Critical role of airway macrophages in modulating disease severity during influenza virus infection of mice

MD Tate, DL Pickett, N van Rooijen, AG Brooks… - Journal of …, 2010 - Am Soc Microbiol
MD Tate, DL Pickett, N van Rooijen, AG Brooks, PC Reading
Journal of virology, 2010Am Soc Microbiol
Airway macrophages provide a first line of host defense against a range of airborne
pathogens, including influenza virus. In this study, we show that influenza viruses differ
markedly in their abilities to infect murine macrophages in vitro and that infection of
macrophages is nonproductive and no infectious virus is released. Virus strain BJx109
(H3N2) infected macrophages with high efficiency and was associated with mild disease
following intranasal infection of mice. In contrast, virus strain PR8 (H1N1) was poor in its …
Abstract
Airway macrophages provide a first line of host defense against a range of airborne pathogens, including influenza virus. In this study, we show that influenza viruses differ markedly in their abilities to infect murine macrophages in vitro and that infection of macrophages is nonproductive and no infectious virus is released. Virus strain BJx109 (H3N2) infected macrophages with high efficiency and was associated with mild disease following intranasal infection of mice. In contrast, virus strain PR8 (H1N1) was poor in its ability to infect macrophages and highly virulent for mice. Depletion of airway macrophages by clodronate-loaded liposomes led to the development of severe viral pneumonia in BJx109-infected mice but did not modulate disease severity in PR8-infected mice. The severe disease observed in macrophage-depleted mice infected with BJx109 was associated with exacerbated virus replication in the airways, leading to severe airway inflammation, pulmonary edema, and vascular leakage, indicative of lung injury. Thymic atrophy, lymphopenia, and dysregulated cytokine and chemokine production were additional systemic manifestations associated with severe disease. Thus, airway macrophages play a critical role in limiting lung injury and associated disease caused by BJx109. Furthermore, the inability of PR8 to infect airway macrophages may be a critical factor contributing to its virulence for mice.
American Society for Microbiology