Fig. 3.

Anti-PD-L1 blockade enhances T cell infiltration but does not trigger anti-tumor antibody responses. a IHC analysis of tumors from six different mice, treated with either control rat IgG (left) or anti-PD-L1 antibody (right). Antibodies for CD3 perforin (clone CB5.4). All images were taken with a Nikon digital camera, coupled to an Olympus microscope, at ×20 magnification. b Expression of cell surface MUC1 on 2F8 via flow cytometry. Gate shows percent MUC1-positive cells, outside of isotype control area. c ELISA measurement of anti-MUC1 IgG antibodies. The optical density (OD) is shown on the y axis. Values shown represent average values from duplicate wells, calculated after background extraction (sera incubated on MUC1 peptide-coated plates minus same sera incubated on bovine serum albumin-coated plates). OD optical density, N/S not significant, Student’s t test