Parasite Inhibits Your Immune System, Changes Your Behaviour
September 22, 2011 2 Comments
Via Science Daily: There’s a protozoan parasite called Toxoplasma gondii that can manipulate behaviour; for example, causing rodents to seek out felines, as a means of getting T. gondii to their breeding ground in the feline intestine (here’s a video of a zombie-rat in action). In humans, T. gondii have been linked “to behavioral and personality shifts, schizophrenia and population variations, including cultural differences and skewed sex ratios.” Sounds like powerful stuff. Good thing our baller immune system can destroy it… right?
No 😦 .
These highly contagious protozoa infect more than half the world’s population, and most people’s immune systems never purge the intruders…
“We found that Toxoplasma quiets its host’s alarm system by blocking immune cells from producing certain cytokines, proteins that stimulate inflammation…”
When immune cells meet intruders, they release cytokines that summon more immune cells, which produce more cytokines, rapidly causing inflammation. T. gondii must allow cytokines to trigger enough of an immune response to keep its own numbers in check and ensure host survival. But too many cytokines cause an overwhelming immune response that could damage the host or eliminate the parasites…
“Cells infected with Toxoplasma produced no messages to trigger inflammation,” Denkers said. “Our colleagues at Stanford University found that Toxoplasma produces a specific protein called ROP16 to suppress inflammatory responses. Collaborating with parasitologists at Dartmouth Medical School, we found that Toxoplasma sends ROP16 to infiltrate communication channels in immune cells, causing them to lower cytokine production.
Apparently, this is the first known parasite to wield this superpower. Who knows what other kind of creepy crawlies are lurking inside of us? Now, go off into the world, acting strangely, and intelligently inform people that the T. gondii made you do it.