Mechanism of action of glucocorticoid-induced immunoglobulin production: II. Requirement for fetal calf serum.

Corticosteroids have been reported to stimulate immunoglobulin (Ig) production by otherwise unstimulated peripheral blood mononuclear cells. In this paper we confirm that observation but report the necessity for an additional minor antigenic stimulus. Lymphocytes cultured with HB101, a complete medium not requiring serum supplement, did not increase Ig production after addition of hydrocortisone, but did if small concentrations (1-10%) of fetal calf serum were added. Various antigens such as candida, tetanus, and albumin of different sources could substitute for fetal calf sera in allowing corticosteroids to stimulate Ig production in resting lymphocytes. We conclude that corticosteroids do not stimulate Ig production by lymphocytes de novo; rather, corticosteroids greatly enhance the Ig production stimulated by the foreign antigens present in fetal calf sera.