Study of interleukin-10 and interleukin-12 productions in response to lipopolysaccharides extracted from two different Brucella strains.

The aim of the present study is to investigate the cytokines induction by smooth lipopolysaccharides (S-LPS) extracted from Brucella melitensis (Rev1 vaccine strain) and Brucella abortus (a field isolate). These lipopolysaccharides were used to induce inflammatory cytokines production in peripheral blood cell culture of healthy individuals. Secretion of IL-10 and IL-12 (p70) were measured by means of specific Elisa. In addition, intracellular expression of IL-12 was assessed in CD14+ cells by flow cytometry. It was shown that Brucella LPS is a potent inducer of IL-10. However interferon gamma (IFN-gamma) priming was able to significantly decrease the production of IL-10. Flow cytometry studies showed that LPS alone was not able to induce intracellular IL-12 expression in CD14+ cells. Nevertheless, IFN-gamma priming significantly increased the percentage of CD14+ IL-12+ cells. In conclusion, it was demonstrated that the Brucella LPS could be a potent inducer of IL-10 and induction of IL-12 production needs the most favorable conditions.