Fig. 3

Dynamics of recruited EGFP+ cells in the mouse ear pinna after inoculation of Staphylococcus aureus. a and b Live confocal imaging after micro-injection of S. aureus mCherry-LYO-S2 in its planktonic (a) or biofilm (b) form in the ear pinna of LysM-EGFP transgenic mice at early time points. Innate immune cell recruitment towards planktonic bacteria and biofilms was observed between 3.20 to 3.50 hpi and 4.20 to 4.40 hpi, respectively. A progressive recruitment of EGFP+ innate immune cells was observed at the injection site with cell-bacteria contact areas (filled white arrowheads). White empty circles show cell accumulation over time for the planktonic or biofilm inoculum at early time points. *: autofluorescent hair (also in magenta). Scale bar: 100 μm. (c and d) Live confocal imaging at late time points after micro-injection of planktonic (c) or biofilm (d) bacteria, at 24.20 hpi and 26.20 hpi, respectively. Empty white arrowhead indicates the presence of remaining planktonic form after 24 h (low magenta signal) whereas biofilms were still easily detectable. Scale bar: 100 μm. a–d Images show average intensity projections of green (innate immune cells) and magenta (bacteria) fluorescence. One representative experiment is shown for each group of mice from three independent experiments