The B-cell development independent of the bursa of Fabricius but dependent upon the thymus in chickens treated with testosterone propionate.

Spleen cells taken from chickens treated with testosterone propionate, surgically bursectomized and immunized, were treated with anti-bursa-cell antiserum in the presence of complement, and transferred together with the mixed antigens into immunodeficient chickens. The recipient chickens showed restored capacity for antibody response to sheep red blood cells. In contrast, adoptive immune responses by spleen cells from normal chickens were abolished by treating with anti-bursa-cell antiserum in the presence of complement. These findings indicate that antibody-forming cells in TP-treated chickens do not bear cell-surface antigens specific for bursa cells; Testosterone-treated chickens were thymectomized at 7 days of age and immunized with the mixed antigens; the chickens thus treated were not able to produce antibodies. Thymocytes and thymus-derived cells taken from normal chickens were transferred into the testosterone-treated and surgically thymectomized chickens; but the antibody responses were not restored, indicating that absence of antibody formation in testosterone-treated, thymectomized birds is not due to lack of T cells as such. This result was confirmed by using adoptive transfer of B cells taken from testosterone-treated chickens together with T cells.