Glycoconjugates for Adjuvants and Self-Adjuvanting Vaccines

Bacterial glycans functions as non-self molecules for the host animals and work as antigens for the adaptive immune system. Therefore, bacterial-derived glycans have been used for many years in vaccines development. In the case of cancer cells, the cell surface glycan structures are altered from normal cells and these glycans are called tumor-associated carbohydrate antigens (TACAs). So far various cancer vaccine candidates based on TACAs have been developed, but none have been put into practical use. On the other hand, many bacterial and fungus molecules such as glycoconjugates and β-glucans activate innate immunity. Innate immunity activation is essential for activation of acquired immunity and antibody production. Therefore, innate immune stimulators have been developed as adjuvants that enhance the function of immunity. Furthermore, self-adjuvanting vaccines composed of antigens and adjuvants have been developed as efficient vaccine platforms. Self-adjuvanting vaccines can promote antigen up-take and innate immune activation to induce immune response specific to the antigen incorporated in self-adjuvanting vaccine. Here, development of adjuvants based on immunostimulating glycolipid lipid A is reviewed. Self-adjuvanting vaccines based on carbohydrate antigens and glycoconjugate adjuvants are also described.