(a) CFU numbers at 48 h post-Lm infection in the spleen, liver, grafts and native hearts of B6 mice that were either not transplanted (Naïve), or were tolerant to an allogeneic B/c heart (Tol) or had received a syngeneic heart (Syn) at least 60 days before Lm infection. Results are pooled from two independent experiments: naïve+Lm (n=7), Tol+Lm (n=10), Syn+Lm (n=3). NA, not applicable. *P<0.05 by Kruskal–Wallis with Dunn's post test. (b) The total number of Kb:OVA-binding Lm-specific T cells in the graft and spleen of syngeneic (Syn) or tolerant (Tol) mice, on D0 or D7 post infection, was determined by flow cytometry. Syn D0 n=2, Syn+Lm D7 n=4, Tol D0 n=4, Tol+Lm D7 n=5. Data are pooled from two independent experiments. **P<0.01 or ***P<0.001 by two-way analysis of variance (ANOVA) with Bonferroni post test. (c) Total numbers of CD4+, CD8+ and CD4+ Foxp3+ T cells within syngeneic (Syn) or tolerated (Tol) grafts, or 7–8 days post-Lm infection, and in grafts from untreated mice undergoing AR (data pooled from three independent experiments. Syn n=2, Syn+Lm n=4, Tol n=8, Tol+Lm n=8 and AR n=4). *P<0.05 or ***P<0.001 by two-way ANOVA with Bonferroni post test. (d) Tol+Lm mice that had rejected their allografts following Lm infection (3–5 × 106 CFU i.p. on D0) were re-transplanted in the same location (abdominal area) on days 19–21 post Lm with B/c allografts (abd n=5). AR mice (non-Tol) were re-transplanted in the abdominal area on days 21–34, (n=3, P<0.01 by log-rank test). (e) Example (from d) of a white fibrotic rejected first allograft in a Tol+Lm mouse (white arrow), and of the second well-vascularized beating allograft transplanted immediately below the rejected allograft 3 weeks after Lm infection, in the absence of immunosuppression (red arrow; Supplementary Movie 1). The photograph was taken at D60 after second transplantation. (f) Representative histology of first abdominal B/c graft (Tol+Lm 1st abd, left) and second B/c abdominal graft (Tol+Lm 2nd abd, right) of the mice described in (d,e) taken at D60 post transplantation of the second allograft at lower (top) and higher (bottom) magnifications. Scale bars, 200 μm. (g) Composite histological scores (mean±s.e.m. of four hearts per group).