Fig. 6

a Expression of human MHC Class I (HLA-ABC), Class II (HLA-DR) and PD-L1 on cells in MDA-MB-231 tumors from hu-CB-BRGS mice. Tumors extracted from hu-CB-BRGS mice were prepared into single cell suspensions and stained for mCD45, hCD45 and Epcam. The mean fluorescence intensities (MFIs) of HLA-ABC MHC Class I b, HLA-DR MHC Class II c and PD-L1 d were determined on both the human hematopoetic (hCD45+) and the tumor cells (m,hCD45-). Expression of these molecules on PBMCs were included as a positive control for each graph. Each dot represents data from an individual tumor from mice receiving either no drug (Vehicle), nivolumab alone (Nivo), Rexahn-5902 alone (RX-5902) or a combination of Nivolumab and RX-5902 (Combo) treatment. Lines represent arithmetic means. p-values: * < 0.05, ** < 0.01