Natural blood plasma-based hydrogels as tumor vaccines delivery systems to enhance biomimetic recruitment of antigen presenting cells for tumor immunotherapy

Tumor vaccines can inhibit or eliminate tumors by vaccinating hosts with tumor antigens to activate antigen-specific immune responses and have gained wild attention. However, their clinical application efficacy is often comprised due to the low safety and poor efficiency of vaccine adjuvants/carriers. Specifically, the adjuvants/carriers usually could not efficiently recruit antigen presenting cells (APCs) to capture the vaccines or directly damage these cells. Therefore, ideal tumor vaccine adjuvants/carriers should effectively recruit APCs and be friendly to the cells for well keeping their bio-functions. In this work, injectable natural blood plasma hydrogel was used for the first time to encapsulate tumor antigens and adjuvant (Mn(2+)) for the construction of a personalized tumor vaccine. This kind of natural hydrogel with extremely high bio-safety has great potential to friendly recruit APCs in a biomimetic manner by simulating the natural degradation process of subcutaneous blood stasis. The obtained results show that the natural blood plasma hydrogel-based tumor vaccines could significantly promote the recruitment of APCs, well maintain the immuno-functions of the cells, and finally induce efficient anti-tumor immune responses. Compared with traditional tumor vaccines, this natural blood plasma-based hydrogel provides a new strategy for the development of safe and effective tumor vaccines.