P196 Establishment of a co-culture air-liquid-interphase lung model utilizing human macrophages

Airways of CF patients often get infected by Pseudomonas aeruginosa (Pa), which initially is antibiotic-susceptible, but over time develops resistance towards several antibiotics. Moreover, CF patients have difficulties regulating the inflammatory response. Much is known about the neutrophil response during Pa infection since polymorpho-nuclear leucocytes can be found in large numbers in the sputum. However, the dysregulation of the innate immune response is not elucidated to the same degree. In recent years researchers have started to investigate the role of other innate immune cells, such as macrophages. Macrophages play key roles as a first line of defense against pathogens, but they also participate in immune regulation. There is some disagreement about whether macrophages have a hyper-response to Pa, or if there is a lack of a response. To elucidate the role that macrophages play during Pa airway infection, we have developed an air-liquid-interphase (ALI) infection model, which allows us to investigate how Pa, airway epithelial cells, and macrophages interact. This model closely mimics the infection in CF airways. We have used flow cytometry and confocal microscopy to monitor the differentiation of the macrophages and to visualize the adhesion to the basolateral side of the ALI cultures. In conclusion, we have successfully established an ALI airway culture model and we have managed to differentiate monocytes to macrophages and get them to adhere to the basolateral side of the ALI culture. The next step will be in depth-characterization of the bacterial immune interaction in the ALI model.