Campylobacter-stimulated INT407 cells produce dissociated cytokine profiles

Objectives. To study the action of factors produced by living Campylobacter jejuni (C. jejuni) against those present within sonicated and filtrated bacteria on induction of potential cytokines by the human intestinal cell tine INT407. Methods. We used immunohistochemical technique modified to detect intracellular production of cytokines protein and RT-PCR to read RNA messages for evaluation of de novo cytokine synthesis. Results. The data herein display dissociation of cytokine profiles induced on by living C. jejuni. Exposure of INT407 cells to 10(6) live bacteria showed the highest numbers of cytokine producing cells of all examined cytokines. IFN-gamma was the highest induced cytokine followed by IL-10, TNF-alpha and lastly IL-4. Also, abrogation of induction of the proinflammatory cytokines IFN-gamma and TNF-alpha but not the antiinflammatory cytokines IL-4 and IL-10 by sonicated and filtrated bacteria was depicted. At the mRNA level, TNF-alpha signals were noted in accordance with its protein levels since increased TNF-alpha mRNA signals were registered only after stimulation with living bacteria. Very low or no induction of TNF-alpha was registered with non-stimulated cells. Conclusions. These results illustrate for the first time a role for factors from living bacteria in directing the immune response towards Th1 type. Characterization of such factors may be essential for future immunotherapeutic interventions during severe bacterial infections. (C) 2003 The British Infection Society. Published by Elsevier Ltd. ALL rights reserved.