Fig. 2

PRLR-DbsAb cytotoxicity correlates with the target cell PRLR expression. (a) FACS histograms of PRLR expression in different breast cancer cell lines (MDA-MB-231, MCF-7, SKBR-3, and T47D). Gray histogram, nonspecific IgG antibody fluorescence signal. (b) Cytotoxicity mediated by PRLR-DbsAb and control PRLR mAb with the same dose of 100 ng/ml at different ratios of effect cells to target cells (2.5:1-20:1). (c–f) Detection of LDH release after freshly isolated PBMCs were incubated with target cells at 10:1 (E: T) for 20 hours under different treatments. PRLR-DbsAb mediates T-cell killing of PRLR-expressing T47D cells with dose-dependent (f), and weaker killing of PRLR cells MDA-MB-231 (c), MCF-7 (d), and SKBR-3 (e). (g) The EC50 values and Top cytotoxicity were calculated by fitting the dose-response curve with Graphpad Prism software. (h) The combination of PRLR mAb and CD3 mAb did not mediate T cell killing of T47D cells. Three independent experiments were performed and the data were presented as the Mean ±SEM. *P <0.05, **P <0.01 and ***P <0.001