more efficacious in protecting against S. enteritidis infection by enhancing innate and adaptive immunity than fermented milk and normal dahi. Results of the present study suggest that prefeeding of probiotic dahi may strengthen the consumer's immune system and may protect infectious agents like S. enteritidis.
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PMID:Probiotic dahi containing Lactobacillus casei protects against Salmonella enteritidis infection and modulates immune response in mice. 1962 6