TNF-α augments endocytosis of P. gingivalis through PI3K pathways. A PI3K inhibitor suppressed TNF-a-augmented invasion of P. gingivalis in Ca9-22 cells. Ca9-22 cells were preincubated with wortmannin (Wort, 300 nM) at 37°C for 3 h and were then incubated with TNF-α. Viable P. gingivalis in the cells was determined as described in Methods. (Means ± standard deviations [SD] [n = 3]). ††, P < 0.01 versus control + TNF-α (-); **, P < 0.01 versus control + TNF-α (+).