Antibody-mediated targeting of antigen to DC-SIGN results in antigen presentation. (A) iDCs were incubated with medium (control), 5 μg/mL KLH, or 5 μg/mL hD1-KLH for one hour at 4°C or 37°C. Subsequently, iDCs were washed and cocultured with autologous KLH-responsive PBLs, derived from the patients enrolled in the vaccination trial. After 4 days, cellular responses were assessed in a proliferation assay. Data are mean proliferation indices relative to medium control for experiments performed in triplicate ± SD. Significant difference from medium control according to analysis of variance (ANOVA) and Bonferroni test: *P < .05; **P < .001. (B) iDCs were incubated with medium (control), 5 μg/mL hD1-KLH, 5 μg/mL hD1-KLH and 100 μg/mL hD1 (hD1-KLH + hD1), 5 μg/mL hD1-KLH and 100 μg/mL 5G1.1 (hD1-KLH + 5G1.1), or 5 μg/mL hD1 and 5 μg/mL KLH (hD1 + KLH) for one hour at 4°C. Subsequently, iDCs were washed and cocultured with autologous KLH-responsive PBLs, derived from patients enrolled in the vaccination trial. After 4 days, cellular responses were assessed in a proliferation assay. Data are mean proliferation indices relative to medium control for experiments performed in triplicate ± SD. Significant difference from medium control according to ANOVA and Dunnett test: *P < .05; **P < .01. (C) Production of IFN-γ, TNF-α, and IL-2 in the coculture experiment described in panel B. After 16 hours of coculturing iDCs and PBLs, supernatants were taken and cytokine levels were determined. Data represent cytokine levels in pooled samples of experiments performed in triplicate.