The thymus is relevant in the migration of mature lymphocytes
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The thymus is a primary lymphoid organ where T lymphocyte proliferation and selection takes place. The different subsets of lymphocytes leave the thymus as recent thymic emigrants. Peripheral dendritic cells migrate to the thymus. In addition to the homing of hematopoietic progenitor cells to the thymus, there is evidence for lymphocyte entry from peripheral lymphoid tissues mainly into the medulla. The entry sites are the venules in the medullary part near to the cortex with a higher endothelium. Furthermore, there are also B lymphocytes in the thymus. The thymus is not only a primary lymphoid organ but is well integrated in lymphocyte traffic as shown in several different species.
KeywordsThymus Medulla Lymphocyte entry Peripheral lymphoid organs B lymphocytes
Gesellschaft der Freunde der Medizinischen Hochschule Hannover supported the work on this review. The help with the figures by M. Peter and the secretarial assistance of S. Wallbaum and S. Fryk for polishing the English are gratefully acknowledged.
The original experiments had been supported by the Deutsche Forschungsgemeinschaft (DFG) by several grants.
Compliance with ethical standards
Conflict of interest
The author declares that there is no conflict of interest.
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