Cytokine expression in macrophages stimulated with P. gingivalis.

Macrophages were stimulated with medium, 1x10⁸ CFU/ml heat-inactivated P. gingivalis clinical isolates, P. gingivalis ATCC 33277 or E. coli ATCC 25922 (positive control) for 24 h, washed and then challenged with medium, 1x10⁸ CFU/ml P. gingivalis clinical isolates, P. gingivalis ATCC 33277 or E. coli ATCC 25922 for another 24 h. Expression levels of TNF-α (A), IL-1β (B) and IL-10 (C) in the cell-free supernatants were detected by ELISA. Data are presented as the mean±SD (n = 5 per group). *p<0.05.