Figure 2.

Strategies of dendritic cells (DCs) targeting. Diverse approaches to deliver antigens to DCs are shown. (A) Recombinant antibody or single-chain variable fragment (scFv) specific for DC receptors are chemically conjugated with antigen and adjuvant molecules. scFv reduced dimension confers them higher tissue-penetrating properties. (B) Viral vector-based vaccines or naked DNA exploit the encoding machinery of DCs to translate antigens, adjuvants but also co-stimulatory molecules (“signal 2”) and cytokines (“signal 3”) increasing the activatory profile of DCs. Naked DNA could be delivered conjugated to nanoparticles (NPs) and liposomes. (C) Polymer-based NPs display physical and chemical properties that allow encapsulation or conjugation of antigens and adjuvants as well as ligands for specific DC receptors. Different polymer compositions provide diverse properties and dimension, allowing easy diffusion and/or retention in lymph node. (D) Liposomes allow both the encapsulation and intercalation in the phospholipid bilayer of antigens and adjuvants, depending on their chemical properties, as well as the functionalization of the surface with ligands of DC receptors.