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

IFNg was not produced in response to the epitope after in vitro immunization with the epitope in combination with the HCV core 20-33 T-helper epitope linked to tripalmitoyl-S-cysteine. However, IFNg was produced after immunization with a fragment of the epitope source protein, HCV core 20-44, linked to tripalmitoyl-S-cysteine, but not after immunization with HCV core 20-44 alone, demonstrating that the immunostimulatory role of lipopeptides requires the lipid is directly linked to the epitope.