Differential onset of apoptosis in avian influenza H5N1 and seasonal H1N1 virus infected human bronchial and alveolar epithelial cells: an in vitro and ex vivo study

Abstract

INTRODUCTION: Human disease caused by highly pathogenic avian influenza (HPAI) H5N1 virus is associated with fulminant viral pneumonia and mortality rates in excess of 60%.1 Cytokine dysregulation is thought to contribute to its pathogenesis.2,3 We previously found delayed onset of apoptosis in H5N1 infected human macrophages and, therefore, a longer survival time of the target cells for prolonged virus replication and cytokine and chemokine secretion, which may contribute to the pathogenesis of H5N1 disease in humans.4 As bronchial and alveolar epithelial cells are target cells of influenza virus because of their proximal physiological location and interaction with macrophages, we further investigated if the differential onset of apoptosis could be found in influenza H5N1 and seasonal influenza H1N1 infected human respiratory epithelia. We dissected the apoptotic pathways triggered by influenza virus infection …