Characterization of hepatitis E virus recombinant ORF2 proteins expressed by vaccinia viruses.

Hepatitis E virus (HEV), an enterically transmitted pathogen, is one of the major causes of acute hepatitis in humans worldwide, being responsible for outbreaks and epidemics in regions with suboptimal sanitary conditions, in many of which it is endemic. In industrialized countries, hepatitis E is rarely reported, but recent studies have revealed quite high human seroprevalence rates and the possibility of porcine zoonotic transmission. There is currently no specific therapy or licensed vaccine against HEV infection, and little is known about its intracellular growth cycle, as until very recently no efficient cell culture system has been available. In the present study, vaccinia viruses have been used to express recombinant HEV ORF2 proteins, allowing the study of their glycosylation patterns and subcellular localization. Furthermore, the expressed proteins have been shown to be good antigens for diagnostic purposes and to elicit high and long-lasting specific anti-HEV titers of antibodies in mice that are passively transferred to the offspring by both transplacental and lactation routes.