Cell culture
Primary NECs were harvested from the inferior surface of the anterior
turbinate using a purpose designed curette (ASI Rhino-Pro, Arlington
Scientific, USA). Scrapings were suspended in 2ml of RPMI (Roswell Park
Memorial Institute) media and immediately transported to the
laboratory 6. Cells were pelleted by centrifugation,
grown in submerged culture until they reached passage 2 (approximately 3
weeks) and then cryopreserved 6. When required, cells
were thawed and grown in ALI culture into a well differentiated
epithelium, validated by the presence of beating cilia under light
microscopy (see online supplement). Epithelial integrity was validated
by measuring the resistance to an electric current travelling across the
cell culture (Trans-epithelial electrical resistance, TEER) using an
EVOM2 Epithelial Voltohmmeter (World Precision Instruments Inc.,
Sarasota, FL, USA) connected to STX2 Chopstick Electrode (World
Precision Instruments Inc.).