In order to search for the immunogenic NP peptide sequence, nine potential peptides were predicted using SYFPEITHI software. Various assays were used to determine the immunogenicity of the peptides and the desirable ones (i.e., those with both the highest binding affinity to HLA-A*0201 positive cells and the ability to stimulate human CD8+ T cells) were selected for further in vivo experimentation. In order to determine their binding affinity to HLA-A*0201 positive cells, the peptides were synthesized and a T2-cell binding assay was performed. T2 cells normally express unstable HLA molecules on the cell surface and therefore if a peptide is able to fit into the peptidebinding groove of an HLA molecule, it will form a more stable structural complex with the HLA molecule in the presence of b 2 -microglobulin. This complex can be detected with an anti-human HLA-A2 antibody via flow cytometry. In our assay, a flu peptide (GILGFVFTL), which is an HLA-A*0201 epitope, was used as a positive control for the experiment. The results indicate that the NP373 (AMDSNT-LEL), NP189 (MVMELIRMI), and NP458 (FQGRGVFEL) showed the highest scores in the T2-cell binding assay (Fig. 1) .