Comparative analysis of TIL and autologous PBL phenotype isolated from rat osteosarcoma. TIL were isolated from rat osteosarcoma biopsies (n = 8) by enzymatic treatment and cultured for 14 days in X-VIVO 15 supplemented with 900 UI/ml IL-2. Autologous PBL were isolated from peripheral blood samples after gradient density centrifugation and cultured in the same conditions for 14 days. After the culture period, the phenotype of TIL (hatched bars) and PBL (dark bars) were analyzed by flow cytometry. The percentages of positive cells are given as median value.