The structures of norovirus could help develop therapies to fight against food-borne diseases

Noroviruses are one of the leading causes of outbreaks of foodborne illness and account for 58% of all outbreaks. They cause 685 million cases each year in the world. There is no effective treatment against them. Knowing the complex structure of the outer layer of noroviruses, the capsid, which allows the virus to bind to its human host, could contribute to the development of the vaccine.

In vaccines, specific antibodies recognize the capsids and bind to them so that they can no longer interact with human cells.

We need to understand what the shapes of the norovirus capsid look like and the differences in shape between different strains. "

James Jung, postdoctoral fellow in Dr. Leemor Joshua-Tor's laboratory at the Cold Spring Harbor Laboratory (CSHL).

Jung and Joshua-Tor led a team charged with solving the high-resolution structures of four different strains of norovirus using a cryo-electron microscope. This allowed them to see the complex architecture of virus envelopes in high definition. Their results are published in the journal PNAS.

Jung has collected new ideas that could help guide the development of treatments to combat norovirus infection. "Previously, it was thought that norovirus shells existed in simple bademblies consisting of 180 building blocks and 90 surface spikes, 60 building blocks with 30 surface peaks farther apart from each other." said.

The spikes on the shell interact with the host. Jung found that the distance and orientation of the tips varied according to the different norovirus strains. "This means that each strain will interact differently with human cells," explained Jung. "The way in which antibodies bind will also be different.Vaccines must be formulated to take into account variations between strains and structural forms."

Source:

Cold Spring Harbor Laboratory

Journal reference:

Jung, J. et al. (2019) High-Resolution Cryo-EM Structures of Epidemic Human Norovirus Shells Reveal Large Variations. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.1903562116.