Immunologic response in vaccinated mice during long-term exposure to nitrogen dioxide

Swiss albino mice were continuously exposed to either 2 ppm NO 2, 0.5 ppm NO 2 with daily 1-hour peaks of 2 ppm NO 2, 5 days a week, or to filtered air. After a 12-week exposure the mice were vaccinated with A 2/Taiwan influenza virus vaccine and the exposures to the various environmental conditions continued for an additional 28 weeks. At 2 weeks after vaccination, the serum neutralizing (SN) antibody titers and SN seroconversion rates were depressed to a various extent in mice exposed to NO 2. At 4 weeks after the vaccination and later, the SN antibody titers did not differ significantly among the various groups. Nonvaccinated mice exposed to NO 2 for 12 weeks showed a marked decrease in concentrations (mg/ml) of serum IgA, and an increase in serum IgM, IgG 1 and IgG 2 immunoglobulins. When concentrations of immunoglobulins were adjusted for age of mice after vaccination, a significant elevation was observed in serum IgM, IgG 1 and IgG 2 of mice exposed to NO 2 as compared to controls. During the 2-week period immediately following the vaccination, exposure to NO 2 appeared to be the predominant factor influencing the percentage concentration of the four serum immunoglobulins.