Effects of influenza A virus on lectin-binding patterns in murine nasopharyngeal mucosa and on bacterial colonization.

To clarify the role of viral infection in otitis media, we intranasally inoculated mice with influenza A virus and examined histologic changes in the nasopharyngeal mucosa using a battery of lectins. Additionally, live Haemophilus influenzae or Streptococcus pneumoniae was injected into the nasopharynx after virus inoculation, and the clearance of bacteria from the nasopharynx was examined. Staining of the mucous blanket and epithelial cell surfaces in the nasopharynx with peanut agglutinin, succinyl wheat-germ agglutinin, and Bandeiraea simplicifolia agglutinin was significantly enhanced with intranasal virus inoculation when compared with that in control animals. The nasopharynx was moderately stained with Maachia amurensis agglutinin and wheat-germ agglutinin in control animals, and the staining was enhanced after virus inoculation. These findings were most remarkable 5 and 9 days after virus inoculation. The numbers of bacteria cultured from the nasopharynx were significantly increased when bacteria were injected 5 days after virus inoculation. These results suggest that an alteration in the glycoconjugate structure lining the nasopharyngeal mucosa caused by the influenza virus might be associated with the reduction in bacterial clearance.