Effects of dietary vitamin E and selenium on in vitro cellular immune responses in cattle.

Four groups of calves depleted of alpha-tocopherol and selenium (Se) were supplemented with alpha-tocopherol or Se or alpha-tocopherol and Se or received no supplement. In vitro lymphocyte proliferative responses were measured in fetal calf serum (FCS), in autologous serum and in pooled sera from each group. In FCS, the responses to pokeweed mitogen were significantly enhanced for calves supplemented with alpha-tocopherol. In autologous serum, the mean responses to keyhole limpet haemocyanin (KLH) were greatest for calves supplemented with Se alone. In pooled sera from each group, lymphocytes from calves supplemented with Se alone showed enhanced responses to KLH in the presence of serum from calves supplemented with alpha-tocopherol. The calves depleted of alpha-tocopherol had increased circulating percentages of BoCD2 lymphocytes, apparently due to changes in the BoCD4 subpopulation. The percentages of B cells were greatest in calves supplemented with alpha-tocopherol and Se. The results indicate that alpha-tocopherol and Se have interactive effects on lymphocyte responses to antigen and suggest that micronutrient status is important when interpreting the results of in vitro assays of lymphocyte function.