Fig. 2.

NOX2 activity does not affect phagosomal acidification, phagosome-lysosome communication, or phagosomal β-galactosidase activity in macrophages. (A and B) Phagosomal pH following phagocytosis was calculated using excitation ratio fluorometry of the pH-sensitive carboxyfluorescein on IgG-coupled beads followed by regression to a standard curve. (A) Representative acidification profiles in resting BMMØs. (B) Final lumenal pH at 30 min postinternalization in resting BMMØs from four independent experiments. Error bars represent SEM. (C) Profile of phagosome-lysosome communication in real time using FRET efficiency between a particle-restricted donor fluor and a fluid-phase lysosomal acceptor fluor. Relative fluorescent units (RFU) correlate to the concentration of lysosomal constituents within the phagosome at a given point in time. (D) Profile of β-galactoside hydrolysis in phagosomes in real time.