Figure 1. Induction of T-cell immunity against breast cancer through a HER2 protein vaccine targeted to dendritic cells (DCs) in vivo. Maturation of DCs is induced by the Toll-like receptor 3 (TLR3 = ligand polyI:C. HER2 protein is delivered to DCs via an anti-DEC205 hybrid antibody. DCs are able to process the HER2 protein to liberate peptides for presentation on MHC Class I and II complexes to CD8⁺ and CD4⁺ T cells, respectively.