Identification of the natural counterpart of CD11b^hiIa^lo DCs in vivo. (A-B) Isolation of the natural counterpart of CD11b^hiIa^lo DCs. (A) CD4⁺CD8⁺B220⁺ splenocyte cells from normal mice or from IL-10–KO mice were first depleted by negative selection by using MACS system, and CD4^–CD8^–B220^– splenocytes were stained by Ia-FITC, CD11b-PE, and PE-Cy5 conjugated anti-CD11c mAbs. To sort CD11c^loCD11b^hiIa^lo cells, CD11c^lo cells were first gated and further sorted using CD11b and Ia marker by FACSDiva (wt-mice), and the percentage of CD11b^hiIa^lo DCs among all CD4^–CD8^–B220^–CD11c⁺ DCs was analyzed (wt-mice and IL-10–KO mice). (B) CD11b^hiIa^lo cells sorted from wt-mice in vivo or induced by ESSCs in vitro were added into the CD4/mDC coculture system, respectively, to compare their inhibitory functions. After 3 days of culture, the relative cell number of viable CD4 T cells was assayed by FACS. *P < .001.