In vitro cytotoxic effect of guinea-pig natural killer cells (Kurloff cells) on homologous leukemic cells (L2C)

The Kurloff cell (KC) of the guinea-pig develops natural killer cytotoxic activity in heterologous systems. We report in this paper the effective in vitro cytotoxic activity of the KC in a homologous guinea-pig system, i.e. against the guinea-pig target leukemic L2C cells. A dual-color flow analysis of homologous effector-target conjugates, using calcein-labeled KC and hydroethidine-labeled L2C shows a 40% frequency KC-L2C conjugation. The specific cytotoxicity of KC against L2C (78%) was estimated as the target-loss of green fluorescence due to hydrolysed carboxy-fluorascein diacetate after 4 hours at 37 o C