Definition

A population of engineered autologous T lymphocytes in which the gene encoding for the programmed cell death protein 1 (PDCD-1) is deleted, with potential immunomodulating activity. Following collection of peripheral blood lymphocytes and selection of T cells, the PDCD-1 gene was knocked out and the T cells were expanded. Upon reinfusion of the PDCD-1 knockout T lymphocytes, these T cells target and lyse cancer cells. The PDCD-1 protein, found on activated T cells and often overexpressed on T cells in cancer patients, negatively regulates T-cell activity; it plays a key role in immune evasion and prevents tumor cell lysis. PDCD-1 knockout enhances cytotoxicity and T-cell-mediated anti-tumor immune responses.