Pan-filovirus T-cell vaccine protects mice from Ebola and Marburg

Developing an effective vaccine against filovirus outbreaks is an important public health aim. Vaccine candidates being developed for a small number of filoviruses that most commonly cause outbreaks all employ the virus glycoprotein as the vaccine immunogen, which triggers a protective immune response. However, antibodies induced by such glycoprotein vaccines are typically limited to the other members of the same filovirus species. By contrast, T-cell vaccines offer the possibility to design a single pan-filovirus vaccine that protects against all known and even likely existing, but as yet un-encountered, members of the filovirus family. In the new study, Hanke and colleagues constructed vaccines using cross-filovirus immunogens -- conserved regions of filovirus proteins -- with the aim of inducing protective T-cell responses against viruses across the filovirus family.

The authors demonstrated that T-cell responses can protect two strains of mice against a high lethal virus challenge in the absence of glycoprotein antibodies. Moreover, a single T-cell vaccine can do so against distant members of the filovirus family: Ebola and Marburg viruses. This suggests the possibility that this candidate vaccine also protects against other known, as well as yet un-encountered, viruses of the filovirus family. According to the authors, a successful pan-filovirus vaccine would have multiple uses, such as generating vaccine stockpiles to contain future outbreaks, eliminating the 2013 and 2018 outbreak remnants, eliminating virus reservoirs in survivors, providing long-term protection in high-risk populations including health workers, and even saving highly endangered western gorillas.

Hanke adds, "A universal pan-filovirus vaccine might be possible, which induces killer T cells against the most conserved regions of the inner filovirus proteins very similar among all the member viruses from Ebola to Marburg. Such T-cell vaccine can complement any existing vaccines inducing antibodies against the surface glycoprotein."