Figure 3.

A: Anti-HCV NS5 ELISA showing mean levels of specific antibodies after genetic immunization with HCV-NS5-expressing plasmid. Controls included wells coated with BSA and sera derived from mock-immunized mice. Each group comprised 10 BALB/c mice and mice sera were pooled before the assay. ELISA plates were coated with HCV-NS5-4, therefore, antibody levels may be underestimated; B: T-cell proliferation assay (n = 10 mice/group) with different amounts of stimulating recombinant HCV NS5-4 protein (0.01-1 µg/mL). An increase of thymidine incorporation was seen after stimulation with 0.1 and 1 µg/mL recombinant protein. However, levels of T-cell proliferation after co-immunization with Flt3-L were only slightly higher than in NS5-immunized mice. Note that stimulation with a non-relevant protein (HBsAg) induced only background activity, demonstrating the antigen specificity (data not shown).