FIGURE 1.

Supernatants (SNs) from non-typeable Haemophilus influenzae (NTHi)-exposed chronic obstructive pulmonary disease (COPD) small airway epithelial cells (SAECs) have a diminished impact on the phagocytic capacity of macrophages. a) Schematic of the experimental procedure. SAECs obtained from non-COPD and COPD-diagnosed individuals were cultured in an air–liquid-interface set-up to full differentiation. On the apical surface, fully differentiated SAECs were exposed to vehicle (PBS) or heat-inactivated NTHi for 3 h or 24 h. Washings from the apical chamber or media from the basolateral chamber was used for subsequent incubation with human monocyte-derived macrophages (MDMs) to investigate the effects on MDM phagocytosis of the fluorescently labelled pHrodo Escherichia coli particles (based on the fluorescence emission when particles encounter the acidic environment of the phagosome). b–e) MDMs from three healthy donors were exposed to apical washing SN (b, d) or basolateral SN (c, e) obtained from non-COPD (blue) and COPD (grey) SAECs (n=9) exposed to PBS or heat-inactivated NTHi for 3 h (b, c) or 24 h (d, e) (each MDM donor+SAEC donor represents a unique pair). The impact of SN on phagocytosis of pHrodo E. coli particles by MDMs was measured using an IncuCyte S3 Live-Cell Analysis System over time (2 h, 4 h and 6 h time points depicted). Data are presented as a mean relative phagocytosis of MDMs exposed to SN obtained from NTHi-stimulated SAECs to corresponding PBS-exposed SAECs. Means were compared using Kruskal–Wallis test followed by Dunn's post test; *: p<0.05.