Fig. (3) Association of wild-type and ΔvicK bacteria with rabbit (A)and horse (B) PMNs. FITC-labeled bacteria (10⁷ cfu) were incubated with 100 µl heparinized blood at 37°C for 5 or 15 min. Red blood cells were lysed using an Immunolyse kit, and percentages of PMNs with associated (bound and phagocytosed) bacteria determined by flow cytometry are presented. A S. pyogenes spy1718::aad mutant was included as a positive control.