Pulmonary alveolar epithelial cells (PAEpiC), comprised of alveolar type I and type II epithelial cells, line more than 99% of the internal surface area of the lung. Type I cells are large squamous cells whose thin cytoplasmic extensions cover >95% of the internal lung surface. They contain aquaporins and exhibit the highest osmotic water permeability of any mammalian cell type. Studies suggest that Type I cells also regulate ion and fluid transport and may contribute to the development of pulmonary fibrosis. Additionally, recent coronavirus research indicates that alveolar type I cells play a critical role in the proinflammatory cytokine and chemokine response. Type II cells, which cover 2-5% of the internal lung surface, produce, secrete, and recycle pulmonary surfactant. Furthermore, Type II cells maintain pulmonary fluid homeostasis by regulating active Na+ transport in the lungs. Notably, PAEpiC express the ACE2 gene, which SARS-CoV-2 utilizes to infect the host. ScienCell’s Mouse PAEpiC (MPAEpiC) show high levels of the ACE2 by gene expression analysis. MPAEpiC are a useful model for studying pulmonary fibrosis and other lung diseases. MPAEpiC from ScienCell Research Laboratories are isolated from C57BL/6 mouse lung. MPAEpiC are cryopreserved at passage one and delivered frozen. Each vial contains >1 x 106 cells in 1 ml volume. MPAEpiC are characterized by immunofluorescence with antibodies specific to CK-18. MPAEpiC are negative for, mycoplasma, bacteria, yeast, and fungi. MPAEpiC are guaranteed to further culture under the conditions provided by ScienCell Research Laboratories, however, this cell type is not recommended for expanding or long term cultures because the cells differentiate to type I alveolar epithelial cells immediately after plating and type I alveolar epithelial cells do not proliferate. Recommended Medium It is recommended to use Alveolar Epithelial Cell Medium (AEpiCM, Cat. #3201) for culturing MPAEpiC in vitro.