To ensure that T cells can successfully bind to self-MHC molecules with low affinity

To eliminate T cells that bind too strongly to self-antigen/MHC complexes, thereby preventing autoimmunity

To allow T cells to exit the bone marrow and migrate toward the secondary lymphoid organs

To stimulate the rearrangement of the T cell receptor (TCR) alpha and beta chains

To promote the differentiation of "double-positive" (CD4+/CD8+) thymocytes into "single-positive" cells