Injectable immunogel based on polymerized phenylboronic acid and mannan for cancer immunotherapy

The recent development and prospects of cancer immunotherapy have led to diversification of the types of therapeutic agents used. By simultaneously administering various agents, a more effective therapeutic effect can be expected due to the synergistic effects of multiple therapeutics. In particular, if a substance with adjuvanticity and tumor antigen is delivered at the same time, enhanced cancer immunotherapy can be achieved through high cross-presentation and antigen-presenting cell (APC) maturation. To this end, we developed a polymerized phenylboronic acid (pPBA)-based immunogel for the simultaneous delivery of mannan, which has adjuvanticity and tumor antigen. The immunogel was formed by simple mixing of the polysaccharide mannan with pPBA through the formation of phenylboronic ester between the diol of mannose monomers and phenylboronic acids of pPBA. The immunogel was slowly degraded by hydrolysis to release the loaded tumor antigen. In addition, the released mannan played a key role in both APC maturation in vitro and the upregulation of cross-presentation. Finally, the pPBA-mannan immunogel exhibited a significant anticancer effect in the 4 T1 cell-inoculated mouse model, implying the potential of a codelivery system of antigens and adjuvants for effective cancer immunotherapy.