"These findings reveal an important new detail about the molecular mechanism Toxoplasma uses to penetrate cells," says study leader L. David Sibley, Ph.D., professor of molecular microbiology. "Identifying the molecular interactions that govern motility may allow development of small molecules that block this mechanism and perhaps lead to new treatments for diseases such as toxoplasmosis and malaria. That's an ambitious undertaking, and there are many hurdles to overcome, but given the importance of these diseases, it is a possibility we must explore."
About 35 million people in the United States and up to a quarter of the world's population are thought to be infected with Toxoplasma. But only those with weakened immunity typically develop severe toxoplasmosis, which can lead to birth defects, brain inflammation and vision problems. People usually acquire the infection by accidentally swallowing spores from contaminated soil, water, cat litter or objects that have had contact with cat feces or by eating raw or undercooked meat, especially chicken, pork, lamb or venison.
Once consumed, the parasite bores into cells, where it reproduces asexually. These organisms then bore into other cells and reproduce again.
Previous research had shown that Toxoplasma uses a protein known as MIC2 (micronemal protein 2) to recognize and attach to host cells. MIC2 molecules bind to receptors on the host cell, thus gripping the membrane. The parasite moves these adhesin-receptor complexes over its surface from front to back like a tractor tread. This concerted actio
Contact: Darrell E. Ward
Washington University School of Medicine