The role of CD4⁺ and CD8⁺ T-cell subsets in the antitumor response in mice immunized with DCs expressing reduced invariant chain levels. Role of CD4⁺ and CD8⁺ T-cell subsets. Mice were immunized with OVA mRNA-transfected DCs and challenged with B16/F10.9-OVA tumor cells as described in Figure 4A. Mice were depleted of CD4⁺- or CD8⁺-expressing cells before tumor challenge, as indicated. Mice immunized with Flu M1 RNA or treated with PBS also received isotype Ab. Black circles represent individual tumor measurements and white bars represent average tumor size of the treatment group. Day-25 measurements are shown (5 mice per group).