['To better understand the parameters that govern spore dissemination after lung exposure using in vitro cell systems.', 'We evaluated the kinetics of uptake, germination and proliferation of Bacillus anthracis Sterne spores in association with human primary lung epithelial cells, Calu-3 and A549 cell lines. We also analysed the influence of various cell culture medium formulations related to spore germination.'] Do bacillus anthracis spores germinate extracellularly at air-liquid interface in an in vitro lung model under serum-free conditions?