Lj. Lorenzo et al., Expression and immunological evaluation of the Escherichia coli-derived hepatitis C virus envelope EI protein, BIOT APP B, 32, 2000, pp. 137-143
Immunological response against envelope protein El is very important in nat
ural hepatitis C virus (HCV) infection, although it is insufficient to clea
r the viraemia, The HCV genomic region encoding the first 149 amino acids o
f the envelope EI protein (EI340, amino acids 192-340) was expressed in Esc
herichia coli (to a level of 30% of the whole cellular proteins) and purifi
ed to 85%, We measured the immune response in rabbits and mice as well as t
he reactivity against 37 human sera raised against the whole recombinant pr
otein and EI-encoding peptides, From this, 51.1 % of human sera were found
to react with EI340. High-level antibodies against EI340 were obtained in r
abbits and mice when immunized. These antibodies had a similar peptide-reco
gnition pattern to that described previously for human sera. The most react
ive region was located at the N-terminus of the EI protein. Cellular immuni
ty in mice was evaluated by delayed-type hypersensitivity assay. It reveale
d the induction of a CD4+ T-cell-mediated response by this protein. This EI
340 protein and the animal-derived anti-EI sera are immunological tools tha
t could aid in the monitoring and development of anti-HCV therapies.