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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Hemopoietic lineage commitment can be breached by concomitant expression of the c-myc and v-raf oncogenes. Switching to the myeloid lineage occurred frequently when B lineage cells, from either lymphomas or preleukemia bone marrow cells of Emu-myc transgenic mice, were infected with a retrovirus bearing v-raf. Cloned pre-B and B cell lines changed into either mature or immature macrophages as assessed by morphology, adherence, phagocytic activity, surface markers, and lysozyme production, but retained clonotypic immunoglobulin gene rearrangements. Although expression of the Emu-myc transgene was reduced or abolished in the more differentiated lines, the lines remained tumorigenic. The converted lines produced the myeloid growth factor GM-CSF, and most had karyotypic alterations. These results suggest that constitutive myc plus raf expression can provoke genetic reprogramming in lymphocytes.
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PMID:Hemopoietic lineage switch: v-raf oncogene converts Emu-myc transgenic B cells into macrophages. 245 46

Human granulocyte-macrophage colony stimulating factor (GM-CSF) has been synthesized in high yield using a temperature inducible plasmid in Escherichia coli. The human GM-CSF is readily isolated from the bacterial proteins because of its differential solubility and chromatographic properties. The bacterially synthesized form of the human GM-CSF contains an extra methionine residue at position 1, but otherwise it is identical to the polypeptide predicted from the cDNA sequence. The specific activity of 2.9 X 10(7) units/mg of protein for purified bacterially synthesized human GM-CSF indicates that despite the lack of glycosylation, the molecule is substantially in its native conformation. This molecule stimulated the same number and type of both seven- and 14-day human bone marrow colonies as the CSF alpha preparation from human placental conditioned medium. Human GM-CSF had no activity on murine bone marrow or murine leukemic cells. There was no detectable, direct stimulation of adult human erythroid burst forming units (BFU-E) by the bacterially synthesized human GM-CSF. Although impure preparations containing native human GM-CSF (eg, human placental conditioned medium) stimulated the formation of mixed colonies, even in the presence of erythropoietin, the bacterially synthesized human GM-CSF failed to stimulate the formation of mixed colonies from adult human bone marrow cells. The bacterially synthesized human GM-CSF increased N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced superoxide production and lysozyme secretion. Antibody-dependent cytotoxicity and phagocytosis by human neutrophils was stimulated by the bacterially synthesized human GM-CSF and eosinophils were also activated in the antibody-dependent cytotoxicity assay.
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PMID:Purification and properties of bacterially synthesized human granulocyte-macrophage colony stimulating factor. 302 61

To date no hematopoietic progenitors of dendritic Langerhans' cells (DLC), which represent an highly efficient class of antigen presenting cells, have been identified or the cytokines they elaborate have been defined. Here we describe an acute leukemia patient whose blasts (90-96% in peripheral blood and bone marrow) had a phenotype consistent with putative progenitors of DLC. The patient was treated with ara-C and VP-16 but did not achieve remission. The blasts had lobulated nuclei, no cytoplasmic vacuolation or Auer rods and were weakly positive for acid phosphatase and non-specific esterase and negative for PAS, granzyme A, dipeptidyl aminopeptidase IV, ATPase/ADPase and lysozyme production. The blasts were positive for CD1a, CD4, CD16, CD35, HLADR, HLADQ, CD11b, CD11c, CD14, CD33, CD34, CD11a, CD71, CD19, CD25, IL-2R beta and negative for CD2, CD7, CD8, CD10, CD22, CD56, CD57, surface or cytoplasmic CD3, TCR delta and TCR beta, HTLV-1p19 and P-glycoprotein. On liquid culture with or without 5 x 10(-9) M 12-O-tetradecanoylphorbol-13-acetate (TPA) for 3 days, the blasts formed aggregates of proliferating and elongating cells on the wall of the flasks with a decline in CD34, numerous dendritic processes appeared on the cells and there was strong positivity for ATPase/ADPase, but no other changes in phenotype. No macrophages were observed, indicating derivation from separate DLCs. Cytogenetic analysis showed chromosomal abnormalities and electron microscopy showed Birbeck granules. Southern blotting of DNA showed rearrangement of one allele for both JH and TCR beta but no HTLV-1 related sequences. Culture supernatants from blasts cultured with or without TPA showed the production of large amounts of IL-8, IL-6, TNF-alpha, MIP-1 alpha, IL-10 and interferon gamma and modest amounts of IL-1 alpha, GM-CSF and stem cell factor. The presence not only of CD1a, HLADR, HLADQ and many other characteristics including Birbeck granules, but also differentiation along the lines of DLC with appearance of dendritic processes on the cells and expression of ATPase/ADPase activity, indicate that the leukemic blasts in our patient represented a leukemic counterpart of normal progenitors of DLC and the leukemia a new entity which could possibly be classified as AML-M8. Lastly, many pro-inflammatory cytokines produced by DLC could contribute to inflammation and IL-10 to immunosuppression.
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PMID:Phenotype, genotype and cytokine production in acute leukemia involving progenitors of dendritic Langerhans' cells. 791 55

Dendritic cells (DC) are the most potent APCs within the immune system. We show here that highly purified CD14(bright) peripheral blood monocytes supplemented with granulocyte-monocyte (GM)-CSF plus IL-4 develop with high efficacy (>95% of input cells) into DC. They neo-expressed CD1a, CD1b, CD1c, CD80, and CD5; they massively up-regulated CD40 (109-fold) and HLA-DQ and DP (125- and 87-fold); and significantly (>5-fold) up-regulated HLA-DR, CD4, CD11b, CD11c, CD43, CD45, CD45R0, CD54, CD58, and CD59. CD14, CD15s, CD64, and CDw65 molecules were down-regulated to background levels, and no major changes were observed for HLA class I, CD11a, CD32, CD33, CD48, CD50, CD86, CDw92, CD93, or CD97. Monocytes cultured in parallel with GM-CSF plus TNF-alpha were more heterogeneous in expression densities but otherwise similar in their surface molecule repertoire. They clearly differed, however, in their accessory cell capacity. Only GM-CSF plus IL-4-cultured cells were found to be potent stimulators in allogeneic and autologous MLR and they presented tetanus toxoid 100- to 1000-fold more efficiently than other cell populations tested. Furthermore, only cytokine-treated monocytes formed clusters with resting T cells. At variance from all these similarities between in vitro-generated monocyte-derived DC and in vivo-developing DC, the DC populations generated by us contained significant amounts of myeloperoxidase and also expressed lysozyme. At least in this respect they, thus, differ from "classical" DC types.
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PMID:Molecular and functional characteristics of dendritic cells generated from highly purified CD14+ peripheral blood monocytes. 889 15

We studied the effects of TNF-alpha or GM-CSF on the production of reactive oxygen species (as measured by chemiluminescence) and degranulation responses of neutrophils to opsonized inflammatory microcrystals. TNF-alpha in the 10-2000 pM or GM-CSF in the 2-200 pM concentration range caused the concentration-dependent amplification of neutrophil chemiluminescence responses to both calcium pyrophosphate dihydrate (CPPD) and monosodium urate monohydrate (MSUM) crystals. Degranulation responses, as measured by the extracellular release of the granule enzymes myeloperoxidase or lysozyme, were amplified by approximately 50-100% for both MSUM or CPPD crystal-induced neutrophil activation when cells were pretreated with TNF-alpha at 2000 pM or GM-CSF at 75 pM.
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PMID:The priming action of tumour necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on neutrophils activated by inflammatory microcrystals. 918 88

We investigated in H-2k mice bearing a genetically disrupted invariant chain (Ii) gene, the MHC class II expression and antigen presentation ability of dendritic cells (DC) freshly purified from the spleen (SpDC) or derived from bone marrow precursors (BMDC) upon treatment with GM-CSF. In the absence of Ii, class II alpha/beta heterodimers are expressed on the DC membranes to a similar extent than in control mice, in contrast to splenic B cells. Class II molecules immunoprecipitated from the plasma membrane of Ii deficient DC are compact indicating that the dimers are stabilized by antigenic peptides. Furthermore DC from Ii mutant mice are able to present to CD4+ T lymphocytes, epitopes derived from the processing of the hen egg lysozyme (HEL) that normally require expression of the Ii molecule for presentation by B cells. All together, our results show that the antigen processing machinary of DC provides peptides that can reach class II molecules and stabilize their conformation in the absence of Ii mediated targeting of class II complexes.
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PMID:Dendritic cells from mice lacking the invariant chain express high levels of membrane MHC class II molecules in vivo. 928 61

The distribution of myeloid lineage-associated cytokine receptors and lysosomal proteins was analyzed in human CD34+ cord blood cell (CB) subsets at different stages of myeloid commitment by reverse-transcriptase polymerase chain reaction (RT-PCR). The highly specific granulomonocyte-associated lysosomal proteins myeloperoxidase (MPO) and lysozyme (LZ), as well as the transcription factor PU.1, were already detectable in the most immature CD34+Thy-1+ subset. Messenger RNA (mRNA) levels for the granulocyte-colony stimulating factor (G-CSF) receptor, granulocyte-macrophage (GM)-CSF receptor alpha subunit and tumor necrosis factor (TNF) receptors I (p55) and II (p75) were also detected in this subset in addition to c-kit and flt-3, receptors known to be expressed on progenitor cells. By contrast, the monocyte-macrophage colony stimulating factor (M-CSF) receptor was largely absent at this stage and in the CD34+Thy-1-CD45RA- subsets. The M-CSF receptor was first detectable in the myeloid-committed CD34+Thy-l-CD45RA+ subset. All other molecules studied were found to be expressed at this stage of differentiation. Different cocktails of the identified ligands were added to sorted CD34+Thy-1+ single cells. Low proliferative capacity was observed after 1 week in culture in the presence of stem cell factor (SCF) + Flt-3 ligand (FL) + G-CSF. Addition of GM-CSF to this basic cocktail consistently increased the clonogenic capacity of single CD34+Thy-1+ cells, and this effect was further enhanced (up to 72.3 +/- 4.3% on day 7) by the inclusion of TNF-alpha. In conclusion, the presence of myeloid-associated growth factor receptor transcripts in CD34+ CB subsets does not discriminate the various stages of differentiation, with the exception of the M-CSF receptor. In addition, we show that TNF-alpha is a potent costimulatory factor of the very immature CD34+Thy-1+ CB subset.
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PMID:Analysis of myeloid-associated genes in human hematopoietic progenitor cells. 932 52

Murine bone marrow cultured with GM-CSF produced dendritic cells (DCs) expressing MHC class II (MHC-II) but little CD40, CD80, or CD86. Oligodeoxynucleotides (ODN) containing CpG motifs enhanced DC maturation, increased MHC-II expression, and induced high levels of CD40, CD80, and CD86. When added with Ag to DCs for 24 h, CpG ODN enhanced Ag processing, and the half-life of peptide:MHC-II complexes was increased. However, Ag processing was only transiently enhanced, and exposure of DCs to CpG ODN for 48 h blocked processing of hen egg lysozyme (HEL) to HEL(48-61):I-A(k) complexes. Processing of this epitope required newly synthesized MHC-II and was blocked by brefeldin A (BFA), suggesting that reduced MHC-II synthesis could explain decreased processing. Real-time quantitative PCR confirmed that CpG ODN decreased I-A(beta)(k) mRNA in DCs. In contrast, RNase(42-56):I-A(k) complexes were generated via a different processing mechanism that involved recycling MHC-II and was partially resistant to BFA. Processing of RNase(42-56):I-A(k) persisted, although at reduced levels, after CpG-induced maturation of DCs, and this residual processing by mature DCs was completely resistant to BFA. Changes in endocytosis, which was transiently enhanced and subsequently suppressed by CpG ODN, may affect Ag processing by both nascent and recycling MHC-II mechanisms. In summary, CpG ODN induce DC maturation, transiently increase Ag processing, and increase the half-life of peptide-MHC-II complexes to sustain subsequent presentation. Processing mechanisms that require nascent MHC-II are subsequently lost, but those that use recycling MHC-II persist even in fully mature DCs.
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PMID:CpG DNA induces maturation of dendritic cells with distinct effects on nascent and recycling MHC-II antigen-processing mechanisms. 1112 Aug 13

Immune cells in the milk are most important in combating pathogens that invade the mammary gland. This study investigated the immune competence and viability of somatic milk cells that are already resident in milk and udders free of infection. Cells were studied in freshly removed milk to simulate conditions in the udder. Effects of incubation, cell preparation, and immunological stimulation with 0.5 mug/ml lipopolysaccharide (LPS) from Escherichia coli were analysed. Viability and differential counts of milk cells between high and low somatic cell count (SCC) quarters, and cisternal and alveolar milk with and without LPS stimulation were compared. Incubation and preparation of cells caused a cell loss which further increased with time independently of SCC and milk fraction. The viability of these cells was stable until 3 h post incubation and decreased until 6 h. Cell populations differed between both investigations, but did not change during the course of the experiment. mRNA expression of immune and apoptosis factors of the cells, measured by qPCR, did not change substantially: mRNA expression of caspase 3, Toll like receptor 4, and GM-CSF did not change, whereas the expression of the death receptor Fas/APO-1 (CD95), lactoferrin and lysozyme was decreased at 6 h. Cyclooxygenase-2 and TNF-alpha mRNA expression were decreased after 6 h of LPS treatment. In comparison with other studies in vivo or in vitro (in cell culture), in this study where cells are studied ex vivo (removed from the udder but kept in their natural environment, the milk) resident milk cells seem to be more vulnerable, less viable, less able to respond to stimulation, and thus less immune competent compared with cells that have freshly migrated from blood into milk after pathogen stimulation. The cell viability and differential cell count differed between high- and low-SCC milk and between cisternal and alveolar milk depending on the individual cow. In conclusion, the results support the view that for a most effective defence against invading pathogens the mammary gland is reliant on the recruitment of fresh immune cells from the blood.
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PMID:Cell population, viability, and some key immunomodulatory molecules in different milk somatic cell samples in dairy cows. 1944 29


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