Figure 5

pDCs promote TLR7-mediated Ag-specific CD8⁺ T-cell responses in vivo.

(a,b) CFSE-labeled CD45.1⁺OT-I CD8⁺ T cells were transferred into the C57BL/6-background WT mice (n = 6), Siglech^kd mice (n = 6) and pDC-ablated mice (n = 6) and then the mice were immunized with OVA protein plus IMQ. Ag-specific division of CD45.1⁺OT-I CD8⁺ T cells was analyzed 3 days after the immunization by flow cytometry. (a) Data are presented as a histogram and numbers represent the proportion of the dividing cells among gated CD45.1⁺OT-I CD8⁺ T cells in each histogram. (b) Data are the mean percentage of positive cells ± s.d. from six individual samples in a single experiment. (c–h) The C57BL/6-background WT mice (n = 6), Siglech^kd mice (n = 6) and pDC-ablated mice (n = 6) were immunized with OVA protein, IMQ and anti-CD40 mAb and then a mixture of unpulsed CFSE^low cells plus Ag-pulsed CFSE^high cells was injected 5 days after the immunization. At 6 days after the immunization, splenocytes were analyzed for the generation of MHC I-OVA tetramer⁺CD44^highCD8⁺ T cells (c,d), for intracellular IFN-γ-producing CD8⁺ T cells (e,f) and for cytotoxic activity in vivo (g,h) by flow cytometry. Data are presented as a dot plot (c,e) and numbers represent the proportion of MHC I-OVA tetramer⁺CD44^high cells (c) and IFN-γ⁺ cells (e) among gated CD8⁺ T cells in each quadrant, or by a histogram (g) and numbers represent the ratio of unpulsed CFSE^low cells to Ag-pulsed CFSE^high cells in each histogram. (d,f,h) Data are the mean percentage of positive cells (d,f) or ratio (h) ± s.d. from six individual samples in a single experiment. *P < 0.01 compared with WT mice. All data are representative of at least three independent experiments.