Enhancement of the immunogenicity of synthetic carbohydrate vaccines by chemical modifications of STn antigen.

The abnormal glycans expressed on the surface of tumor cells, known as tumor-associated carbohydrate antigens, increase the chance to develop carbohydrate-based anticancer vaccines. However, carbohydrate antigenspose certain difficulties, and the major drawback is their weak immunogenicity. To tackle this problem, numerous structurally modified STn antigenswere designed and synthesized in this work. These synthetic antigenswere screened in vitro by using competitive ELISA method, and the antigenswith positive response were conjugated to the protein carrier for vaccination. The vaccination results on mice showed that some fluorine-containing modifications on the STn antigencan significantly increase the anti-STn IgG titers and improve the ratios of anti-STn IgG/IgM. The antisera can recognize the tumor cells expressing the native STn antigen.