ROLE OF IL-7 IN THE SHAPING OF THE PULMONARY GAMMA-DELTA 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 vir tually absent in the pulmonary epithelia of nude mice. The intraepithe lial dominance of gamma delta T cells that express this particular TCR is thought to result from a preferred thymic pathway of gene rearrang ement and not from TCR-mediated positive selection. We now show that g amma delta T cell precursors in the lung epithelium of both euthymic a nd athymic neonatal mice generate this rearrangement in situ. In athym ic mice, these clonotypes do not survive, but can be rescued in vitro and in vivo by the lymphokine IL-7.