Tumor infiltrating lymphocytes (Lion Biotechnologies, Inc.)

TIL cultures are initiated by explantation of a small (2mm³) tumor fragment or by plating 10⁶ viable cells of a single-cell suspension of enzymatically digested tumor tissue into 2 ml of complete medium (RPMI 1640 with human serum (10%)) containing IL-2 (6000 IU/ml). The cultures are maintained at cell concentrations between 5 x10⁵ - 2 x 10⁶ cells/ml until several million TIL cells are available, usually within 2-4 weeks. Multiple independent cultures are screened by cytokine secretion assay, for recognition of autologous tumor cells (if available) and HLA-A2+ tumor cell lines. 2-6 independent TIL cultures exhibiting the highest cytokine secretion are further expanded until the cell number is over 5 x 10⁷ cells (typically 3-6 weeks after tumor excision). TIL cultures that maintain specific tumor cell recognition are expanded for treatment, using one cycle of a rapid expansion protocol with irradiated allogeneic feeder cells, anti-CD3 (OKT3) antibody and IL-2 (6000 IU/ml). This results in 1000-fold expansion of cells within 14-15 days of expansion initiation.