Adhesion (A) and invasion (B) of F62 wild-type (black columns) and F62Δ pIII (white columns) strains to ectocervical, endocervical and urethral cells. Cells were infected for 3 hours at an MOI of 100:1. Total cell-associated bacteria and intracellular gentamicin-resistant bacteria were quantified after lysis of cell membranes with 1% saponin followed by dilution and plating. In competition experiments, ectocervical cells were pre-incubated with 25 μg/mL of pIII protein before infection (grey column). Results are means ± SEM from three independent experiments, each performed in triplicate. The high variability in the values shown in the Figure 3B was due to the very low number of the intracellular bacteria. ** p < 0.01. C. Ectocervical cells were infected for 3 hours with F62 wild-type (left panel) and F62ΔpIII (right panel) strains and, after washing, were fixed and stained for confocal immunoflurescent microscopy. Bacteria were labeled by an anti-OM serum and a secondary fluorescent antibody (green). DNA and cellular actin were stained with DAPI (blue) and Phalloidin-Alexa Fluor 568 (red), respectively.