Microparticles from human the lower airway show inhibitory activity against respiratory syncytial virus

Airway microparticles (MPs) have been shown previously to inhibit influenza virus by trapping virions on their surface through their surface viral receptor. It was hypothesized that airway MPs may carry most of the epithelial cell surface molecules, including receptors for respiratory viruses, and may be able to inhibit various respiratory viruses. We show here that MPs from human bronchoalveolar lavage (BAL) can inhibit respiratory syncytial virus (RSV). Those MPs stained positive for the RSV receptor, CX3CR1. Furthermore, incubating the MPs with a monoclonal antibody against CX3CR1 reduced the anti-RSV activity. These data indicate that MPs can contribute to respiratory innate antiviral defense.