The human body has the ability to ward off viruses by activating a naturally occurring protein at the cellular level, setting off a chain reaction that disrupts the levels of cholesterol required in cell membranes to enable viruses to enter cells. The findings, discovered by researchers in molecular microbiology and immunology at the Keck School of Medicine of USC, hold promise for the development of therapies to fight a variety of viral infections.
"Previous studies have shown that our bodies are already equipped to block viruses such as Ebola, influenza, West Nile, and SARS," said Jae U. Jung, principal investigator and distinguished professor and chair of the Molecular Microbiology and Immunology Department. The study, "The antiviral effector IFITM3 disrupts intracellular cholesterol homeostasis to block viral entry," was published in the journal Cell Host & Microbe on April 17, 2013.
"We showed how this occurs," Jung said. "When a virus tries to enter, the immune system gets stimulated by interferon, which produces almost 300 host proteins, including IFITM3. This protein then disrupts the interaction between two other proteins, which, in turn, significantly increases the level of cholesterol in cells, and thereby blocks the virus."
Jung added that the increase in cholesterol is only within the endosome compartment of cells and has no impact on or effect from the level of cholesterol in the bloodstream.
Joining Jung in the study were Samad Amini-Bavil-Olyaee, Keck School postdoctoral research associate and first author of the paper, as well as Youn Jung Choi, Keck School graduate student and second author, and researchers from the University of California, Riverside and Scripps Research Institute. The research was funded by the National Institutes of Health (grants CA082057, CA31363, CA115284, DE019085, AI073099, AI083025, HL110609) and the Fletcher Jones Foundation.
Scientists long have known that interfe
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University of Southern California - Health Sciences