Recent Advance in Tumor-associated Carbohydrate Antigens (TACAs)-based Antitumor Vaccines

Cancer cells can be distinguished from normal cells by displaying aberrant levels and types of carbohydrate structures on their surfaces. These carbohydrate structures are known as tumor-associated carbohydrate antigens (TACAs). TACAs were considered as promising targets for the design of anticancer vaccines. Unfortunately, carbohydrates alone can only evoke poor immunogenicity because they are unable to induce T-cell-dependent immune responses, which is critical for cancer therapy. Moreover, immunotolerance and immunosuppression are easily induced by using natural occurring TACAs as antigens due to their endogenous property. This review summarizes the recent strategies to overcome these obstacles: (1) covalently coupling TACAs to proper carriers to improve immunogenicity, including clustered or multivalent conjugate vaccines, (2) coupling TACAs to T-cell peptide epitopes or the built-in adjuvant to form multicomponent glycoconjugate vaccines, and (3) developing vaccines based on chemically modified TACAs, which is combined with metabolic engineering of cancer cells.