Fig. 3From: Establishment and comparison of air-liquid interface culture systems for primary and immortalized swine tracheal epithelial cellsScanning electron microscopy (SEM) analysis of immortalized STEC line and primary STECs cultured under Ali conditions. Immortalized STEC line and primary STECs were cultured under Ali conditions for 21Â days, and cilia differentiation on the cells was evaluated by SEM at D7, D14 and D21Back to article page