V delta 1+ gamma/delta T lymphocytes infiltrating human lung cancer express the CD8 alpha/alpha homodimer

Murine gamma/delta T lymphocytes localize to different epithelial tissues and are phenotypically distinct from peripheral gamma/delta T cell-populations in that they show limited TCR diversity, express the CD8 alpha/alpha homodimer and lack the CD8 beta chain. In humans, a compartmentalization of gamma/delta cells sharing similar phenotypic features has been documented to date only in the case of intestinal epithelium. In the present study we show that about half of V delta 1+ (as well as V delta 1-V delta 2-) gamma/delta lymphocytes, which can be selectively expanded from human lung cancers, coexpress the CD8 alpha/alpha homodimer. The accumulation of intraepithelial CD8+ gamma/delta+ lymphocytes might then be a more general phenomenon, possibly as a result of common mechanisms operating at those sites.