Role of IL-7 in the shaping of the pulmonary γ δ T cell repertoire

Gamma delta T cells bearing the canonical fetal-type V gamma 6/V delta 1 rearrangements are the predominant gamma delta T cells in the lungs of adult mice. In contrast, these V gamma 6/V delta 1 T cells are virtually absent in the pulmonary epithelia of nude mice. The intraepithelial dominance of gamma delta T cells that express this particular TCR is thought to result from a preferred thymic pathway of gene rearrangement and not from TCR-mediated positive selection. We now show that gamma delta T cell precursors in the lung epithelium of both euthymic and athymic neonatal mice generate this rearrangement in situ. In athymic mice, these clonotypes do not survive, but can be rescued in vitro and in vivo by the lymphokine IL-7.