Antigens targeted to the DC-SIGN neck domain on DCs are presented to CD4⁺ and CD8⁺ T cells. The specificity and efficacy by which antibody/OVA conjugates induce antigen presentation via MHC I and II were determined using BMDCs from human DC-SIGN transgenic mice. (A) To specifically deliver antigen to the neck domain of DC-SIGN, anti-neck/OVA and its control isotype/OVA were incubated with transgenic BMDCs at 4°C. Next, LPS was added to the medium to induce BMDC maturation. OT-I or OT-II T cells were added and cells were co-cultured for 3 days before determining T-cell proliferation. Two independent experiments were performed showing similar results. Data represent mean values of 1 experiment performed in triplicate ± SEM. *P < .05 (t test). **P < .001 (t test). To evaluate the efficacy of neck-targeted antigens, BMDCs were incubated with various concentrations of anti-neck/OVA, isotype/OVA, or nonconjugated OVA for 3 hours. Next, antigens were removed and LPS was added to the medium to induce BMDC maturation, and (B) OT-I or (C) OT-II T cells were added. T-cell proliferation and IFN-γ levels were determined. Two experiments were performed with similar results. Data represent mean ± SEM for 1 experiment performed in duplicate.