Identification of target actin content and polymerization status as a mechanism of tumor resistance after cytolytic T lymphocyte pressure.

To investigate tumor resistance to T cell lysis, a resistant variant was selected after specific cytolytic T lymphocytes (CTL) selection pressure. Although the resistant variant triggered perforin and granzyme B transcription in specific CTLs, as well as their degranulation, it exhibited a dramatic resistance to cytotoxic T cell killing. It also displayed strong morphological changes with alterations of the actin cytoskeleton.