Figure 3.

EplA contributes to E. chaffeensis infection of host cells. Pretreatment of E. chaffeensis with anti-EplA reduces infection of THP-1 cells. Host cell-free E. chaffeensis DC organisms were incubated with rat polyclonal antiserum raised against His-EplA or rat preimmune serum. The treated bacteria were incubated with THP-1 cells for 60 min. After removal of unbound bacteria, the infection was allowed to proceed. After 24 h, the cells were fixed and examined by fluorescence microscopy to determine percentages of infected cells (A) and numbers of EcVs per cell (B). Data are presented as the mean values ± SD from triplicate samples and are representative of experiments performed three separate times. Statistically significant values are indicated. **P < 0.01; ***P < 0.001.