GB-VIRUS-C E2-GLYCOPROTEIN - EXPRESSION IN CHO-CELLS, PURIFICATION AND CHARACTERIZATION

A 315 amino acid recombinant segment of the GB virus C (GBV-C) E2 enve lope glycoprotein (E2-315) was expressed and secreted from CHO cells. E2-315 was purified by affinity chromatography using a monoclonal anti body directed to a FLAG sequence genetically engineered onto the C ter minus of the recombinant protein. The secreted protein had a molecular mass of 48-56 kDa and was shown to be N-glycosylated. Amino acid sequ encing confirmed the expected N-terminal sequence. Purified E2-315 was used to develop an ELISA for detection of E2 antibodies in human sera . Antibodies to GBV-C E2 appeared to be directed toward conformational epitopes since human sera reactivity was detected in ELISA using nati ve E2-315, but it was extremely weak or non-existent with denatured E2 protein. The use of an ELISA which can detect human GBV-C E2 antibodi es will be important in further understanding of the clinical signific ance and epidemiology of GBV-C.