Protective effect of Bifidobacterium infantis CGMCC313-2 on ovalbumin-induced airway asthma and β-lactoglobulin-induced intestinal food allergy mouse models

Figure 1 Protocols used for establishment of the mouse models. A: Allergic asthma; B: Prevention; C: Pre-treatment of OVA-induced airway allergy with B. infantis CGMCC313-2.

Figure 2 Protocols used for establishment of the mouse models. A: Food allergy; B: Prevention; C: Pre-treatment of β-lactoglobulin-induced food allergies with B. infantis CGMCC313-2.

Figure 3 Effect of B. infantis CGMCC313-2 on the reversal of IgE and IgG1 in ovalbumin-induced asthma and β-lactoglobulin-induced food allergy mouse models. A and B: There were significant increases in OVA-specific IgE and IgG1 expression in the positive control (PC; Group 2) group compared with the normal control (NC; Group 1) group in the allergic asthma mouse model. The prevention (pre; Group 3) and pre-treatment (tre; Group 4) groups following B. infantis CGMCC313-2 administration showed decreased expression; C: A significant increase in total IgE expression was seen in the positive control (PC; Group 2) group compared with the normal control (NC; Group 1) group in the BLG-induced food allergy mouse model. The prevention (pre; Group 3) and pre-treatment (tre; Group 4) groups following B. infantis CGMCC313-2 administration showed decreased expression. The statistical differences are represented as follows: ^aP < 0.05; ^bP < 0.01, and ^cP < 0.001.

Figure 4 Effect of B. infantis CGMCC313-2 on body weight in BLG-induced food allergy mice. Average body weight decreased significantly in the positive control (PC; Group 2) group compared with the normal control (NC; Group 1) group. The prevention (pre; Group 3) and pre-treatment (tre; Group 4) groups following B. infantis CGMCC313-2 administration showed an increase in body weight. The statistical differences are represented as follows: ^aP < 0.05; ^bP < 0.01, and ^cP < 0.001.

Figure 5 Effects of B. infantis CGMCC313-2 on infiltrating cells in the lungs of ovalbumin-induced allergic asthma mice. Total cell number in BALF increased significantly in the positive control (PC; Group 2) group compared with the normal control (NC; Group 1) group. The prevention (pre; Group 3), and pre-treatment (tre; Group 4) groups following B. infantis CGMCC313-2 administration showed a decrease. The statistical differences are represented as: ^aP < 0.05; ^bP < 0.01, and ^cP < 0.001.

Figure 6 Effects of B. infantis CGMCC313-2 on OVA-induced airway inflammation. Lung tissues were obtained from the (C) prevention group and (D) pre-treatment group treated with B. infantis CGMCC313-2, and from (A) the normal control group and (B) the ovalbumin sensitized/challenged group on Day 29. The tissues were stained and observed under × 200 magnification. The positive control group showed severe airway inflammation, while the groups treated with B. infantis CGMCC313-2 showed attenuation of airway inflammation.

Figure 7 Effects of B. infantis CGMCC313-2 on BLG-induced intestinal inflammation. Intestinal tissues were obtained from (A) the normal control group and (B) the BLG-sensitized/challenged group on Day 29, and from the (C) prevention group and (D) pre-treatment group which were treated with B. infantis CGMCC313-2. The tissues were stained and observed under 200 × magnification. The positive control group showed severe intestinal inflammation, while the groups treated with B. infantis CGMCC313-2 showed attenuated intestinal inflammation.

Figure 8 Effects of B. infantis CGMCC313-2 on cytokines in serum and bronchoalveolar lavage fluid. IL-4, IL-10, and IL-13 in serum and BALF were determined in BLG-induced food allergy mice and OVA-induced allergic asthma mice, respectively. A: Serum IL-4 in the prevention (pre; Group 3) group; B: serum IL-13 in the prevention (pre; Group 3) and pre-treatment (tre; Group 4) groups were significantly decreased compared with the positive control (PC; Group 2) group; C: There was no significant difference in IL-10 between the positive control group (PC; Group 2), prevention group (pre; Group 3), and pre-treatment (tre; Group 4), which was significantly decreased when compared with the normal control (NC; Group 1) group; D: The concentrations of BALF IL-4 and (E) BALF IL-13 were significantly decreased in the prevention (pre; Group 3) group and the pre-treatment (tre; Group 4) group treated with B. infantis CGMCC313-2. The statistical differences are represented as follows: ^aP < 0.05; ^bP < 0.01, and ^cP < 0.001.