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Priming of human peripheral blood mononuclear cells with lipopolysaccharides for enhanced arachidonic acid release and leukotriene synthesis
Author(s) -
Surette Marc E.,
Nadeau Marie,
Borgeat Pierre,
Gosselin Jean
Publication year - 1996
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.59.5.709
Subject(s) - arachidonic acid , leukotriene b4 , peripheral blood mononuclear cell , leukotriene , cd14 , biology , priming (agriculture) , stimulation , monocyte , arachidonate 5 lipoxygenase , biochemistry , immunology , endocrinology , immune system , in vitro , enzyme , inflammation , botany , germination , asthma
In a previous study, we have shown that the ability of lipopolysaccharides (LPS) to prime isolated neutrophils for enhanced leukotriene B 4 (LTB 4 ) synthesis was dependent on the presence of plasma and involved the CD14 antigen. In the present study, we have investigated the priming of human peripheral blood mononuclear cells (PBMC) with LPS for the subsequent release and metabolism of arachidonic acid. When PBMC were incubated with LPS for up to 2 h or when freshly isolated PBMC were stimulated with N ‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) or with LPS alone, little or no synthesis of 5‐lipoxygenase products nor arachidonic acid liberation were detected. However, the preincubation of PBMC with IPS for as little as 5 min primed cells for the subsequent synthesis of LTB 4 upon stimulation with fMLP. Maximal priming was observed following a 15‐min preincubation period and the priming effect was transient as cells preincubated with IPS for 90 min or more were no longer primed for leukotriene synthesis. Monocytes were found to be responsible for the enhanced response to fMLP since purified lymphocytes did not produce LTB 4 nor LTC 4 in contrast to monocyte‐enriched suspensions. The priming for leukotriene synthesis coincided with an increased capacity for the release of free arachidonic acid as measured by mass spectrometry; IPS‐primed cells released 8–15 times more arachidonic acid than unprimed cells within 1 min of stimulation with fMLP. Pruning was observed with as little as 0.001‐0.01 μg LPS/mL when cells were incubated in the presence of 10% autologous plasma. Interestingly, in the absence of plasma, priming was only observed at IPS concentrations of 0.1 μg/mL or greater. Pretreatment of cells with anti‐CD14 antibodies significantly decreased the priming effect observed with 0.01 μg/mL IPS but did not affect pruning with 1 μg/mL IPS. These results indicate that the priming of human PBMC with IPS for the subsequent synthesis of arachidonic acid metabolites via the 5‐lipoxygenase pathway is dependent on plasma and CD14 at lower concentrations of IPS (0.001–0.01 μg/mL) but not at IPS concentrations of 0.1 μg/mL or greater.