CD11c⁺ DCs drive IFN-γ production by CD4⁺ T_EFF cells <i>in vivo</i>.

<p>(<b>A</b>) Mice received GFP⁺ gDT-II cells prior to HSV-1 skin infection. IFM analysis of skin 5 days post-infection after staining with anti-MHC-II and -IFN-γ antibodies. Arrows indicate IFN-γ⁺ gDT-II cells. Scale bars: <b>A-i</b>, 100 µm; <b>A-ii</b>, 20 µm; <b>A-iii</b>, 20 µm. (<b>B</b>,<b>C</b>) CD11c.DTR mice received naïve gDT-II cells prior to HSV-1 skin infection and 4 days post-infection were treated with diphtheria toxin (DT) or PBS (Ctrl). Analysis of IFN-γ⁺ gDT-II cells in skin (collagenase digestion). ***, <i>P</i><0.001 by Mann Whitney test; <i>n</i> = 11–15 mice/group from 3 experiments. (<b>D</b>) Wild-type mice received naïve gDT-II or gBT-II cells prior to infection and 4 days post-infection were treated with anti-CD80/86 (αCD80/86) or isotype control (Isotype) antibodies. Analysis of IFN-γ⁺ gDT-II cells in skin (collagenase digestion) and axillary LNs, and of IFN-γ⁺ gBT-I cells in epidermal sheets (dispase digestion) days 5 post-infection. *, <i>P</i><0.05; **, <i>P</i><0.01; ns, not significant by Mann Whitney test; <i>n</i> = 6–7 mice/group from 2–3 experiments.