In vitro manipulations of vitamin C and vitamin E concentrations alter intracellular O−2 production of hybrid striped bass (Morone chrysops×Morone saxatilis) head-kidney cells

To examine the mechanism by which vitamins C and E alter phagocyte function, a series of in vitro manipulations were conducted with cells isolated from the head-kidney of hybrid striped bass (average weight 680 g) fed a diet supplemented with minimum requirement levels of vitamins C and E for 2 weeks. Head-kidney phagocytes were cultured in media containing physiologically deficient (23 μm), adequate (45 μm) or excessive (182 μm) concentrations of vitamin C, and physiologically deficient (5 μm), adequate (9 μm) or excessive (32 μm) concentrations of vitamin E for 18 h. Following culture and stimulation, levels of reactive oxygen intermediates and hydrogen peroxide were determined. There were no effects of vitamin C or vitamin E concentrations on hydrogen peroxide or extracellular O−2 generation. Intracellular O−2 production, however, was significantly (P≤ 0·05) affected. When vitamin C was supplied at deficient levels to the medium, vitamin E elevated O−2 production to levels not different from those of cells incubated with requirement levels of both vitamins. Similarly, when vitamin E was deficient in the media, vitamin C supplementation at requirement levels normalised intracellular O−2 production. This data provides support for the presence of a vitamin C and vitamin E sparing mechanism in phagocytic head-kidney cells of hybrid striped bass and yield some insight into the mechanisms by which vitamin C and vitamin E function in immunomodulation.