The Process of Adoptive T Cell Immunotherapy.

T cells are harvested either from tumor (tumor-infiltrating lymphocytes, TILs) or peripheral blood (peripheral blood lymphocytes, PBLs). TILs can be expanded non-specifically since they are preferentially tumor-specific prior to culture. In contrast, tumor specificity must be induced in PBLs, either through antigen-specific expansion or genetic engineering. After several weeks of expansion in culture, tumor-specific T cells can be reinfused into the cancer patient.