Thymus-derived lymphocytes: humoral and cellular reactions distinguished by hydrocortisone.

Lymphocytes derived from the thymus (T cells) take part in the induction of humoral antibody and also effect cell-mediated graft-versus-host reactions. Preliminary treatment of mice with hydrocortisone caused an inhibition of T-cell function in humoral immunity, while enhancing the graft-versus-host reactivity of the same population of spleen cells. This suggests that different types of T cells participate in cellular and humoral immune reactions.