Understanding norovirus structures to develop food poisoning treatments

An image to illustrate food poisoning, which might be helped by norovirus structures research
© iStock/Panya_sealim

Cold Spring Harbor Laboratory has conducted research on norovirus structures, which could help to develop food poisoning treatments.

Studying the intricate norovirus structures, the capsid, which allow the virus to attach to the human host could help to develop food poisoning treatments such as vaccines.

The need for food poisoning treatments

Noroviruses are a leading cause of food-borne illness outbreaks. According to the Cold Spring Harbor Laboratory, they account for 58% of all outbreaks and cause 685 million cases globally per year. Despite this, there is no therapeutic which is effective currently.

Understanding norovirus structures

In vaccines, specific antibodies will have to recognise and bind to capsids. James Jung, a postdoctoral fellow in Dr. Leemor Joshua-Tor’s lab, explained: “We need to understand what the norovirus capsid shapes actually look like, and the shape differences between different strains.”

What do the capsids look like?

The team used a cryo-electron microscope to analyse four different strains of norovirus structures in high resolution.

Jung said: “Previously, it was thought that the norovirus shells exist in single-sized assemblies consisting of 180 building blocks and 90 surface spikes.”

“What we found was an unexpected mixture of different shell sizes and shapes. We found a smaller form, which consists of just 60 building blocks with 30 surface spikes placed further apart. We also found larger shells made out of 240 building blocks with 120 surface spikes that are lifted significantly above the base of the shell and form a two-layered architecture that could interact differently with the human cells.”

Developing vaccines

Jung concluded: “Each strain will interact differently with human cells. The way the antibodies bind is also going to be different. Vaccines should be formulated to take into account the variations across strains and structural forms.”

The findings on the architecture of the norovirus shells are published in the journal PNAS, titled “High-resolution cryo-EM structures of outbreak strain human norovirus shells reveal size variations.”

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