Polymer Implant Vaccine Successful in Mouse Cancer Model

A new type of vaccine based on implantation of an infection-mimicking polymer with potential application against cancer as well as against infectious and autoimmune has been successfully tested in a mouse cancer model.

Investigators at Harvard University (Cambridge, MA, USA) have based their presumptive vaccine on small plastic disks (eight millimeters in diameter) that were impregnated with cytokines and specific tumor antigens before being inserted into tumor-bearing mice.

The polymer vaccine was designed so that dendritic cells would be attracted by the cytokines to the porous interior of the disk. The immune cells would then interact with the tumor antigens that coat the polymer. Finally, the dendritic cells would spread to nearby lymph nodes where they would trigger a general immune response against cancer cells bearing the tumor antigens.

The investigators reported in the January 11, 2009, online edition of the journal Nature Materials that the specific and protective antitumor immunity generated by the polymer resulted in 90% survival of mice that otherwise would have died from cancer within 25 days.

"Our immune systems work by recognizing and attacking foreign invaders, allowing most cancer cells - which originate inside the body - to escape detection," explained senior author Dr. David J. Mooney, professor of bioengineering in Harvard University. "This technique, which redirects the immune system from inside the body, appears to be easier and more effective than other approaches to cancer vaccination."

"Much as an immune response to a bacterium or virus generates long-term resistance to that particular strain, we anticipate our materials will generate permanent and body-wide resistance against cancerous cells, providing durable protection against relapse," said Dr. Mooney. "This study demonstrated a powerful new application for polymeric biomaterials that may potentially be used to treat a variety of diseases by programming or reprogramming host cells. The system may be applicable to other situations in which it is desirable to promote a destructive immune response (for example, eradicate infectious diseases) or to promote tolerance (for example, subvert autoimmune disease)."

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