Induction of proinflammatory responses in the human monocytic cell line THP-1 by Campylobacter jejuni

Campylobacter jejuni can cause an enteritis that is associated with an acute inflammatory response at the gut epithelial surface. The signals inducing inflammation are unknown. C. jejuni can penetrate the intestinal epithelial barrier and may then interact with leucocytes, potentially inducing proinflammatory responses. To investigate this, we studied the interaction of C. jejuni with the human monocytic cell line THP-1 and show that a range of proinflammatory cytokines and chemokines is induced. These include interleukin-1alpha (IL-1alpha), IL-1beta, IL-6, IL-8, and tumor necrosis factor alpha. Responses can be induced by killed Campylobacter as well as live bacteria and do not depend on the cytolethal distending toxin. C. jejuni infection of THP-1 cells triggers both nuclear translocation of functional NF-kappaB and stimulation of IL-1alpha, indicating that NF-kappaB-dependent and -independent stimulation is occurring. The extent of proinflammatory cytokine stimulation suggests that monocytes might significantly contribute to intestinal inflammation and disease pathology.