Fig. 4.

TLR9 is required for efficient release of the diced siRNA from EE. (A) Representative images from time-lapse confocal microscopy in WT and Tlr9^−/− primary bone-marrow derived macrophages treated using CpG-siRNA labeled with pH-sensitive fluorescent dye (pHrodo) for 0.5 h. Shown are single confocal Z layers, scale bars: 10 μm (A), and the relative average intensity of pHrodo emission as a function of time (B). Results are averaged from 2 to 3 individual cells; mean ± SEM. Shown are the results from one of two (WT) or three (Tlr9^−/−) independent experiments. (C) TLR9 is required for efficient translocation of diced siRNA from endosomes to the ER. Confocal microscopy in live WT and Tlr9^−/ primary BMDM treated using CpG–siRNA^5′SS-Cy3 for indicated times with intravital staining using green ER Tracker. Single Z layers, scale bars: 5 μm.