Alloreactive memTNF T cells cause less liver and gut damage than wt T cells and have intact proliferation, activation, and cytolytic activity. (A-E) Lethally irradiated (850 cGy) BALB/c mice received 5 × 10⁶ TCD wt B6 BM cells in combination with 1 × 10⁶ wt (black bar) or memTNF (gray bar) B6 T cells. (A) Liver, small bowel, and large bowel were harvested on day 21. Hematoxylin and eosin–stained slides were analyzed and scored for histopathological damage. Shown is the mean ± SEM for 7 mice per group. (B) Thymic cellularity (total cell counts and CD4⁺CD8⁺ thymocytes) was determined by flow cytometric analysis on day 21. Shown is the mean (± SEM) for 9 mice per group. (C-D) Recipient spleens were harvested at day 14 for flow cytometric analysis of CD44, CD62L, and CD25 expression on CD4⁺ and CD8⁺ T cells. Shown is the mean (± SEM) for 10 mice per group. (E) Serum cytokine levels were measured by CBA at days 7 and 14. Shown is the mean (± SEM) for 10 mice per group. (F-G) Lethally irradiated (850 cGy) BALB/c mice received 20 × 10⁶ CFSE-labeled wt or memTNF B6 T cells. Recipient spleens were harvested after 72 hours for flow cytometric analysis. Data shown are from 1 representative mouse of 4 mice from 2 experiments. Histogram overlays for CFSE-labeled wt (black line) and memTNF (gray line) are shown for donor CD4⁺ (G) and CD8⁺ (H) T cells. (H) In vitro–activated splenocytes were used as effectors in a ⁵¹Cr cytotoxicity assay. Targets were allogeneic P815 and third-party EL4.