Figure 2. Acidification of the CCV is required for Dot/Icm dependent effector translocation.

Translocation assays were performed in the presence of chemical inhibitors to determine host requirements for translocation by the C. burnetii Dot/Icm secretion system. HeLa cells were infected with C. burnetii NM expressing BlaM, BlaM-77, BlaM-1823 or BlaM-1524 at a MOI of 100 and the infection was allowed to proceed for 24 h before translocation positive cells were quantified. At the time of infection, either BafA (100 nM), chloroquine (100 µM), BFA (1 µg/ml) or an equivalent volume of DMSO were also applied to the cells. DMSO and BFA treatments did not significantly alter the translocation efficiency of the BlaM reporters however no translocation was detected in the presence of BafA or chloroquine. Fluorescent micrographs are representative images of at least three independent experiments.