FIG. 6.

Specific cytotoxic activity of CD4⁺ or CD8⁺ T cells. Four weeks after immunization, splenocytes from mice immunized with pcDNA-SOD or the parental plasmid pcDNA3 were stimulated for 5 days with J774.A1 macrophages infected with B. abortus RB51-SOD. These effector cells were recovered and sorted into CD4⁺ and CD8⁺ T cells. The separated T-cell subsets were incubated with target cells (J774.A1 cells infected with RB51-SOD), and cytotoxic activity was measured 16 h later by neutral red assay. The data are means for triplicate estimations, and standard deviations did not exceed 20% of the means.