Plasma Cells in the Bursa of Fabricius of the Chickens

In the chicken, the structure and histogenesis of the bursa of Fabricius have been studied by many workers. The bursa is known as a central lymphoid organ in the development of the humoral antibody forming system. However, comparatively little is known of the occurrence of plasma cells in the organ. In this study the occurrence of plasma cells in the bursa of Fabricius was examined and the results are shown in Table 1. The first apperance of plasma cells in the bursa of Fabricius was recognized in the lamina propia of 1-week-old chickens, though the nunber of cells was limited (Figs. 1, 2). In the chickens older than 3 weeks, especially in 3-week-old chickens, many plasma cells were found even in the bursal lymphoid nodules (Figs. 3, 4). On the basis of this study the sighificance of the apperance of these plasma cells in the bursa was discussed.