Expression data from human melanoma specific CD8+ T cell clones

The optimal T cell attributes for the adoptive immunotherapy of cancer and viral diseases are currently unclear. Recent adoptive transfer clinical trials using ex vivo expanded tumor infiltrating lymphocytes has provided evidence that differentiated effector T cells can mediate durable responses in selected cancer patients. The capacity of these transferred cells to persist in the host was found to strongly correlate with their clinical activity. Thus, there is significant interest in identifying intrinsic markers that define antigen specific effector T cells that can develop into long-lived memory cells rather than undergoing apoptosis after infusion in humans. We recently reported the long term persistence of ex vivo expanded tumor specific CD8+ T effector clones in refractory metastatic melanoma patients after adoptive T cell transfer. By utilizing these highly homogeneous clone populations, we sought to define the pre-infusion cellular and molecular attributes associated with their effector to memory transition. Comparative transcriptional profiling found the pre-infusion clone mRNA expression levels of the IL-7 receptor (IL-7Ra) and the proto-oncogene, c-myc, directly correlated with the level of clonal persistence after adoptive transfer in humans. The predictive value of these markers was further established by utilizing IL-7R protein, induced pSTAT5, and c-myc mRNA expression to prospectively identify human tumor specific effector clones that could engraft after controlled adoptive transfer into highly immunodeficient mice. These findings support that IL-7R and c-myc expression are valuable cell intrinsic markers that can predict the fate of effector CD8+ T cells after adoptive transfer.

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Chandran SS, Paria BC, Srivastava AK, Rothermel LD, Stephens DJ, Kammula US