Entamoeba histolytica (green) ingesting bites of human T cells (purple).KATHERINE RALSTONFor decades, scientists assumed that the intestinal parasite Entamoeba histolytica killed human tissues with toxic molecules before ingesting them. They were wrong; it’s actually the other way around, according to a study published in Nature today (April 9).
Katherine Ralston, a postdoctoral researcher at the University of Virginia, has shown that E. histolytica—a single-celled amoeba—tears chunks from host cells and eats them. These attacks eventually kill the cell, at which point the parasite moves on. E. histolytica is the only parasite known to attack tissues in this way—a process known as trogocytosis, after “trogo,” the Greek word for “nibble.”
“It was a complete surprise,” said Virginia’s William Petri, Jr., who led the study. “I have focused my professional career on studying this parasite and I hadn’t appreciated it, nor had anyone else in the field. Katie [Katherine] came into the lab and took a fresh look at things.”
Ralston made her discovery after watching the amoebae under a microscope, while they were attacking ...
