Responses of B16 melanoma cell lines, F1 and F10, to hyperthermia, lymphokine-activated killer cells and a combination of both in vitro.

The cytolytic and/or cytostatic effects of hyperthermia, lymphokine-activated killer cells (LAK cells) and the combination of both were assayed using F1 and F10 B16 melanoma cell lines. F10 cells with a high metastatic potential showed a greater sensitivity to hyperthermia than F1 cells which have low metastatic potential. The F10 cells were lysed to a lesser extent by LAK cells than the F1-B16 cells. When the cell lines were subjected to hyperthermia at 43 degrees C for 3 h and then interacted with LAK cells, the maximum cytolysis reached almost 100%. When the interaction with LAK cells was followed by hyperthermia at 43 degrees C, the total release of 51Cr from the cell lines was 75-85%. The extent of 51Cr release from the B16 melanoma cell lines was inversely correlated with the survival rate as calculated by the plating efficiency of the incubated cells. The survival rate of mice intravenously injected with B16-F10 cells and subjected to hyperthermia at 41 degrees C for 3 h in vitro increased compared to that of controls. This was further increased by the simultaneous administration of LAK cells.