The successful immune response against hepatitis C nonstructural protein 5A (NS5A) requires heterologous DNA/protein immunization.

The aim of this study was to evaluate the immunogenicity of NS5A protein of human hepatitis C virus (HCV) when delivered as naked DNA (NS5A DNA), or recombinant protein (rNS5A). DBA/2J mice received NS5A DNA, rNS5A, or NS5A DNA/rNS5A in different prime-boost combinations with a peptidoglycan Immunomax((R)). The weakest response was induced after rNS5A prime and NS5A DNA boost; rNS5A alone induced an immune response with a strong Th2-component; and NS5A DNA alone, a relatively weak secretion of IL-2 and IFN-gamma.