‘Trojan Horse’ Antibody Strategy Shows Promise Against Ebola Viruses
Scientists have found a hidden weak spot shared by all five known types of the deadly Ebola virus and successfully targeted it with two antibodies that blocked its ability to invade human cells. In early stage laboratory experiments published in the journal Science, the researchers developed a "Trojan horse" strategy that allows engineered antibodies to hitch a ride on Ebola to where the virus is most vulnerable before hitting it. "The success in co-opting the virus itself to dispatch a lethal weapon … marks a turning point in development of smart therapeutics against infectious diseases," said M. Javad Aman, a scientist and president at the U.S. biotech firm Integrated BioTherapeutics who worked on the team. Although years of testing lie ahead before any fully approved treatment might be developed for Ebola patients, Aman said similar strategies could also be devised against several other viral and bacterial pathogens. No approved treatments Ebola is an extremely deadly and contagious disease for which there are currently no regulator-approved vaccines or treatments. A vast outbreak of the Zaire strain of the virus, which causes hemorrhagic fever, killed more than 11,000 people and infected around 29,000 in West Africa in 2014-15. Monoclonal antibodies, which bind to and neutralize specific pathogens and toxins, have emerged as the most promising treatments for Ebola. But a critical problem is that most antibody therapies — including the most promising experimental therapy, ZMapp — target only one specific Ebola virus. In this work, the research team found a way around this by targeting a weak spot — in the so-called lysosome of the cell — to where antibodies could hitch a ride on Ebola and deliver a punch that blocked the virus' exit and ability to replicate. The strategy could eventually be developed for use in a range of other viruses, the scientists said, including cousins of Ebola such as Marburg, and other viral diseases such as dengue or Lassa. "It's impossible to predict where the next Ebola virus outbreak will occur or which virus will cause it," said Jon Lai of the Albert Einstein College of Medicine in New York City, who co-led the work. "We hope that further testing in nonhuman primates will establish our antibodies as safe and effective for treating those exposed to any Ebola virus."