AKT1 and infection: In order to substantiate that the detected differences in Lck and Akt activities in SpnWT-infected vs. SpnΔlctOΔspxB-infected H441 cells are predominantly due to pneumococcal H2O2 (Figures 5, 7), we performed infection experiments in the presence of exogenously added H2O2 (1 mM) in cells infected with SpnΔlctOΔspxB.