Effector Mechanisms against Neuroblastoma Cells and Their Modulation by Lymphokines

Abstract The susceptibility of four neuroblastoma (NB) cell lines, SKN‐DZ, GOTO, IMR‐32, and NB‐1 to natural killer (NK) cells and cytotoxic T cells (CTL) and its modulation by lymphokines were studied using a 51 Cr‐release assay in vitro. The cytotoxic activity against 4 NB cell lines differed very much from person to person. However, the activity from every donor was significantly enhanced by culturing of peripheral blood lymphocytes (PBL) with lymphokines, interleukin‐2 (IL2) or interferon (IFN), for 12 hours. Cold target inhibition assay revealed that the cytotoxic activity of IL2– or IFN‐treated cells against NB cell lines was nonspecific and was inhibited by NK‐sensitive K562. In addition, the CTL were not induced by culturing of PBL with mitomycin C‐treated NB cell lines for five days, even in the presence of IL2. These results suggest that it is not cytotoxic T cells but NK cells that are important as effector cells to NBs and that the increase in NK cell activity due to lymphokines may be of profound biological significance in immune surveillance of NBs.