Antibody-based therapies shown to protect against Ebola, Marburg

U.S. Army scientists recently demonstrated that antibody-based therapies are capable of protecting primates from the potential bioweapon Ebola and Marburg viruses.

The animals were fully protected when the treatment was administered two days after the onset of infection.

Ebola and Marburg, both filoviruses, cause severe hemorrhagic fever in humans with fatality rates as high as 90 percent. There is currently no available vaccine or therapy approved for use in humans. The development of a successful treatment has been a high priority for army scientists.

In the study, which was conducted at the U.S. Army Medical Research Institute of Infectious Diseases, researchers used antibody from monkeys that had previously survived laboratory-controlled challenges by flioviruses. The survivors had developed high levels of antibody while fighting the infection.

The scientists collected blood serum from the animals and tested its ability to neutralize the viruses. Initially, a new set of monkeys were exposed to filoviruses and then treated with the antibodies 15 to 30 minutes later, and then again four and eight days later.

The primates were found to be completely protected and had no detectable levels of the virus in their bodies. All of the monkeys generated an immune response to the Marburg virus and were capable of surviving repeated challenges.

In another set of studies, monkeys were infected with either Ebola or Marburg and given post-exposure treatment after 48 hours, and then again four and eight days later. In each group, two of the three test subjects showed no signs of illness, and a third had mild symptoms.

According to the study, which will be published in the online version of the Proceedings of the National Academy of Sciences, antibody-based therapies have been disregarded for nearly a decade.

"The use of antibodies as a treatment for infectious diseases is a well-established technology, with multiple products having received approval from the Food and Drug Administration," study coauthor John Dye said. "With these findings, we have provided proof-of concept that antibody-based therapies can indeed be used to effectively treat filovirus infections."