Abstract

An experimental study on the influence of cortisone and ACTH upon the antibody formation in rabbit was performed counting the pyroninophilic cells in the spleen, lymphnode and thymus. The following results and conclusion were obtained. 1. Administration of cortisone and ACTH with immunization produced a decreased number of pyroninophilic cells in the spleen and lymphnodes comparing that of the controls. 2. This suppressive effects of cortisone and ACTH on the pyroninophilic cells were prominent in the rabbits that has been treated with cortisone and ACTH prior to immunization, simulataneous treatment and post-immunization treatment in decreasing order of effects. 3. Cortisone seems to have stronger effects on the pyroninophilic cells in rabbits comparing that of ACTH though it is influenced by the time of immunization. 4. Cortisone and ACTH administration without antigenic stimulation also produced a slighthy increased pyroninophilic cells in the lymphoid tissues. 5. Pyroninophilic cells in the thymus of the mature rabbits are negligible in number and seems not influenced by the treatment of cortisone and ACTH with or without immunization.