Building Blocks of Deadly Ebola Virus Identified

ABC News ^ | Aug. 15 | Merritt McKinney

[Apollo]

NEW YORK (Reuters Health) - Scientists have moved a step closer to understanding the inner workings of the Ebola virus, which has caused deadly outbreaks of hemorrhagic fever in Africa.

There is currently no treatment for Ebola virus infection, which kills 80% to 90% of its victims.

Dr. Gary J. Nabel and colleagues at the Vaccine Research Center at the National Institutes of Allergy and Infectious Diseases in Bethesda, Maryland, report that three proteins are essential for the formation of Ebola virus particles.

Using a technology that allowed them to insert individual genes from the Ebola virus into human cells, Nabel's team tested a variety of gene combinations to see which ones were essential for the virus's formation and survival. Ebola virus would not form, they found, if the genes for three proteins--VP24, VP35 and NP--were not all present. The three proteins interact to modify the NP protein, according to the researchers.

When all three proteins were present, structures similar to the Ebola virus formed in the human cells, Nabel and colleagues report in the August issue of the journal Molecular Cell. But when any one of the proteins was missing, this process was interrupted.

There is still a lot to learn about Ebola, but Nabel told Reuters Health that the identification of the proteins could eventually lead to treatment for the infection, which causes fever, diarrhea and severe bleeding.

"These studies teach us how Ebola virus forms within cells at a molecular and a genetic level," Nabel said. He added that the research "points to specific pathways in cells which are critical to the virus."

By getting an idea of how the virus forms, "we learn fundamental lessons about how complex, but organized, structures like viruses are assembled within cells at the same time that we identify possible leads for the development of antiviral drugs."

In the report, the researchers note that the discovery of the proteins' roles could lead to a better understanding of other similar viruses, such as Marburg virus, another deadly infection that occurs in Africa. Both viruses are called filoviruses because of their resemblance to strings or filaments.

Now that the importance of these proteins has been identified, Nabel said that it may be possible to harness them for good purposes. One possibility, he said, is that the proteins, which are not themselves infectious, "could be used to deliver foreign proteins to the immune system." In this way, he said, they could be useful for developing vaccines.