Fig. 2
Basal and trastuzumab-mediated cytotoxicity of BC cell lines induced by PBMCs derived from BC patients in the NEO and MTS setting. PBMCs were analyzed for their cytolytic activity in an ADCC assay using trastuzumab (2 µg/ml) and SKBR3, BT474 and MCF-7 cell lines at different effector to target cell ratios (E:T = 2:1, 5:1, 10:1, 20:1). PBMCs were incubated with target cells in medium alone (BASAL) or in the presence of trastuzumab (ADCC). Results are expressed as % of 51Cr specific release and are the mean ± SD of experiments with 10 MTS and 15 NEO patients. NEO neoadjuvant, MTS metastatic, ADCC antibody-dependent cellular cytotoxicity. Asterisks on the bars indicate statistically significant ADCC at the specified E:T ratio evaluated using a paired Student’s t test (see “Results” for P values)