VtaA2 has no role in the bacterial interaction with PAMs; bacteria stained with SYTO9. E. coli BL21 clones (pLGR-vtaA2; dark grey bars) and empty vector pACYC184 (black bars) were stained with SYTO9, incubated for 1 h with PAMs and the interaction with the macrophages was analyzed by flow cytometry. Results are shown as the percentage of fluorescent macrophages. Macrophages without bacteria were included as negative (light grey bars). Bars represent the mean ± standard deviation.