[The antitumor effects of tumor-infiltrating lymphocytes (TIL) being proliferated in vitro]

Tumor-infiltrating lymphocytes (TIL) were isolated from 19 solid tumors by means of in vitro digestion and discontinuous density gradient centrifugation. The average amount of TIL harvested from one gram of tumor tissue was 1.3 x 10(6). A four-week long term cultivation procedure was performed in 8 of the 19 specimens with rIL-2, and the number of TIL had then been expanded for 30 to 150 times more. Phenotypic analysis showed that most of TILs obtained were OKT3+ lymphocytes, and the ratio of OKT4+ and OKT8+ was decreased coincidently during the cultivation in vitro. The experiment showed that TILs exhibited stronger anti-autologous tumor effects than that to the allogeneic tumors through both in vitro and in vivo studies.