Pathologic cells are CD8α⁺ cDCs. (A) CD11c⁺ DCs were magnetically purified from spleen of WT, healthy (2 months old), and sick Mushi1 Tg mice and analyzed by FACS. The percentage of CD11c⁺ gated cells expressing the indicated DC subtype marker is shown. (B) The indicated activation markers were analyzed on CD11c⁺ purified cells from littermate (LM) or sick Mushi1 Tg (TG) mice. CD11c⁺ CD8α⁺ gated cells are shown with or without antibody for activation marker (Ab−). (C) Langerin was analyzed on skin-draining LN (pLN), MLN, and spleen cells from littermate (LM) or 3.5-month-old Mushi1 Tg mice with splenomegaly (TG). Fixed and permeabilized CD11c⁺ CD24⁺ gated cells are shown with (Ab+) or without (Ab−) Langerin antibody. The percentage of Langerin-positive cells is indicated. (D) The indicated mRNAs were quantified by real-time RT-PCR in magnetically purified B cells and macrophages (Mφ) from WT mice, and FACS-purified spleen CD8α⁻ and CD8α⁺ DC subsets from Mushi1 sick Tg and non-Tg mice. (E) Levels of CIITA isoform mRNA before and after activation with interferon-γ (IFN-γ) and lipopolysaccharide (LPS) or LPS alone were quantified by real-time RT-PCR using an absolute quantification titration curve. The indicated cells were purified as in panel C.