Fig. 7

PD-1 inhibition increases PRLR-DbsAb mediated cytotoxicity of PRLR expression target cell. FACS histograms of PDL1 expression on different breast cancer cell lines including MDA-MB-231 (a) and T47D (e). The gray histogram is the fluorescent signal of non-specific IgG control antibody. Freshly isolated PBMCs and the target cells of MDA-MB-231 (b) or T47D (f) were incubated with or without addition of PD-1 mAb in different concentrations of PRLR-DbsAb at the ratio of 10:1 (E: T) for 20 hours. MDA-MB-231 (c) and T47D (g) cells were treated with 100 ng/ml PRLR-DbsAb at different time points (3, 10 and 20h) with or without adding PD-1 mAb and LDH release was detected. The expression of PD-L1 (d and h) on the corresponding effector cells and target cells is measured by Flow cytometer, respectively. (i) FACS histogram of the PD-L1 expression of target T47D with or without addition of 100 ng/ml PRLR mAb. (j) PD-L1 expression on CD4+ and CD8+ T cells. PBMCs and target T47D cells were incubated with 100 ng/ml PRLR-DbsAb at the ratio of 10:1 (E: T) for 20 hours. Three independent experiments were performed and the data was represented as the Mean ±SEM. *, ** and *** respectively indicate a statistically significant difference of at least P <0.05, <0.01 and <0.001