Figure 11. Ectopically increasing primary granule fusion with Gc phagosomes reduces intracellular Gc viability by a protease-dependent process.

PMNs were infected with Gc and treated with LPC (B, D) or left untreated (A, C) as described in Figure 9. Prior to infection, PMNs were treated with protease inhibitor cocktail (C, D). Viable Gc (green) and nonviable Gc (red) were discriminated using Baclight viability dyes SYTO9 and propidium iodide, and extracellular Gc were labeled with soybean lectin (blue). Extracellular viable Gc appear teal, intracellular nonviable Gc appear red, and intracellular viable Gc appear green. Arrows indicate viable, intracellular Gc and arrow heads indicate nonviable, intracellular Gc. The percent of viable extracellular and intracellular Gc in control PMNs, protease inhibitor treated PMNs, LPC treated PMNs, and PMNs treated with both the protease inhibitor and LPC is reported in E. Asterisks indicate P < 0.05 by Student’s two-tailed t test. The proteolytic activity of cathepsin G, neutrophil elastase, and proteinase 3 was measured for PMNs treated with the protease inhibitor cocktail and is expressed relative to untreated PMNs (F).