Smallpox was an unstoppable plague in 18th Century Europe until very late in the century when an English physician, Dr. Edward Jenner, acted on his suspicions that immunity to the often lethal disease could be conferred to individuals if they were vaccinated with a serum containing smallpox’s milder cousin, cowpox.

It was common knowledge of the day that cowpox would produce a brief fever and some discomfort. Cowpox was especially a workplace hazard for milkmaids. Lucky for them, for their mild case of cowpox stimulated their immune systems to be on high alert to seek out and destroy the dreaded smallpox virus were they to be exposed to it.

Our powerful immune system also has the ability to rid the body of mutant cells that divide and proliferate out of control, a process that goes by the name of cancer.

Some scientists, like Mark A. Suckow, director of the Freimann Life Science Center and research associate professor in the Department of Biological Sciences, have reasoned that Jenner’s approach to protecting people against smallpox may also offer a measure of success against cancer.

“It may be very possible to use tumor material from another species, and deactivate the material so it is not only safe for the patient but yet causes our immune system to respond very vigorously to it,” Suckow said. “This would be a rejection not of an organ, but of a tumor. This type of xenogeneic vaccine offers us that possibility.”

Using tumor material derived from rats, Suckow has achieve striking results against prostate cancer in rats - so much so that he is allowing himself to make a bold statement that “Our goal is complete prevention - and possibly even complete cure of prostate cancer with these vaccines.”

Up until now there is virtually no effective treatment for prostate cancer.

Clinical trials involving vaccines not developed through Suckow’s approach have preliminarily been shown to extend lifespan for a year. “What that amounts to is the patient getting an additional 12 months of misery,” he said. “But if we can show that we can completely eliminate prostate cancer from a patient using our method, then that would be unbelievable,” he said.

“We have shown that a tumor tissue vaccine eliminates metastasis in nearly 70 percent of individuals after a tumor has been diagnosed. This is amazing news - since the big problem with prostate cancer is not really the tumor in the prostate, since it can be surgically reduced, the problem is with metastasis to distant sites such as the lungs and the spine. Thus, this approach supports the idea that a tissue vaccine is an effective treatment for prostate cancer,” he said. “Furthermore, we have shown, in a complicated set of experiments using immunodeficient mice that grow tumors from human prostate cancer cells, that a tissue vaccine created from a rat tumor reduced the incidence of tumors from the human prostate cell line by almost 70 percent. This means that a xenogeneic tissue vaccine is a viable and innovative approach to prostate cancer.” Studies with collaborators at the Center for Cancer Care in nearby Goshen, Indiana have shown that the efficacy of the vaccine is increased even further when combined with irradiation of prostate tumors.

Suckow has even shown that a tumor tissue vaccine can prevent prostate cancer. “In fact, one preparation was able to reduce the incidence of prostate cancer in our rat model by 70 percent; another preparation by an astounding 90 percent,” he said. Suckow reasons that vaccines created from whole tumor tissue should generate an immune response to a much broader range of tumor components. “Early work in humans showed some promise, but was abandoned due to the limited amount of tumor material available for vaccine preparation,” he said.

 He believes that this principle could possibly be exploited further by using cancer cells from an entirely separate species to create a vaccine. “By doing so, a very vigorous immune response should result, one that is potentially capable of aggressively attacking the tumor.”

 This may not be as outlandish as it seems. For example, in human patients vaccinated with mouse prostatic acid phosphatase (PAP), stronger immune responses to human PAP developed compared to patients vaccinated with human PAP; thus, PAP from another species stimulated a much greater immune response than host PAP.

Secondly, clinical use of materials from other species is not without precedent. For example, there is a long history of safe use in people of insulin from cattle and swine. And tissue from swine has been safely used for applications in repair of tendons and wound healing.

Suckow and his colleagues have gone as far as to develop a unique vaccine adjuvant. “Our material allows cancer cells, either harvested directly from a tumor or those grown in the laboratory, to grow in a way that more closely resembles their morphology in an intact tumor. This means that the adjuvant allows the vaccine to look more like a cancer to the immune system; in this way then, the immune system is more apt to recognize the cancer and eliminate it after vaccination,” he said. This method enhances the utility of laboratory-grown cells, either allogeneic (cells that are those obtained from another individual of the same species) or xenogeneic as vaccine components. In a number of studies, he has shown that this vaccine adjuvant reduces growth of prostate cancer by an additional 30-50 percent.