A Novel System for the Quantification of the ADCC Activity of Therapeutic Antibodies

Figure 13

Quantification of the ADCC activity of Herceptin using iLite effector cells and ERBB2⁺ target cells in the presence of normal human serum. Frozen RTU iLite effector cells V-variant (1.2 × 10⁵ cells/well), ERBB2⁻, and ERBB2⁺ target cells were thawed rapidly, and the effector cells were mixed with the ERBB2⁻ or ERBB2⁺ target cells at an E:T ratio of 4 : 1 and incubated for 6 hours at 37°C in the presence of RPMI 1640 medium +10% FBS alone or together with a 1/20 final dilution of samples of human serum from normal donors in the presence of increasing concentrations of Herceptin prior to the addition of Nano-Glo Dual-luciferase reagent b (Promega, Madison, WI) and the sequential determination of FL and NL activity. Results are expressed as fold induction relative to the control sample without trastuzumab. (a) Fold induction and (b) fold induction following subtraction of the values obtained with the iLite effector cells and the ERBB2⁻ target cells.

(a)

(b)