The IgG Fc receptor, CD16, interacts with LPS and is internalized during the in vitro stimulation of human monocytes.

Chylomicron remnants (CMRs) contribute directly to human monocyte activationin vitro, by increasing reactive oxygen species (ROS) production and cell migration. In this study, the effects of the oxidative state of CMR on the degree of monocyte activation was investigated. CMR-like particles (CRLPs) were prepared in three different oxidative states, normal (CRLPs), protected from oxidation by incorporation of the antioxidant, probucol (pCRLPs), or oxidised with CuSO4(oxCRLPs). Lipid accumulation and ROS production were significantly increased in primary human monocytes incubated with CRLPs, whilst secretion on monocyte chemoattractant protein-1 was reduced, but oxCRLPs had no additional effect. In contrast, pCRLPs were taken up by monocytes to a lesser extent and had no significant effect on ROS or MCP-1 secretion. These studies suggest that the oxidative state of CMRs modulates their stimulation of the activation of peripheral blood human monocytes and that dietary antioxidants may provide some protection against these atherogenic effects.

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Decreased Fc-receptor binding in human monocytes exposed to ethanol in vitro

Alcohol ◽

10.1016/0741-8329(85)90108-9 ◽

1985 ◽

Vol 2 (3) ◽

pp. 425-428 ◽

Cited By ~ 10

Author(s):

Berit Mørland ◽

Magne K. Fagerhol ◽

Jørg Mørland

Keyword(s):

Receptor Binding ◽

Fc Receptor ◽

Human Monocytes

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Monocyte-platelet interaction in immune and nonimmune thrombocytopenia

Blood ◽

10.1182/blood.v74.4.1328.bloodjournal7441328 ◽

1989 ◽

Vol 74 (4) ◽

pp. 1328-1331

Author(s):

MN Saleh ◽

DL Moore ◽

JY Lee ◽

AF LoBuglio

Keyword(s):

Standard Therapy ◽

Immune Thrombocytopenia ◽

Fc Receptor ◽

Rosette Formation ◽

Receptor Interaction ◽

Human Monocytes ◽

Platelet Destruction ◽

Platelet Surface ◽

Refractory Itp

Platelets from 24 patients with immune thrombocytopenia resistant to standard therapy (refractory ITP), 35 patients with nonimmune thrombocytopenia (non-ITP), and 32 normal donors were studied in regard to platelet surface-bound IgG (PBIgG) and the ability of these platelets to be bound by human monocytes in vitro (monocyte-platelet rosette assay). Fourteen (58%) of the platelet samples from refractory ITP patients but none (0%) from the non-ITP or control donors had PBIgG greater than 800 molecules IgG/platelet. Seventeen of 24 (71%) of the ITP patients had platelets which demonstrated increased monocyte- platelet rosette formation [rosette index (RI) greater than 2], whereas only four (11%) of the non-ITP patients had such platelets. There was a direct correlation between PBIgG and rosette index for the platelets from resistant ITP patients. There was no correlation of severity of thrombocytopenia with PBIgG or rosette index. Monocyte-platelet interaction in the presence of elevated PBIgG is mediated through the monocyte Fc-receptor. Platelets from five of ten refractory ITP patients with PBIgG less than 800 molecules IgG/platelet had increased rosette formation. Monocyte-platelet interaction in the absence of increased PBIgG may be due to small amounts of platelet surface IgG which are still able to mediate monocyte Fc-receptor interaction or to alternate membrane receptor interaction through the monocyte C3 receptor. Our data underscore the pathophysiologic relevance of monocyte/macrophage-mediated interaction in immune platelet destruction syndromes.

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Inhibition of multiplication of Toxoplasma gondii by human monocytes exposed to T-lymphocyte products.

Journal of Experimental Medicine ◽

10.1084/jem.141.2.483 ◽

1975 ◽

Vol 141 (2) ◽

pp. 483-496 ◽

Cited By ~ 72

Author(s):

J S Borges ◽

W D Johnson

Keyword(s):

Toxoplasma Gondii ◽

T Lymphocyte ◽

Immune Cells ◽

Phase Contrast ◽

Parasite Growth ◽

Human Monocytes ◽

Immune Lymphocytes ◽

Contrast Microscopy ◽

Stimulation Of

The multiplication of Toxoplasma gondii was quantitated in human monocytes in vitro by phase-contrast microscopy. Toxoplasma multiplication was identical in monocytes from subjects byt was significantly inhibited in cells from both sources if the monocytes were preincubated with immune lymphocytes and toxoplasma monocytes were preincubated with immune lymphocytes and toxoplasma antigen. Supernates prepared from toxoplasma-immune lymphocytes incubated with toxoplasma antigen were also effective in inducing in monocytes the capacity to inhibit toxoplasma multiplication. Supernative acitivty was evident after lymphocytes and antigen were incubated for as little as 15 min. The instruction of monocytes was also repid and reversible. Monocytes were fully induced to inhibit toxoplasma multiplication after a 2 h exposure to an active supernate, but they lost their inhibitory capacity on culture in vitro for 48 h in the absece of immune cells or their products. The lymphocytes particupating in the monocyte induction were identified as t cells. The in vitro stimulation of monocytes appeared to exhibit some specificity, since no inhibition of toxopreotein derivative and lymphocytes from tuberculin-positive subjects, concanavalin a-stimulated lymphocytes, or their supermates. Supernates which induced monocytes to inhibit toxoplasma multiplication did not influence parasite growth in HeLa cells.

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Lectin Stimulation of Tissue Thromboplastin Activity in Human Monocytes in vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657060 ◽

1979 ◽

Vol 42 (05) ◽

pp. 1574-1579 ◽

Cited By ~ 4

Author(s):

T Lyberg ◽

H Prydz

Keyword(s):

Protein Synthesis ◽

Concanavalin A ◽

Wheat Germ ◽

Actinomycin D ◽

De Novo ◽

Human Monocytes ◽

Tissue Thromboplastin ◽

De Novo Protein Synthesis ◽

Stimulation Of

SummaryLectins (phytohaemagglutinin, concanavalin A and wheat germ agglutinin) trigger an increase in tissue thromboplastin activity of human monocytes in vitro. The presence of serum was not necessary and did not enhance the activity. The increase was inhibited by cycloheximide and actinomycin D, suggesting that de novo protein synthesis is involved.

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