First T cells during embryonic
development: γδ T cells
Fetal thymic “waves”
1st wave: populates adult
epidermis: dendritic
epidermal T cells (dETCs)
2nd wave: epithelia of the
reproductive tract
Canonical rearrangements; no N-nucleotides at junctions between
V, D, and Jè Absence
of TdT from these fetal T cells
Adult thymus
γδ T cells are produced continuously after initial waves; much more
junctional diversity,
N segments and V gene usage; small % compared to α:ß