Concanavalin-A-induced suppressor lymphocytes in normal individuals

Suppressor lymphocytes are now known to play an important role in the control of immune responses. It has been demonstrated that lymphocytes stimulated by the mitogen concanavalin A (Con A) have the ability to suppress the normal lymphocyte response to antigens. It has further been shown that this suppressive action is reduced when the suppressing lymphocytes are derived from patients with disorders (e.g. systemic lupus erythematosus) in which it has been suggested that suppressor cell function is abnormal. In this study we have examined several aspects of the Con A-induced suppression. The induction of suppression required viable cells, and both the induction and the action of the suppressor cells were radio-resistant. The induction of suppressor cells by Con A was independent of DNA synthesis but not of protein synthesis. The action of these suppressor cells was enhanced by the addition of prednisolone to the cultures. This latter observation is of interest in view of the action of steroids in diseases in which a defect of suppressor cells is suggested to be present and lends support to the importance of suppressor cells in the aetiology of these disorders.