Figure 1.

Propagation of liver B220⁺ DCs. (a) Yield of B220⁺ DCs per liver from female NOD, NOR and BALB/c mice at different ages. In animals younger than 11 weeks, the number of B220⁺ DCs propagated from NOD mice was not statistically different from that of age-matched NOR and BALB/c mice (P > 0·05). However, it is extremely difficult to propagate these DCs from NOD mice older than 11 weeks (P < 0·05 compare with age-matched NOR and BALB/c). (b) Surface antigen expression on liver B220⁺ DCs that were propagated from 6-week-old NOD mice. Cell surface antigen expression was determined by staining with fluorescein isothiocyanate-conjugated mAbs, and analysed by flow cytometry (filled histograms). Appropriate species-matched isotype immunoglobulins were used as controls (open histograms). (c) Liver B220⁺ DCs do not produce IFN-α. MDCs, liver B220⁺ DCs, or PDCs generated from NOD mice (2 × 10⁶/ml) were cultured in completed medium in the presence of CpG (10 μm, InvivoGen, San Diego, CA) for 2 days. The supernatant IFN-α levels were determined by enzyme-linked immunosorbent assay. In contrast to PDCs that secreted large amount of IFN-α, MDCs and liver B220⁺ DCs produced very low IFN-α (P < 0·05 compared with PDCs; P > 0·05 compared with MDCs).