FIG 4.

Effects of anti-Hsa, anti-PadA, and control sera on S. gordonii-induced platelet aggregation. Sera (10 μl) were preincubated with 10⁸ CFU of S. gordonii (100 μl), and then platelet aggregability was assessed. Lag time (A) indicates the time between the addition of bacterium-serum mixtures to the PRP suspensions and the onset of aggregation response, and maximal aggregation (B) represents the total number (percent) of aggregated platelets. Results are expressed as the mean ± standard deviation from four samples from four individual rats per group, which were obtained in two independent assays. Lag times of 20 min indicate that there was no aggregation in the time window used to monitor platelet aggregation. *, P < 0.005 compared to controls (Student's t test); **, P < 0.001 compared to anti-Hsa and anti-PadA groups (Student's t test).