Abstract
Relatively little is understood about the antigen recognition and target structures used by natural killer (NK) cells. The purpose of this study was to analyze the relationship of a multidrug-resistant cell line expressing the P-glycoprotein (GP170 surface glycoprotein) derived from the parent non-drug-resistant malignant tumor cell line for susceptibility to lysis by either NK or lymphokine-activated killer cells. Our results demonstrate no significant difference in NK activity against either the non-drug-resistant or drug-resistant malignant cell line; Interleukin-2 induces a significant increase in cytolytic activity toward the multidrug-resistant cell line. These data suggest that malignant cells refractory to treatment or occurring after successful treatment are susceptible to immunotherapeutic intervention.