FIG. 3.

Frequency of LLO- and p60-specific CD8 T cells in spleens of mice immunized with nontransfected serovar Typhimurium strain SB824 or SB824 bearing the indicated plasmid. Spleens from mice infected with L. monocytogenes sv1/2a EGD were used as controls. The frequency of LLO- and p60-specific T cells was determined by ELISPOT assay as described in Materials and Methods. The frequency of cells reactive with LLO_91-99 (open bars) or p60_217-225 (filled bars) is shown as the number of reactive cells per 10⁵ splenocytes. The dotted line at 0.2 × 10⁻⁵ indicates the detection limit (DL) of the ELISPOT assay. The standard deviation of triplicate cultures is indicated.