An ELISA for Detection of Antibodies to the E2 Protein of GB Virus C

An ELISA was developed for detection of antibodies to GB virus C (GBV-C)using a recombinant E2 protein expressed in CHO cells. Seroconversion to anti-E2 positivity was noted among several persons infected with GBV-C RNA-positive blood through transfusion. Of6 blood recipients infected by GBV-C RNA-positive donors, 4 (67%)became anti-E2 positive and cleared their viremia. Thus, anti-E2 seroconversion is associated with viral clearance. The prevalence of antibodies to E2 was relatively low (3.0%–8.1%) in volunteer blood donors but was higher in several other groups, including plasmapheresis donors (34.0%), intravenous drug users (85.2%),and West African subjects (13.3%), all of whom tested negative by GBV-C reverse-transcription polymerase chain reaction (RT-PCR). These data demonstrate that testing for anti-E2 should greatly extend the ability of RTPCR to define the epidemiologyand clinical significance of GBV-C.