Figure 2 – PD-1 mAb restored the function of TIL targeting p15E in MOC1_ova tumors.

A, MOC1_ova TIL specific for OVA:H-2K^b or p15E:H-2K^b were assessed for PD-1 expression by flow cytometry. Representative histogram of PD-1 staining is shown on the left, with qualification of PD-1 expression on all tetramer positive cells (median fluorescent intensity) as well as the percentage of positive cells (dashed grey line) shown on the right (n = 5 independent tumors).

B, WT B6 mice bearing MOC1_ova tumors were treated with PD-1 mAb or isotype control (days 7 and 10). TIL were cultured from day 14 tumors, and after 7 days of culture, TIL were assessed for tetramer positivity by flow cytometry. Representative dot plots are shown on the left. Quantity of tetramer positive TIL is shown on the right (n = 5 independent tumors each condition).

C, TIL cultured from day 14 MOC1_ova tumors treated with PD-1 mAb or isotype control were assessed for IFNγ production upon exposure to antigenic peptides by ELISpot. Representative photomicrographs of ELISpot wells are shown on the left, with quantification of spot counts on the right (n = 5 independent tumors each condition).

D, TIL cultured from day 14 MOC1_ova tumors treated with PD-1 mAb or isotype control were co-cultured with pMOC1 target cells and loss of target cell viability was assessed by impedance analysis. Representative impedance plot is shown on the left. Quantification of loss of target cell index 12 hours after initiation of co-culture (vertical dashed line) is shown on the right (TIL pooled from 5 independent tumors each condition).

All data shown is representative data from one of at least two independent experiments.

*, p < 0.05; **, p < 0.01; ***, p < 0.001, student’s t-test