Figure 2: CRPVE1/161-169 and CRPVE1/303-311 peptide vaccinated HHD mice (A and B) and DNA vaccinated HLA-A2.1 transgenic rabbits (C and D) generated specific cytotoxic T cells. 51Chromium release assay were conducted on the bulk CTLs of these two epitope peptide immunized HHD mice or DNA vaccinated HLA-A2.1 transgenic rabbits in vitro as shown in materials and methods. A) Significantly higher levels of specific killing were found in cultures of HHD mice cells against T2 cells pulsed with CRPVE1/161-169 (A) peptides vs. T2 cells pulsed with CRPVE1/303-311 (P<0.05, unpaired student t test) following vaccinated with CRPVE1/161-169 or vice versa (B); Similar results were found from rabbit cells against T2 cells pulsed with CRPVE1/161-169 peptides vs. T2 cells pulsed with CRPVE1/303-311 (P<0.05, unpaired student t test) following vaccination with CRPVE1/161-169 epitope DNA vaccine (C) and vice versa (D). The data were representative of three individual rabbits. CRPVE1/303-311 epitope vaccinated animals generated relatively higher levels of specific killing CTLs when compared with CRPVE1/161-169 epitope vaccinated animals. Other three epitopes (CRPVE1/245-253, 42-50, 149-157) were unresponsive for this test (data not shown).