PTX⁺ and PTX^- OT-1 cells kill SIINFEKL-pulsed BC-CML cells in mice that received transplant. (A) Experimental design. Irradiated CB6F1 mice were reconstituted with B6 BM, without or with B6 T cells. On day +13, mice received BC-CML cells that were SIINFEKL pulsed (unlabeled) or unpulsed (CMTMR labeled). Three hours later, mice were injected with PTX⁺ or PTX^– OT-1 effectors. Another group received BC-CML cells but not OT-1 cells. Mice were euthanized the next day, and pulsed and unpulsed BC-CML cells in spleen and BM were enumerated. (B) Representative flow cytometry (gated on BC-CML cells based on expression of a nonsignaling form of the human NGFR and EGFP). (C) Ratios of SIINFEKL pulsed to unpulsed cells in BM and spleen. (D) Numbers of BC-CML cells enumerated in each experimental group. Data are combined from 2 experiments, with 4 mice per group in each. Significance was determined by a 2-tailed Student t test. ∗P < .01; ∗∗P < .001; ∗∗∗P < .0001. EGFP, enhanced green fluorescent protein; NGFR, nerve growth factor receptor; ns, not significant; SP, spleen.