The pathophysiology of enhanced susceptibility to murine cytomegalovirus respiratory infection during short-term exposure to 5 ppm nitrogen dioxide.
To determine whether exposure to nitrogen dioxide (NO2) affects respiratory tract susceptibility to viral infection, CD-1 mice were inoculated intratracheally with murine cytomegalovirus (MCMV) during exposure to varying concentrations of NO2. Exposure lasted for 6 h per day; it began 2 consecutive days prior to instillation of MCMV and continued for 4 days after virus inoculation. Exposure to 5 ppm NO2 resulted in MCMV proliferation and a mild bronchopneumonia in some animals inoculated with 10(2) plaque-forming units of virus. Importantly, this inoculum was too low to produce either viral replication or histologic abnormalities in the lungs of air-exposed animals. We also found that the amount of virus required to infect animals exposed to 5 ppm of NO2 was 100-fold lower than that needed to consistently produce infection in air-exposed animals. Animals exposed to 5 ppm NO2 also exhibited depressed phagocytosis of colloidal Au198 in vivo as well as diminished macrophage destruction of instilled MCMV compared to air-exposed animals. These results demonstrate that exposure to 5 ppm NO2, although not associated with evidence of overt lung injury per se, is nevertheless capable of predisposing the lower respiratory tract to viral infection.
Rose
R M
RM
Department of Medicine, New England Deaconess Hospital, Boston, MA 02215.
Fuglestad
J M
JM
Skornik
W A
WA
Hammer
S M
SM
Wolfthal
S F
SF
Beck
B D
BD
Brain
J D
JD
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000378:metabolism / Q000473:pathology; D003586:Cytomegalovirus Infections / Q000276:immunology*; D004198:Disease Susceptibility / Q000503:physiopathology; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009585:Nitrogen Dioxide / Q000494:pharmacology*; D010587:Phagocytosis / Q000187:drug effects; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects; D012141:Respiratory Tract Infections / Q000139:chemically induced* / Q000276:immunology
D009585:Nitrogen Dioxide