[In vivo antitumor effect of LAK cells induced from various lymphocytes--experimental study in rats]

A MRMT-1 was inoculated in the thigh of SD rats. On day 7, regional lymph node lymphocytes (TB-LN), thymus cells (TB-TC) and spleen cells (TB-SC) or non-tumor bearing spleen cells (NB-SC), were obtained. LAK were induced with lug/ml of R-IL2 (TGP-3) using above lymphocytes, and were examined as for their in vivo and in vitro cytotoxic activities. In vitro: Against MRMT-1, cytotoxic activity of LAK increased with lapse of culturing time. Thus on day 4 of culture, it was the highest (46.5%) in TB-SC-LAK, while that of TB-LN-LAK was the lowest (5.8%). Against YAC-1, they also increased except TB-LN-LAK. In vivo: When the mixture of MRMT-1 and LAK was sc inoculation, diameter of the tumor were the smallest in TB-LN-LAK and the largest in TB-SC-LAK. When it was injected intraperitoneally, in non-irradiated rats, the survival prolongation was the best in TB-LN-LAK and the worst in TB-SC-LAK. In pre-irradiated rats; the cytotoxicity was almost the same as the results of in vitro. When it was injected intravenously, number of lung metastatic nodes were the smallest in TB-LN-LAK and the largest in TB-SC-LAK. R-IL2 substitution therapy was also effective. In conclusion, the effectiveness of LAK-AIT was estimated more accurately by in vivo cytotoxic assay. TB-LN was most useful as a source of LAK cells.