3. Authentic Lung Cell Culture Models
Authentic cell culture models are essential for the study of viral infection in vitro. The “gold standard” for the study of respiratory pathogens, such as SARS-CoV-2, are currently 2-dimensional models based on primary airway epithelial cells, which reflect molecular and functional aspects of the human respiratory epithelium. The so-called “airway epithelial cultures” (AEC) are grown in an air-liquid interphase (ALI; air liquid interphase) and are characterized by a high similarity to the lung epithelium in vivo, including the presence of different cell types such as ciliated cells, secretory cells, and basal cells in “pseudostratified” cell layers. In addition to airway epithelial cells, organ-like 3-dimensional tissue cultures called organoids represent an alternative cell culture system. Organoids are a reliable model system that overcomes many limitations of conventional cell culture systems and animal experiments. They are suitable for studying viral diseases, understanding pathogenesis, and testing potential drugs. Different lung organoid types can be differentiated from various cell types such as pluripotent or embryonic stem cells and primary cells such as human bronchial epithelial cells, offering a variety of possibilities to address different research questions individually. In our group, we use a variety of cellular systems (Heinen et al., 2021), in addition to 1-dimensional tumor cell cultures, 2D airway epithelial cells and 3D lung organoids to study coronavirus infection and identify host factors that may influence virus infection.