Could cat poop hold the key to cure cancer?

A mutated strain of a cat poop parasite has been found to reprogramme the natural power of the immune system to kill cancer cells, scientists say. Toxoplasma gondii (T gondii) is a single-celled parasite found in a cat's intestines, but it can live in any warm blooded animal. T gondii affects about one-third of the world's population. 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 T gondii. A healthy immune system responds vigorously to T gondii in a manner that parallels how the immune system attacks a tumour. (Read: Can grape seeds cure prostate cancer?)

'We know biologically this parasite has figured out how to stimulate the exact immune responses you want to fight cancer,' said David J Bzik, professor of Microbiology and Immunology, Geisel School of Medicine at Dartmouth. In response to T gondii, the 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 T gondii into a tumour environment can jump start the immune system. (Read: Can cancer be cured with alternative therapies?)

'The biology of this organism is inherently different from other microbe-based immunotherapeutic strategies that typically just tickle immune cells from the outside,' said Barbara Fox, senior research associate of Microbiology and Immunology. 'By gaining preferential access to the inside of powerful innate immune cell types, our mutated strain of T gondii reprogrammes the natural power of the immune system to clear tumour cells and cancer,' Fox said. Since it isn't safe to inject a cancer patient with live replicating strains of T gondii, Bzik and Fox created 'cps,' an immunotherapeutic vaccine. Based on the parasite's biochemical pathways, researchers 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. (Read: Cell division secrets hold the cure for cancer)

Even when the host is immune deficient, cps still retains that unique biology that stimulates the ideal vaccine responses. 'Aggressive cancers too often seem like fast moving train wrecks. Cps is the microscopic, but super strong, hero that catches the wayward trains, halts their progression, and shrinks them until they disappear,' said Bzik.Published laboratory studies from the Geisel School of Medicine labs have tested the cps vaccine in extremely aggressive lethal mouse models of melanoma or ovarian cancer and found unprecedented high rates of cancer survival. (Read: Can the measles virus cure cancer?)

What is cancer?

Cancer is a group of over one hundred diseases characterised by abnormal, uncontrolled cell growth. Ina healthy body cells grow, die and are replaced in a very controlled way. Damage or change in the genetic material of cells by environmental or internal factors result in cells that don't die and continue to multiply until a massive cancer or a tumour develops. Most cancer related deaths are due to metastasis, malignant cells that penetrate into the circulatory system and establish colonies in other parts of the body. Join the War on Cancer.

With inputs from PTI

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