FIG 2.

H₂O₂ concentration in culture medium of RAW 264 cells infected with S. oralis. (A) RAW 264 cells were infected with the S. oralis WT for 3 h. The cells were washed with PBS and cultured for an additional 21 h (total, 24 h) in fresh medium containing antibiotics. The H₂O₂ concentration of the culture supernatants was determined using a hydrogen peroxide colorimetric detection kit. (B) The H₂O₂ concentration of the culture supernatants of S. oralis cultured in the same medium was also determined.