High Dietary Intakes of Vitamin E and Cellular Immune Functions in Rats

Abstract
High dietary intakes (100–2500 mg/kg diet) of vitamin E (dl-α-tocopheryl acetate) modified the functions of splenic lymphocytes and alveolar macrophages (AM). The numbers of splenocytes and AM obtained from male F344 rats fed high vitamin E diets significantly increased at 10 d after the onset of the experiment. Splenic lymphocytes' responses to concanavalin A and natural killer cell activity also increased with increasing contents of vitamin E in the diets. Furthermore, the ability of AM to phagocytose opsonized sheep red blood cells increased with increasing contents of vitamin E in diets and showed a fivefold increase in rats fed the diet with the highest vitamin E content (2500 mg/kg diet) compared with rats in the control group. The lavage fluid of lungs from rats fed a high vitamin E diet (500 mg/kg diet) increased phagocytic activity of AM from rats fed a basal diet; it also induced a 72% increase in activity compared to that in control rats. The phagocytic activity of AM was not enhanced when the large molecules (MW > 10,000) were removed by ultrafiltration from the lavage fluid of lungs of rats fed the high vitamin E diet (500 mg/kg diet). These data suggest that there is macrophage-activating factor-like material in the lavage fluid of lungs of rats fed high vitamin E diets and that high vitamin E diets may activate not only splenic lymphocytes but also AM.

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