Altered serum OVA-specific IgE levels.

<p>OVA-specific IgE levels were apparently higher in low-fiber group than in the AAD model group. However, the levels in fiber-intervened mice were significantly inhibited, especially in the pectin group. Bars indicate the mean secretion ng/ml ± SEM, n = 8~10; *<i>p</i><0.05, **<i>p</i><0.01.</p

Altered allergic response.

<p>Compared with the AAD model group, the control group showed no or fewer allergic symptoms, whereas the low-fiber group showed remarkable frequency of nasal rubbing and sneezing. The frequency was significantly decreased with dietary fiber intervention. Data are shown by box and whisker plots, with whisker ends indicating minimal and maximal values and horizontal bars representing medians, n = 10; *<i>p</i><0.05, **<i>p</i><0.01 as conducted.</p

Goblet cell metaplasia inalcian blue-periodic acid Stiff (AB-PAS)-stained tissue sections of the nasal mucosa and lung.

<p>Original magnification was × 400 for nose and × 200 for lung (A). Goblet cells were counted as the positively stained blue cells. Percentages of goblet cell metaplasia were calculated from the total cell numbers counted around the nasal mucosa (B) and the lung (C). Goblet cell metaplasia was relatively minor in mice fed with dietary fiber. Scale bars, 200 μm for Nose; scale bars, 50 μm for Lung. Data are expressed as mean ± SEM, n = 10;*<i>p</i><0.05, **<i>p</i><0.01.</p

Absolute numbers of inflammatory cells in 1.2 ml of NALF and BALF at 24 h after final challenge.

<p>Total inflammatory cells and eosinophils in NALF (A) and BALF (B) were significantly inhibited by dietary fiber, whereas low-fiber diet aggravated the inflammatory response of AAD. Scale bars, 50μm.Each bar represents the mean cell number ± standard error of the mean (SEM), n = 10; *<i>p</i><0.05, **<i>p</i><0.01 as conducted.</p

Eosinophil inflammation assessed with hematoxylin and eosin (HE)-stained tissue sections of the nasal mucosa and lung.

<p>Original magnification was × 400 for nose and × 200 for lung (A). Numbers of eosinophils in the nasal mucosa (B) and inflammation scores of the lung (C) were counted to verify the altered inflammation among groups. Eosinophil infiltration was significantly higher in low-fiber group than in the AAD model group. Interestingly, dietary fiber intervention drastically suppressed eosinophil inflammation. In addition, numbers of eosinophils in pectin group were lower than in the cellulose group. Scale bars, 200 μm for Nose; scale bars, 500 μm for Lung. Data expressed as mean ± SEM, n = 10; *<i>p</i><0.05, **<i>p</i><0.01 as conducted.</p

Altered levels of cytokines IL-4, IL-10 and IFN-γ in NALF (A) and BALF (B).

<p>Dietary fiber significantly inhibited IL-4 levels accompanied by increased IFN-γ levels, as well as increased IL-10 secretion. Data are represented as the mean secretion pg/ml ± SEM, n = 8~10; *<i>p</i><0.05, **<i>p</i><0.01 as conducted.</p

Dietary fiber facilitates the growth and proliferation of probiotic bacteria.

<p>Long-term intervention with dietary fiber significantly elevated the concentration of <i>Lactobacillus</i>, <i>Bifidobacterium</i> and <i>E</i>.<i>coli</i>, compared with the standard diet, and the level of <i>Enterococcus</i> spp was proportionally reduced. Bars indicate the mean relative ratio ± SEM, n = 8; *p<0.05, **p<0.01 as conducted.</p

Dietary fiber modulates microbial community structure.

<p>Compared with AAD model group, the proportion of Bacteroidetes and Actinobacteria in fiber-fed group was proportionally increased, while the population of Firmicutes and Proteobacteria was distinctly reduced, compared with the decreased proportions of Firmicutes to Bacteroidetes. These changes are closely correlated with the development of allergic diseases. Data are expressed as mean relative ratio± SEM, n = 8; *p<0.05, **p<0.01 as conducted.</p

Absolute numbers of inflammation cells in 1.2 ml of NALF and BALF at 24 h after final challenge.

<p>Original magnification was ×400 (A, B). Total inflammation cells and eosinophils in NALF (C) and BALF (D) were significantly inhibited by <i>E. coli</i> infection in AAD mice model. Each bar represents the mean cell number ± standard error of the mean (SEM), n = 10. ^*<i>p</i><0.05, ^**<i>p</i><0.01 as conducted.</p

The changes of cytokines IL-4, IL-10, IFN-γ and IL-2 in NALF (A) and BALF (B).

<p>As shown above, administration of <i>E. coli</i> exhibited significant inhibition of levels of Th2 cytokines IL-4. Interestingly, the effect was accompanied by high levels of Th1 cytokines IFN-γ and IL-2, as well as the increased production of IL-10 secreted abundantly by Tregs. Additionally, the effects were more significant in neonatal mice infected with 10⁸CFU <i>E. coli</i>. Data is represented as the mean secretion pg/ml ± SEM, n = 8∼10.^*<i>p</i><0.05, ^**<i>p</i><0.01 as conducted.</p