Antigen delivered to early endosomes is presented on MHCII equally by all DC subsets and is more efficiently presented than antigen delivered to lysosomes. Day 1 isolated DCs from HLA-DPB1*0401 donors were fed with anti-DEC205, anti-CD40, or control isotype antibodies conjugated to NY-ESO-1 (aa 154–180) for 1.5 h. Cells were then washed and cultured with an NY-ESO-1–specific CD4⁺ T cell clone at a ratio of DCs to T cells of 1/1. CD4⁺ T cells were then stained for intracellular cytokines. The percentage of CD4⁺ T cells positive for IFN-γ, IL-2, and TNF are depicted. Shown is one representative experiment of four.