Figure 4.

CD16 engagement is critically required for CIK cell-mediated ADCC. CIK cells were challenged against SKOV-3 (A), IGROV-1 (B), MDA-MB-231 (C) and MDA-MB-468 (D) tumor cell lines. Lytic activity was measured using bulk CIK cells (day 21 of culture) in the absence (open circles) or presence of trastuzumab (gray circles) or cetuximab (half-filled circles), adding an anti-CD16 blocking antibody (open squares) or an isotype antibody (gray squares) to the corresponding specific mAb (trastuzumab in A, and cetuximab in B, C and D). An isotype antibody served as negative control (half-filled square). The symbols refer to the specific lysis of individual CIK cell cultures from different donors at an E/T ratio of 100:1, and bars indicate mean values ± SD. Data were analyzed by Student's t-test (§§§, p ≤ 0.001; §§, p ≤ 0.01; §, p ≤ 0.05; not statistically significant (p > 0.05) if not indicated).