Expression data from human melanoma specific T cell clones

Adoptive immunotherapy using ex vivo expanded tumor reactive lymphocytes can mediate durable cancer regression in selected melanoma patients. Analyses of these trials have associated the in vivo engraftment ability of the transferred cells with their anti-tumor efficacy. Thus, there is significant clinical interest in the prospective isolation of tumor specific T cells that can reliably persist after transfer. Animal studies have suggested that central memory CD8+ T cells (TCM) have divergent capabilities including effector differentiation to target antigen and stem cell-like self renewal that enable long term survival after adoptive transfer. In this study, we sought to isolate human melanoma specific TCM to define their in vivo fate and function after autologous therapeutic transfer to metastatic patients. To facilitate the high throughput identification of these rare cells from patients, we report that TCM have a defined stoichiometric production of IL-2 and IFN-g mRNA after antigen stimulation. Melanoma specific T cells screened for high relative IL-2 production possessed a TCM phenotype and superior in vitro proliferative capacity compared to cells with low IL-2 production. To investigate in vivo effector function and self renewal capability, melanoma specific TCM underwent in vitro expansion and differentiation into lytic effector clones and then were adoptively transferred back into their hosts. These clones targeted skin melanocytes in all five patients and persisted long term and reacquired parental TCM attributes in four patients after transfer. These findings demonstrate the favorable engraftment fitness for human TCM-derived clones, but further efforts to improve their anti-tumor efficacy are still necessary.

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Wang A, Chandran S, Shah SA, Chiu Y, Paria BC, Aghamolla T, Alvarez-Downing MM, Lee CC, Singh S, Li T, Dudley ME, Restifo NP, Rosenberg SA, Kammula US