EFFECTS OF HYDROCORTISONE ON THE IN VITRO PRIMARY IMMUNE RESPONSE OF MOUSE SPLEEN CELLS TO SHEEP ERYTHROCYTES

Abstract

Hydrocortisone, at a concentration of 0.1μg/ml or above, suppressed the in vitro primary response of plaque-forming cells in the mouse spleen to sheep red blood cells and brought about a decreased number of viable cells, but at lower concentrations (0.001-0.01μg/ml) it rather enhanced the plaque-forming cell response.
The most severe suppression of maximum plaque-forming cell response was observed when the steroid (0.1μg/ml) was added at the beginning of culture with sheep red blood cells, but only a slight suppression when it was added at late stages of the antigen stimulation. Similar results were observed in the rosetteforming cell response. We, therefore, conclude that the immunocompetent cells acquire hydrocortisone-resistance by the antigen stimulation.
The capacity of cultured cells for plaque-forming cell response decreased with the lapse of culture time, without antigen stimulation. Under these conditions, it is suggested that hydrocortisone-sensitive immunocompetent cells gradually decrease in number but a small population of the resistant immunocompetent cells is maintained constant.