Cell killing by CIK cultures and anti-CD20 mAbs in presence of human serum. (A) CDC of WSU-NHL cell line in the presence of 10 or 100 μg/mL rituximab or GA101 and 20% HS. (B) Deposition of C3b/iC3b on WSU-NHL cell line was measured by direct immunofluorescence after addition of 10 μg/mL (top panels) or 100 μg/mL (bottom panels) rituximab (left) or GA101 (right). (C) CFSE-labeled WSU-NHL cells were incubated for 4 hours with 10 μg/mL or 100 μg/mL of rituximab or GA101 and CIK cells at effector-to-target ratios of 30:1 in the presence (gray bars) or absence (black bars) of 20% HS. Cell death was measured as a decrease in CFSE⁺/ 7-AAD⁻ cells relative to untreated control. The results are the mean and SD of duplicate wells and are representative of at least 2 independent experiments.