FIG 6.

The H₂O₂ produced by S. oralis induces lysosomal destruction. (A) RAW 264 cells were exposed to the S. oralis WT or spxB KO mutant, S. mutans MT8148, or H₂O₂ for 3 h. The cells were then washed and cultured for an additional 3 h in fresh medium containing antibiotics. (Top) LAMP-1 and DNA were labeled with Alexa Fluor 488-conjugated anti-LAMP-1 monoclonal antibody and DAPI, respectively. (Bottom) Cathepsin B was also labeled with Alexa Fluor 594-conjugated anti-goat IgG. Bar = 10 μm. (B) Measurements of the LAMP-1-positive areas were conducted using ImageJ software. The average fluorescence area for untreated control cells (None) was set to 100%. The results are shown as the mean ± SD for four samples. *, P < 0.05 compared with the control (None).