Contribution of chicken's central lymphoid organs to the cellular composition of the gland of Harder.

The chicken's gland of Harder is characterized by a lymphoepithelial structure and an abundance of plasma cells in the epithelial interstices. Using 3HTdR labelling method, it is revealed that a considerable number of lymphoid cells in the gland of Harder originates from the bursa of Fabricius. However, surgical bursectomy at hatching does not influence the development of the lymphoepithelial structure in the gland of Harder. Testosterone propionate treatment of 3-day-old embryos inhibits the bursal development but not that of the gland of Harder. These findings argue for the relative bursal independence of lymphoid development in the gland of Harder.