T. gondii<\/a><\/em>\u00a0is a single-celled parasite that is happiest in a cat's intestines, but it can live in any warm-blooded animal. Found worldwide,\u00a0T. gondii<\/em> affects about one-third of the world's population, including about 60 million Americans. Most people have no symptoms, but some experience a flu-like illness. Those with suppressed immune systems, however, can develop a serious infection if they are unable to fend off\u00a0T. gondii<\/em>.<\/p>\n A healthy immune system responds vigorously to\u00a0T. gondii<\/em>\u00a0in a manner that parallels how the immune system attacks a tumor.<\/p>\n \"We know biologically this parasite has figured out how to stimulate the exact immune responses you want to fight cancer,\" said\u00a0David J. Bzik, PhD<\/a>, a professor of microbiology and immunology at Geisel.<\/p>\n In response to\u00a0T. gondii<\/em>,\u00a0the body produces natural killer cells and cytotoxic T cells. These cell types wage war against cancer cells. Cancer can shut down the body's defensive mechanisms, but introducing\u00a0T. gondii<\/em>\u00a0into a tumor environment can jump-start the immune system.<\/p>\n \"The biology of this organism is inherently different from other microbe-based immunotherapeutic strategies that typically just tickle immune cells from the outside,\" said\u00a0Barbara Fox<\/a>, a senior research associate of microbiology and immunology. \"By gaining preferential access to the inside of powerful innate immune cell types, our mutated strain of\u00a0T. gondii<\/em>\u00a0reprograms the natural power of the immune system to clear tumor cells and cancer.\"<\/p>\n Since it isn't safe to inject a cancer patient with live replicating strains of\u00a0T. gondii<\/em>, Bzik and Fox created \"cps<\/em>,\" an immunotherapeutic vaccine. Based on the parasite's biochemical pathways, they delete a Toxoplasma gene needed to make a building block of its genome and create a mutant parasite that can be grown in the laboratory but is unable to reproduce in animals or people. Cps<\/em> is both nonreplicating and safe. Even when the host is immune-deficient, cps<\/em>\u00a0retains that unique biology that stimulates the ideal vaccine responses.<\/p>\n \"Aggressive cancers too often seem like fast moving train wrecks. Cps<\/em> is the microscopic, but super strong, hero that catches the wayward trains, halts their progression, and shrinks them until they disappear,\" said Bzik.<\/p>\n Published laboratory studies from Geisel School of Medicine labs have tested the cps<\/em> vaccine in extremely aggressive lethal mouse models of\u00a0melanoma<\/a>\u00a0and\u00a0ovarian cancer<\/a>\u00a0and found unprecedented high rates of cancer survival.<\/p>\n \"Cps<\/em> stimulates amazingly effective immunotherapy against cancers, superior to anything seen before,\" said Bzik. \"The ability of cps<\/em> to communicate in different and unique ways with the cancer and special cells of the immune system breaks the control that cancer has leveraged over the immune system.\"<\/p>\n This new weapon against cancer could even be tailored to an individual patient. \"In translating cps<\/em> therapy to the clinic, we imagine cps<\/em> will be introduced into cells isolated from the patient. Then Trojan Horse cells harboring cps<\/em> will be given back to the patient as an immunotherapeutic cancer vaccine to generate the ideal immune responses necessary to eradicate their cancer cells and to also provide life-long immunity against any future recurrence of that cancer,\" said Bzik.<\/p>\nAn anti-cancer agent in nature?<\/h4>\n
Engineering\u00a0T. gondii<\/em>\u00a0as a cancer vaccine<\/h4>\n
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Laboratory success in melanoma and ovarian cancers<\/h4>\n
A promising future for a personalized cancer vaccine<\/h4>\n