Scientists from Grenoble University Alpine figured out how toxoplasmosis is known for its ability to change the behavior of infected organisms, disarm the human immune system. It turned out that the key role played by protein GRA24 by which a microbe controls protective reaction of the body.
Toxoplasma gondii belongs to the protist is a parasite that infects mostly cats. It is known that getting into rats and mice, the simplest change their behavior, like the zombie infection from a science fiction movie. As a result, the rodents begin less fearful of cats and are more likely to be victims of these predators. Scientists suggest that the microbes may also modify the identity of an infected person. However, in order to be a long time in the host organism, Toxoplasma gondii needs to neutralize the immune system, but not destroy it completely, otherwise the victim will die.
The researchers found that Toxoplasma secretes protein GRA24 affecting the host immune system through binding to p38α protein. When the body is invaded by a parasite, it is recognized by the cells, triggering a series of reactions that eventually activate the protective system. The protein p38α is involved in this chain, moving into the nucleus where it switches on genes responsible for inflammation.
GRA24 associated with p38α much stronger than the proteins belonging to the infected cell. Toxoplasma is possible to control the intensity of the inflammatory response and prevent disabling it. Protective reactions become not effective enough to cope with the parasite, however, they can effectively deal with other infections. Thus, Toxoplasma is only a threat to pregnant women and people with weakened immune systems.