Genotype-Specific Neutralization of Norovirus Is Mediated by Antibodies Against the Protruding Domain of the Major Capsid Protein

Abstract

Human noroviruses are the most common viral agents of acute gastroenteritis. Recently, human intestinal enteroids were shown to be permissive for norovirus infection. We tested their suitability as a system to study norovirus neutralization. Hyperimmune sera raised against virus-like particles (VLPs) representing different genotypes showed highly specific neutralization activity against GII.4 and GII.6 noroviruses. Carbohydrate blocking assays and neutralization exhibited similar patterns in antibody responses. Notably, sera produced against chimeric VLPs that presented swapped structural shell and protruding (P) domains, from different genotypes showed that neutralization is primarily mediated by antibodies mapping to the P domain of the norovirus capsid protein. This study provides empirical information on the antigenic differences among genotypes as measured by neutralization, which could guide vaccine design.

Norovirus-specific immunoglobulin A in breast milk for protection against norovirus-associated diarrhea among infants

“…Virus-like particles were produced as described elsewhere. [23 , 24] Wells of polystyrene microtiter-plates (BM6001; BMBIO, Tochigi, Japan) were coated with 100 µL/well of 0·5 µg/ml (GII) or 0·25 µg/ml (GI) VLPs in carbonate-bicarbonate buffer (pH 9·6). Following blocking with 5% Blotto (37530; Thermo Scientific, Massachusetts, USA), the wells were incubated with 100 µL of 1:50, 1:100, 1:500, 1:1000, 1:5000, and 1:10,000 dilutions of breast milk serum for two hours.…”

Understanding the relationship between norovirus diversity and immunity

“…35,36 Importantly, it has been recently shown that carbohydrate blockade assays and neutralization in HIE present similar patterns in antibody reactivity. 11,37 As the HIE culture system exhibits evident disadvantages, such as limited scalability to high-throughput and/or the inability of certain noroviruses to replicate in the cells, the blockade assays are a good alternative to determining the antigenic relationships between strains and to study antibody-mediated protection. 11,12,37,38 While some animal models have been developed for human noroviruses, 14,39-41 they either do not recapitulate disease or replication has been shown for only a limited number of strains.…”

“…Preliminary neutralization experiments in HIE and analyses of natural reinfection cases over time suggest that some norovirus genotypes are antigenically distinct from each other. 11,17,42,[53][54][55] Despite all these studies, extensive analyses of the functional (blockade/neutralizing) antibodies between all human norovirus genotypes have not been performed.…”

“… 11 , 37 As the HIE culture system exhibits evident disadvantages, such as limited scalability to high-throughput and/or the inability of certain noroviruses to replicate in the cells, the blockade assays are a good alternative to determining the antigenic relationships between strains and to study antibody-mediated protection. 11 , 12 , 37 , 38…”

“…8,9 Unfortunately, most data indicate that protective antibodies map to the variable P domain. [10][11][12][13][14] The P domain is further divided into the P1 and P2 subdomains. The P1 subdomain is partially conserved, while the P2 subdomain contains the highest sequence variability, including highly variable motifs that are involved in cellular attachment and antibody recognition (Figure 1, panel B).…”