Extrathymic origin of V gamma 1/V delta 6 T cells in the skin.

The dendritic epidermal cells (dEC) from young (8-week-old) athymic mice were found to express mRNA for gamma/delta T cell receptors (TcR). The mRNA found in the dEC from athymic mice was expressed only for V gamma 1-J gamma 4-C gamma 4 and V delta 6-J delta 1-C delta with both chains having productive rearrangements and junctional diversity. On the other hand, the dEC from euthymic mice carried V gamma 5-J gamma 1-C gamma 1 and V delta 1-J delta 2-C delta in addition to the V gamma 1/V delta 6 subset found in athymic mice. Therefore, this V gamma 1/V delta 6 subset, which has been implicated in the murine gamma/delta T cell responses to mycobacterial antigens and self heat-shock proteins, is the product of extrathymic maturation in the dEC from both athymic and euthymic mice.