Gram-positive and Gram-negative bacteria induce different cytokines from human peripheral blood mononuclear cells irrespective of taxonomic relatedness

Abstract number: p1182

Johansson  S., Bigsten  A., Hessle  C., Wold  A.


Upon bacterial stimulation tissue macrophages produce a variety of cytokines that orchestrate the immune response necessary to clear the infection. Earlier studies have shown that Gram-positive bacteria induce higher levels of IL-12, IFN-gamma and TNF from human peripheral blood mononuclear cells (PBMC) than Gram-negative bacteria, whereas Gram-negatives induce much more IL-6, IL-8 and IL-10 than Gram-positives. The aim of this study was to examine if this dichotomy is true for Gram-positive and Gram-negative bacteria irrespective of their position in the taxonomical system, and to relate cytokine production to phagocytosis.


PBMCs from healthy blood donors were incubated with 37 species of UV-inactivated Gram-positive and Gram-negative bacteria well spread in the taxonomical system. IL-12, TNF, IL-1beta, IL-6 IL-8 and IL-10 were measured in the supernatants after 24 h and IFN-gamma after 5 d with ELISA. Phagocytosis was studied in cytospin preparations after 30 min incubation.


Irrespective of their position in the phylogenetic tree, Gram-positive bacteria induced more IL-12, IFN-gamma and TNF than Gram-negatives, while Gram-negative bacteria were more potent stimulators of IL-6, IL-8 and IL-10 than Gram-positives. IL-1beta was induced in equal amounts from Gram-positive and Gram-negative bacteria. Production of IFN-gamma and TNF were strongly correlated, as were IL-6 and IL-8, and IL-6 and IL-10. There was no difference between Gram-positive and Gram-negative bacteria in the degree of phagocytosis. Nor were there any correlations between cytokine production and bacteria phagocytosed.


The results confirm that Gram-positive and Gram-negative bacteria trigger different cytokine patterns in human monocytes, irrespective of their genetic relatedness. Differences in composition of the bacterial wall are likely to account for these differences.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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