The presence of an early form of the CD8⁺ cDC lineage within the CD4⁻8⁻ cDC preparations, and its capacity to produce IFN-γ. (A) CD4⁻8⁻ cDCs, sorted from NK-marker–depleted cDC preparations as in Figure 1 and analyzed as in Figure 3A, were segregated into CD172a⁺ (Sirpα⁺), typical CD4⁻8⁻ cDCs and into a minor subset of CD172a⁻ (Sirpα⁻) cells, which when analyzed were less developed (by surface MHC II expression) and which had the CD172a⁻ CD24⁺ phenotype of the typical CD4⁻8⁺ cDCs. Gray lines represent background fluorescence from samples with only the relevant stain omitted; black lines represent the fluorescence of the positively stained sample. (B) IFN-γ production (in ng/mL) was measured in the supernatant 65 hours after culture with IL-12 and IL-18 of 10⁵ cells (in 0.2 mL) of the fractions from panel A. Results are the means plus or minus SD of 4 cultures from the one experiment, typical of 3.