Figure 5. OVA-specific OT-I T cells fail to be purged from the periphery of iFABPtOVA mice with acute GVHD.

(A) Murine transplantation model to investigate peripheral deletion of self-reactive T cells. Acute GVHD was induced in iFABPtOVA male BMT recipients by cotransfer of female TCDBM and Mh CD8⁺ T cells. No-GVHD controls received TCDBM alone. Male B6 recipients undergoing F→M BMT with or without acute GVHD served as further controls. Six weeks after BMT, 1 × 10⁶ OT-I T cells were transferred and mice were analyzed after 16 days (data derived from 8 independent experiments). (B) Weight change in recipient mice after OT-I T cell transfer is shown as percentage of initial body weight (defined as time point of OT-I transfer). (C) Flow cytometry plots depict surface expression of CD45.1 and Thy1.1 among CD8⁺ T cells (OT-I T cells are identified as CD45.1⁺Thy1.1^–; Mh T cells are identified as CD45.1⁺Thy1.1⁺). Frequencies of OT-I T cells among total live cells in MLNs and the IEL are summarized in dot plots (right panel). (D) Absolute numbers of OT-I T cells in MLNs and the IEL (data derived from 7 independent experiments). (E) Flow cytometry plots depict intracellular IFN-γ expression among CD8⁺CD45.1⁺ OT-I T cells in MLNs and the IEL. Percentage of IFN-γ⁺ OT-I T cells is summarized in dot plots (right panel). (F) Absolute numbers of IFN-γ⁺ OT-I T cells in MLNs and the IEL (data derived from 8 independent experiments). (G and H) IFN-γ secretion was measured in acute GVHD⁺ recipients in the absence or presence of donor-derived CD11c⁺ DCs. Percentage (G) and absolute numbers (H) of IFN-γ⁺ OT-I T cells are shown for MLNs and the IEL (data derived from 3 independent experiments). Data represent mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001 by Mann-Whitney U test (C–F) or Kruskal-Wallis ANOVA (B, G, and H).