Intracellular Delivery of Tumor Antigenic Peptides in Biodegradablepolymer Adjuvant for Enhancing Cancer Immunotherapy

Tumor antigenic peptides therapeutics is a promising field for cancer immunotherapy; advantages include convenient synthesis and modification of antigenic peptides, as well as little toxicity associated with its administration. Vaccination of the peptides derived from tumor-associated antigen (TAA) was specifically designed for T cells in the context of MHC molecules. In the past decades, tumor antigenic peptides have been examined in clinic but numbered success has been obtained because of the stability of peptide and delivery approaches, consequently leading to an inefficient antigen presentation and low response rates in cancer patients. Thus, the appropriate and efficient peptide vaccine carrier systems still continue to be a major obstacle. However, both sipuleucel-T vaccine and anti-CTLA-4 antibody have been approved by FDA for the treatment of metastatic prostate cancer and melanoma, respectively. PLGA has been recently used as the adjuvant to elicit enhanced immune responses while delivering tumor antigenic peptides. Intracellular delivery of the peptides derived from TAA into DCs would prolong antigen presentation of APC to T cells. This article aims to describe a new delivery method regarding tumor antigenic peptides and rationales of DCs-based vaccination.