Figure 2.

TEIPP T cell activation is mediated by direct priming on tumor cells. Mice received naïve LnB5 tg T cells and were injected with irradiated tumor cells. (A) Analysis of phenotype of T cells in blood of mice injected with allogeneic P815 or P815.Trh4 cells, five days after the second injection. IFNγ production by TEIPP T cells was measured by overnight stimulation with short Trh4 peptide. Data pooled from two independent experiments, with 4 mice per group, shown as mean and SEM. (B) Expression of H2-D^b and H2-K^b molecules on RMA.Trh4 cells generated by Crispr/CAS9 technology: wildtype (wt), D^b-/− or K^b-/− cells. Plots representative for at least two experiments. (C) IFNγ release by the LnB5 T cell clone upon in vitro co-culture with the decreasing amounts of cells from the RMA.Trh4 cell panel. Data shown as mean and SD, from one of two experiments with comparable results. (D) Naïve LnB5 tg T cells were transferred to recipient mice that were then injected twice with irradiated RMA.Trh4, RMA.Trh4 D^b-/− or RMA.Trh4 K^b-/− cells. LnB5 T cell activation was measured in blood after the second injection. IFNγ production by TEIPP T cells in blood, upon overnight stimulation with short Trh4 peptide. Data pooled from two independent experiments, with 4 mice per group, shown as mean and SEM. Student T-test: n.s. = not significant, **P < 0.01, ***P < 0.001.