DALLAS—Immunology researchers at UT Southwestern Medical Center found that bacteria present in the human gut help initiate the body’s defense mechanisms against Toxoplasma gondii, the parasite responsible for toxoplasmosis.
Toxoplasmosis is generally a mild infection, but it can have serious and potentially fatal effects in pregnant women, their fetuses and others with weakened immune systems.
In mice, T gondii directly activates a specific immune protein in the host, called toll-like receptor 11 (TLR-11), which helps control the animals’ immune response to the parasite. Humans, however, don’t have an active form of this receptor.
In a new study appearing online and in the Aug. 20 issue of Cell Host & Microbe, researchers at UT Southwestern suggest that instead of activating toll-like receptors directly, T gondii’s first interaction in the human gut is with the helpful bacteria that live inside us. Those bacteria then release signaling molecules, alerting the human host to the invader.
“While this is very early data, our results suggest that looking at the bacteria present in each patient’s gut could help physicians understand their susceptibility to infectious diseases,” said Dr. Felix Yarovinsky, assistant professor of immunology at UT Southwestern and senior author of the paper. “It also suggests the possibility of developing novel probiotic strategies for treating parasitic infections such as toxoplasmosis and cryptosporidiosis, a related disease caused by the parasite Cryptosporidium.”
