Figure 6.

β7-Integrin-mediated immigration of inflammatory monocytes drives colitis. (a) Flow cytometric detection of β7-integrin surface expression on CD45⁺CD11b⁺Ly6C^hiCD64^low cells isolated from bone marrow of recombination activating gene-2-deficient (RAG-2 Δ/Δ) mice. (b and c) Comparison of the migration efficiency of 5-(and 6) carboxyfluorescein diacetate (CFSE)-labeled CD115-enriched wild-type (WT) or β7-integrin-deficient (β7 Δ/Δ) bone marrow monocytes into the colonic lamina propria lymphocyte (LPL) fraction, intraepithelial lymphocyte (IEL) fraction, and spleen of dextran sodium sulfate (DSS)-treated RAG-2 Δ/Δ mice 16 h after intravenous transfer. (b) Representative FACS plots. (c) Quantification of immigrated CD45⁺CFSE⁺ WT (green bars) and β7 Δ/Δ (red bars) monocytes. Data are representative of three independent experiments. (d) Percentage (%) of body weight loss (measured daily over the course of DSS treatment), (e) disease activity index (DAI), and (f) histology score at day 10 of acute DSS colitis of RAG-2 Δ/Δ mice (black squares, black bar, n=7), RAG-2 Δ/Δ-β7Δ/Δ mice (gray squares, gray bars, n=4), RAG-2 Δ/Δ-β7-integrin Δ/Δ mice that had received WT monocytes (green squares, green bars, n=5), and RAG-2 Δ/Δ-β7-integrin Δ/Δ mice that had received β7 Δ/Δ monocytes (red squares, red bars, n=5). Data are representative of three independent experiments. Data represent mean±s.e.m. and significance is indicated as follows: NS=nonsignificant; *P<0.05; **P<0.01; ***P<0.001; and ****P<0001. (c) One-tailed t-test. (d–f) One-way analysis of variance (ANOVA) with Tukey's post-test.