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Variable level expression of hepatitis C virus core protein in a prokaryotic system. Analysis of the humoral response against it in rabbits

Abstract:

Experimental evidence suggests that the hepatitis C virus (HCV) core protein has several biological properties and is implicated as a viral factor in HCV-mediated pathogenesis. In this study, CoE1.339, Co.176 and Co.120 variants of the HCV capsid protein were produced at variable levels in Escherichia coil from pNCoE1, pN12 and pSLCo120 plasmids, respectively. The chimera CoE1.339 spans the first 339 amino acids of the viral polyprotein, fused to the 45 amino acids stabilizer peptide from P64K protein of Neisseria meningitidis. Co.176 is a non-fused variant encompassing amino acids 1-176 of the capsid protein sequence. Both CoE1.339 and Co.176 were expressed under the transcriptional control of the tryptophan promoter and the protein was only detected by Western blot. However, Co.120, a variant truncated at the C- terminus which contains amino acids 1-120 of the HCV core protein fused to a leader tag of six histidines, was successfully produced under the control of the T7 promoter in BL21 (DE3) cells. Like Co.176 and CoE1.339, Co.120 was efficiently recognized by human anti-HCV positive serum. Purified Co.120 antigen showed to be immunogenic in rabbits. Synthetic peptides covering amino acids 1-40 of the core protein showed the greatest reactivity to the rabbit anti-Co.120 serum.