FIGURE 1.

Lin⁻c-Kit⁺ cells purified from lupus spleens (L⁻K⁺_pure) are the main inducers of Th17 response to nuclear autoantigens. (A–B) Isolated APC types (designated by color key) were co-cultured with splenic T cells from lupus-prone SNF1 at optimal ratios (Methods), and IFN-γ (A) and IL-17 (B) responses of the T cells to nucleosomes were measured at 24 and 48 hr respectively in ELISPOT assays (Y-axis), as shown by bars. Data (mean and s.e.m.) represent 5 independent experiments with 35 mice. Lin⁻c-Kit⁺ cells cultured by themselves without nucleosomes or with nucleosomes (at 10–30 μg/ml) produced 30±5 and 34±6 ELISPOTs respectively. Co-cultures of APC and T cells without nucleosomes produced 15 ± 8 background spots. (C) Gating c-Kit+ (CD117⁺) cells in Lin⁻ splenocytes (left) and Giemsa staining of sorted CD117⁺cell (right). Scale bar =10 μm. (D) Irradiated Lin⁻c-Kit⁺ cells (APC) were cocultured with T cells and nucleosomes, or pulsed with nucleosomes for 1 h and then cocultured for IL-17 response of the T cells, as shown. (E) Lin⁻c-Kit⁺ _pure cells in SCF only supplemented media did not differentiate into DCs. (F) Clone 5-4 derived by limiting dilution of above culture (E) has only CD117⁺CD11b⁻ cells. (G) Clone 5-4 cocultured as APC with SNF1 T cells, induced only Th17 response to nucleosomes.