CPG therapy increases T-cell resistance to AICD.

CD4⁺ (A) or CD8⁺ (B) T cells were purified splenocytes derived from untreated (■), CpG-ODN–treated (●) or Neg-ODN–treated (▵) mice one day after the final ODN injection. Purified T cells were cultured in anti-CD3 (1 μg/mL) antibody–coated culture plates together with an anti-CD28 antibody (1 μg/mL) for 48 hours in the presence of 50 U IL-2/mL. T cells were then induced to undergo AICD by plating these cells with varying concentrations of immobilized anti-CD3 Ab for about 14 hours. The percent of dead cells was evaluated via flow cytometric analysis using annexin-V staining. Error bars represent the standard error obtained from 3 different mice. Asterisks denote points where statistical significance was observed between the CpG-ODN–treated group and the control groups.