Vaccine Protects Animals From Ebola

Photo: Ebola virus looking like a long knotted string

The vaccine under developement
fights ebola with Ebola virus-like
particles; © public domain

“The findings are significant in that the vaccine is not only extremely safe and effective, but it is also produced by a method already established in the pharmaceutical industry,” says Ricardo Carrion, one of the primary authors of the study.

Ebola viruses are considered a dangerous threat to public health because of their high fatality rate, ability to transmit person-to-person, and low lethal infectious dose. While some vaccines show protection in non-human primate studies, the strategies used may not be uniformly effective in the general human population due to pre-existing immunity to the virus-based vaccines.

In the new study, a vaccine using Ebola virus-like particles (VLPs) was produced in insect cells using traditional bio-engineering techniques and injected into laboratory mice. A VLP vaccine is based upon proteins produced in the laboratory that assemble into a particle that, to the human immune system, looks like the virus but cannot cause disease.

Two high-dose VLP immunisations produced a high level immune response in mice. And when the twice-immunised mice were given a lethal dose of Ebola virus, they were completely protected from the disease. In contrast, mice that were not immunised had a very low immune system response and became infected. In another experiment, a three low-dose VLP immunisation effectively boosted immune system response in mice and protected them against the Ebola virus. This finding is important because it demonstrates that since the vaccine produces immunisation in dilute quantities, many more vaccine doses can be generated compared with a poorly immunogenic vaccine.

VLPs are attractive candidates for vaccine development because they lack viral genomic material and thus are not infectious, are safe for broad application, and can be administered repeatedly to vaccinated individuals to boost immune responses. The findings will be validated in additional animal systems.; Source: Southwest Foundation for Biomedical Research (SFBR)