Periodontal pathogens stimulate CC-chemokine production by mononuclear andbone-derived cells

Background: Chemokines are chemotactic cytokines that stimulate recruitment of leukocytes. Monocyte chemoattractant protein-1, macrophage inflammatory protein-1 alpha, and RANTES (regulated on activation, normal T cell expres sed, and secreted) are 3 well-characterized CC-chemokines that regulate mon onuclear cell recruitment. The recruitment of inflammatory cells is of part icular importance in the oral cavity because of the likelihood that cells w ill be challenged with bacteria either during acute infection or following surgical procedures. Porphyromonas gingivalis and Actinobacillus actinomyce temcomitans are putative periodontal pathogens that may be harbored in subg ingival and supragingival plaque. The capacity of the host to respond to th ese bacteria by the elaboration of chemoattractants may represent an import ant defense mechanism. Methods: In the present study, we examined CC-chemokine production by human mononuclear cells and bone-derived cells in response to P. gingivalis, A. actinomycetemcomitans and lipopolysaccharides (LPS) stimulation in vitro. T he chemokines produced were measured by ELISA. Results: The results demonstrate that P. gingivalis and A. actinomycetemcom itans induce high levels of MIP-la in mononuclear cells. P. gingivalis and A. actinomycetemcomitans stimulated high levels of MCP-1 in bone-derived ce lls and induced moderate levels of RANTES production in both mononuclear an d osteoblastic cells. In mononuclear cells, LPS induced high levels of MIP- 1 alpha and RANTES and moderate levels of MCP-1; in osteoblasts LPS only in duced MCP-1. Conclusions: The capacity of bacteria to induce a given chemokine depends u pon the cell type stimulated. That different cell types would exhibit diffe rences in the CC-chemokines produced under the same stimulus provides a mec hanism to explain tissue-specific recruitment of leukocytes.