Fig. 3

Anti-PDL1 blockade enhances the therapeutic efficacy of A_II therapy. A Growth of orthotopically transplanted MDA-MB-231 tumors in female NOG mice treated with either anti-PDL1 (n = 6), A_II (n = 5), A_II in combination with anti-PDL1 (n = 5), CD3⁺ enriched A_II cells (n = 4), or CD3⁺ enriched A_II cells in combination with anti-PDL1 (n = 5). Tumor size is presented as mean ± SEM. B Excised MDA-MB-231 tumors from (A) with tumor masses presented as mean ± SD, demonstrating that combined A_II and anti-PDL1 exert anti-cancer activity, which is retained in the CD3⁺ enriched fraction. C-F As in A-B but using two other HLA-A2 + donors, demonstrating anti-cancer activity of combined A_II and anti-PDL1 (donor 2: untreated (n = 8), A_II (n = 3), and A_II + anti-PDL1 (n = 3). Donor 3: untreated (n = 5), A_II (n = 5), and A_II + anti-PDL1 (n = 5). G Upon tumor excision tumors were analyzed by IHC. Panels show representative images of tumors stained for CD3 and PDL1 demonstrating tumor infiltration of CD3⁺ cells in tumors treated with A_II and A_II in combination with anti-PDL1 as well as increased tumor PDL1 expression. H Quantification of the density of CD3⁺ cells in tumors from C-F. In all experiments mice were administered 200 µg anti-PDL1 i.p. on day 0 and 3, followed by a weekly injection until termination. Statistical difference was determined by the Mann Whitney test B, F or Student’s t-test D, H, *0.05 > P ≥ 0.01, **0.01 > P ≥ 0.001, ***0.001 > P. NS, non-significant; a-PDL1, anti-PDL1. White scale bar 100 μm