Figure 4.

Formula feeding (FF) enhances the susceptibility of mouse pups to anti-CD3 mAb-induced intestinal injury. Neonatal mice [postnatal day (P)0] from multiple litters were subjected to dam feeding (DF) and FF. On P2, both DF and FF pups were treated with anti-CD3 mAb (10 mg/kg) or isotype IgG subcutaneously. Pups were monitored for 24 h after treatment (P3). A: relative levels of FD-10S in serum as a measure of intestinal permeability. The fluorescent marker was administered orally 4 h before the end of the experiment. Intestinal permeability assay was run in duplicate for each sample. Data are presented as means ± SD; n = 6 in each group. Data represent 2 independent experiments and were analyzed by 2-way ANOVA with Tukey posttest. B: analysis of the 24-h survival rate after indicated treatment. Log-rank test was used for survival curve. C: analysis of body weight (BW) changes after indicated treatment. D: representative microscopic images of hematoxylin-eosin (H&E) staining of ileum tissue samples of DF and FF pups with or without anti-CD3 mAb treatment. Scale bars, 100 μm. E: histological scores using a necrotizing enterocolitis (NEC) scoring system as indicated in materials and methods. NEC-like injury was defined as histological grade ≥ 2. Histological score was analyzed by χ² test. C and E: data are presented as means ± SD; n = 13 DF + isotype group, n = 13 DF + anti-CD3 group, n = 19 FF + isotype group, n = 19 FF + anti-CD3 group. Data represent 3 independent experiments and were analyzed by 2-way ANOVA with Tukey posttest. ns, No significance. **P < 0.01, ****P < 0.0001. Changes are considered statistically significant if P < 0.05.