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EXPOSURE TO DIESEL EXHAUST ENHANCES THE SEVERITY OF AN ONGOING INFLUENZA INFECTION.
Citation:
GOWDY, K., J. CIENCEWICKI, I. JASPERS, Q. T. KRANTZ, E. BOYKIN, W. P. LINAK, AND M I. GILMOUR. EXPOSURE TO DIESEL EXHAUST ENHANCES THE SEVERITY OF AN ONGOING INFLUENZA INFECTION. . Presented at American Thoracic Society Annual Meeting, San Francisco, CA, May 18 - 23, 2007.
Description:
Numerous studies have shown that air pollutants including diesel exhaust (DE), alter host defense responses to decrease resistance to respiratory infection. The purpose of this study was to evaluate the effects of DE exposure on the severity of an ongoing influenza infection in mice. BALB/c mice were intra-tracheally instilled with 50 plaque forming units (PFUs) of A/HongKong/8/68 and immediately exposed to air or 0.5 mg/m3 DE from a diesel truck (4 hrs/day, 14 days). Mice were necropsied at day 1, 4, 8 and 14 post-infection and lung tissue was assessed for virus titers by TCID50 and mRNA expression of IFN-ß, IL-6, and MIP2. Lung injury was measured by differential cell counts and the levels of LDH, microalbumin, and protein in bronchoalveolar lavage fluid (BAL). Inflammatory cytokines including IL-1ß, RANTES, IP-10, GM-CSF, and TNF-¿ were assessed in the BAL by immunoassay. Exposure to 0.5 mg/m3 DE during the course of infection caused an increase in viral titers at days 4 and 8 post-infection which was associated with a significant decrease in total cell and lymphocyte counts in the BAL. Production of inflammatory cytokines and chemokines were also decreased in mice exposed to DE and these results reached statistical significance for GM-CSF and MIP-2. Increase of virus load was not caused by decreased interferon levels, since IFN-ß levels were enhanced in these mice. We conclude that exposure to moderate levels of DE (0.5 mg/m3) during an influenza infection results in suppressed inflammatory responses which are important for the recruitment of lymphocytes that limit viral proliferation. (Funded by EPA CT829470. This abstract does not reflect EPA policy).