Figure 4.

The activated and proliferating T-cell infiltrate in ear skin at 48 hours after challenge. Single-cell suspensions were made from ear skin 48 hours after challenge from unsensitized (Unsen) and sensitized (Sens) mice. A: Gated CD45⁺ cells were analyzed for CD4⁺CD3⁺ and CD8⁺CD3⁺ T-cell expression. Unsensitized mice contain a resident population of CD4⁺ T cells and CD3^high CD4⁻CD8⁻ cells, but no CD8⁺ T cells in skin. Percentages of gated CD45⁺ cells are shown. Skin-derived T cells are predominately activated CD44^hiCD62L⁻ cells (B) and are BrdU⁺ (C) in unirradiated sensitized mice. Percentages of gated CD4⁺CD3⁺ or CD8⁺CD3⁺ are shown.