[Low susceptibility of choriocarcinoma cell lines to lymphokine activated killer (LAK) cells].

We investigated the anti-tumor effect of lymphokine activated killer (LAK) cells on various carcinoma cell lines as it may play an important role in the immunotherapy of gynecologic cancers. Peripheral blood lymphocytes (PBL) were cultured in 10 U/ml of recombinant interleukin-2 (rIL-2). The cytotoxic action of LAK and natural killer (NK) on carcinoma cell lines was measured by a standard 4-hr 51Cr-releasing assay. Daudi and RPMI 1788, NK resistant B cell lines were lysed by rIL-2 activated PBL although they were not killed by human fresh PBL. LAK cells thus induced were markedly cytotoxic to sixteen carcinoma cell lines. However, five choriocarcinoma cell lines were resistant to LAK action because specific action was less than 30% at effector/target ratio of 20. The cold target competitive inhibition experiments showed that the choriocarcinoma cell line GCH-1 induced much lower inhibition than Daudi cells. These results indicate that the low susceptibility of the choriocarcinoma cell lines to LAK cells could be due to the lack of the effector molecules recognized by killer cells.