A breakthrough study confirmed what scientists have long suspected: Ebola attaches itself to a singular, “gateway” protein to infect hosts. When mice were genetically engineered to lack the protein, these failed to become infected. Though extremely early, these promising results suggest Ebola outbreaks could be contained using vaccines that inhibit the protein either to stop the spread or prevent infection altogether. Nine out of ten infected Ebola patients die, and last year was the worst outbreak in history killing more than 11,000 people in Africa in official numbers, and likely twice as much in reality.
Ebola has an Achilles’ heel
In 2011, a virologist called Kartik Chandran at the Albert Einstein College of Medicine in New York City identified the protein in question, called NPC1, as a likely Ebola partner in crime. Chandran and colleagues found the protein rests in cell membranes and helps the virus slip past a cell’s defenses. Then, once inside the host organism it’s all free lunch. But they weren’t able to confirm their findings at the time. It remained a hunch.
In a new paper published in mBio, Chandran wanted to see what happened if the protein went missing, so they studied Ebola infection under three scenarios: 1) mice engineered with no copy of NPC1 2) mice with only one copy of the protein 3) mice with with two copies of NPC1, which is typical. The latter dropped like flies; mice with half the copies of the protein had a lower rate of infection and a lower rate of death versus the normal mice. The mice with no trace of the carrier protein came out healthy with no sign of Ebola infection.
“When we saw that you could not detect the virus at all, that was the ah-ha moment,” said John Dye, chief of viral immunology at the U.S. Army Medical Research Institute of Infectious Diseases. “I’ve looked at a lot of knockout mice over time and never seen that before.”
NPC1 is involved in transporting cholesterol through a cell. People lacking the protein develop Niemann-Pick disease which can lead to dementia and early death. However, a drug or vaccine that inhibits the protein for a short while, say a couple of months, could act as a shield for doctors going on life threatening missions in outbreak areas or massively deployed in those areas where the local population is at risk. For instance, in Guinea dead bodies are moved around using public transportation. It’s superfluous to mention how wrong this is.
“What the data suggests is that people who are completely deficient in it would never know they had been exposed [to Ebola], vs. having a single copy, those people may become sick, but probably would have a subclinical infection; they might not go to the hospital,” said co-first author Andrew Herbert, senior research scientist in the viral immunology branch of the U.S. Army Medical Research Institute of Infectious Diseases.
One could also imagine a situation where it could be used as a prophylactic, where a doctor who’s going into a very high risk clinic for a month or two could take it preventatively,” Dye said. “It’s very important when we’re asking doctors to risk their lives to provide care to provide some level of protection.”
According to Dye, a FDA-approved drug wouldn’t be ready for 5-10 years, but given emergency use there’s hope it could ready in 1-2 years.