AUGMENTATION OF SPECIFIC TUMOR KILLING ACTIVITY BY TUMOR-INFILTRATINGLYMPHOCYTES (TIL) IN THE PRESENCE OF TNF-S-AM2

The effect of TNF-S-AM2 on cytotoxic activity of tumor-infiltrating ly mphocytes (TIL) was investigated. TIL were prepared from 11 human canc er patients. They were propagated by double in vitro stimulation with anti-CD3 monoclonal antibody and interleukin-2, and cultured for 3 wee ks. The cytotoxic activity of TIL was tested with standard 4h Cr-51-re lease assays in the presence or the absence of TNF-S-AM2. In the prese nce of TNF-S-AM2 (500U/ml), the mean cytotoxic activity against autolo gous tumor cells was significantly augmented compared to that in its a bsence. However, the fact that cytotoxic activity against K562 and Dau di showed no difference whether substance was present or not, indicate s that LAK and NK activity were not affected by TNF-S-AM2. Direct cyto toxicity by exogenously added TNF-S-AM2 to tumor cells was measured in 9 out ofll cases and this revealed that cytotoxicity solely by TNF-S- AM2 was seen in 3 tumors. However, there was no correlation between th e augmentation of cytotoxicity by TIL in the presence of TNF-S-AM2 and the cytotoxicity shown by TNF-S-AM2 alone. These results suggested th at TIL therapy combined with administration of exogenous TNF may exert a synergistically stronger therapeutic effect on cancer.