Characterization of the fusion antigens transiently expressed in HeLa cells by Western blotting. After separation by a 12.5% SDS-PAGE, the proteins were blotted onto a nitro-cellulose membrane and incubated with (A) anti-S McAb (H166, 1:300 diluted), (B) anti-HCV E2 (450-565) polyclonal antiserum RE2-116 (1:500 diluted) respectively. (A) lane 1-7, fusion proteins expressed by pcDNA3, pcDNA3S, pcDNA3SE2-A, pcDNA3SE2-B, pcDNA3SE2-C, pcDNA3SE2-D and pcDNA3SE2-E respectively. (B) lane 1-5, fusion proteins expressed by pcDNA3E2-pcDNA3, pcDNA3SE2-C, pcDNA3SE2-D, pcDNA3SE2-E respectively.