CpG ss-ODN amplifies CTL response to K25V.

(A) Mice were immunized with K25V twice, either including CpG (♦) or non-CpG (▴), or without ss-ODN (●). Spleens were harvested after 14 days, and one IVS was performed as described in “Materials and methods.” Conditions for CRA and calculation of specific cytotoxicity were identical to those described in the legend to Figure 1. (B-G) Flow cytometry analysis of splenocytes whose CRA result is shown in panel A. Two-color flow cytometry was employed, as described in “Materials and methods,” using CD8-FITC and HLA A2.1 tetramer-PE complexed with pp65_495-503 (B-D) or p53_149-157 (E-G) in separate dimensions. Percentages of cells that are in the top right quadrant are shown above each profile. For each histogram, 20 000 events were collected, and electronic gates were used to exclude cells that did not fall into the small lymphocyte size range.