T-cell responses contribute to viral control and protection against severe disease for diverse types of viruses. Because T cells can recognize conserved viral epitopes, they may potentially cross-react between related viruses. However, whether VSV-EBOV vaccination also induces T cells that recognize BDBV in humans has remained unknown.

A DZIF research team led by Dr. Leonie Mayer and Prof. Marylyn Addo from the Institute for Infection Research and Vaccine Development at the University Medical Center Hamburg-Eppendorf and Prof. Christof Geldmacher and Dr. Rolanda Londt from the Institute of Infectious Diseases and Tropical Medicine at the LMU University Hospital Munich therefore analyzed and mapped T-cell responses against EBOV, BDBV and Sudan virus (SUDV) in VSV-EBOV-vaccinated individuals. The glycoproteins of the three viruses are phylogenetically distant, with EBOV and BDBV sharing 66.3 percent amino acid identity, compared with 56.3 percent between EBOV and SUDV.

„Using multiple sequence alignments—the parallel comparison of multiple amino acid sequences—we identified several sequences that are highly conserved among the glycoproteins of EBOV, BDBV, and SUDV, and tested these regions for their interactions with the immune systems of vaccine recipients,” says first author Mayer from the UKE. The researchers then assessed cross-reactive T cell responses in 20 vaccine recipients at day 28 after VSV-EBOV vaccination. Of these vaccine recipients, 16 showed EBOV-glycoprotein-specific T cell responses, 13 showed BDBV-glycoprotein-reactive T cell responses and seven showed SUDV-glycoprotein-reactive T cell responses at day 28 after vaccination. Most vaccinees with a positive EBOV-glycoprotein response also had BDBV-reactive T cells.