CD8⁺ T cell interactions with macrophages are largely nonproductive. (A) LN OT-I cells dividing in response to s.c. delivery of VV-NP-S-eGFP. 5 × 10⁶ OT-I CFSE-labeled OT-I cells were transferred into CD11c-DTR-eGFP mice. 12 h later, mice were treated with DTx or PBS (untreated). After an additional 12 h, mice were infected with VV (untreated and DTx) or left uninfected (naive). Cells were analyzed at 48 hpi for division. Far right panel shows overlays. Untreated mice, black lines; DTx-treated mice, red lines; uninfected DTx-treated, filled grey lines. Numbers = OT-I cells recovered. (B) Graph showing percentage of dividing OT-I cells. Dots represent individual nodes. (C–E) Activation marker profile of T cells. Histograms were only gated on dividing cells. Untreated mice, black lines; DTx-treated mice, red lines; uninfected DTx-treated, filled grey lines. Numbers in top right corner indicate time after infection. (F) IFN-γ production (y axes) versus division (indicated by CFSE dilution; x axes) at 2 days after infection with VV-Ova. (G) Graphical representation of data shown in F. Dots represent individual nodes. (H) 2 × 10⁶ OT-I cells were transferred into CD11c-DTR-eGFP mice (expressing CD45.2) that were treated with DTx (middle) or PBS (right) before intradermal infection with VV-SIINFEKL in the ear pinnae. 4 days after infection, ears were removed and analyzed for the percentage of OT-I cells present (CD8⁺CD45.1⁺ cells). (I) Graphical representation of data in H. All experiments were performed at least three times with three to six animals/group yielding similar results.