Understanding the relationship between norovirus diversity and immunity

Figures & data

Figure 1. Structure and variable antigenic sites of the human norovirus major capsid protein, VP1. (a) The norovirus capsid is composed of 90 dimers of VP1 arranged in a T = 3 icosahedral symmetry. (b) The VP1 protein is divided into the conserved Shell (S) and the variable Protruding (P) domains. The P domain is further divided into the P1 and P2 subdomains. The surface-exposed P2 subdomain is thought to dictate binding to the cellular attachment factors, histo-blood group antigen (HGBA) carbohydrates (highlighted in green), while the S domain forms the core of the viral particle.² (c) The known variable antigenic sites (A, C, D, E, and G) located on the surface of the P2 subdomain of GII.4 norovirus are highlighted. The structural models were rendered using UCSF Chimera (version 1.11.2) and the following Protein Data Bank (PDB) files: 1IHM and 2ZLE (Norwalk virus, GI.1) and 2OBS (VA387 virus, GII.4 Grimsby variant). (d) Residues mapping on the variable antigenic sites of GII.4 noroviruses. Changes on these sites correlate with the emergence of GII.4 variants. (e) Amino acid variation in the P domain of the VP1 protein and its correlation with GII.4 variant distribution was quantified with Shannon entropy (left) and adjusted Rand index (right). Dataset includes sequences collected from 1995 to 2016, as described in Tohma et al., 2019.⁷⁰ Entropy values were calculated using the Shannon Entropy-One tool, as implemented in Los Alamos National Laboratory (www.hiv.lanl.gov) for six major GII.4 variants. The boxplot shows mean and standard deviation from each antigenic and non-antigenic site of major variants and all-in sequences that included a maximum of 50 randomly subsampled strain/variant to reduce sampling bias (n = 474). The dotted line indicates the mean of entropy values from non-antigenic sites in the subsampled all-in dataset. Adjusted Rand index, in which higher index values indicate a higher degree of correlation between variant distribution and the amino acid variation, was calculated with the subsampled all-in dataset using R and presented in a dot plot. Each circle represents the index from each antigenic and non-antigenic site

Table 1. Current and prospective human norovirus vaccines

Vaccine Candidate	Affiliation/Investigators	Current Stage	Antigen	Adjuvant (if any)	Route of Administration	Citation
VLP-based, bivalent	Takeda Pharmaceuticals	Phase 2b	GI.1, GII.4c*	Monophosphoryl Lipid A (MPL) + Alum	intramuscular	[62], [87]
Recombinant adenovirus vector expressing VP1, bivalent	Vaxart, Inc.	Phase 1b	GI.1, GII.4	dsRNA hairpin (TLR3 agonist)	oral	[88], [89]
Norovirus VLP and recombinant rotavirus combination, trivalent	Tamminen et al.	preclinical	GI.3, GII.4, recombinant rotavirus VP6	rVP6**	intramuscular	[80], [91]
VLP-based, monovalent	Santi et al.	preclinical	GI.1 produced in Tobacco Mosaic virus expression system	Cholera toxin (CT)	oral	[93]
Recombinant adenovirus vector expressing VP1, monovalent	Guo et al.	preclinical	GII.4	n/a	intranasal	[94]
Recombinant vesicular stomatitis virus vector expressing VP1, monovalent	Ma et al.	preclinical	GII.4	n/a	intranasal and oral	[95]
P-particles, monovalent or as a carrier linked to rotavirus VP8	Su et al.; Tan et al.	preclinical	GII.4 P-particle expressed in E. coli or yeast, alone or with rotavirus VP8	Freund’s adjuvant	subcutaneous	[96], [97]

*GII.4c = GII.4 consensus VLP derived from three variants

** rVP6 = recombinant rotavirus VP6 protein

n/a = not applicable

Prasad BV, Hardy ME, Dokland T, Bella J, Rossmann MG, Estes MK. X-ray crystallographic structure of the Norwalk virus capsid. Science. 1999;286(5438):287–290. doi:10.1126/science.286.5438.287.

 Google Scholar

Tohma K, Lepore CJ, Gao Y, Ford-Siltz LA, Parra GI, Baric RS, Estes MK. Population Genomics of GII.4 Noroviruses Reveal Complex Diversification and New Antigenic Sites Involved in the Emergence of Pandemic Strains. MBio. 2019;10(5). doi:10.1128/mBio.02202-19.

 Google Scholar

Parra GI, Bok K, Taylor R, Haynes JR, Sosnovtsev SV, Richardson C, Green KY. Immunogenicity and specificity of norovirus Consensus GII.4 virus-like particles in monovalent and bivalent vaccine formulations. Vaccine. 2012;30(24):3580–3586. doi:10.1016/j.vaccine.2012.03.050.

 Google Scholar

Atmar RL, Cramer JP, Baehner F, Han C, Borkowski A, Mendelman PM. An exploratory study of the salivary immunoglobulin a responses to 1 dose of a norovirus virus-like particle candidate vaccine in healthy adults. J Infect Dis. 2019;219(3):410–414. doi:10.1093/infdis/jiy529.

 Google Scholar

Vaxart’s Tableted Oral Bivalent Norovirus Vaccine Meets Primary and Secondary Endpoints in Phase1b Study. 2019 September 25, [ cited 2020 August 12]; https://investors.vaxart.com/news-releases/news-release-details/vaxarts-tableted-oral-bivalent-norovirus-vaccine-meets-primary.

 Google Scholar

Kim L, Liebowitz D, Lin K, Kasparek K, Pasetti MF, Garg SJ, Gottlieb K, Trager G, Tucker SN. Safety and immunogenicity of an oral tablet norovirus vaccine, a phase I randomized, placebo-controlled trial. JCI Insight. 2018;3(13). doi:10.1172/jci.insight.121077.

 Google Scholar

Matsushima Y, Ishikawa M, Shimizu T, Komane A, Kasuo S, Shinohara M, Nagasawa K, Kimura H, Ryo A, Okabe N, et al. Genetic analyses of GII.17 norovirus strains in diarrheal disease outbreaks from December 2014 to March 2015 in Japan reveal a novel polymerase sequence and amino acid substitutions in the capsid region. Euro Surveill. 2015;20(26). doi:10.2807/1560-7917.ES2015.20.26.21173.

 Google Scholar

Tamminen K, Lappalainen S, Huhti L, Vesikari T, Blazevic V, Zhou P. Trivalent combination vaccine induces broad heterologous immune responses to norovirus and rotavirus in mice. PLoS One. 2013;8(7):e70409. doi:10.1371/journal.pone.0070409.

 Google Scholar

Santi L, Batchelor L, Huang Z, Hjelm B, Kilbourne J, Arntzen CJ, Chen Q, Mason HS. An efficient plant viral expression system generating orally immunogenic Norwalk virus-like particles. Vaccine. 2008;26(15):1846–1854. doi:10.1016/j.vaccine.2008.01.053.

 Google Scholar

Guo L, Wang J, Zhou H, Si H, Wang M, Song J, Han B, Shu Y, Ren L, Qu J, et al. Intranasal administration of a recombinant adenovirus expressing the norovirus capsid protein stimulates specific humoral, mucosal, and cellular immune responses in mice. Vaccine. 2008;26(4):460–468. doi:10.1016/j.vaccine.2007.11.039.

 Google Scholar

Ma Y, Li J. Vesicular stomatitis virus as a vector to deliver virus-like particles of human norovirus: a new vaccine candidate against an important noncultivable virus. J Virol. 2011;85(6):2942–2952. doi:10.1128/JVI.02332-10.

 Google Scholar

Tan M, Fang P, Chachiyo T, Xia M, Huang P, Fang Z, Jiang W, Jiang X. Noroviral P particle: structure, function and applications in virus-host interaction. Virology. 2008;382(1):115–123. doi:10.1016/j.virol.2008.08.047.

 Google Scholar

Su W, Gao J, Zang Y, Wu H, Wang L, Hu H, Yu X, Kong W, Jiang C. Production, characterization and immunogenicity of P particles derived from norovirus GII.4 genotype 2004 variant. Acta Virol. 2015;59(1):33–39. doi:10.4149/av_2015_01_33.

 Google Scholar