Researchers have captured the first-ever high-resolution images of yellow fever virus (YFV), which could pave the way for vaccine design. 

Scientists at the University of Queensland, Australia, revealed structural differences between the vaccine strain (YFV-17D) and the virulent, disease-causing strains of the virus. Researchers combined yellow fever’s structural genes with the backbone of the harmless Binjari virus, developed by the university, to produce virus particles examined with a cryo-electron microscope. 

“The particles of the vaccine strain had a smooth and stable surface layer, while the particles of the virulent strain had bumpy uneven surfaces,” said Dr Summa Bibby from UQ’s School of Chemistry and Molecular Bioscience. 

“The bumpier, irregular surface of the virulent strains exposes parts of the virus that are normally hidden, allowing certain antibodies to attach more easily,” Bibby added.

“The smooth vaccine particles keep those regions covered, making them harder for particular antibodies to reach.” 

Yellow fever is a potentially deadly viral disease transmitted by mosquitoes that affects the liver. The disease is a major public health concern in parts of South America and Africa and, with no approved antiviral treatments, vaccination is the primary means of prevention. 

The findings, revealed in Nature Communications, could pave the way for the development of improved vaccines and other antiviral strategies. 

“The yellow fever vaccine remains effective against modern strains and seeing the virus in such fine detail lets us better understand why the vaccine strain behaves the way it does,” said Professor Daniel Watterson from UQ’s School of Chemistry and Molecular Bioscience.

“We can now pinpoint the structural features that make the current vaccine safe and effective.

“The findings could even inform future vaccine design for related viruses like dengue, Zika and West Nile.” 

Bruno Quinney, Content Team, DDW