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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously shown the development in vitro of tryptase+ human mast cells from fetal liver cells cocultured with murine 3T3 fibroblasts. In this study, recombinant human stem cell factor (rhuSCF), the ligand for the c-kit proto-oncogene product called Kit, stimulated the growth and differentiation primarily of mast cells from dispersed fetal liver cells, whereas recombinant human interleukin-3 (rhuIL-3) stimulated the differentiation of basophils along with other cell types. Cultures of fetal liver cells were initiated and maintained in the presence of rhuSCF or rhuIL-3 for up to 6 weeks. Metachromatic cells in cytospins were identified as mast cells primarily on the basis of tryptase expression, and as MCT or MCTC by immunohistochemistry using monoclonal antibodies against tryptase and chymase, whereas basophils were metachromatic, polymorphonuclear, and lacked these proteases. Levels of tryptase and histamine were measured by radioimmunoassay, tryptase and chymase activities by peptide hydrolysis, and cell surface Kit by flow cytometry with the monoclonal antibody YB5.B8. The predominant presence of mast cells occurred only in the cultures supplemented with rhuSCF. The percentage and total number of mast cells increased over time with increasing concentrations of rhuSCF and reached a plateau at 55 ng/mL. At this concentration of rhuSCF, mast cells first appeared by day 7; by day 42, 106% of the starting number of cells were present and 85% of these were tryptase+, 31% being weakly chymase+. These mast cells appeared immature by ultrastructural criteria; most cells were mononuclear, but some had nuclei with deeply divided lobes. DNA synthesis in tryptase+ mast cells at days 21 and 28 of culture with rhuSCF was demonstrated by incorporation of bromodeoxyuridine. Calculated levels of histamine (1.2 pg/mast cell) and tryptase (0.9 pg/mast cell) were similar to those determined previously in coculture experiments with murine 3T3 fibroblasts. Chymase activity was undetectable in most cell extracts. On day 0, 4% to 20% of fetal liver cells expressed cell surface Kit. In the presence of rhuSCF, the percentages and total numbers of Kit+ cells and the apparent concentration of Kit per cell increased along with the number of tryptase+ cells. In the presence of rhuIL-3, toluidine blue+, tryptase- cells first and maximally appeared at day 14 (11% +/- 2.5%). The percentage of these toluidine blue+ cells then declined to about 6% by days 21 and 35, while the total number of positive cells declined over 10-fold. Kit+ cells in the presence of rhuIL-3 declined from 9% on day 3 to 2% on day 35.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Recombinant human stem cell factor stimulates differentiation of mast cells from dispersed human fetal liver cells. 128 84

Cocultures of dispersed human fetal liver cells with murine Swiss 3T3 fibroblasts resulted in the development of human mast cells after 1 to 4 weeks of culture. Mast cells were detected by immunohistochemistry using a murine monoclonal anti-tryptase antibody, before metachromasia appeared with toluidine blue. When subjected to double immunohistochemistry using murine monoclonal anti-chymase and anti-tryptase antibodies, 94% +/- 10% (SD) of the mast cells seen at day 30 of culture were of the MCT type. These results contrast with those obtained with human mast cells derived from cord blood mononuclear cells cocultured with murine 3T3 fibroblasts which are comprised of substantially greater numbers of MCTC cells, averaging 48% +/- 31% (SD) at day 30 of culture. Mast cells developed in vitro from fetal liver cells or cord blood mononuclear cells contained similar amounts (+/- SD) of histamine (0.9 +/- 0.5 pg/cell and 1.1 +/- 1 pg/cell, respectively) and tryptase (1.7 +/- 0.4 pg/cell and 1.9 +/- 1.2 pg/cell, respectively) on day 30 of culture. Fetal-liver-derived mast cells from a 30-day-old culture were identified by immunoelectron microscopy using gold-labelled antitryptase antibody. Typically, these mast cells appeared immature as they had large nuclear to cytoplasmic ratio and a small number of ill-formed cytoplasmic granules. For both fetal-liver- and cord-blood-derived mast cells, there was no evidence of conversion of the MCT type into the MCTC type provided by this study. These results suggest that commitment to develop as an MCT or MCTC type of mast cell may have occurred in mast cell precursors present in fetal liver and cord blood mononuclear cells, prior to granulation.
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PMID:Characterization of human mast cells developed in vitro from fetal liver cells cocultured with murine 3T3 fibroblasts. 139 60

The immunohistology of the nasal mucosa was examined in 13 grass pollen-sensitive patients and in seven normal nonatopic control subjects before and during the pollen season. Cryostat sections (6 microns) of biopsy specimens from the inferior turbinate were immunostained with the alkaline-phosphatase antialkaline-phosphatase method and a panel of monoclonal antibodies. Mast cell subtypes were measured with a double sequential immunostaining method. Within the submucosa, seasonal increases in total (MBP+, p less than 0.01) and "activated" (EG2+, p less than 0.01) eosinophils were observed for the patients, which were significant when these counts were compared with counts for those of control subjects (MBP+ p less than 0.01; EG2+ p less than 0.001). Within the nasal epithelium, seasonal increases in total (p less than 0.05) and "activated" (p less than 0.02) eosinophils were also observed. Mast cell counts revealed seasonal increases in tryptase-only positive mast cell (MCT) (p less than 0.02) but not chymase plus tryptase-positive mast cells (MCTC) within the epithelium that were significant when counts were compared with those of control subjects (p less than 0.03). No significant changes were observed within the submucosa or epithelium for total leukocytes (CD45+ cells) or T-lymphocytes (CD3+, CD4+, CD8+, and CD 25+ cells) for either group. Similarly, no significant changes were observed for neutrophils (antielastase), macrophages (CD68+), nor HLA-DR+ cells. In the subjects with rhinitis, seasonal submucosal CD3+ counts correlated with MBP+ eosinophils (r = 0.56; p less than 0.05) and MCTS (r = 0.65; p less than 0.02). Similarly, seasonal epithelial EG2+ eosinophil counts correlated with MCTs (r = 0.56; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunohistology of the nasal mucosa in seasonal allergic rhinitis: increases in activated eosinophils and epithelial mast cells. 153 8

Human mast cells can be divided into two subsets based on serine proteinase composition: a subset that contains the serine proteinases tryptase and chymase (MCTC), and a subset that contains only tryptase (MCT). In this study we examined both types of mast cells for two additional proteinases, cathepsin G and elastase, which are the major serine proteinases of neutrophils. Because human mast cell chymase and cathepsin G are both chymotrypsin-like proteinases, the properties of these enzymes were further defined to confirm their distinctiveness. Comparison of their N-terminal sequences showed 30% nonidentity over the first 35 amino acids, and comparison of their amino acid compositions demonstrated a marked difference in their Arg/Lys ratios, which was approximately 1 for chymase and 10 for cathepsin G. Endoglycosidase F treatment increased the electrophoretic mobility of chymase on SDS gels, indicating significant N-linked carbohydrate on chymase; no effect was observed on cathepsin G. Immunoprecipitation and immunoblotting with specific antisera to each proteinase revealed little, if any, detectable cross-reactivity. Immunocytochemical studies showed selective labelling of MCTC type mast cells by cathepsin G antiserum in sections of human skin, lung, and bowel. No labeling of mast cells by elastase antiserum was detected in the same tissues, or in dispersed mast cells from lung and skin. A protein cross-reactive with cathepsin G was identified in extracts of human skin mast cells by immunoblot analysis. This protein had a slightly higher Mr (30,000) than the predominant form of neutrophil cathepsin G (Mr 28,000), and could not be separated from chymase (Mr 30,000) by SDS gel electrophoresis because of the size similarity. Using casein, a protein substrate hydrolyzed at comparable rates by chymase and cathepsin G, it was shown that about 30% of the caseinolytic activity in mast cell extracts was sensitive to inhibitors of cathepsin G that had no effect on chymase. Hydrolytic activity characteristic of elastase was not detected in these extracts. These studies indicate that human MCTC mast cells may contain two different chymotrypsin-like proteinases: chymase and a proteinase more closely related to cathepsin G, both of which are undetectable in MCT mast cells. Neutrophil elastase, on the other hand, was not detected in human mast cells by our procedures.
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PMID:Identification of a cathepsin G-like proteinase in the MCTC type of human mast cell. 221 56

Two types of mast cells were previously defined based on neutral protease composition and ultrastructurally distinguished by granule morphology. The MCT cell contains tryptase with little, if any, chymase and was noted to have varying numbers of irregularly-shaped granules with discrete scrolls or particulate or beaded material. The MCTC cell contains both tryptase and chymase and was noted to have more regularly-shaped electron-dense granules with characteristic grating or lattice substructures. This study reports the use of electron microscopy and immunogold staining with antibodies against tryptase and chymase to demonstrate in mature unstimulated MCTC cells in situ, the focal occurrence of discrete or complete scrolls in peripheral regions of certain granules where chymase is deficient. these scrolls often appeared to be protruding from the granule. Granules containing discrete scrolls were observed in 10 of 340 mature MCTC cells, accounting for less than 1% of MCTC granules. Other granules in such cells as well as other regions of the granule under consideration, showed strong staining for both tryptase and chymase. These results strengthen the association of morphology with protease composition in human mast cell secretory granules, but weaken the use of morphology alone to identify the MCTC and MCT types of human mast cells. Whether the uncommon occurrence of focal absence of chymase in MCTC cells arises by chance or as a result of factors relating to mast cell development, interconversion, activation, or regranulation will require further clarification. In conclusion, the appearance of grating or lattice structures in mast cells indicates the presence of chymase and tryptase, characteristic of the MCTC phenotype, whereas multiple discrete scrolls in irregularly shaped granules suggests the MCT phenotype.
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PMID:Human MCTC type of mast cell granule: the uncommon occurrence of discrete scrolls associated with focal absence of chymase. 223 9

Lesional (n = 15) and non-lesional (n = 10) skin of subjects with mastocytosis was analysed for the distribution and concentration of trypase positive, chymase negative mast cells (MCT) and tryptase positive, chymase positive mast cells (MCTC) cells and compared to normal skin (n = 23) and non-lesional skin of subjects with unexplained anaphylaxis or flushing episodes (n = 6). Skin biopsies were fixed in Carnoy's fluid and subjected to double immunohistochemical staining with biotinylated mouse monoclonal anti-chymase antibody followed by alkaline phosphatase-conjugated mouse monoclonal anti-tryptase antibody. MCTC cells were the only type of mast cells seen in all specimens analysed and in each case were more numerous in superficial compared to deep regions of dermis. The concentration (mean +/- s.d.) of mast cells in the superficial dermis of mastocytosis lesions (40 985 +/- 21 772 mast cells/mm3) was significantly increased over that in corresponding areas of non-lesional skin from subjects with mastocytosis (7178 +/- 3607 mast cells/mm3), skin from subjects with idiopathic anaphylaxis or flushing episodes (6974 +/- 3873 mast cells/mm3) and normal skin (7347 +/- 2973 mast cells/mm3). The exclusive presence of MCTC cells in skin lesions of mastocytosis which are characterized by non-malignant hyperplasia of mast cells suggests involvement of local tissue factors in mast cell recruitment and differentiation.
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PMID:Mast cells in cutaneous mastocytosis: accumulation of the MCTC type. 231 Sep 82

In order to gain insights into the dynamics of mast cell subpopulations in normal and diseased skin, a novel enzyme-histochemical double and triple staining method was employed that allowed the detection of metachromasia (toluidine blue) and the mast cell proteases tryptase and chymase within the same cell. Cryostat sections were used of skin biopsies from the following specimens: normal skin (N = 4), psoriasis (N = 13), atopic eczema (N = 7), lichen planus (N = 6), interferon alpha 2a injection sites (N = 1) of a leukemic infiltrate and corresponding normal skin of the same patient before and after treatment. (i) Equal numbers of tryptase- and chymase-positive mast cells (MCTC) were obtained in all normal and diseased specimens in papillary and reticular dermis, with threefold increases around appendages. (ii) Tryptase-positive mast cells (MCT) were absent in normal skin, but were markedly increased in a disease-specific pattern within the papillary dermis, the inflammatory infiltrate and around appendages. (iii) Marked increases of MCT were also noted at interferon injection sites within the leukemic infiltrate, but not in the normal skin of the same patient. These data suggest that disease-dependent mast cell dynamics involve only MCT in cutaneous inflammation and that MCT numbers are controlled by distinct, disease-specific local tissue factors.
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PMID:Analysis of mast cell subpopulations (MCT, MCTC) in cutaneous inflammation using novel enzyme-histochemical staining techniques. 753 9

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

Mast cell neutral proteases are the most precise markers of heterogeneity among human mast cells. Two types of human mast cells have been recognized. MCTC cells contain tryptase together with chymase, cathepsin-G like protease, and mast cell carboxypeptidase; MCT cells contain tryptase, but lack the other neutral proteases present in MCTC cells. All mast cells develop from hemopoietic stem cells. In vitro procedures for studying mast cell growth have been developed, using the major human mast cell growth factor, stem cell factor (SCF, also called Kit-ligand). Cultures of hemopoietic progenitor cells in the presence of SCF alone result in selective differentiation to mast cells. The same progenitor cells can be induced to differentiate into other lineages when SCF is used with various lineage-specific colony-stimulating factors such as erythropoietin for erythrocytes. Mast cell development from hematopoietic progenitors may represent a "default pathway," occurring optimally in a permissive microenvironment such as skin, bowel, and lung. The presence or absence of certain cytokines in blood and bone marrow may create a non-permissive environment, thus the absence of granulated mast cells in such locations.
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PMID:Human mast cell heterogeneity. 772 Oct 78

Competitive reverse transcription-PCR assays developed for human tryptase, chymase, Fc epsilon RI alpha, and Fc epsilon RI gamma mRNA molecules were applied to the HMC-1 leukemic mast cell line, the KU812 leukemic basophil cell line, mast cells dispersed from lung and skin, and peripheral blood basophils. Relative amounts of alpha-tryptase and beta-tryptase mRNA were determined by analysis of BseAI digests of PCR products. Tryptase expression was highest in tissue-derived mast cells, lowest in basophils and KU812 cells, and intermediate in HMC-1 cells. beta-Tryptase mRNA predominated in HMC-1 and KU812 cells; mixtures of alpha- and beta-tryptase were found in tissue mast cells; and alpha-tryptase predominated in basophils. Chymase mRNA was more abundant in skin-derived (nearly all of the MCTC type) than lung-derived (variable amounts of MCTC and MCT cells) mast cells. Small amounts of chymase mRNA were detected in HMC-1 cells; none was found in basophils, in KU812 cells, or in the one preparation of 100% MCT cells derived from lung. Comparable amounts of Fc epsilon RI alpha and Fc epsilon RI gamma mRNA molecules were measured in basophils and tissue-derived mast cells, lesser amounts were detected in KU812 cells, and almost none was detected in HMC-1 cells. Thus, steady state levels of the granule and membrane resident molecules examined in our study are transcriptionally regulated in mast cells and basophils.
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PMID:Quantitation of tryptase, chymase, Fc epsilon RI alpha, and Fc epsilon RI gamma mRNAs in human mast cells and basophils by competitive reverse transcription-polymerase chain reaction. 773 Jun 49


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