Can cat poop help with fighting cancer?
This sounds a strange concept - that your cat's poop may give you an edge against one of the most deadly diseases in the modern world. However recent scientific studies have shown that there may be some truth in the far-fetched idea. And behind it all is Toxoplasma gondii (T. gondii). This is a bug which infected cats can transmit to humans via their feces. It's notoriously dangerous for pregnant women to be exposed to T.gondii (see: Cats, toxoplasmosis and (human) pregnancy ), but if the spread of the disease is the nasty Mr Hyde, the parasite is now showing its more benevolent Dr Jekyll side.
It appears that when healthy - and non-pregnant - individuals become infected with T. gondii, this stimulates a vigorous immune response. The body arms itself against the invader with fighting cells - predominantly cytotoxic T cells and the wonderfully-named NK (Natural Killer) cells. These are used by the immune system to kill intruders and, as it happens, the cells are the same as those which are needed to fight cancers. |
One problem with tumours is that the cancers are very good at blocking the immune responses that the body needs to fight them, so often the killer cells never have a chance to get going against a cancerous growth. Thanks to interference from the tumour, the immune system is never properly aware that the tumour is there. And that's where T.gondii steps in. Scientists from the Norris Cotton Cancer CenterDartmouth-Hitchcock Medical Center have shown that exposure to this parasite can-jump start the immune system. When T.gondii is introduced into a body environment that includes a tumour, the cells that the body produces to fight T.gondii appear to also turn their attention to the cancer.
Of course introducing a live pathogen such as T.gondii into a human body is always dangerous. And this is particularly true when dealing with people with cancer, because their immune systems are already in poor shape. So David J Bzik (professor of Microbiology and Immunology) and Barbara Fox (senior research associate of Microbiology and Immunology) went about things differently. They designed an immunotherapeutic vaccine known as 'cps'. By deleting specific genes from the T. gondii genome they created a mutation. The result is a parasite which can be grown in the laboratory but which can not reproduce when injected into a host body. (T.gondii usually reproduces happily in almost any mammal.)
'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 ‘By gaining preferential access to the inside of powerful innate immune cell types, our mutated strain of T. gondii reprograms the natural power of the immune system to clear tumor cells and cancer.'
The 'cps' vaccine is both non-replicating and safe. And what's more it is still capable of stimulating an ideal response from even an immunodeficient patient. Although there have not yet been any human studies, in the laboratory treatment with the cps vaccine has been very effective against aggressive melanomas and ovarian cancer in mice.
'Cps stimulates amazingly effective immunotherapy against cancers, superior to anything seen before', said Bzik. 'The ability of cps 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'.
As for tests on humans, there is still a long way before the vaccine leaves the laboratory and moves into clinics. Nevertheless the researchers believe that they found something special - especially as this new vaccine can even be individually tailored to each cancer patient.
'In translating cps therapy to the clinic, we imagine cps will be introduced into cells isolated from the patient. Then 'Trojan Horse' cells harboring cps 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 professor Bzik.
Exciting stuff - though the concept of a cancer vaccine has offered false promises many times before. A lot of testing remains to be done before scientists can be sure that in this case the contents of a feline litter tray may actually carry the basis of a life-saving treatment.
Note: This information is for guidance only. It is not intended to replace consultation with a licensed veterinary practitioner or a doctor.
