Self-amplifying RNA vaccine protects mice against lethal Ebola virus infection

The Zaire Ebola virus (EBOV) is a member of the family Filoviridae, and causes an average case fatality ratio of 50% among the infected population. The viral genome encodes for seven structural proteins: the nucleoprotein NP, VP35, VP30, VP24, and the polymerase L forming the nucleocapsid, and VP40 forming a matrix layer around the nucleocapsid and is associated with the viral lipid envelope into which the surface glycoprotein GP is inserted. In this study, self-amplifying RNAs expressing the EBOV GP alone or in combination with the NP were constructed and tested in mice against EBOV. The mice were first vaccinated intramuscularly with a vaccine containing either GP or NP alone or a combination of GP and NP. This was followed by an infection with a lethal dose of EBOV days later. Results showed that mice that received either GP alone or GP+NP combination had more IgG levels in their serum compared to the mice that received the NP alone vaccine. Furthermore, the GP alone and GP+NP vaccines provided protection against EBOV but not the NP alone vaccine. The experiment also showed that intramuscular administration of the vaccine conferred better protection compared to intradermal route.
(WWN)