Baclight viability dyes (Invitrogen) were used to assess Gc survival intracellularly and extracellularly in the presence of PMNs as described (Criss et al., 2009 (link)). In some experiments, PMNs were treated with 1x Protease Inhibitor Cocktail Set V containing AEBSF, aprotinin, E-64, and leupeptin (Calbiochem) during attachment to coverslips and throughout the infection.