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Bloomberg.com: Science: "Ebola Protein Offers Clues for Drugs to Fight Virus (Update1)

By Simeon Bennett
More Photos/Details

Ebola Protein Offers Clues for Drugs to Fight Virus (Update1)

By Simeon Bennett
More Photos/Details

July 9 (Bloomberg) -- Ebola, a highly contagious virus that kills many of those infected within a week, has a critical protein that may point the way to drugs and vaccines, according to a study published today in the journal Nature.

Seen for the first time, the so-called glycoprotein is part of the mechanism the virus uses to enter healthy human cells. Researchers at the Scripps Research Institute in La Jolla, California, said by revealing the protein's shape and understanding how it works, they have exposed chinks in Ebola's armor that could be targeted for treatment.

They're now trying to tailor infection-fighting antibodies to attack those weaknesses, joining companies including Crucell NV and Alnylam Pharmaceuticals Inc in the quest for treatments against a disease for which there are no drugs or vaccine.

``Much about Ebola virus is still a mystery,'' said Erica Ollmann Saphire, who led the research, in an e-mailed statement. ``This structure now reveals how this critical piece of the virus is assembled and, importantly, identifies vulnerable sites that we can exploit,'' she said.

Ebola kills 50 to 90 percent of people who contract it, according to the World Health Organization. The latest outbreak of the disease, which was confirmed by Ugandan health officials in November, was Africa's worst in five years.

More than 1,850 human cases, including 1,200 deaths, have been recorded since Ebola was first identified more than three decades ago in Sudan and the Democratic Republic of Congo. The virus causes high fevers, diarrhea and vomiting and often leads to severe internal bleeding.

Clues from Survivor

Ollmann Saphire and colleagues studied a virus sample isolated from a survivor of a 1995 outbreak in the Democratic Republic of the Congo. The virus was attached to a so-called neutralizing antibody that was fighting it. While research has shown the antibody protects rodents from Ebola, a study last year found it didn't work in monkeys.

By examining which parts of the virus were attached to the antibody, the scientists exposed its weaknesses, providing clues for future research. While they studied the so-called Zaire species of the virus, the most common and deadly type, their findings are relevant to all five strains, Ollmann Saphire said.

They also discovered that some parts of the virus that help it evade the body's immune system are similar in structure to parts of the HIV and Epstein-Barr viruses, suggesting Ebola may help scientists understand why some diseases manage to avoid the body's defenses.

Fooling the Body

The viruses have developed a ``carbohydrate cloak'' that hides the machinery they use to infect healthy cells, fooling the immune system into identifying the virus as a normal cell, Ollmann Saphire said in an e-mail. Gaps in the cloak allow the virus to bind to healthy cells, and may also offer the best opportunities to attack it, she said.

In the case of Ebola, which can survive in bat excrement or partially eaten fruit for long periods, the cloak may also help keep the virus moist, protected and stable between animal hosts, she said.

To contact the reporter on this story: Simeon Bennett in Singapore at sbennett9@bloomberg.net
Last Updated: July 9, 2008 14:25 EDT