Disulfide stabilization of human norovirus GI.1 virus-like particles focuses immune response toward blockade epitopes
Raffaello Verardi,
Lisa C. Lindesmith,
Yaroslav Tsybovsky,
Jason Gorman,
Gwo-Yu Chuang,
Caitlin E. Edwards,
Paul D. Brewer-Jensen,
Michael L. Mallory,
Li Ou,
Arne Schön,
Wei Shi,
Ena S. Tully,
George Georgiou,
Ralph S. Baric,
Peter D. Kwong
Affiliations
Raffaello Verardi
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
Lisa C. Lindesmith
Department of Epidemiology, University of North Carolina
Yaroslav Tsybovsky
Electron Microscopy Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research
Jason Gorman
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
Gwo-Yu Chuang
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
Caitlin E. Edwards
Department of Epidemiology, University of North Carolina
Paul D. Brewer-Jensen
Department of Epidemiology, University of North Carolina
Michael L. Mallory
Department of Epidemiology, University of North Carolina
Li Ou
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
Arne Schön
Department of Biology, Johns Hopkins University
Wei Shi
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
Ena S. Tully
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
George Georgiou
Department of Chemical Engineering, University of Texas at Austin
Ralph S. Baric
Department of Epidemiology, University of North Carolina
Peter D. Kwong
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health
Abstract Human noroviruses are non-enveloped, single-strand RNA viruses that cause pandemic outbreaks of acute gastroenteritis. A bivalent vaccine containing GI.1 and GII.4 virus-like particles (VLPs) has been shown to be safe and highly immunogenic, but its efficacy and durability have been limited. Here, we show that norovirus GI.1 VLPs are unstable and contain a substantial fraction of dissociated VLP components. Broadly reactive, non-neutralizing antibodies isolated from vaccinated donors bound to the dissociated components, but not to the intact VLPs. Engineering of interprotomer disulfide bonds within the shell domain prevented disassembly of the VLPs, while preserving antibody accessibility to blockade epitopes. Without adjuvant, mice immunized with stabilized GI.1 VLPs developed faster blockade antibody titers compared to immunization with wild-type GI.1 VLPs. In addition, immunization with stabilized particles focused immune responses toward surface-exposed epitopes and away from occluded epitopes. Overall, disulfide-stabilized norovirus GI.1 VLPs elicited improved responses over the non-disulfide-stabilized version, suggesting their promise as candidate vaccines.
