Further Studies on the Role of the Bursa of Fabricius in Antibody Production

Summary Removal of the bursa of Fabricius at 1 day of age effectively prevents a large percentage of the animals from producing precipitins to bovine serum albumin (BSA) when inoculations are made to 20 weeks of age. Bursectomy at 10 days is less effective. Two steroid hormones, 19-nortestosterone and 17-ethyl-19-nortestosterone, administered on the 12th or 13th day of incubation, cause a 5- to 20-fold reduction in bursal weight. Correspondingly, precipitin production against BSA is grossly impaired. Spleen, thymus and body weights were not consistently affected.