MiR-155 expression is increased in LPS-stimulated DCs, and recipient miR-155 deficiency decreases GVHD. (A) RNA was isolated from DCs stimulated with 10 ng/mL LPS for the indicated time intervals. MiR-155 expression was analyzed by qRT-PCR. Data are pooled from 3 independent experiments. (B) Allo-HCT was performed as described for the BALB/c into WT (n = 12) and miR-155^−/− (n = 10) C57BL/6 combination. Survival was monitored for 100 days. (C) On day 7 after allo-HCT (BALB/c → WT and miR-155^−/− C57BL/6), organs were isolated and paraffin sections of the small intestine, large intestine, and liver were stained with hematoxylin and eosin. Histopathology scoring was performed as described. (D) On day 7 after allo-HCT (BALB/c → WT and miR-155^−/− C57BL/6), serum was isolated from the recipients, and the concentrations of INF-γ, IL-12, and MCP-1 were determined. (E) On day 1 after allo-HCT (BALB/c → WT and miR-155^−/− C57BL/6), axillary, inguinal, and mesenteric lymph nodes were isolated and CFSE dilution of CD3⁺ H-2K^d+ donor T cells was analyzed.