Figure 2.

Macrophage transplantation reduces colitis in Il10rb^-/- IBD mice. [A] Schematic representation of the experimental set-up. Macrophages were generated from WT BM cells and 5‐10 x 10⁶ cells were transplanted into IBD animals by intraperitoneal [i.p.] injection every 2 weeks [green arrows]. In some experimental groups, clodronate liposomes were administered i.p. [red arrows] to deplete endogenous macrophages before macrophage transplantation. The experiment comprised two to three treatment cycles. [B] Colon histology scoring was performed for untreated WT mice, untreated IBD animals or IBD animals treated two to three treatment cycles with clodronate liposomes [Clodro], bone marrow-derived macrophages [BMDMs], or a combination therapy of clodronate liposomes followed by BMDMs [Clodro/BMDMs]. Data represent five independent experiments, individual values with mean ± SD, n = 8–10 per group. [C] Representative light microscopy of H/E-stained colon paraffin sections. [D and E] Immuno-phenotyping of lamina propria [LP] macrophage populations [pre-gated on: CD45⁺/CD11b⁺/CD103^-/ Ly6G^-/CD64⁺ monocyte/macrophages, see Supplementary Figure 2 for gating strategy, available as Supplementary data at ECCO-JCC online]. [D] Representative flow cytometry plots showing the frequency of Ly6C⁺/MHCII⁺ inflammatory and Ly6C^-/MHCII⁺ anti-inflammatory LP monocyte/macrophages in different treatment groups; and [E] quantification of four independent experiments [individual values with mean ± SD, n = 5–10 per group]. Significances calculated by one-way ANOVA with Dunnett’s multiple comparison test, *p <0.05, **p <0.01, ***p <0.001, ****<0.0001, ns not significant. IBD, inflammatory bowel disease; BM, bone marrow; SD, standard deviation; H/E, haematoxylin and eosin; WT, wild type; ANOVA, analysis of variance.