Potentiation of human natural killer cell activity by recombinant interleukin-2 towards multidrug-resistant human epidermoid carcinoma.

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.