Homologous versus Heterologous Immune Responses to Norwalk‐Like Viruses among Crew Members after Acute Gastroenteritis Outbreaks on 2 US Navy Vessels

Abstract

Host immune responses to human caliciviruses are difficult to study because of the lack of a clear definition of antigenic or serological types. This report describes antibody responses to several Norwalk-like viruses in large outbreaks of acute gastroenteritis on 2 US Navy ships. Enzyme immunoassays (EIAs) were used to measure antibody responses. To understand the antibody response to a homologous strain causing the outbreaks, the viral capsid gene of one isolate (C59) was expressed in baculovirus and included in the EIAs. Significantly greater seroresponses were detected in patients against the homologous strain than against the heterologous strains. Strains within genogroups reacted more strongly than did strains between genogroups. Significantly higher antibody titers against the outbreak strain were detected in acute serum samples from control subjects than in those from case patients. These results indicate that recombinant EIAs are useful for outbreak investigation and that the homologous antibody might be protective against reinfection.

Identification of Cross-Reactive Norovirus CD4 + T Cell Epitopes

“…Immunization of mice with VRPs containing norovirus ORF2 sequences results in an antinorovirus immune response characterized by production of broadly reactive, ligand-blocking antibody in both serum and the gut (15,20,21), which provides protection from MNV infection (21). These experiments suggest that human noroviruses share common antibody epitopes, as has been reported using sera from norovirus-infected humans (9,13,17,18,24). Thus, we chose to utilize this proven immunization approach to evaluate cross-reactive T cell epitopes in a manner similar to that used in studies evaluating antibody epitopes.…”

Genotype 1 and Genotype 2 Bovine Noroviruses Are Antigenically Distinct but Share a Cross-Reactive Epitope with Human Noroviruses

“…Correlation of genotype with serotype was further endorsed when rabbits were vaccinated with human norovirus VLPs, with which a clear antigenic distinction between norovirus genotypes was demonstrated (20). However, some human convalescent antisera showed cross-reactivity between genotypes (5,13,28), which might be the consequence of preexposure to different human norovirus genotypes. The present study demonstrated the advantage of using cattle kept under controlled conditions to prevent preexposure to noroviruses, forming the basis of a norovirus diarrhea model to investigate antigenic relationships and immune responses after infection.…”

“…Human noroviruses were initially demonstrated to be antigenically distinct using immuno-electron microscopy (23,24,29). Subsequent studies demonstrated that genotypes were antigenically distinct within the human norovirus genogroups by ELISA using convalescent antisera with VLPs (5,13,28). Correlation of genotype with serotype was further endorsed when rabbits were vaccinated with human norovirus VLPs, with which a clear antigenic distinction between norovirus genotypes was demonstrated (20).…”

The P Domain of Norovirus Capsid Protein Forms Dimer and Binds to Histo-Blood Group Antigen Receptors

“…The DNA fragments encoding the P domains plus the hinge regions of strains VA387 (16), MOH (5,6), and Norwalk virus (14,15) were PCR amplified and cloned into the vector pGEX-4T-1 (Amersham Bioscience, Piscataway, N.J.) at the BamHI and …”