A novel combined conjugate vaccine: enhanced immunogenicity of bFGF with CRM197 as a carrier protein.

Tumor growth is partly dependent on tumor-asso- ciated angiogenesis, which is regulated by angiogenic growth factors. As the first angiogenic growth factor to be identified, basic fibroblast growth factor (bFGF) plays a major role in angiogensis and tumor growth and has been an effective target for anti-tumor therapy. However, due to its low immu- nogenicity, injection with bFGF alone cannot stimulate the body to produce a strong immune response. In this study, we investigated the role of CF (containing bFGF and CRM197) assisted by CpG and alum in enhancing antigen-specific immune response and suppressing the growth of murine colon carcinoma. The results revealed that compared to bFGF, CF could not stimulate NIH-3T3 fibroblast proliferation even at a concentration of 10 µg/ml in vitro. In vivo, the CF-CpG-alum produced a stronger antigen-specific immune response and inhibited tumor growth. The anti-tumor activity was associ- ated with generating antigen-specific antibody, suppressing angiogenesis, promoting the apoptosis of tumor cells and inducing the mixed Th1 and Th2 responses. This indicates that CRM197 may be an innovative intramolecular adjuvant and provides a rational preservation for mouse CT26 colon carcinoma.