Oxidative stress is thought to contribute to the pathogenesis of
HIV infection in humans. For example, CD4(+) T cells are particularly affected in HIV patients and oxidative stress may also contribute to impairment of neutrophil function in HIV/
AIDS patients. Since cats infected with FIV develop many of the same immunological abnormalites as HIV-infected humans, we investigated effects of acute FIV
infection on oxidative stress in cats. Cats were infected with a pathogenic strain of FIV and viral load, changes in neutrophil number, total blood
glutathione, malondiadehye,
antioxidant enzyme concentrations, and
reduced glutathione (GSH) concentration in leukocytes were measured sequentially during the first 16 weeks of
infection. We found that
superoxide dismutase and
glutathione peroxidase concentrations in whole blood increased significantly during acute FIV
infection. In addition, neutrophil numbers increased significantly during this time period, though their intracellular GSH concentrations did not change. In contrast, the numbers of CD4(+) T cells decreased significantly and their intracellular GSH concentration increased significantly, while intracellular GSH concentrations were unchanged in CD8(+) T cells. However, by 16 weeks of
infection, many of the abnormalities in oxidative balance had stabilized or returned to pre-inoculation values. These results suggest that acute
infection with FIV causes oxidative stress in cats and that CD4(+) T cells appear to be preferentially affected. Further studies are required to determine whether early treatment with
anti-oxidants may help ameliorate the decline in CD4(+) T cell number and function associated with acute FIV
infection in cats.