Figure 6. Ortho IL-2 treatment facilitates donor-specific heart transplantation tolerance.

Recipients of H2^b+ BMT received heart allografts from luc⁺H2^b+ or luc⁺H2^q+ donor mice 2 months after BMT. (A) Representative bioluminescent images show acceptance or rejection of heart allografts in the mice that developed mixed chimerism (chimeric recipient) and in the mice that rejected H2^b+ BMCs (nonchimeric recipient). Survival curve for H2^b+ heart allograft (B) and H2^q+ heart allografts (C) are shown. P values calculated by log-rank test between indicated 2 groups. (D and E) Recipient mice that received oTregs were sacrificed 30 days after H2^q+ heart transplantation. Negatively isolated T cells were cocultured with host type (H2^d+), third-party type (H2^q+), and BM donor type (H2^b+) stimulator cells, and the percentage of proliferating cells was analyzed by flow cytometry on d4. (D) Representative pseudocolor plots showing dilution of proliferation dye. SSC, side scatter. (E) Box plots for percentages of proliferating cells. Dunn’s Kruskal-Wallis multiple comparisons calculated among the 3 treatment groups. Pooled data from 2 independent experiments, including 5 mice per group per experiment. *P < 0.05; ***P < 0.001.