FIG. 8.
CDGA and rHtrA have additive effects on the downregulation of TRP120 and reduction in E. chaffeensis internalization. (A) Host cell-free E. chaffeensis isolated from 2 × 106 heavily infected cells was incubated with exogenous rHtrA (0.25 μg) in the presence or absence of 0.3 mM CDGA for 2 h at 37°C. The amounts of TRP120 and P28/Omp-1F were detected by Western blotting. Relative densities of TRP120 bands are shown below each lane. (B) After incubation with rHtrA, bacteria were incubated with THP-1 cells for 2 h at 37°C. External bacteria and internalized bacteria were differentially stained with FITC-conjugated and Alexa Fluor 555-conjugated anti-dog IgG, respectively, as described for Fig. 4D. The percentage of internalized bacteria in 100 THP-1 cells was determined. The values are the means ± standard deviations (n = 3). Asterisks indicate significant differences (P < 0.01).