Impact of sequential exposures to allergens and ultrafine particles on human bronchial epithelial BEAS-2B cells at the air liquid interface

BEAS-2B cells, at air liquid interface, were exposed to birch pollen extract or house dust mite extract in a cloud chamber and, later, to UFP rich combustion aerosols in an in vitro exposure system. As control the same exposure was performed without allergen containing extracts. The goal was to understand the effect of allergenic pre-exposure to a UFP rich combustion aerosol exposed cells and their effect on allergic sensitization, using an established model that mimics more closely real life exposures. For the subsequent exposure, BEAS-2B cells, at air-liquid interface, were exposed to 30mg/ml birch pollen extract or 25µg/ml house dust mite extract and after 4 h or 24 h to UFP rich combustion aerosol for 2 h. The cells were seeded in 24mm Transwells 72 h before UFP exposure and kept at liquid interface conditions for 48 h before UFP exposure. Effect of subsequent exposure were referenced against cells exposed to clean air and PBS. Two replicates were performed for control and one for each allergen extract as well as incubation time between exposures.