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O3-ENHANCED PULMONARY INFECTION WITH STREPTOCOCCUS ZOOEPIDEMICUS IN MICE: THE ROLE OF ALVEOLAR MACROPHAGE FUNCTION AND CAPSULAR VIRULENCE FACTORS
Citation:
Gilmour, M.I., P. Park, AND M. Selgrade. O3-ENHANCED PULMONARY INFECTION WITH STREPTOCOCCUS ZOOEPIDEMICUS IN MICE: THE ROLE OF ALVEOLAR MACROPHAGE FUNCTION AND CAPSULAR VIRULENCE FACTORS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/376 (NTIS PB93231868).
Description:
Ozone exposure has been shown to increase the susceptibility of mice to pulmonary bacterial infection. n this paper we report differences in susceptibility of two strains of mice (C3H/HeJ and C57BI/6) to pulmonary challenge with Streptococcus zooepidemicus, and demonstrate an association between O3, exposure, reduced alveolar macro mortality to infection. ollowing a 3 hr exposure to either received an infection of bacteria by aerosol. ubsequent mortality observed over a 20 day period any given exposure concentration, was greater in the C3H/HeJ mice than in C57B1/6 mice. aseline phagocytic activity in C3H/Hej mice was lower than that in C57B1/6 mice. icrobiologic assessment of the lungs at various times after infection revealed that the streptococci proliferated rapidly in the lungs of O3-exposed mice, grew quicker upon isolation, and displayed a mucoid colony appearance indicative of increased encapsulation. n vitro assays confirmed that the encapsulated isolates presented binding of the bacteria to AMs, and reinfection of non-exposed mice with the encapsulated isolate resulted in increased mortality, compared to infection with similar numbers of the original unencapsulated bacteria. e have demonstrated that O3 inhalation impairs AM activity in the lung. he streptococci are then able to proliferate and more fully express virulence factors, in particular the anti-phagocytic capsule, which prohibits the ingestion of bacteria by pulmonary phagocytes and leads to increased severity of infection.
