Figure 3. Transplantation in D6^−/− hosts leads to a reduction in alloreactive T-cell frequencies. A: BALB/c or C57BL/6 wild-type (WT) corneas were engrafted onto C57BL/6 D6^−/− or WT (D6^+/+) mice. Kaplan–Meier survival curves are plotted here (n=10 per group). B: Flow cytometry analysis of CD4⁺ interferon-γ⁺ (IFN-γ⁺) T cells of lymph nodes from D6^−/− and WT hosts 3 weeks post-transplantation is shown. *P≤0.05 (n=10 per group). C: Proliferation assay of purified T cells from D6^−/− or WT mice; T cells were isolated 3 weeks post-transplantation of BALB/c corneas onto C57BL/6 D6^−/− or WT mice, and cocultured with BALB/c antigen presenting cells (APCs). Subsequent T-cell proliferation was measured with the bromodeoxyuridine (BrdU) incorporation assay. D: Delayed-type hypersensitivity (DTH) reaction in naïve WT C57BL/6 mice receiving purified T cells from D6^−/− or WT allografted mice and BALB/c APC is shown. Cells were injected into the right pinna, and ear thickness was measured 48 h after injection. The experiment was performed twice, and representative data of one experiment are shown here; mean±standard error of the mean (SEM) of n=5 mice per group. P values indicate comparison of WT and D6^−/−: *p≤0.05, **p≤0.01.