High-Pressure Inactivation of Human Norovirus Virus-Like Particles Provides Evidence that the Capsid of Human Norovirus Is Highly Pressure Resistant

Department of Food Science and Technology, College of Food, Agricultural and Environmental Sciences, The Ohio State University, Columbus, Ohio, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 05/2012; 78(15):5320-7. DOI: 10.1128/AEM.00532-12
Source: PubMed


Human norovirus (NoV) is the leading cause of nonbacterial acute gastroenteritis epidemics worldwide. High-pressure processing (HPP) has been considered a promising nonthermal processing technology to inactivate food- and waterborne viral pathogens. Due to the lack of an effective cell culture method for human NoV, the effectiveness of HPP in inactivating human NoV remains poorly understood. In this study, we evaluated the effectiveness of HPP in disrupting the capsid of human NoV based on the structural and functional integrity of virus-like particles (VLPs) and histo-blood group antigen (HBGA) receptor binding assays. We found that pressurization at 500 to 600 MPa for 2 min, a pressure level that completely inactivates murine norovirus and feline calicivirus, was not sufficient to disrupt the structure and function of human NoV VLPs, even with a holding time of 60 min. Degradation of VLPs increased commensurate with increasing pressure levels more than increasing time. The times required for complete disruption of human NoV VLPs at 700, 800, and 900 MPa were 45, 15, and 2 min, respectively. Human NoV VLPs were more resistant to HPP in their ability to bind type A than type B and O HBGAs. Additionally, the 23-nm VLPs appeared to be much more stable than the 38-nm VLPs. Taken together, our results demonstrated that the human NoV capsid is highly resistant to HPP. While human NoV VLPs may not be fully representative of viable human NoV, destruction of the VLP capsid is highly suggestive of a typical response for viable human NoV.

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    • "In the absence of a robust in vitro cultivation method, the only source of whole viruses for ligand selection is stool samples from infected individuals. As infectious virus in stool is a difficult sample to obtain and work with, virus-like particles (VLPs) are frequently used instead for many types of studies, from disinfection to immune response characterization (Cheetham et al., 2007; Lou et al., 2012; Nilsson et al., 2009; Souza et al., 2007; Vongpunsawad et al., 2013). VLPs demonstrate similar binding behavior to HBGAs as human NoV particles (Huang et al., 2003; White et al., 1996); however, their production and purification can be costly, time consuming, and variable (Koho et al., 2012). "
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    • "HuNoV virus-like particle (VLP) was also proposed as a potential surrogate for HuNoV because VLPs have similar antigenicity and morphology as HuNoV (Lou et al., 2012). However, since VLPs do not contain viral genetic materials, the reliability of using them as a surrogate for HuNoV is compromised, especially in some treatments targeting the genome of HuNoV for inactivation. "
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