Effects of Inhaled 144 CeO 2,on Influenza Virus Infection in Mice 1

Abstract

Summary

The effects of chronic beta-radiation from inhaled ¹⁴⁴CeO₂ that resulted in beta-radiation doses of 16,000 to 19,000 rads to the lung during 8- to 20-wk intervals had little or no effect on the influenza virus concentration or hemagglutinin titers in the lungs of virus inoculated mice when compared with virus inoculated control mice. There was, however, a slight effect in suppressing hemagglutination inhibiting antibody formation. Lung weights, lung lesions and mortality of mice inoculated with influenza virus at 8, 12 and 20 wk after inhaling ¹⁴⁴CeO₂ were reported. Increased mortality occurred at 8 wk, increases in all three parameters at 12 wk and increases in lung weights and lung lesions were observed at 20 wk. Mice that inhaled ¹⁴⁴CeO₂ and were inoculated with virus had significant histo-pathological changes. These were most marked in the mice infected with virus at 20 wk postexposure in which squamous cell differentiation was a prominent finding progressing in one case to a superficial resemblance to epidermoid carcinoma.

The authors acknowledge the helpful assistance of Veterinary Medicine personnel for animal care, and Aerosol Physics personnel for the preparation of the aerosols and inhalation exposure of mice.