T cells also originate in bone marrow but develop in the thymus
Upper anterior thorax
(above heart)
outer
inner
Proliferating immature thymocytes
Mature thymocytes
dentritic cells
macrophages
• Progenitor cells receive signal from stromal cells through Notch1, which is widely used in animal development for lineage fate
Notch1è progenitor to T cell
• Thymocytes also influence the arrangement of the thymic reticular epithelial structure that surrounds the developing thymocytes
Different develop- ment events