Identification of MPs by flow cytometry. Representative dot plots and histograms of MPs from sputum from CF patients and P. aeruginosa and S. aureus. MPs (A), P. aeruginosa PAO1 (B), S. aureus (C) and calibrator beads (10-μm; Beckman Coulter) are represented on a forward-scatter/side-scatter dot-plot histogram. MPs, defined as events with size of 0.1 to 1 μm in diameter, are gated in (a) window when compared with calibrator beads (CAL), gated in (b). Histograms showing the CD66b-FITC labelling of MPs from CF sputum (D), and the lack of staining obtained with control IgM, with P. aeruginosa PAO1 (E) or S. aureus (F).