Distribution and development of the postnatal murine Vδ1 T-cell receptor repertoire

P>Murine gamma/delta T cells express canonical V gamma 5V delta 1 chains in the epidermis and V gamma 6V delta 1 chains at reproductive sites. Both subsets carry an identical V delta 1-D delta 2-J delta 2 chain which completely lacks junctional diversity. These cells are thought to monitor tissue integrity via recognition of stress-induced self antigens. In this study, we showed by reverse transcription-polymerase chain reaction (RT-PCR), complementarity determining region 3 (CDR3) spectratyping and sequencing of the junctional regions of V delta 1 chains from C57BL/6 mice (aged 1 day to 14 months) that the canonical V delta 1-D delta 2-J delta 2 chain is also consistently present at other sites such as the thymus, gut, lung, liver, spleen and peripheral blood. In addition, we found multiple V delta 1 chains with fetal type rearrangements which were also shared among organs and among animals. These V delta 1 chains were typically characterized by a conserved amino acid motif, 'GGIRA'. Furthermore, by analysing the early postnatal period at days 10 and 16, we demonstrated that the diversification of the thymic V delta 1 repertoire is not paralleled by a diversification of extrathymic V delta 1+gamma/delta T cells. This indicates that only fetal type rearrangements survive at extrathymic sites. In conclusion, gamma/delta T cells expressing the canonical V delta 1-D delta 2-J delta 2 chain are not unique to the skin and reproductive sites. Furthermore, we found other gamma/delta T cells expressing fetal type V delta 1 chains which were shared among different organs and animals. Thus, gamma/delta T cells expressing conserved V delta 1 chains are likely to have important functions. We suggest a model in which this subset continuously recirculates throughout the organism and rapidly responds to stress-induced self antigens.