Teffs undergo apoptosis in draining LNs in anti–LFA-1–treated animals. Donor-specific Thy1.1⁺ OT-I T cells were adoptively transferred into B6 recipients; 48 hours later, mice received an mOVA skin graft and were treated as indicated. Draining LNs were harvested on day 10 after transplantation, and donor-reactive Thy1.1⁺ T cells were stained with annexin V as described in “Methods.” (A-B) The frequency of annexin V⁺ graft-specific T cells was higher in anti–LFA-1–treated recipients than in untreated controls (P < .05). Data shown are gated on CD8⁺ Thy1.1⁺ T cells and are representative (A) or a summary (B) of 2 independent experiments with a total of 6 mice per group. (C) OT-I T cells were stimulated in vitro with OVA peptide in the presence or absence of anti–LFA-1 mAb (100 μg/mL). Seventy-two hours later, Thy1.1⁺ CD8⁺ T cells were analyzed for apoptosis using annexin V/propidium iodide staining for flow cytometry. Results indicated no difference in the amount of apoptosis between the treatment groups either in the presence or absence of Ag. Data shown are an average of 3 wells per culture condition and are representative of 2 independent experiments.