FIGURE 5.

CD8⁺ T cells suppress DTH. A, C57BL/6 mice were depleted of CD8⁺ T cells by i.v. injection of 100 μg anti-CD8 Ab beginning 3 d prior to CLP or sham surgery. Four days postsurgery, mice were immunized to the hapten TNP by s.c. injection TNBS. After 4 additional days, mice were challenged with TNBS in the right footpad and PBS in the left footpad. Measurements (μm ± SE) were taken 24 h later and represent the difference between right footpad (Ag challenge) and left footpad (PBS challenge). The data are reported as immune response to TNP. *Significant difference from sham nondepleted mice measured on the same day (p < 0.01). B, C57BL/6 mice were subjected to CLP or sham surgery. Four days following surgery, spleens were isolated, and CD4⁺ and CD8⁺ T cells were purified by negative selection. Mice received an equivalent number (one donor into one recipient) of cells i.v. On the day of cell transfer, mice were immunized s.c. with TNBS. After an additional 4 d, mice were challenged with TNBS in the right and PBS in the left footpad. Measurements (μm ± SE) were taken 24 h later and represent the difference between right (Ag challenge) and left footpad (PBS challenge). *Significant difference from immune control mice measured on the same day (p < 0.05). C, Trail^−/− or Trail^+/+ (C57BL/6 littermates) were subjected to CLP or sham surgery. Four days following surgery, spleens were isolated, and CD4⁺ and CD8⁺ T cells were purified by negative selection. Mice (Trail^+/+) received an equivalent number (one donor into one recipient) of cells i.v. On the day of cell transfer, mice were immunized s.c. with TNBS. After an additional 4 d, mice were challenged with TNBS in the right and PBS in the left footpad. Measurements (μm ± SE) were taken 24 h later and represent the difference between right (Ag challenge) and left footpad (PBS challenge). The data are reported as immune response to TNP. *Significant difference from immune control mice measured on the same day (p < 0.05).