Figure 1

CTLA-4 blockade increases the induction of LCMV gp33_33–41 specific CTLs and in vivo lysis of target cells. (A) C57/Bl6 mice were immunized with peptide LCMV gp33_33–41 loaded DCs in combination with i.p. injection of anti-CTLA-4 mAb. Spleen cells were isolated 7–10 days after the primary immunization and cocultured with LCMV gp33_33–41 peptide + IL-2 and then tested for reactivity against the peptide in an IFN-γ ELISPOT assay. (B) Alternatively, peptide LCMV gp33_33–41 loaded CFSE labeled and peptide unloaded CMTMR labeled spleen cells were injected i.v. in immunized mice and naïve mice and target cell lysis was analyzed after 24 hours by the in vivo VITAL assay. Results are shown as mean ± SD of three mice in 1 representative experiment out of 2. (* p < 0.05)