Search results for "Membrane glycoprotein"
showing 10 items of 312 documents
Purification and characterisation of a plasmin-sensitive surface protein of Staphylococcus aureus.
1996
Certain methicillin-resistant Staphylococcus aureus strains contain a 230-kDa cell-wall protein which is not present on the surface of other staphylococci. The presence of this 230-kDa protein is associated with a negative test result in commercial assays designed to detect fibrinogen-binding proteins and/or protein A on the staphylococcal surface. We have purified and partially characterised the 230-kDa protein from a lysostaphin digest of a non-agglutinating methicillin-resistant S. aureus strain. Partial amino acid sequence data obtained from the purified protein did not reveal any significant similarities to known proteins which indicates that the protein is novel. The 230-kDa protein w…
Characterisation of serotonin transport mechanisms in rainbow trout peripheral blood lymphocytes: role in PHA-induced lymphoproliferation
1999
Abstract AbstractIn this study we investigated the serotonin transport mechanisms in rainbow trout (Oncorhynchus mykiss) peripheral blood lymphocytes We have observed that the transport of serotonin is a membrane transport process that have the properties of a secondary active transport system The binding isotherm of [3H]-paroxetine a serotonin transport blocker demonstrated a high-affinity binding site with a positive type of cooperativity Hill coefficient being higher than unity Known specific inhibitors of the mammalian serotonin transporter significantly inhibited the uptake process in fish lymphocytes In order to demonstrate the physiological relevance of the serotonin transporter in T…
Technical advance: Soluble OX40 molecule mimics regulatory T cell modulatory activity on FCεRI-dependent mast cell degranulation
2011
ABSTRACT Tregs play a central role in modulating FcɛRI-dependent MC effector functions in the course of the allergic response. Cellular interaction depends on the constitutive expression of OX40 on Tregs and the OX40L counterpart on MCs. Study of OX40L signaling on MCs is hampered by the need of a highly purified molecule, which triggers OX40L specifically. We now report that sOX40 mimics the physiological activity of Treg interaction by binding to activated MCs. When treated with sOX40, activated MCs showed decreased degranulation and Ca++ influx, whereas PLC-γ2 phosphorylation remained unaffected. Once injected into experimental animals, sOX40 not only located within the endothelium but a…
Dosage-dependent roles of the Cwt1 transcription factor for cell wall architecture, morphogenesis, drug sensitivity and virulence in Candida albicans.
2009
The Cwt1 transcription factor is involved in cell wall architecture of the human fungal pathogen Candida albicans. We demonstrate here that deficiency of Cwt1 leads to decreased β1,6-glucan in the cell wall, while mannoproteins are increased in the cell wall of exponentially growing cells and are released into the medium of stationary phase cells. Hyphal morphogenesis of cwt1 mutants is reduced on the surfaces of some inducing media. Unexpectedly, the CWT1/cwt1 heterozygous strains shows some stronger in vitro phenotypes compared to the homozygous mutant. The heterozygous but not the homozygous strain is also strongly impaired for its virulence in a mouse model of systemic infection. We sug…
Incorporation of mannoproteins into the walls of aculeacin A-treated yeast cells
1986
Inhibition of the synthesis of alkali-insoluble glucan by aculeacin A in Saccharomyces cerevisiae cells caused a decrease in the incorporation of a high molecular weight heterogeneous mannoprotein material and of a 33,000 mannoprotein into the wall network. This was concomitant with the excretion of the latter molecule into the growth medium. Regenerating yeast protoplasts liberated considerable amounts of the heterogeneous material to the medium independently of the presence of aculeacin. The protoplast walls did lack this component and contained only minor amounts of the 33,000 molecule, which was also completely absent from walls of aculeacin-treated protoplasts. Considerable levels of t…
A role for the MAP kinase gene MKC1 in cell wall construction and morphological transitions in Candida albicans.
1998
The Candida albicans MKC1 gene encodes a mitogen-activated protein (MAP) kinase, which has been cloned by complementation of the lytic phenotype associated with Saccharomyces cerevisiae slt2 (mpk1) mutants. In this work, the physiological role of this MAP kinase in the pathogenic fungus C. albicans was characterized and a role for MKC1 in the biogenesis of the cell wall suggested based on the following criteria. First, C. albicans mkc1Δ/mkc1Δ strains displayed alterations in their cell surfaces under specific conditions as evidenced by scanning electron microscopy. Second, an increase in specific cell wall epitopes (O-glycosylated mannoprotein) was shown by confocal microscopy in mkc1Δ/mkc1…
Identification of epitopes of Mycobacterium tuberculosis 16-kDa protein recognized by human leukocyte antigen-A*0201 CD8(+) T lymphocytes.
2002
CD8(+) T cells could make an important contribution to protection against tuberculosis (TB), but the antigenic determinants recognized in the context of major histocompatibility complex class I molecules remain ill defined. Our aim was to identify nonamer peptides derived from the acr/16-kDa antigen. Two immunogenic peptides (p21-29 and p120-128) were identified by their ability to elicit cytotoxic CD8(+) T cells from juvenile patients recovering from TB. Epitope-specific recognition was demonstrated by the lysis of both Mycobacterium tuberculosis-infected and peptide-pulsed macrophages, the release of cytotoxic granules, and interferon-gamma and tumor necrosis factor-alpha production. CD8(…
Gamma delta T cells inhibit in vitro growth of the asexual blood stages of Plasmodium falciparum by a granule exocytosis-dependent cytotoxic pathway …
2004
Several reports have stated the ability of gamma delta T cells to inhibit the growth of the asexual blood stages of Plasmodium falciparum in vitro. However, little information is available about the mechanisms involved. In this study, in vitro systems were used to study the role of the granule exocytosis-dependent cytotoxic pathway in the growth inhibition/killing of P. falciparum by human gamma delta T cells. Our results show that the inhibition requires cell-to-cell contact and that gamma delta T cells kill the asexual blood stages of P. falciparum through a granule exocytosis-dependent cytotoxic pathway after recognition of certain ligands or molecules expressed on the surface of infecte…
Stimulator cell-dependent requirement for CD2- and LFA-1-mediated adhesions in T lymphocyte activation by superantigenic toxins.
1992
Abstract The staphylococcal enterotoxins and related microbial T cell mitogens stimulate T cells by cross-linking variable parts of the T cell receptor (TCR) with MHC class II molecules on accessory or target cells. We have used cloned human T cells and defined tumor cells as accessory cells (AC) to study the requirements for T cell activation by these toxins. On AC expressing high levels of CD54 (intercellular adhesion molecule-1, ICAM-1) and CD58 (lymphocyte function-associated antigen-3, LFA-3), mAb to CD2 were relatively ineffective in inhibiting the response to the toxins and antibodies to the lymphocyte function-associated antigen-1 (LFA-1) did not inhibit at all. If added together, h…
Identification of a mannoprotein present in the inner layer of the cell wall of Saccharomyces cerevisiae.
1997
Cell wall extracts from the double-mutant mnn1 mnn9 strain were used as the immunogen to obtain a monoclonal antibody (MAb), SAC A6, that recognizes a specific mannoprotein--which we have named Icwp--in the walls of cells of Saccharomyces cerevisiae. Icwp runs as a polydisperse band of over 180 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of Zymolyase extracts of cell walls, although an analysis of the secretory pattern of the mannoprotein shows that at the level of secretory vesicles, it behaves like a discrete band of 140 kDa. Immunofluorescence analysis with the MAb showed that Icwp lies at the inner layer of the cell wall, being accessible to the antibody on…