Mechanism(s) of in vitro macrophage activation with Nocardia rubra cell wall skeleton: the effects on macrophage activating factor production by lymphocytes

1986 ◽  
Vol 22 (2) ◽  
Author(s):  
Tomiya Masuno ◽  
Seiji Hayashi ◽  
Masami Ito ◽  
Toshiyuki Ikeda ◽  
Takeshi Ogura ◽  
...  
Keyword(s):  
Cell Wall ◽  
Macrophage Activation ◽  
Factor Production

scholarly journals TREM2 is a receptor for non-glycosylated mycolic acids of mycobacteria that limits anti-mycobacterial macrophage activation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ei’ichi Iizasa ◽  
Yasushi Chuma ◽  
Takayuki Uematsu ◽  
Mio Kubota ◽  
Hiroaki Kawaguchi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Macrophage Activation ◽  
Mycolic Acid ◽  
Dependent Manner ◽  
Independent Manner ◽  
Lectin Receptors ◽  
Mycobacterial Cell ◽  
Mycobacterial Cell Wall

AbstractMycobacterial cell-wall glycolipids elicit an anti-mycobacterial immune response via FcRγ-associated C-type lectin receptors, including Mincle, and caspase-recruitment domain family member 9 (CARD9). Additionally, mycobacteria harbor immuno-evasive cell-wall lipids associated with virulence and latency; however, a mechanism of action is unclear. Here, we show that the DAP12-associated triggering receptor expressed on myeloid cells 2 (TREM2) recognizes mycobacterial cell-wall mycolic acid (MA)-containing lipids and suggest a mechanism by which mycobacteria control host immunity via TREM2. Macrophages respond to glycosylated MA-containing lipids in a Mincle/FcRγ/CARD9-dependent manner to produce inflammatory cytokines and recruit inducible nitric oxide synthase (iNOS)-positive mycobactericidal macrophages. Conversely, macrophages respond to non-glycosylated MAs in a TREM2/DAP12-dependent but CARD9-independent manner to recruit iNOS-negative mycobacterium-permissive macrophages. Furthermore, TREM2 deletion enhances Mincle-induced macrophage activation in vitro and inflammation in vivo and accelerates the elimination of mycobacterial infection, suggesting that TREM2-DAP12 signaling counteracts Mincle-FcRγ-CARD9-mediated anti-mycobacterial immunity. Mycobacteria, therefore, harness TREM2 for immune evasion.

scholarly journals Structural Properties and Macrophage Activation of Cell Wall Polysaccharides from the Fruiting Bodies of Hericium erinaceus

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 850
Author(s):  
Di Wu ◽  
Shan Yang ◽  
Chuan Tang ◽  
Yanfang Liu ◽  
Qiaozhen Li ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Properties ◽  
Fruiting Body ◽  
Macrophage Activation ◽  
Water Soluble ◽  
Fruiting Bodies ◽  
Cell Wall Polysaccharides ◽  
Hericium Erinaceus ◽  
Soluble Cell

In this study, water-soluble and alkali-soluble cell wall polysaccharides were obtained from fruiting body extracted residual micropowders of Hericium erinaceus, harvested at seven different growing stages. The structural properties and in vitro immunity activities of cell wall polysaccharides extracted successively by hot water and sodium hydroxide solution were studied, and the results indicated that the yield and content of polysaccharides increased during the reproductive growth stage and decreased with the maturity of the fruiting body. Water-soluble cell wall polysaccharides mainly composed of glucose and galactose at a molar ratio of 3.4–14:1.0, and also contained a small ratio of glucuronic acid. The alkali-soluble cell wall polysaccharides were glucans with lower molecular weight and higher macrophage activation activity in vitro than water-soluble ones. Our findings suggest that the growth stages (H4 and H5) are suitable for harvesting H. erinaceus fruiting bodies with higher cell wall polysaccharide yield and functional benefits.

scholarly journals Toll-Like Receptor 2 and Mincle Cooperatively Sense Corynebacterial Cell Wall Glycolipids

2017 ◽  
Vol 85 (7) ◽  
Author(s):  
Judith Schick ◽  
Philipp Etschel ◽  
Rebeca Bailo ◽  
Lisa Ott ◽  
Apoorva Bhatt ◽  
...  
Keyword(s):  
Cell Wall ◽  
Macrophage Activation ◽  
Invasive Disease ◽  
Mycolic Acid ◽  
Toll Like Receptor ◽  
Gamma Chain ◽  
Content Type ◽  
Lectin Receptor ◽  
Toll Like Receptor 2

ABSTRACT Nontoxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans cause invasive disease in humans and animals. Host sensing of corynebacteria is largely uncharacterized, albeit the recognition of lipoglycans by Toll-like receptor 2 (TLR2) appears to be important for macrophage activation by corynebacteria. The members of the order Corynebacterineae (e.g., mycobacteria, nocardia, and rhodococci) share a glycolipid-rich cell wall dominated by mycolic acids (termed corynomycolic acids in corynebacteria). The mycolic acid-containing cord factor of mycobacteria, trehalose dimycolate, activates the C-type lectin receptor (CLR) Mincle. Here, we show that glycolipid extracts from the cell walls of several pathogenic and nonpathogenic Corynebacterium strains directly bound to recombinant Mincle in vitro. Macrophages deficient in Mincle or its adapter protein Fc receptor gamma chain (FcRγ) produced severely reduced amounts of granulocyte colony-stimulating factor (G-CSF) and of nitric oxide (NO) upon challenge with corynebacterial glycolipids. Consistently, cell wall extracts of a particular C. diphtheriae strain (DSM43989) lacking mycolic acid esters neither bound Mincle nor activated macrophages. Furthermore, TLR2 but not TLR4 was critical for sensing of cell wall extracts and whole corynebacteria. The upregulation of Mincle expression upon encountering corynebacteria required TLR2. Thus, macrophage activation by the corynebacterial cell wall relies on TLR2-driven robust Mincle expression and the cooperative action of both receptors.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In vitro assembly of 2-D crystals from partially purified EA1 protein secreted by Bacillus anthracis strain Delta Sterne-1

1994 ◽  
Vol 52 ◽  
pp. 276-277
Author(s):  
Mary Beth Downs ◽  
Wilson Ribot ◽  
Joseph W. Farchaus
Keyword(s):  
Cell Wall ◽  
Molecular Sieves ◽  
Cell Envelope ◽  
Single Species ◽  
Supporting Cell ◽  
Surface Layers ◽  
Rabbit Igg ◽  
In Vitro Assembly ◽  
Covalently Linked

Many bacteria possess surface layers (S-layers) that consist of a two-dimensional protein lattice external to the cell envelope. These S-layer arrays are usually composed of a single species of protein or glycoprotein and are not covalently linked to the underlying cell wall. When removed from the cell, S-layer proteins often reassemble into a lattice identical to that found on the cell, even without supporting cell wall fragments. S-layers exist at the interface between the cell and its environment and probably serve as molecular sieves that exclude destructive macromolecules while allowing passage of small nutrients and secreted proteins. Some S-layers are refractory to ingestion by macrophages and, generally, bacteria are more virulent when S-layers are present.When grown in rich medium under aerobic conditions, B. anthracis strain Delta Sterne-1 secretes large amounts of a proteinaceous extractable antigen 1 (EA1) into the growth medium. Immunocytochemistry with rabbit polyclonal anti-EAl antibody made against the secreted protein and gold-conjugated goat anti-rabbit IgG showed that EAI was localized at the cell surface (fig 1), which suggests its role as an S-layer protein.

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