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Morpholino Targeted at VP24 Protein Protects 75% of Rhesus Monkeys Against Ebola
Scientists protected 75 percent of rhesus monkeys infected with Ebola virus that were treated with a compound targeting the expression of VP24, a single Ebola virus protein--suggesting that VP24 may hold the key to developing effective therapies for the deadly disease. The study, which appears on February 10, 2015 in mBio, the online journal of the American Society for Microbiology, was conducted by the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), in collaboration with the biotechnology firm Sarepta Therapeutics, Inc. For over a decade, USAMRIID and Sarepta have been collaborating to develop and test a class of antisense compounds known as phosphorodiamidate morpholino oligomers (or PMOs), according to principal investigator and first author Travis K. Warren, Ph.D., of USAMRIID. "Antisense drugs are designed to enter cells and eliminate viruses by preventing their replication," Dr. Warren said. The drugs act by blocking the translation of critical viral genetic sequences, preventing the xxx protein from being made, and giving the infected host time to mount an immune response and clear the virus, he explained. In work previously published in Nature Medicine, the team demonstrated that a combination PMO called AVI-6002, a product targeting genes that code for two proteins, VP24 and VP35, prevented Ebola virus infection in rhesus monkeys. The current study compared the activity of the individual components against that of the combination treatment. In this experiment, animals were treated with AVI-7537, which targets VP24 alone; AVI-7539, which targets VP35 alone; or AVI-6002, which targets both proteins. A fourth group served as the untreated control. Animals were treated once a day for up to 14 days beginning approximately one hour after virus exposure.