Reduction of influenza virus pathogenesis by exposure to 0.5 ppm ozone.

Continuous exposure to 0.5 ppm ozone during the course of murine influenza A/PR8/34 virus infection reduced the severity of the disease as quantitated by histologic (morphometric), biochemical (serum albumin in lavage fluid), and gravimetric (lung wt/dry weight ratios) parameters of lung injury. The ozone-mediated abatement of the lung injury was independent of peak pulmonary virus titers. However, determination of the sites of virus multiplication indicated that exposure to ozone resulted in a less widespread infection of the lung parenchyma. Furthermore, ozone exposure reduced the antiviral immune response as shown by reduced numbers of phenotypically quantitated T- and B-lymphocytes recovered from lung tissues and reduction of serum antibody titers. Since the pathogenesis of influenza virus infection depends on both the site of viral replication and the antiviral immune response, these studies suggest that redistribution of virus growth in murine lungs and immunosuppressive mechanisms are factors in the ozone-reduced disease severity.