Table 1.

Human tumor cell lines express variable amounts of PD-L1 and are differentially susceptible to ADCC mediated by anti–PD-L1 MSB0010718C (avelumab) in combination with human PBMC effectors

Cell lineTissue type% Positive cellsNormalized MFIPD-L1 scoreADCC (% lysis)
MDA-MB-231Breast10072743.7
A431Epidermoid8528618.6
ASPC-1Pancreatic18220
PANC-1Pancreatic41335.7
H441Lung10040646.4
H226Lung9021526.9
H157Lung949544.4
CaLU1Lung100109838.1

NOTE: Eight human tumor cell lines were subjected to flow cytometric analysis using anti–PD-L1 MAb (BioLegend) to determine the expression of PD-L1. Data are presented as the percentage of PD-L1–positive cells and normalized PD-L1 MFI (ratio of PD-L1 MFI to control MFI). Each tumor cell line was also scored on a quartile scale (range, 1–4) for both percentage of PD-L1–positive cells and PD-L1 MFI. The combined score of the percentage of PD-L1–positive cells and MFI (range, 2–8) was termed the PD-L1 score for the tumor cell line. Each cell line was subjected to an in vitro ADCC assay as described in Materials and Methods with PBMCs as effectors. Data shown are derived from 40 μg/mL concentration of avelumab with an E:T ratio of 100:1. Lysis shown is the mean of triplicate wells. No lysis was observed in the presence of avelumab and absence of PBMCs.