Figure 2.

Culture filtrates from PSM-expressing S. aureus induce specific activation and degranulation of mFpr2-expressing RBL cells. Culture filtrates of PSM-expressing S. aureus USA300 WT, but not from an isogenic PSM deletion mutant, induce degranulation (A) and calcium influx (B) in mFpr2, but not mFpr1, transfected RBL cells at indicated concentrations. Data represent means ± sem of at least 3 independent experiments. TSB, tryptic soy broth. **P < 0.01, ****P < 0.0001 vs. corresponding medium control, as calculated by Student’s t test.