Microparticle and anti-influenza activity in human respiratory secretion

• Published in: PloS one Vol. 12; no. 8; p. e0183717
• Main Authors: Suptawiwat, Ornpreya, Ruangrung, Kanyarat, Boonarkart, Chompunuch, Puthavathana, Pilaipan, Maneechotesuwan, Kittipong, Charngkaew, Komgrid, Chomanee, Nusara, Auewarakul, Prasert
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 23.08.2017; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Aged, 80 and over; Alveoli; Animals; Antiviral agents; Biology and Life Sciences; Bronchoalveolar lavage; Bronchoalveolar Lavage Fluid; Bronchus; Care and treatment; Cell culture; Cell-Derived Microparticles - metabolism; Defensive behavior; Disease; Dogs; Electron microscopy; Female; Genetic aspects; Hemagglutination; Hemagglutination inhibition; Hospitals; Humans; Influenza; Influenza A virus - physiology; Madin Darby Canine Kidney Cells; Male; Medicine; Medicine and Health Sciences; Microparticles; Microscopy, Electron, Transmission; Middle Aged; N-Acetylneuraminic Acid - metabolism; Neutralization; Particle physics; Particulates; Pathology; Physical Sciences; Physiological aspects; Receptors; Research and Analysis Methods; Respiratory system; Saliva; Secretion; Secretions; Swine flu; Virion - metabolism; Virions; Viruses; Young Adult; Thailand; Bangkok Thailand
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0183717

Respiratory secretions, such as saliva and bronchoalveolar fluid, contain anti-influenza activity. Multiple soluble factors have been described that exert anti-influenza activity and are believed to be responsible for the anti-influenza activity in respiratory secretions. It was previously shown that a bronchial epithelial cell culture could produce exosome-like particles with anti-influenza activity. Whether such extracellular vesicles in respiratory secretions have anti-influenza activity is unknown. Therefore, we characterized bronchoalveolar lavage fluid and found microparticles, which mostly stained positive for epithelial cell markers and both α2,3- and α2,6-linked sialic acid. Microparticles were purified from bronchoalveolar lavage fluid and shown to exhibit anti-influenza activity by a hemagglutination inhibition (HI) assay and a neutralization (NT) assay. In addition, physical binding between influenza virions and microparticles was demonstrated by electron microscopy. These findings indicate that respiratory microparticles containing viral receptors can exert anti-viral activity by probably trapping viral particles. This innate mechanism may play an important role in the defense against respiratory viruses.