M ESSAIDI-LAZIOSI¹, S BENAOUDIA¹, M FERNANDEZ-ROCHA ¹, S CONSTANT¹, L KAISER ¹, C TAPPAREL <sup>1

1</sup>HUG, Laboratoire de Virologie, Division des Maladies Infectieuses, Genève

The human airway epithelium is the first line of defense against respiratory infections. Mucociliary clearance serves as a mechanical barrier against microorganisms while epithelial cells recognize and fight the infection via cytokine secretion. Viral respiratory infections are the most frequent etiologies of acute illnesses worldwide and cause mild to severe diseases such as common cold, bronchiolitis and pneumonia. This study aimed to compare infections by the most frequent human respiratory viruses using standardized in vitro reconstituted human airway epithelia. Differentiated tissues were infected in parallel with clinically relevant strains of rhinovirus, respiratory enterovirus, influenza virus, respiratory syncytial virus and coronavirus and different parameters were compared. For each virus, the replication kinetics, the cell tropism and the impact of the virus on tissue integrity and cytokine secretion was assessed. We observed that all viruses affected negatively the mucociliary clearance except rhinovirus B and coronavirus OC43, while enterovirus D68 and influenza virus H3N2 were the only viruses affecting tissue integrity. Altogether this work provides new insights on the differential in vitro pathogenesis of the most frequent agents of respiratory infections