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Vaccination is a medical intervention that helps the immune system protect against some of those disease-causing microbes. For example, diphtheria, polio and smallpox vaccines alert the immune system so that when the those disease causing pathogens are encountered in the environment, they are rejected. Vaccines keep most of us from developing those deadly diseases but vaccination provides little or no help after we already have the disease. Microbial vaccines are non-therapeutic.
Cancer is a foreign invader that avoids immune detection by invading from within the body. Cancers grow and kill their host without the immune system becoming aware of their existence. However, vaccinating cancer patients with their own cancer cells induces immune response against growing cancers.
Despite the fact that strong immune responses develop following vaccination, powerful cancer vaccines, like powerful microbial vaccines, have little or no effect on disease progression.
The question for immunotherapy is; since it's possible to induce immune responses against an individual's cancer, is it possible to convert vaccination into a therapeutically effective medical intervention? Are there any immune manipulations that can be added to vaccination that could result in significant anti-cancer effects? The solution lies in understanding how the immune system rejects infectious agents.
The immune system protects us against foreign invaders, such as viruses, by producing immune effector cells that immunologists have named cytotoxic ("killer") T cells. Immunity to cancer also is mediated by immune "killer" T cells. "Killer" T cells kill cancer cells. Vaccination, by itself, has little effect on growing cancers because vaccination doesn't produce enough "killer" T cells within the body.
The solution was provided by using a second manipulation to increase the number of "killer" T cells in the body. "Killer" T cell precursors were removed from the body of immunized individuals, converted into "killer" T cells in the laboratory and then reinfused into the bloodstream of the cancer-bearer. "Killer" T cells traveled to sites of cancer growth, entered cancer tissue, killed cancer cells and rejected the cancer. If enough "killer" T cells could be delivered into the cancer patient's bloodstream, the cancer could be completely and permanently eliminated.
Representative references are provided in
the selected references section. In addition, a more extensive list of proof-of-principle scientific publications also is provided.
In
order for those preclinical observations to be successfully translated
to humans, similar immunological manipulations must be possible in humans. Human scientific studies demonstrated that human cancers, like experimental animal cancers, are immunogenic and therefore potentially susceptible to a form of cancer specific immunotherapy that employs "killer" T cells as the primary anti-cancer agent.
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