FIG 1.

P. stomatis and human neutrophil interaction. Neutrophils were challenged with Alexa Fluor 488 S. aureus, opsonized CFSE-labeled P. stomatis (Op P. stomatis), or nonopsonized CFSE-labeled P. stomatis (P. stomatis) for 30 or 120 min. After the 30 min (A to C) or 120 min (A and B) of bacterial challenge, cells were visualized and quantified via ImageStreamX flow cytometry. One thousand neutrophil events were collected and sorted into bacterium-positive or -negative bins based on CFSE/Alexa Fluor 488 intensity and a mask designed to ignore signals from associated or extracellular bacteria. Data are expressed as the means ± standard errors of the means (SEM) of the percentage of bacterium-positive neutrophils from 6 independent experiments. (D) Representative confocal image of WGA-stained neutrophil membrane and CFSE-labeled P. stomatis after 30 min of challenge. (E) Percentage of CFSE-positive neutrophils with internalized-only, attached/internalized (Both), or attached-only P. stomatis. Data are expressed as means ± SEM of percentages of CFSE-positive neutrophils from 3 separate experiments. *, P < 0.05; **, P < 0.001; ***, P < 0.0001.