MODULATION OF TARGET-CELL CULTURE CONDITIONS ALTERS SUSCEPTIBILITY TOLYMPHOCYTE-MEDIATED LYSIS

The culture conditions of the immortalized human breast cell line, 184 B5, can be manipulated to evaluate conditions that influence target ly sis by activated immune effector cells. Exponentially growing 184B5 ce lls (EXP) are more susceptible than growth-factor-deprived (removal of epidermal growth factor and bovine pituitary extract) 184B5 cells (GF D) to lysis by lymphokine-activated killer (LAK) cells, activated natu ral killer (NK) clones, and activated gamma/delta receptor expressing T-cell clones. LAK-cell lysis of contact-inhibited 184B5 cells is simi lar to lysis of GFD, while 184B5 cells with severe nutrient deprivatio n are more easily lysed than GFD by LAK cells. In a cold target inhibi tion assay with LAK effector populations, EXP are better inhibitors th an GFD against several targets. Further analysis of the mechanism by w hich changes of in vitro culture conditions alter target-cell suscepti bility to immune-mediated lysis may assist therapeutic strategies that involve combinations of standard therapies with biologic approaches.