engleski

The kinetics of IL-17 production in lungs and plasma of mice after intratracheal infection with Klebsiella pneumoniae

BACKGROUND: Interleukin-17 is a proinflammatory cytokine predominantly produced by the T cells, which is involved in the innate immune responses to various physiologic and pathophysiologic processes including bacterial host defence. The neutralisation experiments showed that the lack of IL-17 leads to decreased neutrophil emigration and systemic granulopoietic responses to bacterial pathogens and allergens. The aim of our study was to determine the kinetics of IL-17 in plasma and lungs of animals intratracheally infected with Klebsiella pneumoniae. MATERIALS AND METHODS: In our experiments we used eight to twelve weeks old BALB/c male mice. Mice were intratracheally inoculated with 150 CFU of K. pneumoniae strain Caroli. At different time points mice were sacrificed and the lung and blood were aseptically removed and prepared for the cytokine determination. Cytokine determination was preformed by commercial ELISA kit (BenderMed Systems, Vienna, Austria). RESULTS: The IL-17 concentration in lung homogenates slightly increases in the first two hours of infection. Then it slightly decreases and again started to increase 24 hours after the infection. The concentration in lungs reached the maximal value 48 hours post infection. These results are consistent with data previously published by others. On the other hand, we also found increased plasma values of IL-17. Its concentration in plasma started to increase 12 hours after the infection and reaches the peak value 24 hours post infection. These results are in contrast with the results of others that reported no changes in systemic IL-17 production after the intratracheal K. pneumoniae challenge. CONCLUSIONS: The IL-17 in local host defences against Gram- negative pathogens is undoubtedly important for the clearance of microorganisms, but its importance in the systemic host response is still not resolved. Its maximal concentration in plasma correlates with the appearance of the bacteria in the blood after 24 hours, so we speculate that its role is to stimulate systemic proinflammatory cytokines to combat with a release of bacteria and/or their toxic products in the blood system.

interleukin-17; Klebsiella pneumoniae; antilipoplysaccharide immunity; intratracheal infection

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