We previously showed that a single-chain trimer (SCT) system is a promising system for use in the construction of DNA vaccines [2] . Here, we identified two novel HLA-A*0201-restricted H5N1-NP-protein peptides and a modified SCT system was used in vaccine construction. The efficacy of the constructed vaccine candidates was investigated in a special genetically modified HHD transgenic mouse model. Our results suggest that the H5N1 NP373-381 AMDSNTLEL and NP458-466 FQGRGVFEL peptides might be promising candidates for use in H5N1 vaccine construction.