Enhancement of enteric adenovirus cultivation by viral transactivator proteins▽

Abstract

Human enteric adenoviruses (HAdVs; serotypes 40 and 41) are important waterborne and food-borne pathogens. However, HAdVs are fastidious, are difficult to cultivate, and do not produce a clear cytopathic effect during cell culture within a reasonable time. Thus, we examined whether the viral transactivator proteins cytomegalovirus (CMV) IEl and hepatitis B virus (HBV) X promoted the multiplication of HAdVs. Additionally, we constructed a new 293 cell line expressing CMV IEl protein for cultivation assays. We analyzed the nucleic acid sequences of the promoter regions of both ElA and hexon genes, which are considered to be the most important regions for HAdV replication. Expression of either HBV X or CMV IEl protein significantly increased the promoter activities of ElA and hexon genes of HAdVs by as much as 14-fold during cell cultivation. The promotion of HAdV expression was confirmed by increased levels of both adenoviral DNA and mRNA expression. Finally, the newly developed 293 cell line expressing CMV IEl protein showed an increase in viral DNA ranging from 574% to 619% compared with the conventional 293 cell line. These results suggest that the newly constructed cell line could be useful for efficient cultivation and research of fastidious HAdVs. Copyright © 2010, American Society for Microbiology. All Rights Reserved.