Efficient suilysin-mediated invasion and apoptosis in porcine respiratory epithelial cells after streptococcal infection under air-liquid interface conditions

Meng, Fandan; Wu, Nai-Huei; Seitz, Maren; Herrler, Georg; Valentin-Weigand, Peter

as well as polar porcine choroid plexus epithelial cells and human choroid plexus papilloma cells 45, 46 . Recently, we used precision-cut lung slices (PCLS) as a culture system to analyze the co-infection of porcine differentiated respiratory epithelial cells by swine influenza virus and S. suis 37 . PCLS are maintained in culture medium, whereas ALI cultures acquire their nutrients from the medium only via the basolateral membrane, and the apical side of the cells has contact to air. In this respect the ALI system most closely resembles the situation of the airway epithelial cells in their respective host. We found that streptococci efficiently grow on the apical side of the airway epithelial cells in the absence of apical culture medium. Therefore, ALI cultures are an appropriate model system to analyze the infection of well-differentiated airway epithelial cells by S. suis. In the future, it should be interesting also to study the infection by other bacterial pathogens.