Exercise effects on IFN-b expression and viral replication in lung macrophages after HSV-1 infection

Kohut, M. L., J. M. Davis, D. A. Jackson, P. Jani, A. Ghaffar, E. P. Mayer, and D. A. Essig. Exercise effects on IFN-b expression and viral replication in lung macrophages after HSV-1 infection. Am. J. Physiol. 275 (Lung Cell. Mol. Physiol. 19): L1089–L1094, 1998.—Mice exercised to fatigue and exposed to herpes simplex virus type 1 (HSV-1) exhibit greater mortality than control mice. In this study, we examined lung macrophage resistance to HSV-1 after exercise in terms of both viral replication and interferon (IFN)-b production. We utilized the reverse transcriptase-rapid polymerase chain reaction to measure the IFN-b mRNA content in alveolar macrophages. IFN release was measured with a bioassay, and viral replication within the macrophage was assessed by plaque titration. Exercised (Ex) mice ran on a treadmill until fatigue while control (Con) mice remained in lanes above the treadmill. After exercise, alveolar macrophages were removed and incubated with HSV-1. Alveolar macrophage IFN-b mRNA was greater in Ex than in Con mice. Culture supernatant from infected macrophages showed a higher degree of IFN release and a higher number of infectious viral particles in Ex vs. Con mice. It is likely that the increase in IFN-b mRNA occurs in response to a higher degree of viral replication. These results suggest that macrophages from Ex mice are less resistant to infection with HSV-1.