Ebola uses protein decoy to evade immune response

A study published on Thursday by researchers from Emory University determined that the Ebola virus uses a mechanism to change and avoid the immune response of its infected host.

The Ebola virus, a significant public health threat and a potentially devastating biological weapon, causes Ebola hemorrhagic fever, a disease with up to a 90 percent mortality rate. Attempts to create a vaccine for the virus have had limited success due to the complex immune evasion mechanisms the virus employs, Science Daily reports.

In the study, published in PLOS Pathogens, researchers examined the role of a protein that Ebola-infected cells secrete in large quantities. The authors found that by immunizing mice with the secreted protein, the mice's immune systems were compromised and kept from binding to the Ebola virus.

"Our findings provide an explanation for the lack of protective antibodies against the viral surface protein in patients who have survived Ebola virus infection," Chinglai Yang, an assistant professor of microbiology and immunology at the Emory University School of Medicine, said, according to Science Daily. "We hypothesize that the secreted protein allows the virus to subvert the host antibody response in vivo, and that this may enable the virus to cause repeated or sustained infection in its natural reservoir."

The results suggest that a vaccine may need to reach a certain threshold of immunity to neutralize an incoming Ebola virus infection. The vaccines would need to be able to overcome the ability of the secreted decoy protein to interfere with the immune response.