A report of a new treatment for a deadly virus might pass for a movie script — so much so that a version of it is already showing in a theater near you.
Much like the virus that wreaked havoc in the movie “Contagion,” the rare Hendra virus and its close cousin Nipah virus can rapidly kill the people they infect. Researchers have now designed and mass-produced a highly specialized antibody against Hendra and used it as an immune therapy that can halt the infection in monkeys. The drug may also apply to the related Nipah virus, since both invade cells via the same portals, scientists report in the October 19 Science Translational Medicine.
Hendra virus has infected and killed scores of horses in Australia and jumped to people on several occasions. While only a dozen people have contracted Hendra infections, some have died. Nipah virus is carried by pigs and has infected hundreds of people in Malaysia, Singapore and Bangladesh, with fatality rates ranging from 40 to 70 percent (SN: 12/19/09, p. 15).
The viruses cause brain inflammation and severe pneumonia-like illness. Both were first identified in the 1990s and are spread by fruit bats.
Some Nipah infections have been traced to person-to-person contact. Not coincidentally, “Contagion” included a scene in which the words “Nipah virus” pop up briefly as researchers conduct tests. They even mention “paramyxovirus,” a class that includes Nipah and Hendra. There was no treatment for the movie virus, so scientists sought to develop a vaccine.
In the real-life version, a U.S. and Canadian team of scientists tested antibodies and found one called m102 that showed potential in blocking Hendra virus from attaching to a cell. The researchers then modified the antibody and mass-produced it as a drug.
Working in extreme biosafety conditions at the National Institutes of Health’s Rocky Mountain Laboratories in Hamilton, Mont., the researchers infected 14 African green monkeys with Hendra virus by squirting it down the animals’ tracheas.
Two monkeys were left untreated and developed lethal disease within eight days.
The other 12 monkeys received two doses of the antibody treatment, starting 10, 24 or 72 hours after being infected. All survived. The 72-hour delay between exposure to Hendra virus and starting treatment mimicked field conditions, says study coauthor Thomas Geisbert, a virologist at the University of Texas Medical Branch at Galveston.
The experimental antibody blocks infection by binding to two cell-surface proteins that the Hendra and Nipah viruses use as doors to invade, Geisbert says.
In an earlier study of the antibody’s effectiveness against Nipah virus, ferrets given the antibody were able to fend off that infection. The team is now testing the antibody against Nipah in green monkeys, Geisbert says.
The researchers “should be commended for a well-designed efficacy study that provides results that are relevant to the human therapeutic situation,” says Benhur Lee, a physician and researcher at the UCLA School of Medicine, writing in the same issue of Science Translational Medicine. Lee, who wasn’t involved in the study, is encouraged that the antibody lasted 11 days in the body.
The team plans to seek clearance to test the treatment in people. An Australian woman and her daughter received it last year in an emergency after a possible exposure to Hendra virus. They didn’t become sick, but it is unclear whether they were truly exposed.
In “Contagion,” the researchers never say which paramyxovirus they are fighting. But Lee says that a ribbonlike, 3-D diagram of proteins shown in the movie is familiar. “They actually used the crystal structure of the Nipah glycoprotein binding to the ephrin-B2 receptor,” he says. That’s one of the two cell-surface proteins that the viruses commandeer — and the very same ones that the new antibody treatment obstructs. Based on a true story indeed.
