Optimization, Immunological Evaluation, and Combination Study of Mincle-Dependent Self-Adjuvanted Anti-Tn Cancer Vaccines with an External Adjuvant

Nine Tn-based cancer vaccines were designed and synthesized using Mincle agonists as a carrier to elucidate the structure-immunogenicity relationships of Mincle-dependent vaccines. The Immunological evaluation showed that the immune response levels were significantly influenced by the acyl chains of trehalose, coupling site of antigen and carriers, antigen copy number, and coupling mode of acyl chains and trehalose. Notably, installing the antigen onto the lipid chains of the carrier could also effectively improve the immunogenicity. Among them, conjugate 9 showed the highest activity. In the presence of EcMPLA (TLR4 agonist) and aluminum hydroxide (Al), the immunological activity of conjugate 9 could further be improved and significantly inhibit tumor growth, prolonging the survival time of tumor-challenged mice. Survived mice also successfully rejected subsequent tumor attacks without any additional treatment. This work provides guidance for developing and applying self-adjuvanted cancer vaccines using Mincle agonists as both the carrier and "build-in" adjuvant.