Alveolar macrophages contribute to the pathogenesis of human metapneumovirus infection while protecting against respiratory syncytial virus infection

Deepthi Kolli, Meera R. Gupta, Elena Sbrana, Thangam S. Velayutham, Hong Chao, Antonella Casola, Roberto P. Garofalo

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

Human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) are leading causes of upper and lower respiratory tract infections in young children and among elderly and immunocompromised patients. The pathogenesis of hMPVinduced lung disease is poorly understood. The lung macrophage population consists of alveolar macrophages (AMs) residing at the luminal surface of alveoli and interstitial macrophages present within the parenchymal lung interstitium. The involvement of AMs in innate immune responses to virus infections remains elusive. In this study, BALB/c mice depleted of AMs by intranasal instillation of dichloromethylene bisphosphonate (L-CL2MBP) liposomes were examined for disease, lung inflammation, and viral replication after infection with hMPV or RSV. hMPV-infected mice lacking AMs exhibited improved disease in terms of body weight loss, lung inflammation, airway obstruction, and hyperresponsiveness compared with AM-competent mice. AM depletion was associated with significantly reduced hMPV titers in the lungs, suggesting that hMPV required AMs for early entry and replication in the lung. In contrast, AMdepletion in the context of RSV infection was characterized by an increase in viral replication, worsened disease, and inflammation, with increased airway neutrophils and inflammatory dendritic cells. Overall, lack of AMs resulted in a broad-spectrum disruption in type I IFN and certain inflammatory cytokine production, including TNF and IL- 6, while causing a virus-specific alteration in the profile of several immunomodulatory cytokines, chemokines, and growth factors. Our study demonstrates that AMs have distinct roles in the context of human infections caused by members of the Paramyxoviridae family.

Original languageEnglish (US)
Pages (from-to)502-515
Number of pages14
JournalAmerican journal of respiratory cell and molecular biology
Volume51
Issue number4
DOIs
StatePublished - Oct 1 2014

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Keywords

  • Alveolar macrophages
  • Human metapneumovirus
  • Pathogenesis
  • Respiratory syncytial virus
  • Viral infection

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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