The findings will be published in the Dec. 15 issue of Science by a team led by John Boothroyd, PhD, professor of microbiology and immunology. Working with mice, the researchers identified two genes that produce two proteins that Toxoplasma introduces into the cells of the host it infects. What's more, the researchers showed for the first time that certain changes in either of the proteins - called kinases - ramped up 10,000-fold the damage that Toxoplasma inflicted on the lab mice.
"This was a totally unknown phenomenon," said Boothroyd.
Although the majority of people infected by Toxoplasma have no symptoms, it can cause severe infections in individuals with compromised immune systems. In addition, women infected for the first time while pregnant can pass the organism to their fetuses, potentially resulting in sight and hearing problems as well as learning disabilities. The new findings have implications for determining how to treat these and other infected people: More aggressive therapy may be warranted if a strain that contains the proteins that increase virulence is the cause of the infection.
Humans can become infected by the parasite by accidentally consuming or inhaling the cysts from infected cat feces, by eating meat from an infected animal - especially pork, lamb or venison - or by drinking contaminated water. Cats are the primary carriers of Toxoplasma, though they rarely exhibit symptoms.
The significance of these newly discovered proteins is
Source:Stanford University Medical Center