TNF-α-deficient T cells do not differ from TNF-α^+/+ T cells in allospecific responses and cytolytic function in vitro or in vivo. (A) Allospecific proliferation and (B) IFN-γ production were assessed in vitro during a mixed lymphocyte reaction (MLR) with TNF-α^+/+ (▴) or TNF-α^-/- (▪) T cells and allogeneic B6D2F1 stimulators or with TNF-α^+/+ T cells and syngeneic B6 stimulators (▪) as described in “Materials and methods.” (C) Proliferation of TNF-α^+/+ (▪) or TNF-α^-/- (□) T cells with or without ConA stimulation. (D) Alloantigen-specific cytotoxic function of T cells after in vitro priming (bulk MLR) was determined by a chromium release assay using P-815 (H2^d) and EL-4 (H2b) target cells as described (▪, TNF-α^+/+ → P-815; ▪, TNF-α^-/- → P-815; ▴, TNF-α^+/+ → EL-4; ♦, TNF-α^-/- → EL-4). All data presented are from 1 experiment representative of 2. To assess donor T-cell function in vivo, B6D2F1 mice received BMT from syngeneic (□), allogeneic wild-type (▪), or allogeneic TNF-α^-/- (▦) donors as described in Figure 2. (E) The expansion of IFN-γ-secreting splenic CD4⁺ and CD8+ T cells and (F) serum IFN-γ levels were determined 7 days after BMT, and no differences were seen between allogeneic groups. (G) Cytotoxic function of splenic T cells after in vivo priming was determined using the chromium release assay described above 7 days after BMT with TNF-α^+/+ donors (▪ P-815 targets or ▴ EL-4 targets) or TNF-α^-/- donors (▪ P-815 targets, ♦ EL-4 targets). Data are presented as mean ± SEM; ^*P < .05, □ versus ▪ and ▦.