Modulation of Pulmonary Defense Mechanisms Against Viral and Bacterial Infections by Acute Exposures to Nitrogen Dioxide

This report investigated the influence of acute exposure to nitrogen dioxide on susceptibility to and severity of viral and bacterial infection in mice. Dr. Jakab exposed normal and immunosuppressed mice to concentrations of nitrogen dioxide ranging from 1 to 30 ppm before or after bacterial or viral challenge and measured host resistance to infection by physiologic parameters. The threshold exposure level capable of inducing increased susceptibility to and severity of infection was determined, along with potential effect-modifying factors, including sequence of infection and exposure, bacterial species used, and long- versus short-term infection.