We analysed whether hepatitis C virus (HCV)-specific antibody producing B lymphocytes can be induced in vitro with HCV-derived lipopeptides containing different T helper cell epitopes. HCV-specific antibody producing B cells were detected by ELISPOT at the single cell level. HCV-derived lipopeptides, but not their corresponding unlipidated peptides, induced B lymphocytes, which produced antibodies mainly reacting with the HCV-derived lipopeptides. The number of antigen-specific B cells was dependent on the number of added autologous T helper lymphocytes during the incubation period. Thus, HCV lipopeptides are more immunogenic than unmodified peptides and can induce HCV-reactive B lymphocytes in antigen-naïve lymphocytes.