Establishment of ALI-Macrophage co-culture system with porcine alveolar and mouse bone marrow derived macrophages

In ALI cultures, basal cells of the upper respiratory epithelial cells, mainly tracheal and bronchial basal epithelial cells, are used. By using various growth supplements, these cells are allowed to differentiate into pseudostratified ciliated epithelial cells and mucous producing goblet cells in vitro. In addition, the tight and adherens junctions are well established in an air-liquid interface system. This method closely mimics the in vivo situation due to the fact that the polarized ciliated epithelial cells are exposed to air and not immersed in a medium, which makes this system preferable from other cell culture systems. However, the lack of some of the innate immune cells in this system, which are commonly present in the upper respiratory tract, is a drawback in fully representing this model.

Therefore, in the PIGSs project, we aimed to include porcine alveolar and mouse bone marrow-derived macrophages (BMDM) as a co-culture with the differentiated porcine ALI cultures of tracheal and bronchial origin (PTEC- Porcine tracheal epithelial cells; PBEC- Porcine bronchial epithelial cells).

Upon successful establishment of the ALI-macrophage co-culture models by the University of Veterinary Medicine Hannover, we revealed both structural and functional stability of these complex co-cultures confirming that the models could be utilized in the future, with a better representation of the in vivo situation. The protocol could even be optimized by including other resident innate immune cells in the respiratory tract.


Figure legend: Porcine alveolar macrophages stained with Anti-CD163 or isotype control antibodies (mouse IgG) are shown in red. Nuclei are shown in grey.