Respiratory-mucosal lymphocyte populations induced by reovirus serotype 1 infection.

Respiratory virus infections are a serious health challenge. While models exist to study immune mechanisms of the respiratory tract, they have not allowed analysis of the interaction of the lower respiratory tract with other components of the mucosal immune system. This study demonstrates that reovirus 1/Lang, an effective gut mucosal immunogen, also provides a useful model of respiratory mucosal infection. Intra-nasal infection of Balb/c mice resulted in severe viral bronchopneumonia. Major components of the cellular inflammatory response in the lung interstitium and alveolar spaces were CD8 lymphocytes. Lung lymphocyte populations exhibited lysis of reovirus-infected, but not uninfected target cells after in vitro culture. The GCT antigen, a germinal center B-cell and CD8 T-cell marker, was present on 21-60% of the inflammatory lymphocytes. A novel population of GCT-expressing CD4+ lymphocytes unique to reovirus-stimulated lung alveolar and interstitial lymphocyte populations was identified.