Splenic T cells from GVHD mice have a reduced capacity to mediate alloreactivity in vitro and to transfer GVHD in secondary recipients. (A). Spleen cells (adjusted to yield 1 × 105 T cells/well) from either normal B6 (□) or from B6→AKR chimeras undergoing GVHD (■) 19 days after BMT were cultured in triplicate wells in the absence (−STIM) or the presence of AKR CD11c+ dendritic “stimulator” cells (+STIM) (5 × 104) in a standard MLC for 5 days. Data are presented as the mean ± SEM. One of 2 representative experiments is shown. (B-C). Lethally irradiated (1100 cGy) AKR mice were transplanted with Rag-1 BM (5 × 106) alone (n = 19; ○) or together with B6 spleen cells adjusted to yield a dose of 4 to 5 × 105 naive (n = 13; □) or GVHD (n = 17; ●) T cells. Naive T cells were obtained from the spleens of normal B6 mice. GVHD T cells were obtained from sublethally irradiated (750 cGy) AKR animals that received a transplant with TCD B6 BM plus B6 spleen cells adjusted to a dose of 5 × 105 T cells 19 to 20 days after BMT. Spleen cells from individual GVHD mice were each transplanted into 2 to 3 secondary AKR hosts. Actual survival (B) and serial weight curves ± 1 SD (C) are depicted. Data are cumulative results from 6 independent experiments. (D). Colon, lung, and liver tissues from mice transplanted with Rag-1 BM alone (n = 6; □) or Rag-1 BM plus GVHD T cells (n = 17; ■) that were killed 90 days after BMT and examined histologically for evidence of GVHD using a grading system as described in “Material and methods.” Pathology score data are presented as the mean ± SEM. (E). Percentage of donor T-cell chimerism in the spleens of recipients of Rag-1 BM alone (n = 19; hatched bar) or Rag-1 BM plus either naive T cells (n = 3; □) or GVHD T cells (n = 17; ■) 3 to 4 months after BMT. Data are shown as the mean percentage of donor T cells ± SEM and are pooled from 6 independent experiments. Statistics: Rag versus naive, P < .001; Rag versus GVHD, P < .001; naive versus GVHD, P = .07. (F). Lethally irradiated AKR mice were transplanted with B6 Rag-1 BM plus 5 × 105 B6 T cells obtained from the livers of lethally irradiated B6→AKR chimeras with GVHD 24 days after transplantation. Pathology score data are presented as the mean ± SEM and are pooled from 2 experiments.
