[Cytotoxicity of interleukin 2-induced lymphocytes and effects of serum immunosuppressive factors].

IL2-induced lymphocytes (IIL) obtained from normal subjects were examined as to a possibility for induction of tumor-specific killer cells. Moreover, effects of serum on their cytotoxic activity were observed. The IIL which were pre-sensitized with mitomycin C-treated MKN-28 (IILM), showed a markedly increased cytotoxic activity against MKN-28. The IIL which were either pre-cultured with PHA or not, showed augmentation of cytotoxic activity against various human cancer cell lines, although their cytotoxic activity against MKN-28 was lower than that of IILM. The cytotoxic activity of IILM was suppressed by addition to the medium of non-specific immunosuppressive factors (IAP, ferritin, alpha-fetoprotein) or of various sera obtained from gastric cancer patients, in whom histological diagnosis was tub1, por or sig, but the suppression to the IILM activity was significantly milder than that to the activity of peripheral lymphocytes. The degree of suppression by tub1 serum was significantly higher than that by the serum from por or sig. When tub1 serum was added to the medium during pre-sensitization, the cytotoxic activity of IILM against MKN-28 was reduced significantly. However, addition of por or sig serum showed no significant reduction in cytotoxic activity of IILM.