FIG. 2.
P. gingivalis inhibition of IL-8 accumulation. F. nucleatum (108 bacteria) and various amounts of P. gingivalis 33277, MP4-504, 381, or DPG3 were mixed before addition to GEC. After coincubation with GEC for 18 h, the level of IL-8 was determined as described in the text. The amount of IL-8 inhibition was determined by comparing the amount of IL-8 detected after incubation with the combination of P. gingivalis and F. nucleatum to that obtained with F. nucleatum alone. Three separate experiments were performed for each strain. In each experiment, at most datum points, there was either complete or no inhibition of IL-8 accumulation, depending upon the concentration of bacteria examined. When partial inhibition occurred, an average of the three experiments is presented.