The adjuvant of α-galactosylceramide presented by gold nanoparticles enhances antitumor immune responses of MUC1 antigen-based tumor vaccines

Background: Therapeutic tumor vaccines are one of the most promising strategies and have attracted great attention in cancer treatment. However, most of them have shown unsatisfac-tory immunogenicity, there are still few available vaccines for clinical use. Therefore, there is an urgent demand to develop novel strategies to improve the immune efficacy of antitumor vaccines. Purpose: This study aimed to develop novel adjuvants and carriers to enhance the immune effect of MUC1 glycopeptide antigen-based antitumor vaccines. Methods: An antitumor vaccine was developed, in which MUC1 glycopeptide was used as tumor-associated antigen, α-GalCer served as an immune adjuvant and AuNPs was a multi-valent carrier. Results: Immunological evaluation results indicated that the constructed vaccines enabled a significant antibody response. FACS analysis and immunofluorescence assay showed that the induced antisera exhibited a specific binding with MUC1 positive MCF-7 cells. Moreover, the induced antibody can mediate CDC to kill MCF-7 cells. Besides stimulating B cells to produce MUC1-specific antibodies, the prepared vaccines also induced MUC1-specific CTLs in vitro. Furthermore, the vaccines significantly delayed tumor development in tumor-bearing mice model. Conclusion: These results showed that the construction of vaccines by presenting α-GalCer adjuvant and an antigen on gold nanoparticles offers a potential strategy to improve the antitumor response in cancer immunotherapy.