Antibody and Gland Studies in Cortisone and ACTH-Injected Birds,

Summary Chicks were injected intramuscularly with 2.5 or 7.5 mg cortisone acetate (CA) two times a day for the first 5 days after hatching or i.m. injected once a day for the same period with 4 or 8 USP units of adrenocorticotropic hormone (ACTH). Body and bursa weights were significantly reduced 12 hr after the last injection of CA or ACTH. The mean weight of the spleen was significantly reduced in the CA-treated birds. The number of splenic germinal centers was reduced in the 7.5-mg CA birds. Adrenal weight and adrenal cholesterol were significantly increased and decreased, respectively, 12 hr after the last injection of ACTH. The bursa and thymus of approximately 3- and 6-week-old chicks from the CA and ACTH groups appeared, on histologic examination, to have recovered from the regressive influence of these hormones. The antibody response to BSA was significantly reduced in 4 ½ to 5-week-old birds from the 7.5 mg CA group while the mean antibody titer of the birds from the 2.5-mg CA and ACTH groups were similar to their respective controls. On the other hand, a primary injection of BSA into 8-week-old birds from the 7.5-mg CA group produced precipitin levels comparable to the antibody titer of control birds. The delay in normal antibody response of birds in the 7.5 mg CA group may, in part, be explained by an interference with normal bursa development.