This study describes the first primate model of immune protection against Ebola virus, a model that may allow scientists to rationally design a vaccine that prevents this dreaded disease in humans. We have not known if immunity to the virus exists or what parts of the immune response are important. Our studies show that animals can launch an effective immune response against Ebola virus, and we can use knowledge of this response to design a vaccine that protects non-human primates from infection. Although much more work needs to be done, we hope this moves us closer to new vaccines and treatments for Ebola and other viruses. Ebola virus kills quickly, giving the body little time to launch an effective immune response.
Infected individuals suffer severe pain, high fever and extensive internal bleeding.
Although the virus periodically strikes humans, scientists do not know where it resides in nature between outbreaks. Dr. Nabel and colleagues had previously tested genetic Ebola vaccines strands of DNA containing genes that encode Ebola virus proteins for their ability to induce immune responses in rodents and to protect against disease. Unlike traditional vaccines, typically made from viral proteins, DNA vaccines more closely mimic virus infection because they enter a cell and use that cell's machinery to manufacture new viral proteins. Researchers believe this strategy might better trick the immune system into thinking a real virus infection has occurred. Previously, Dr. Nabel's laboratory and a second research team independently showed a DNA vaccine could protect mice and guinea pigs from a specially adapted Ebola virus strain lethal to rodents.