FIG. 2.

Time-dependent translocation of hybrid YopE proteins into host cells visualized by immunofluorescence microscopy. P388D₁ cells were infected with wild-type Y. pseudotuberculosis pIB102 or the isogenic yopK-null mutant strain pIB155 expressing translocated chimeric YopE/LLO/M45 for 30 min or 2 or 5 h at an MOI of 10. Left panels, extracellular bacteria were detected by using an anti-Yersinia LPS polyclonal antiserum conjugated with TRITC (red signal), and translocated chimeric YopE protein was visualized by using an anti-M45 MAb conjugated with FITC (green signal). Right panels, phase contrast of corresponding images.