scholarly journals Characteristics of lipopolysaccharide interaction with human peripheral-blood monocytes

1985 ◽  
Vol 232 (2) ◽  
pp. 379-383 ◽  
Author(s):  
S J Warner ◽  
N Savage ◽  
D Mitchell

The interaction between radioiodinated lipopolysaccharide from Escherichia coli 0111:B4 (125I-LPS) and human peripheral-blood monocytes was studied. The association of 125I-LPS with monocytes at 37 degrees C appeared to depend on binding to the cell membrane with subsequent internalization of the molecule, and was not saturable with time (up to 2 h) or 125I-LPS concentration (up to 10 micrograms/ml). There was no apparent difference in the behaviour of unlabelled LPS and 125I-LPS with respect to monocyte association. 125I-LPS association with monocytes was inhibited by LPS and O-polysaccharide from E. coli 0111:B4 and Salmonella typhi 0901, but not by lipid A or polymyxin B. We propose that the mechanism of human monocyte stimulation by LPS involves polysaccharide-dependent binding to the cell membrane followed by internalization of the LPS molecule. We were unable to demonstrate a specific LPS receptor such as that found on murine B-lymphocytes.

1982 ◽  
Vol 156 (6) ◽  
pp. 1794-1806 ◽  
Author(s):  
C L Anderson

The Fc receptors for IgG from a human monocyte line (U937) and from highly purified human peripheral blood monocytes were solubilized, purified, and partially characterized. Both sources of cells gave indistinguishable results. Two molecules (or sets of molecules), one of about 72,000 mol wt and the other of 40,000-43,000 mol wt were discerned on autoradiograms of sodium dodecyl sulfate (SDS)-polyacrylamide gels analyzing acid eluates from Sepharose-IgG columns over which detergent lysates of radioiodinated cells had been passed. The larger of the two molecules, p72, accounted for greater than or equal to 90% of the radioactivity. This component was noted to be heterodisperse both by size on SDS gels and by charge on isoelectric focusing gels. The charge heterogeneity, being virtually eliminated by neuraminidase and tunicamycin, was probably due to variable glycosylation. Several lines of evidence indicated that p72 is probably all or part of the Fc receptor: (a) radiolabeling of this molecule using chloroglycouril was blocked by IgG of the Fc receptor; (b) in soluble form this molecule expressed ligand specificity identical to the in situ receptor; (c) the molecule was not recovered from affinity adsorbants bearing proteins that do not bind to the Fc receptors, nor (d) from a human T cell line that does not bear Fc receptors. The smaller of the two molecules isolated, p40-43, is at least in part actin. Its relationship to p72 is not understood.


Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 579-582
Author(s):  
LJ Weisberg ◽  
DT Shiu ◽  
PR Conkling ◽  
MA Shuman

Factor XIII is the fibrin-stabilizing factor that covalently cross- links fibrin monomers to form a highly organized, stable fibrin clot. The plasma form of factor XIII is a heterodimer, a2b2, consisting of two a-chains and two b-chains; the intracellular form, such as in platelets and placenta, is a dimer, a2, consisting of a-chains only. The catalytic function of factor XIII, a transglutaminase, resides in the a-chain. To address questions regarding sites of synthesis of factor XIII a-chain, an EcoRI restriction fragment from the protein- coding region of the factor XIII a-chain cDNA was used as a probe for Northern blot analysis. The cDNA probe showed hybridization with a single approximately 4.0-kilobase (kb) message in poly (A)+ mRNA prepared from normal human peripheral blood monocytes and normal human liver. The results demonstrate conclusively that factor XIII a-chains are actively synthesized in circulating monocytes and in liver. To our knowledge, these data represent the first demonstration of synthesis of any blood coagulation factor in primary uncultured and unstimulated monocytes or macrophage cells.


Critical Care ◽  
10.1186/cc29 ◽  
1997 ◽  
Vol 1 (Suppl 1) ◽  
pp. P023
Author(s):  
M Gerlach ◽  
D Keh ◽  
S Spielmann ◽  
T Kerner ◽  
R Peter ◽  
...  

1996 ◽  
Vol 316 (2) ◽  
pp. 593-597 ◽  
Author(s):  
Nicolas J. GOULDING ◽  
L PAN ◽  
Kathleen WARDWELL ◽  
Veronica C. GUYRE ◽  
Paul M. GUYRE

Recombinant human annexin I and a monoclonal antibody specific for this protein (mAb 1B) were used to investigate surface binding of this member of the annexin family of proteins to peripheral blood monocytes. Flow cytometric analysis demonstrated trypsin-sensitive, saturable binding of annexin I to human peripheral blood monocytes but not to admixed lymphocytes. A monoclonal antibody that blocks the anti-phospholipase activity of annexin I also blocked its binding to monocytes. These findings suggest the presence of specific binding sites on monocytes. Furthermore, surface iodination, immunoprecipitation and SDS/PAGE analysis were used to identify two annexin I-binding proteins on the surface of monocytes with molecular masses of 15 kDa and 18 kDa respectively. The identification and characterization of these annexin I-binding molecules should help us to better understand the specific interactions of annexin I with monocytes that lead to down-regulation of pro-inflammatory cell functions.


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