Magnitude of the ELISPOT response to D1V-NS4b
and heterologous peptides in HLA-A*0201 transgenic mice immunized with peptides. Splenocytes were isolated from the peptide-immunized mice and were stimulated in vitro with cognate peptide or heterologous peptide. The numbers of IFN-γ SFCs/1×105 splenocytes were detected using ELISPOT assay. *Indicating the positive response to a peptide.