Development of a novel immunoperoxidase monolayer assay for detection of swine Hepatitis E virus antibodies based on stable cell lines expressing the ORF3 protein

Abstract

Hepatitis E virus (HEV) strains are classified into 4 genotypes by nucleotide sequencing. Genotypes 3 and 4 infect humans and animals via HEVcontaminated food or water. HEV RNA was detected by PCR and antibodies were detected by ELISA. Since human studies showed that HEV IgG antibodies in sera can persist for extended periods, diagnosis of HEV infection in swine or humans is mainly based on serological detection using commercial ELISA kits. However, there is no supplemental method to verify ELISA results. Hence, we developed a novel method used for mutual correction of these common processes. Here, a modified stable HepG2 cell line was transfected with pcDNA3.1-ORF3 to express the swine HEV ORF3 protein. Based on this cell line, a novel immunoperoxidase monolayer assay (IPMA) was developed to detect antibodies against HEV. The results show that this method has good specificity, sensitivity and repeatability. When used to investigate 141 porcine serum samples, the IPMA had a coincidence rate of 92.2% with a commercial ELISA kit. The established IPMA described herein is valuable as a supplemental method to ELISA and can differentiate infections by HEV and other viruses.

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“…LFA has been widely used for detecting various targets, such as cancer marker, microorganisms, heavy metal, mycotoxins and pesticides (34). The advantages of LFA are low cost, easy operation, user friendly, rapidly test and visual detection by naked eyes (34,60,61). The LFA is composed of a chromatography (separation of mixed components in environment), immuno-chromatography reaction (reaction between specific antigen-antibody, and nucleic acid-target analyses (62).…”