Healthy primary epithelial cells show an elevated inflammatory response to bacterial stimulus compared to COPD cells

Exacerbations are frequently occurring events in the progression of COPD and are characterised by a sudden reduction in lung function associated with increased airway inflammation and sputum production. Triggers such as bacterial infection can lead to hospitalisation and increased mortality.

The aim of this study was to investigate differences in the response of COPD and healthy airway cells to bacterial stimulus by measuring levels of host inflammatory mediators.

Two clinically relevant strains of bacteria (Streptococcus pneumoniae and Haemophilus influenzae) were heat-inactivated and co-cultured at an established non-toxic multiplicity of infection (MOI) 25:1 for 24 hours with primary human airway epithelial cells obtained from a healthy and COPD donor, grown at airliquid interface. Cell-conditioned media was removed and analysed using the Bioplex human inflammatory mediator panel (37-plex) (Bio-Rad).

Cytokines and other pro-inflammatory proteins, as previously established, were generally stimulated in response to heatinactivated pathogens. However, on assessment of the Bioplex panel as a whole, H. influenzae showed increased potential to induce the production of cytokines/proteins to a greater level than S. pneumoniae. The greatest overall increases were seen with the healthy cells (28/37 analytes), indicating that they are potentially more capable of mounting an acute inflammatory response than COPD cells.