Submitted to: Emerging Infectious Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/14/2012
Publication Date: 3/4/2013
Citation: Herbst-Kralovets, M.M., Radtke, A.L., Lay, M.K., Bolick, A.N., Sarker, S.S., Kingsley, D.H., Arntzen, C.J., Estes, M.K., Nickerson, C. 2013. Correlation between lack of norovirus replication and histo-blood group antigen expression in 3D-intestinal epithelial cultures. Emerging Infectious Diseases. Volume 19(3):431-438. Interpretive Summary: Noroviruses, the leading cause of gastroenteritis and foodborne illnesses, have not been successfully cultured in the laboratory and there are no practical lab animals for study of these viruses. An initial report by Straub et al. (Emerg. Infect. Dis 13:396-403) suggested that norovirus could be cultured using a rotating 3D bioreactor system and the intestinal epithelial cell line, INT407. This publication describes efforts to replicate the initial report of Straub et al. and finds that norovirus does not replicate in this system. This conclusion is based on the lack of increased norovirus observed after introducing the virus to this culture system and the lack of detectable norovirus receptors (histoblood group antigens). The previous results obtained by Straub et al. are attributed to endotoxins present in the virus preparation.
Technical Abstract: Noroviruses (NoV) are a leading cause of gastroenteritis worldwide. An in vitro model for NoV replication remains elusive, making study of the virus difficult. One publication utilizing a 3-dimensional (3D) intestinal model derived from Int407 cells reported NoV replication and extensive cytopathic effects (CPE). Using the same 3D model with highly purified Norwalk virus (NV), we find no evidence of NV replication by real-time PCR analysis of viral RNA or by immunocytochemical detection of viral structural and nonstructural proteins. Immunocytochemical analysis of the 3-D cultures also showed no detectable presence of histoblood group antigens that participate in NV binding and host tropism. To determine the potential cause of CPE observed in the previous study, we exposed the 3D cultures to lipopolysaccharide concentrations consistent with contaminated stool, and observed morphology similar to CPE. We conclude from these data that the 3D Int407 model does not support NV replication.