CD19 and infection: Though no differences could be detected in Annexin V binding to PMNs following infection with USA300, USA300Δhla, USA300Δhla comp, or USA300ΔsaeR/S (Figure 6A), significantly decreased Annexin V binding was observed for CD3+, CD14+, and CD19+ PBMCs at 3 hours post-infection with USA300Δhla and USA300ΔsaeR/S relative to USA300 (Figure 6C, 6E, and 6G).