Hepatitis C virus-derived lipopeptides differentially induce epitope-specific immune responses in vitro.

IFNg was produced in response to the epitope after in vitro immunization with a fragment of the epitope source protein, HCV core 20-44, linked to tripalmitoyl-S-cysteine. IFNg was not produced after immunization with HCV core 20-44 alone or after immunization with the epitope in combination with the HCV core 20-33 T-helper epitope linked to tripalmitoyl-S-cysteine, demonstrating that the immunostimulatory role of lipopeptides requires the lipid is directly linked to the epitope. HLA-A2 restriction was demonstrated through blocking antibody. Production of IFNg correlated with expression of TLR2 on CD14+ monocytes prior to stimulation.