Immunological evaluation of Escherichia coli-derived hepatitis C virus second envelope protein (E2) variants

Two variants of the hepatitis C virus (HCV) E2 envelope protein, lacking th e C-terminal domain and comprising amino acids 458-650 (E2A) and 382-605 (E 2C), respectively, were efficiently produced in BL21 (DE3) Escherichia coli cells. E2A and E2C were used to immunize mice. The E2C variant induced the maximal mean antibody titer. Anti-E2C mouse sera reacted mainly with E2 sy nthetic peptides covering the 70 amino acid N-terminal region of the E2 pro tein. Moreover, a panel of anti-HCV positive human sera recognized only the E2C protein (28.2%) and the synthetic peptides covering the HVR-1 of the E 2 protein (23.1%). These data indicate the existence of an immunologically relevant region in the HVR-1 of the HCV E2 protein.