DETECTION OF ANTIBODY TO HEPATITIS-C VIRUS E2 RECOMBINANT ANTIGEN AMONG SAMPLES INDETERMINATE FOR ANTI-HCV AFTER WIDE SEROLOGICAL TESTING AND CORRELATION WITH VIREMIA

The detection of antibody to the second envelope protein (E2) of the h epatitis C virus (HCV) has been hampered by the lack of suitable antig ens. A previously described E2 recombinant antigen (CHO-E2) expressed as a non-fused, highly glycosylated protein in mammalian cells was use d to detect specific antibody (anti-E2) in samples from blood donors a nd viraemic patients showing positive or indeterminate results for ant i-HCV after a wide serological study. Anti-E2 was detected in 50-75% o f the donors positive for anti-HCV; 80% of viraemic immunocompetent pa tients with anti-NS3 alone and 28% of non-viraemic donors with anticor e alone. In donors with anti-NS3 (15 samples) or anti-NS4 (51 samples) alone, anti-E2 was found occasionally (3 cases). Moreover, two anti-E 2-positive samples from viraemic patients were misidentified by some c ommercial assays for screening anti-HCV. These results suggest that te sting for anti-E2 may be useful for improving the performance of the c urrent assays for anti-HCV screening and confirmation.