Purification and diagnostic utility of a recombinant hepatitis E virus capsid protein expressed in insect larvae

We report here the expression and purification of a truncated form of the hepatitis E virus ORF2 protein (ORF2delta111/deltaTM), from the fat bodies of Spodoptera litura larvae infected with a recombinant baculovirus. The purified protein migrated as a doublet of approximately 56 kDa on SDS-PAGE and was found to be glycosylated by staining with concanavalin A-linked horseradish peroxidase. The protein was used in a sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to HEV. The results showed complete concordance with those obtained using a commercial kit for the detection of anti-HEV antibodies. Antigen expression in the insect larvae system presents a rapid and low-cost method that obviates the need for expensive tissue culture scale-ups or special equipment.