The role played in immune surveillance by gamma delta T cells residing
in various epithelia has not been clear. It is shown here that activa
ted gamma delta T cells obtained from skin and intestine express the e
pithelial cell mitogen keratinocyte growth factor (KGF). In contrast,
intraepithelial alpha beta T cells, as well as all lymphoid alpha beta
and gamma delta T cell populations tested, did not produce KGF or pro
mote the growth of cultured epithelial cells. These results suggest th
at intraepithelial gamma delta T cells function in surveillance and in
repair of damaged epithelial tissues.