hD1-KLH–treated DCs activate naive T cells recognizing KLH epitopes. iDCs derived from a healthy donor were incubated with medium (control), 10 μg/mL KLH, or 10 μg/mL hD1 for one hour at 37°C. Subsequently, cells were washed and matured with LPS. mDCs were cocultured with autologous PBLs that had been repeatedly stimulated with DCs treated with hD1-KLH as described in “Patients, materials, and methods.” Some cocultures of KLH-pulsed mDCs and PBLs were supplemented with w6/32 antibody (KLH + class I block), IVA-12 (KLH + class II block), both w6/32 and IVA-12 (KLH + class I + class II block), or total mouse IgG (KLH + antibody control). Data are mean proliferation indices relative to medium control for experiments performed in triplicate ± SD. Significant difference according to ANOVA, followed by the Student-Newman-Keuls test: *P < .01; **P < .001.