Generation of CD11b⁺ MHCII^high CDC-like cells from CCR9⁻ MHCII^low PDCs. CCR9⁺ and CCR9⁻ PDC populations were sorted from primary BM cells, incubated with medium or IEC-SN for 48 hours, and stained for FACS analysis. Surface expression of BST2 versus CD11c is shown in the dot plots. Expression levels of CD11b, MHC class II, CD80, and CD86 in BST2^high IEC-SN PDCs and BST2^low IEC-SN DCs generated from CCR9⁻ BM PDCs after treatment with IEC-SN are shown in the histograms (A, filled histograms: FMO control, results of one representative of 5 experiments). CCR9⁺ and CCR9⁻ PDCs were incubated with medium or 50% IEC-SN. After 24 hours, CpG 2216 (0.5μM) was added and cytokine concentrations were measured in the supernatants by ELISA after further 24 hours (B, mean ± SD, n = 3). Cells were isolated from Peyer patches digested with DNase/collagenase and subsequently analyzed by FACS for surface expression of the depicted markers. Dot blots show expression of BST2 and CD11c in propidium iodide-negative cells. Expression of the indicated markers in BST2^high CD11c⁺ (R1), BST2^low CD11c^high (R2) and CD11c^high (R3) is shown below (C, filled histograms: FMO control). *P < .05. **P < .01.