Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mouse monocytic leukemia Mm cells are a line of spontaneously differentiated cells obtained from mouse myeloblastic leukemia M1 cells. The effect of interleukin 4(IL-4) on the proliferation of Mm cells in the presence or absence of growth inhibitory substances was investigated. In semi-solid agar culture, IL-4 markedly inhibited colony formation by Mm cells, reducing the number of colonies to 50% of that in control cultures at concentration of 3 U/ml. In contrast, IL-4 did not inhibit colony formation by the parent M1 cells. In liquid culture, IL-4 alone inhibited the proliferation of Mm cells only slightly. However, a combination of IL-4 and 1 alpha,25-dihydroxyvitamin D3 (VD3), which alone did not inhibit growth significantly, markedly inhibited the growth of Mm cells. This combination also increased the lysozyme activity of Mm cells significantly. On the other hand, IL-4 suppressed the antiproliferative effects of interferon alpha, beta and IL-6, which are growth inhibitory cytokines for these Mm cells. These results indicate that IL-4 can modulate the growth of monocytic leukemia Mm cells and that its modulatory effects depend on growth inhibitory substances.
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PMID:Interleukin 4 potentiates the antiproliferative effect of 1 alpha, 25-dihydroxyvitamin D3 on mouse monocytic leukemia cells but antagonizes the antiproliferative effects of interferon alpha, beta and interleukin 6. 146 28

Blood monocytes (MO) undergo maturation into macrophages (MAC) upon migration from the capillary bed to tissue sites of inflammation where they are exposed to environmental signals. Functional competence and phenotype heterogeneity is the result of both differentiation-inducing and -activating events. In vitro, MO to MAC maturation is induced by serum factors, can be followed by the expression of specific maturation-associated antigens and is accompanied by a characteristic change in the secretory repertoire of MAC in comparison to MO. Here we report that bacterial lipopolysaccharides (LPS) at subnanogram quantities very effectively inhibited the serum-induced maturation of human MO in vitro. At the same time LPS induced the up-regulation of CD14 antigens. The lipid A moiety was shown to be responsible for this novel biological activity of the LPS molecule. Inhibition of maturation was not due to secondary LPS-induced signals like interleukin (IL)-1, IL-6, tumor-necrosis factor (TNF)-alpha or interferon (IFN)-alpha--even though the latter by itself suppressed MAC maturation in vitro. The inhibitory activity of IFN-alpha could be abolished by neutralizing anti-IFN-alpha antibodies whereas these antibodies had no effect on LPS-induced suppression of MAC maturation. Functional analysis of LPS-treated MO long-term cultures showed that the pattern of secretory products released was similar to that of freshly-isolated immature blood MO: compared with mature MAC, LPS-treated MO released high amounts of IL-6 but significantly less TNF-alpha, neopterin, lysozyme and beta-2-microglobulin. At the same time, in LPS-treated MO cultures the MAC maturation-associated molecules alpha-2-macroglobulin and fibronectin could be detected only in trace amounts. The ability to secrete IL-1, however, was lost both in control as well as in LPS-treated MO cultures. The results indicate that endotoxins may influence the biology of the MO/MAC system distinctively: they not only induce a functional activation but also interfere with the ontogeny of this cell family.
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PMID:Inhibition of in vitro differentiation of human monocytes to macrophages by lipopolysaccharides (LPS): phenotypic and functional analysis. 171 Sep 26

We report the selection and characterization of a U-937 subline which is capable of long-term growth in serum-free medium and can be induced to differentiate. The subline (U-937-1SF) can be maintained in standard RPMI-1640 medium supplemented by antibiotics only. As compared to the serum-dependent U-937 parental cell line, U-937-1SF produced lower amounts of lysozyme and elastase and had a decreased surface expression of complement receptor 1 (CD35) and myeloid antigens CDw17 and CD38. Apart from these alterations, the U-937-1SF cells appear to be morphologically, cytogenetically and phenotypically similar to the parental U-937 clone-1 cells. The capacity of U-937 clone-1 cells to undergo phorbol myristic acid (PMA)-, vitamin D3 (VitD3)- and retinoic-acid (RA)-induced differentiation was retained in the U-937-1SF cells as evidenced by the induced growth arrest, development of a monocyte/macrophage morphology and increased expression of differentiation-associated antigens, e.g. CD11b, CD11c, CD14 and CD18. The growth-inhibitory response to cytokines involved in the activation and differentiation of monocytes, IFN-gamma, TNF-alpha, IL-1 beta, IL-6 and GM-CSF, was normal. Our results suggest that the U-937-1SF subline can be used as a serum-free model system for studies on various aspects of monocyte differentiation.
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PMID:Characterization of a U-937 subline which can be induced to differentiate in serum-free medium. 172 6

NF-IL6 was originally identified as a DNA binding protein regulating interleukin-1 (IL-1)-stimulated IL-6 expression. Direct cloning of NF-IL6 showed its homology with C/EBP, a hepatocyte- and adipocyte-specific transcription factor. This study showed that the expression of NF-IL6 messenger RNA (mRNA) increased markedly during the differentiation to a (mRNA) increased markedly during the differentiation to a macrophage lineage in mouse myeloid leukemia cells M1, human histiocytic leukemia cells U937, promyelocytic leukemia cells HL-60, and human peripheral monocytes. Particularly in HL-60 cells that undergo granulocyte or macrophage differentiation depending on inducers, NF-IL6 mRNA was specifically upregulated during macrophage differentiation but not granulocyte differentiation. It was also shown that the functional NF-IL6 protein increased during the differentiation of U937 cells. Furthermore, recombinant NF-IL6 was found to bind to the regulatory regions of the IL-1, tumor necrosis factor, granulocyte colony-stimulating factor, and lysozyme genes, which are expressed in mature macrophages. These results suggest that NF-IL6 may possibly be involved as an important transcription factor in the process of activation and/or differentiation of macrophages.
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PMID:Macrophage differentiation-specific expression of NF-IL6, a transcription factor for interleukin-6. 173 90

Proximal tubular (PT) epithelial cells express MHC class II (Ia) antigens in immunologically-mediated renal injury. To study the role of PT as accessory cells, we generated several murine PT-like epithelial cell lines by transformation with origin-defective SV40 DNA. These transformed cell lines display typical alkaline phosphatase and gamma-glutamyl-transpeptidase enzyme activity, proliferation to epidermal growth factor (EGF) and sodium-dependent glucose uptake. Clonal lines of transformed tubular cells from both normal C3H/FeJ and autoimmune MRL-lpr mice do not constitutively express Ia antigens or mRNA for class II. However, stimulation with recombinant interferon-gamma(rIFN-gamma) induces Ia mRNA and surface product in the cell lines. These Ia-positive cells can process and present hen egg-white lysozyme (HEL) to antigen-specific Iak-restricted T cell hybrids. Unstimulated tubular cells do not express detectable IL-1 alpha, IL-1 beta, TNA-alpha, or IL-6 mRNA. However, stimulation with IL-1 alpha or LPS induces TNF-alpha transcripts. We conclude that these cell lines have characteristics most consistent with a proximal tubular origin. They also bear characteristics of accessory cells such as processing and presentation of antigen and TNF-alpha gene expression. We speculate that PT have the capacity to participate in the pathogenesis of immune renal injury.
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PMID:MHC class II, antigen presentation and tumor necrosis factor in renal tubular epithelial cells. 240 90

Using an in vitro expansion and differentiation system for human CD34+ cord blood (CB) progenitor cells, we analyzed the induction and expression kinetics of the granulomonocyte associated lysosomal proteins myeloperoxidase (MPO), lysozyme (LZ), lactoferrin (LF), and macrosialin (CD68). Freshly isolated CD34+ CB cells were negative for LZ and LF, and only small proportions expressed MPO (4% +/- 2%) or CD68 (3% +/- 1%). Culturing of CD34+ cells for 14 days with interleukin (IL)-1, IL-3, IL-6, stem cell factor, granulocyte-macrophage colony-stimulating factor (GM-CSF), and G-CSF resulted in on average a 1,750-fold amplification of cell number, of which 83% +/- 7% were MPO+. Without addition of GM-CSF and G-CSF, lower increases in total cell numbers (mean, 211-fold) and lower proportions of MPO+ cells (54% +/- 11%) were observed. The proportion of MPO+ cells slightly exceeded but clearly correlated with the proportion of cells positive for the granulomonocyte associated surface molecules CD11b (Mac-1), CD15 (LeX), CD64 (Fc gamma RI) CD66, or CD89 (Fc alpha R). At day 14 MPO+ and LZ+ cells were virtually identical. However, at earlier time points during culture (days 4 and 7), single MPO+ or LZ+ cell populations were also observed, which only later acquired LZ and MPO, respectively. Maturation of cells into the neutrophilic pathway was indicated by the acquisition of MPO, followed by LZ. In contrast, maturation of cells into the monocytic pathway was indicated by the acquisition of LZ followed by MPO and CD14. CD68 was found to be expressed at day 4 by the majority of cells and was not restricted to the granulomonocytic cells, as cells with megakariocytic (CD41+) or erythroid (CD71hi) features were CD68+. LF expression was observed only in GM- plus G-CSF-supplemented cultures, in which only 26% +/- 5% of cells expressed LF by day 14.
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PMID:Granulomonocyte-associated lysosomal protein expression during in vitro expansion and differentiation of CD34+ hematopoietic progenitor cells. 749 68

Bacterial lipopolysaccharide (LPS) stimulates the production and release of endogenous mediators [e.g., tumor necrosis factor (TNF), interleukins-1 and -6 (IL-1 and IL-6), and Platelet Activating Factor [PAF] responsible for the pathophysiologic changes and the mortality associated with sepsis. We recently demonstrated that lysozyme (LZM) bound to LPS (LZM-LPS complex) suppresses LPS-induced tumor necrosis factor-alpha (TNF-alpha) production in vivo. In the present study, we investigated the effect of LZM-LPS complex formation on LPS-induced IL-6 production, both in vitro and in vivo. With the addition of LZM-LPS complex, TNF-alpha and IL-6 release was significantly reduced compared with that by LPS in a dose-dependent manner in mouse macrophage-like cells, RAW264.7. IL-6 production in serum by LPS in carrageenan (CAR)-primed mice peaked at 2 hr following injection. LZM-LPS and LZM-Escherichia coli cell complex (as 1 microgram of LPS per mouse) released significantly reduced concentrations of IL-6 in serum (P < 0.01 and P < 0.001 versus CAR-pretreated LPS- or cell-injected mice). These results emphasize the important role of LZM in vivo in the neutralization of endotoxin. However, in the case of IL-6, by administration of a lethal dose of LPS (as 100 micrograms of LPS per mouse), the IL-6 level was reduced by LZM, but a significant concentration of IL-6 was still released; although the TNF- alpha concentration was negligible in this experimental condition. Thus, it is suggested that LZM might regulate the systemic inflammation induced during Gram-negative bacterial infections by inhibiting the release of cytokines in serum.
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PMID:Lysozyme regulates LPS-induced interleukin-6 release in mice. 762 57

The SCL gene is a member of the helix-loop-helix family of transcription factors. First identified because of its involvement in a rare chromosome translocation in human T cell acute lymphoblastic leukemia, it is now recognized to be involved in up to 25% of T cell leukemias. Normally within the hemopoietic system the gene is expressed in progenitor cells, erythroid cells, mast cells and megakaryocytes. During macrophage differentiation the level of SCL mRNA and protein becomes undetectable. To examine this further, SCL was over expressed in murine M1 cells. This resulted in perturbation of macrophage differentiation induced by leukemia inhibitory factor (LIF) and oncostatin-M (OSM) but not interleukin (IL)-6. Moreover the perturbation of LIF-induced differentiation applied to some components of macrophage differentiation but not others. This suggests that signaling through the gp130 homodimer (as occurs with IL-6) does not utilize an SCL-inhibitable pathway. In contrast the LIF receptor/gp130 heterodimer does utilize an SCL-inhibitable pathway for some elements of macrophage differentiation (e.g., lysozyme induction) but not others (e.g., M-CSF receptor induction).
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PMID:The SCL transcription factor and differential regulation of macrophage differentiation by LIF, OSM and IL-6. 769 58

Inflammatory cells in lymph nodes of eighteen patients suffering from culture-proven tuberculous lymphadenitis were examined by histological and immunohistochemical techniques. Ten patients suffered from symptomatic HIV-infection and eight patients were immunocompetent individuals without HIV-1 serology. Characteristic granulomas with or without caseation were observed in eight immunocompetent and four HIV-1-infected patients with less marked lymphopenia of CD4 positive peripheral blood lymphocytes. No epitheloid cell formation was present in lymph nodes of HIV1-infected patients with more severe depression of CD4 positive peripheral blood lymphocyte count. Foamy macrophages were found instead of these cells. While many cells--predominantly lymphocytes--express CD25 (IL-2 receptor) in cases with typical epitheloid granulomas there is no such CD25 expression in cases without any epitheloid cell formation. This result suggest that T cell function is necessary for epitheloid granuloma formation in human tuberculosis. The phenotype of macrophages underwent progressive changes parallel to decreasing numbers of CD4 positive peripheral blood lymphocytes. Foamy macrophages in Mycobacterium avium-intracellulare infection represented an end-stage phenotype. They were positive for S100 protein and they did not express lysozyme, alpha-1-anti-chymotrypsin, L1 antigen (Mac387) and CD4, whereas positivity for HLA-DR, CD68 and Ki-M8 was preserved. In situ immunohistochemical demonstration of IFN-alpha, IFN-beta, TNF-alpha, IL-1 and IL-6 revealed that foamy cells in M. tuberculosis infection were highly active effector cells. They contained higher concentrations of the examined cytokines than epitheloid cells in the lesions of HIV+ and HIV-patients. Corresponding to these findings the histological proof of acid-fast bacilli was generally not successful in typical HIV-associated tuberculosis. The foamy appearance may result from the lipid-rich cell membranes of destroyed acid-fast bacilli. In contrast acid-fast bacilli-packed foamy macrophages in AIDS patients with M. avium-intracellulare (MAI) infection did not produce any of the examined cytokines.
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PMID:Immunohistochemical analysis of cell composition and in situ cytokine expression in HIV- and non-HIV-associated tuberculous lymphadenitis. 771 49

BCG infection of mice provides a convenient model to study natural and cellular immunity to mycobacteria and the mechanisms of granuloma formation and repair. We have used a range of macrophage (M phi) membrane molecules and secretory products to investigate resident M phi-pathogen interactions and T lymphocyte-dependent recruitment and activation of M phi in different tissues of immature, normal adult and gamma interferon deficient animals. In situ hybridization (ISH), RT-PCR and immunocytochemical analysis of M phi gene and product expression have been correlated with in vitro study of endocytic and secretory activity in which biogel polyacrylamide bead-elicited peritoneal M phi are exposed to Th1 and Th2 cytokines, LPS, BCG and other stimuli. The role of resident and newly recruited M phi responding to BCG in liver, spleen, lung and brain has been defined by means of antigen markers expressed by M phi (F4/80, 7/4, CR3, macrosialin, sialoadhesin and scavenger receptor) and/or T and B lymphoid cells (MHC Class II, CD4, CD8, B220). Heterogeneity in M phi secretory activity was revealed by ISH analysis of lysozyme, TNF-alpha, IL-1 IL-6 and MCP-1, by in vitro assay of NO and superoxide anion production, and by RT-PCR studies of Th1 (interferon gamma) and Th2 (IL-4, IL-13, IL-10) lymphokine mRNA in tissues. Our studies confirm the importance of interferon gamma as a critical mediator of host resistance to mycobacterial infection and raise intriguing questions in regard to T cell and M phi functional heterogeneity in distinct tissue microenvironments.
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PMID:BCG-induced granuloma formation in murine tissues. 771 50


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