FIG. 6.

Measurement of YCV acidification using Lysotracker and fluorescence microscopy. J774A.1 macrophages on coverslips were infected with live KIM5/GFP (A to C) or fixed KIM5/GFP (D to F) in the presence of Lysotracker Red DND-99. At 1.25 h postinfection the samples were fixed, and representative images were obtained by using a fluorescence microscope equipped with a digital camera. The images show the GFP signal (A and D), the Lysotracker signal (B and E), or an overlay of the two signals (C and F). (G) Percent colocalization of GFP and Lysotracker signals at the indicated time points, as quantified using three independent experiments. The symbols indicate averages, and the error bars indicate standard deviations.