Highly differentiated human airway epithelial cells: a model to study host cell–parasite interactions in pertussis

Abstract

Background: Bordetella pertussis colonizes the human respiratory mucosa. Most studies on B. pertussis adherence have relied on cultured mammalian cells that lack key features present in differentiated human airway cells or on animal models that are not natural hosts of B. pertussis. The objectives of this work were to evaluate B. pertussis infection in highly differentiated human airway cells in vitro and to show the role of B. pertussis fimbriae in cell adherence. Methods: Primary human airway epithelial (PHAE) cells from human bronchi and a human bronchial epithelial (HBE) cell line were grown in vitro under air–liquid interface conditions. Results: PHAE and HBE cells infected with B. pertussis wild-type strain revealed bacterial adherence to the apical surface of cells, bacteria-induced cytoskeleton changes, and cell detachment. Mutations in the major fimbrial subunits Fim2/3 or in the minor fimbrial adhesin subunit FimD affected B. pertussis adherence to predominantly HBE cells. This cell model recapitulates the morphologic features of the human airway infected by B. pertussis and confirms the role of fimbriae in B. pertussis adherence. Furthermore, HBE cells show that fimbrial subunits, and specifically FimD adhesin, are critical in B. pertussis adherence to airway cells. Conclusions: The relevance of this model to study host–parasite interaction in pertussis lies in the striking physiologic and morphologic similarity between the PHAE and HBE cells and the human airway ciliated and goblet cells in vivo. These cells can proliferate in vitro, differentiate, and express the same genetic profile as human respiratory cells in vivo.

Keywords:

• Bordetella pertussis
• fimbriae major subunit Fim2 or Fim3
• minor subunit FimD
• adherence

Acknowledgments

We are grateful to Dr Joseph Zabner at the Department of Medicine, University of Iowa, for critical discussions and helpful scientific advice. We are thankful to Central Microscopy Research Facility, In Vitro Models and Cell Culture Core and Cystic Fibrosis Research Center staff at the University of Iowa Carver College of Medicine for technical assistance. We are grateful to Dr Janice Williams at the Electron Microscopy Core Laboratory, Vanderbilt University for technical assistance and helpful discussions.

Declaration of interest

Research support was provided to O.G.G-D. by Sanofi Pasteur; Department of Pediatrics, University of Iowa Carver College of Medicine; and Department of Pediatrics, Vanderbilt University School of Medicine. Research support was provided to J.A.G. from the Department of Veterans Affairs CDA-2 1IK2BX001701. Imaging experiments were performed in part through the use of the VUMC Cell Imaging Shared Resource supported by NIH Grants CA68485, DK20593, DK58404, DK59637, and EY08126.