PDCs generated after alloHSCT with TCD STAT1^−/− BM have features of suppressor cells. (A) Lethally irradiated recipients received TCD miHA-mismatched BM from STAT1^+/+ or STAT1^−/− donors (129 → B6 × C3H.SW), and on day +14 pDCs were isolated from spleen by magnetic cell selection and were pooled together from 12 recipients/group. cDNA was generated and hybridized to an Affymetrix genechip mouse genome 430 2.0 array. Samples were normalized by RMA algorithm to a log₂ intensity value and were analyzed by Ingenuity Pathway Analysis v8.5 software. Genes that showed at least twofold increased or decreased expression are shown after analysis using the Benjamini-Hochberg method of multiple testing correction, P < .01. Microarray was performed once from pDCs pooled from 12 mice/group. (B) Splenic pDCs from recipients of TCD STAT1^−/− BM were isolated by negative selection using Miltenyi microbeads, and total RNA was isolated. cDNA was reverse transcribed using an Invitrogen RT-PCR kit. Quantitative RT-PCR was performed using TaqMan probes designed by Applied Biosystems for S100A8 and S100A9. Samples were normalized to a GAPDH housekeeping gene, and expression of S100A8 or S100A9 by STAT1^−/− pDCs was compared with STAT1^+/+ pDCs. Fold change was calculated from triplicates using the 2^|ΔΔCt| method. (C) Lethally irradiated recipients received TCD miHA-mismatched BM from S100A9^+/+ or S100A9^−/− donors (B6 → C3H.SW), and on day +14 some groups were treated with 20 × 10⁶ DLI to induce GVHD. Some recipients did not receive a DLI as a negative GVHD control. Mice who developed clinical GVHD scores >0 were scored as an event. (D) pDCs pooled from the spleen and BM of recipients of TCD STAT1^+/+ (WT) or STAT1^−/− BM were isolated and activated with IL-6, then assessed for STAT3 expression by quantitative RT-PCR and (E) ELISA. N = 3 to 7 mice/group, data are representative from 1 of 2 similar experiments. * = P < .05, ** = P < .01.