Background Respiratory syncytial virus (RSV) remains the leading cause of serious viral bronchiolitis and pneumonia in infants and young children throughout the world. The burden of disease is significant, with 70% of all infants being infected with RSV within the first year of their life. 40% of those children discharged from hospital have recurrent, repeated respiratory symptoms and wheezing for at least 10 years. The infection is also an important illness in the elderly and immunocompromised individuals. Ongoing symptoms relate to continued lung inflammation. One cytokine that is associated with RSV infection is IL-1β, but the mechanism of activation remain unclear.

Human rhinoviruses have been linked with underlying lung disorders, such as asthma and chronic obstructive pulmonary disease, in children and adults. However, the mechanism of virus-induced airway inflammation is poorly understood. In this study, using virus deletion mutants and silencing for nucleotide-binding oligomerization domain-like receptors (NLRs), we show that the rhinovirus ion channel protein 2B triggers NLRP3 and NLRC5 inflammasome activation and IL-1β secretion in bronchial cells. 2B protein targets the endoplasmic reticulum and Golgi and induces Ca(2+) reduction in these organelles, thereby disturbing the intracellular calcium homeostasis. NLRP3 and NLRC5 act in a cooperative manner during the inflammasome assembly by sensing intracellular Ca(2+) fluxes and trigger IL-1β secretion. These results reveal for the first time that human rhinovirus infection in primary bronchial cells triggers inflammasome activation.