Methods: Whole cells of T. denticola ATCC 35405, wild type strain, and dentilisin-deficient mutant K1 were added to HUVECs (first passage), and then incubated at 37°C. After incubation, the levels of IL-8 and MCP-1 in the culture supernatants were determined by ELISA. mRNA levels of IL-8 and MCP-1 in the HUVECs were determined by a quantitative PCR method. Degradation of MCP-1 by T. denticola was determined using immunoblot analysis.
Results: The amounts of IL-8 in the culture supernatants of the HUVECs infected with wild type strain were significantly higher than those in uninfected cells. The amounts of MCP-1 were almost the same between HUVECs exposed to uninfected cells and those to wild type strain. Expression of IL-8 and MCP-1 mRNA in the HUVECs was upregulated after exposure to wild type strain. The MCP-1 levels in the HUVECs exposed to dentilisin-deficient mutant, however, were significantly higher than those found in uninfected HUVECs.
Conclusion: T. denticola induces an IL-8 and MCP-1 response in HUVECs. Furthermore, degradation of these cytokines by T. denticola may disturb the immune response through dysregulation of the cytokine network. This may contribute to the progression of atherosclerosis.