Allostimulatory properties of dermal DC and macrophages. (A) [³H]thymidine incorporation of allogeneic CD4⁺ T cells stimulated by CD1a⁺ DC or macrophages. The left and right show representative examples of six experiments in which APC were titrated against naive and memory T cells as indicated. Stimulation with anti-CD3/28 beads + naive CD4 produced 442 × 10³ cpm and with anti-CD3/28 beads + memory CD4 produced 430 × 10³ cpm. Results are the mean ± SEM of triplicate wells. The middle shows the cumulative results and mean of at least seven independent experiments at an APC/T cell ratio of 1:10 compared with medium alone controls (T). The stimulation index (SI) was normalized to the proliferation of naive T cells with DC. (B) Intracellular IL-17 and IFN-γ production by memory CD4⁺ T cells in response to DC, macrophages, anti-CD3/28 beads, or medium alone. Representative examples of four independent experiments are shown on the left, with gating for IL-17–expressing Th17 cells and IFN-γ–expressing Th1 cells. The mean and cumulative results of four independent experiments are shown on the right, expressed as the percentage of Th17, Th17/1, or Th1 cells in each. (C) [³H]thymidine incorporation of allogeneic CD8⁺ T cells stimulated by dermal DC or macrophages or medium alone (T). The left shows a representative example of the data at an APC/T cell ratio of 1:10. Results are the mean ± SEM of triplicate wells. The right shows the cumulative results and mean of six independent experiments. (D) IFN-γ secretion into the medium of CD8⁺ T cells stimulated with DC, macrophages, medium alone (T), or anti-CD3/CD28 beads (beads). Results show the mean ± SEM of six independent experiments. (E) Activation antigen expression by CD8⁺ T cells stimulated by DC, macrophages, anti-CD3/28 beads, or medium alone. Representative examples of the data with gating for positive cells are shown on the left. The mean and cumulative results of four independent experiments are shown on the right, expressed as the percentage of positive cells in each.