CD44^lo CD45RB^hi IL-10⁺ CD8 T cells appear in an inflammatory site in vivo. C57BL/6 mice were injected with 10⁷ OT-1 CD8 and 10⁷ OT-2 CD4 cells intravenously on day 0. On days 0 and 3 they were challenged intranasally with 50 μg OVA + 10 μg CpG 1826 oligonucleotide in 50 μL PBS (right) or PBS alone (left). On day 6, mice were killed, and T cells were extracted from lung tissue by collagenase digestion. T cells (10⁶) were labeled with anti-CD44 + anti-CD8 (A), anti-CD45RB + anti-CD8 (B), or anti-CD8 alone (C), then restimulated with anti-CD3 + anti-CD28 for 5 hours followed by intracellular cytokine staining. Gated CD8⁺ cells are shown in all plots. Representative results from groups of 4 mice are shown. Similar data were obtained in 3 independent experiments.