Figure 3. Conventional DCs are mandatory for the induction of CTL responses by IDLV-OVA.

PBS and DT treated-BDCA2-DTR (A-C) and -CD11c-DTR → C57BL/6 chimeric mice (DF) were injected i.v. with PBS, 10⁶ (A, D) or 5×10⁶ TUs IDLV-OVA (B, C, E, F) or OVA/CpG (A, D) or CpG (B, C, E, F). Seven days later, anti-OVA CTL responses were assessed by in vivo killing and IFN-γ ELISPOT assays (A, D). The results are expressed as the percentage of specific lysis for CTL activity and IFN-γ SFC per 10⁶ splenocytes for ELISPOT. Each dot represents an individual mouse. The results represent the means ± SEM of cumulative data from 6 to 8 mice collected from three independent experiments (A) or 3 to 5 mice from two independent experiments (D). Eighteen hours after injection, the expression of CD40, CD86 or PDC-TREM by cDCs (B, C) and pDCs (E, F) was assessed by flow cytometry. The results are represented as histograms from one representative experiment (B, E) or expressed as the fold-increase in MFI ± SEM compared to pDCs or cDCs from PBS-injected mice (C, F). They represent the cumulative data from 4 to 6 mice (C) or 2 to 5 mice from two independent experiments (F). Statistical analysis was performed by unpaired Student’s t-test in comparison with the PBS-treated mice or between PBS and DT treated-mice, as indicated by the horizontals bars (ns p > 0.05, * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001). See also Figures S4 and S5.