Part I: targeted particles for cancer immunotherapy

Dendritic cells (DCs) are the key antigen presenting cells that link innate and adaptive immunity. In the periphery, DCs capture antigens, process them and migrate into the regional lymph nodes where they could initiate antigen specific T cell immune responses. Immunotherapeutic strategies that aim to deliver tumor antigens specifically to DCs could not only boost anti-tumor immune responses but also could alleviate non-specific immune activation and/or unwanted side effects. Nano-sized particulate delivery systems are efficient modalities that can deliver tumor antigens to DCs in a targeted and specific manner. This review will provide general information on the rationale behind targeting antigens to DCs and the crucial role of DCs in initiating antigen specific T cell responses. Different strategies that have been employed in delivering antigens to DCs will be also discussed. A special emphasis will be put on specific targeting of cancer vaccine formulations to DC-specific receptors (e.g. CD11c, CD40, Fcγ, CCR6, pathogenic recognition receptors such as Toll-like receptors (TLRs) and C-type lectin receptors (CLRs)).