The effect of selenium on T cell PHA response, on the IL2 productionand on the proliferative response of lymphocytes to IL-2 was studied on in vitro normalblood. Lymphocytes of normal peripheral blood cultured in the presence of sodium sele-nite showed increased proliferation in response to PHA and produced more IL-2 thanthose cultured with PHA alone. But the proliferative response of lymphoblasts to IL-2was not effected by sodium selenite.