Modulation of target-cell culture conditions alters susceptibility to lymphocyte-mediated lysis.

The culture conditions of the immortalized human breast cell line, 184B5, can be manipulated to evaluate conditions that influence target lysis by activated immune effector cells. Exponentially growing 184B5 cells (EXP) are more susceptible than growth-factor-deprived (removal of epidermal growth factor and bovine pituitary extract) 184B5 cells (GFD) to lysis by lymphokine-activated killer (LAK) cells, activated natural killer (NK) clones, and activated gamma/delta receptor expressing T-cell clones. LAK-cell lysis of contact-inhibited 184B5 cells is similar to lysis of GFD, while 184B5 cells with severe nutrient deprivation are more easily lysed than GFD by LAK cells. In a cold target inhibition assay with LAK effector populations, EXP are better inhibitors than GFD against several targets. Further analysis of the mechanism by which changes of in vitro culture conditions alter target-cell susceptibility to immune-mediated lysis may assist therapeutic strategies that involve combinations of standard therapies with biologic approaches.