Two T cell receptor gamma/delta + murine dendritic epidermal T cell (DETC) lines with cytotoxic potential towards various tumor cell lines are shown to express perforin and granzyme A both at the mRNA and protein levels. Furthermore, mRNA transcripts for granzyme B and at least one of the other granzymes D, E, F and G are detected in amounts equivalent to a murine IL-2-dependent alpha/beta + cytotoxic T lymphocyte cell line. Hemolytic granules containing serine-esterase (granzyme A) activity are isolated from a DETC line. Thus, cytolytically-active Thy-1+ DETC lines contain the granule-associated pore-forming protein, perforin, and at least one member of each of the three subgroups of granzyme serine esterases (granzyme A, B and D/E/F/G). These data support the proposed role of gamma/delta + DETC in immune surveillance, possibly exerting cytolytic functions against virus- or parasite-infected, transformed or stressed cells.