Figure 1
Graft-derived interleukin-22 (IL-22) increases signal transducer and activator of transcription factor-1 (STAT1) phosphorylation and inflammatory cytokine production in the colon of recipient mice during acute graft-versus-host disease (aGVHD). Lethally irradiated BALB/c recipients were transplanted with 5 × 106 B6.WT T cell-depleted bone marrow (TCD BM) only or with 1 × 106 B6.WT T cells or 1 × 106 B6.IL-22−/− T cells (n=5 per group and three independent experiments). (a) Survival data are shown (log-rank test, P<0.05 for BM+WT T cells vs. BM+ IL-22 deficient (IL-22−/−) T cells). (b) GVHD clinical scores were determined as described in Methods and were significantly decreased in BM+IL-22−/− T cell recipients at day 9 post allogeneic hematopoietic cell transplantation (allo-HCT), P<0.005 (c,d). Quantitative reverse transcriptase–PCR analysis for each indicated gene was performed using RNA isolated from the large intestine at day 7 after allo-HCT. Mean±s.e.m. of gene expression levels are represented. Data are combined from at least three independent experiments (n=12). (e,f) Total protein was isolated from the large intestine collected at day 7 after allo-HCT. (e) Cellular content of phosphorylated (P) STAT1, total (t) STAT1, and β-actin was evaluated by western blot analysis. One representative experiment is shown. (f) P-STAT1/t-STAT1 ratio was evaluated using the Cell Signaling cytometric bead array kit (CBA) (n=3 per group and 6 independent experiments).
