Scientists at the University of Queensland have captured the first near‑atomic, high‑resolution 3D images of the yellow fever virus, detailing how the surface of the long‑used vaccine strain differs from virulent, disease‑causing strains. The work sheds light on how the virus is recognised by the immune system and could support improved vaccines for yellow fever and related mosquito‑borne diseases.
Yellow fever virus (YFV) is a mosquito‑borne infection that can severely damage the liver and is potentially fatal in severe cases. Researchers at the University of Queensland (UQ) have now produced what they describe as the first complete three‑dimensional structure of a fully mature YFV particle at near‑atomic resolution, using cryo‑electron microscopy.
To safely study the virus, the team used the Binjari virus platform, in which yellow fever’s structural genes are combined with the backbone of a harmless virus. This approach enabled detailed imaging while avoiding the risks of handling fully pathogenic yellow fever. As Dr. Summa Bibby of UQ’s School of Chemistry and Molecular Bioscience explained in a statement released through UQ and reported by ScienceDaily, "By utilizing the well‑established Binjari virus platform developed here at UQ, we combined yellow fever's structural genes with the backbone of the harmless Binjari virus and produced virus particles that could be safely examined with a cryo‑electron microscope."
The cryo‑EM images revealed marked differences in the outer surface of different YFV strains. According to UQ’s news release and coverage by outlets including Phys.org and ScienceDaily, the vaccine strain YFV‑17D forms particles with a smooth, stable surface layer, while virulent, disease‑causing strains show a noticeably bumpy, uneven texture.
These structural variations change how the body’s immune system recognises the virus. "The bumpier, irregular surface of the virulent strains exposes parts of the virus that are normally hidden, allowing certain antibodies to attach more easily," Dr. Bibby said. "The smooth vaccine particles keep those regions covered, making them harder for particular antibodies to reach."
Yellow fever remains a major public health concern in parts of South America and Africa, where the virus is transmitted by mosquitoes. With no approved antiviral treatments available, vaccination is the primary means of prevention, according to UQ’s summary of the work.
Professor Daniel Watterson of UQ said the findings provide important new insight into yellow fever biology and help explain the continued performance of the long‑standing vaccine. "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," he said. "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."
The research, which focuses on how a single amino‑acid residue in the virus’s envelope protein can alter virion architecture and antigenicity, was published in the journal Nature Communications.
