Abstract Title
Characterization of Binding and Antigenic Properties in Emerging GII.17 Norovirus Variants
Presenter
Francisco Morais Esteves, Erasmus MC
Co-Author(s)
Stefan T. van der Krieken*, Francisco Morais Esteves*, Ray Izquierdo-Lara*, Putri Ayu Fajar*, Nele Villabruna**, Claudia Schapendonk*, Lonneke Leijten*, Roman Koning***, Corine Geurts van Kessel*, Marion Koopmans*, Miranda de Graaf*
*Department of Viroscience, Erasmus Medical Centre, Wytemaweg 80, 3015 CN Rotterdam, Netherlands
**Institute of Biochemistry & Research Centre for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
***Electron Microscopy Facility, Cell and Chemical Biology, Leiden University Medical Centre, Leiden, Netherlands
Abstract Category
Molecular Epidemiology & Evolution
Abstract
In the winter seasons of 2014-2015, the previously rare GII.17 genotype emerged, leading to large outbreaks worldwide and temporarily predominating in several countries. In 2024, a novel GII.17 variant led to an increased number of outbreaks, becoming the most dominant genotype in the Netherlands and several other regions. This study characterizes the binding and antigenic properties of the GII.17_2024 strains by comparing them with previous GII.17 strains from 2005, 2014 and 2015, and a GII.4_Sydney_2012 strain.
Norovirus virus-like particles (VLPs) were used to assess binding to human intestinal tissues through immunohistochemistry. VP1-NanoLuc® fusion proteins were used to evaluate the binding-blocking capacity of 75 sera from healthy adults without a known history of norovirus, collected during three time periods (winters of 2009-2010, 2015 and 2024). Additionally, histo-blood group antigen (HBGA) binding was analyzed using both saliva and synthetic HBGA.
The GII.17_2024 strains exhibit amino acid substitutions in antigenic domains and HBGA binding sites compared to older variants, showing the highest similarity to the 2014 strain. Binding-blocking assays confirm that the 2024 variant is antigenically distinct from the 2005 and 2015 GII.17 strains, but closely related to the 2014 variant, which circulated at lower levels compared to the 2015 strain. None of the GII.17 strains attached to non-secretor saliva, but all post-2005 GII.17 strains showed a broader HBGA binding profile compared to the GII.17_2005 strain, likely contributing to their more successful spread.
Understanding the factors influencing norovirus genotype fitness is essential for improving surveillance and preventive strategies against future norovirus epidemics.
Norovirus virus-like particles (VLPs) were used to assess binding to human intestinal tissues through immunohistochemistry. VP1-NanoLuc® fusion proteins were used to evaluate the binding-blocking capacity of 75 sera from healthy adults without a known history of norovirus, collected during three time periods (winters of 2009-2010, 2015 and 2024). Additionally, histo-blood group antigen (HBGA) binding was analyzed using both saliva and synthetic HBGA.
The GII.17_2024 strains exhibit amino acid substitutions in antigenic domains and HBGA binding sites compared to older variants, showing the highest similarity to the 2014 strain. Binding-blocking assays confirm that the 2024 variant is antigenically distinct from the 2005 and 2015 GII.17 strains, but closely related to the 2014 variant, which circulated at lower levels compared to the 2015 strain. None of the GII.17 strains attached to non-secretor saliva, but all post-2005 GII.17 strains showed a broader HBGA binding profile compared to the GII.17_2005 strain, likely contributing to their more successful spread.
Understanding the factors influencing norovirus genotype fitness is essential for improving surveillance and preventive strategies against future norovirus epidemics.