Immunization of mice with gold nanoparticles conjugated to thermostable tumor antigens prevents tumor development during transplantation

Gold nanoparticles as part of vaccines greatly increase antigen stability, antigen accumulation in the lymph nodes, and antigen uptake by antigen-presenting cells. The use of such particles as part of anticancer vaccines based on heat shock proteins to increase vaccine effectiveness is timely. We prepared and characterized nanoconjugates based on 15-nm gold nanoparticles and thermostable tumor antigens isolated from MH22a murine hepatoma cells. BALB/c mice were injected with the conjugates and then received transplants of MH22a cells. The immunized mice showed no signs of tumor growth for 24 days. They also showed decreased production of the INF-γ, IL-6, and IL-1 proinflammatory cytokines, as compared to the mice immunized through other schemes. This study is the first to show that it is possible in principle to use gold nanoparticles in combination with thermostable tumor antigens for antitumor vaccination. Antitumor vaccines based on thermostable tumor antigens can be largely improved by including gold nanoparticles as additional adjuvants.