CORTICOSTEROIDS AND HUMORAL IMMUNE-RESPONSE OF MICE .1. DIFFERENTIAL EFFECT OF CORTICOSTEROIDS UPON ANTIBODY-FORMATION TO SHEEP RED BLOOD-CELLS IN SPLEEN AND BONE-MARROW

The effect of injection of the synthetic corticosteroid dexamethasone upon the secondary response to sheep red blood cells (SRBC) was studied in mouse spleen and bone marrow. Daily corticosteroid injections, starting either one day before or five days after the booster injection of SRBC, suppressed the IgM, IgG, and IgA plaqueforming cell (PFC) response in the spleen. The higher the dose of corticosteroids, the more the splenic PFC response was suppressed. Bone marrow IgM, IgG, and IgA PFC were found to be rather resistant to corticosteroid-mediated suppression. These responses were not affected by daily doses of the corticosteroid up to 4 mg/kg body weight (BW). A dose of 16 mg/kg BW did decrease the bone marrow PFC response if corticosteroid injections were started before the booster injection. When corticoseroid injections were started 5 days after the booster injection, the dose of 16 mg/kg BW did not suppress the bone marrow PFC response. These results show that the extent of corticosteroid mediated suppression of thymus-dependent antibody formation is dependent on (a) the lymphoid organ studied, and (b) the moment that corticosteroid injections were started. © 1978 Academic Press, Inc. All rights reserved.