Fig 2.

Protective and lung-injurious roles of neutrophils during respiratory tract viral infection. Neutrophil-induced mucus production limits access of viral particles to the epithelium but obstructs airflow. Degranulation releases antimicrobial mediators that are also cytotoxic to host cells. Phagocytosis of (opsonized) viral particles and virus-infected cells limits viral spread. NETs capture and deactivate viral particles but also damage healthy bystander cells. ECM, Extracellular matrix; PRMs, pattern recognition molecules.