A team of international researchers has used a human vaccine to cure prostate tumors in mice without side effects. 

Richard Vile, Ph.D., study leader and Mayo Clinic immunologist, along with Alan Melcher, Ph.D., and Peter Selby, Ph.D., both from the Cancer Research UK Clinical Centre at St. James' University Hospital, have developed a cure for prostate cancer in mice that also shows promise for other cancers and melanoma as well. 

Scientists have attempted to accomplish this in the past, but were hindered by the inability to isolate a diverse collection of antigens in tumor cells. This then causes tumors to mutate and survive the body's immune system. 

But Vile and his team were able to overcome this by first piecing together parts of genetic code from human prostate tissue into a complementary DNA (cDNA) library. The cDNA were then placed into a mob of vesicular stomatitis viruses (VSV), which were cultured. They were then given to the mice as a vaccine through several intravenous injections. 

Tumors have a unique "fingerprint" called an antigen, which triggers an immune system response through a molecular protein tag. By releasing the human vaccine prostate cancer antigens into the mutated VSV vector, the mice's T-cells were able to launch an attack. The animals' immune systems then became familiar with the antigens expressed in the virus after being exposed to the mutated virus, and created a potent immune response. This attacked the prostate tumors. 

Vile's immunotherapy research differed from others because it made use of viruses as vectors for cDNA libraries. This eliminates the challenge of isolating antigens in tumor cells because it offers an in-depth profile of the cancer. 

"Nobody really knows how many antigens the immune system can really see on tumor cells," said Vile. "By expressing all of these proteins in highly immunogenic viruses, we increased their visibility to the immune system. The immune system now thinks it is being invaded by the viruses, which are expressing cancer-related antigens that should be eliminated."

Clinical trials are expected to begin in two years.