Figure 4.

Treatment with anti–CTLA-4 mAb during in vivo immunization with DC enhances the direct, Ag-specific cytotoxicity measured in vitro. C57BL/6 recipient mice received 5 × 10⁶ Vα2⁺Vβ8⁺CD8⁺ T cells from line 318 transgenic donors, were treated with either control IgG or anti–CTLA-4 mAb, and were immunized with 3 × 10⁴ LCMV_33–41 peptide–loaded DC from C57BL/6 or MHC class II^−/− mice as described for Fig. 2. 7 d after immunization, spleen cell suspensions were prepared and depleted of CD4⁺ T cells and Ig⁺ cells by magnetic adherence. Cytotoxic activity was measured in vitro by JAM test on EL4 targets or on EL4 + LCMV_33–41 peptide.