Transplantation of bursal stem cells into cyclophosphamide-treated chicks. Lymphoid repopulation of splenic...

After transplantation of bursal stem cells into cyclophoshamide-treated newly hatched chicks, the first lymphoid cells in the spleen of the recipients were observed on the first day after the cell transfer and the first plasma cells on day 3. The repopulation of the Schweigger-Seidel sheaths started from their periphery on day 6. The first germinal centers were detected 20 days after the cell transfer. In cyclophosphamide-treated birds without cell transplantation, only the periphery of the Schweigger-Seidel sheaths became repopulated, and no plasma cells or germinal centers were observed. The results indicate that already at the age of 3 days the bursa contains some cells of postbursal maturity, able to home to the spleen.