Thymocytes

Thymocytes are developing T cell precursors within the thymus. They originate from bone marrow-derived progenitors that migrate to the thymus. Here, they undergo a rigorous process of maturation involving proliferation, TCR gene rearrangement, and positive/negative selection. Only those with a functional TCR that recognizes self-MHC with moderate affinity (positive selection) but not self-antigens too strongly (negative selection) survive to become mature, naive T cells.