Fig 8.

S. oralis triggers a TLR2-dependent oxidative response in neutrophils.A. ROS production was measured after 1 h incubation of HL-60 leucocytes with S. oralis 34 whole cell sonicates. TLR2 receptors on leucocytes were blocked by the addition of a neutralizing anti-human TLR2 or isotype control (IgG2a) antibody (both at 10 μg ml⁻¹). Results represent means and standard deviations of duplicate experiments, with all conditions set up in triplicate, and are expressed as Activation Index i.e. as the ratio of fluorescence in the presence/absence of stimulus. *P < 0.05, for a comparison between S. oralis alone and S. oralis + anti-TLR2 antibody.B. Primary mouse TLR2^−/− and wild type neutrophils were stimulated with live, germinated C. albicans cells (10⁵ cells per well) or S. oralis 34 whole cell sonicates (10⁶ cells per well) for 30 min and fluorescence was measured at 0 min and 30 min, post challenge. Results are expressed in relative fluorescence units (T_30minRFU − T_0minRFU) and represent means and standard deviations of neutrophil responses from 4 WT and 4 TLR2^−/− animals. Negative values indicate progressive loss of activation/fluorescence during the 30 min incubation period. **P < 0.01 compared with TLR2^−/− cell stimulation with S. oralis.