Canine-derived Lactobacillus acidophilus modulates Th2-driven allergic inflammation via IL-10-mediated immune regulation in murine models.

BACKGROUND

Asthma and atopic dermatitis (AD) are allergic diseases characterized by an excessive T-helper type 2 (Th2) immune response. Recently, several probiotics including Lactobacillus spp., have been used to modulate allergic inflammation. This study aimed to evaluate the effects of canine-derived Lactobacillus acidophilus strains on murine models of asthma and AD.

METHODS

Four L. acidophilus strains isolated from healthy dogs were administered as a mixture to the asthma murine model. Each strain was screened for interleukin (IL)-10 production and acid tolerance using immune cell lines. Two strains, M40 and M53, were selected and tested individually in the asthma and AD models. Immune cells in the lymph nodes and bronchoalveolar lavage fluids (BALF) were analyzed by flow cytometry, and cytokine levels were measured in CD3/CD28-stimulated cultures and lung tissue.

RESULTS

Both strains suppressed IL-5 and IL-13 production under CD3/CD28 stimulation, and downregulated IL-5 and IL-13 expression in the lungs. Improvements in pulse oxygen saturation (SpO2), reductions in lymph node T cells, B cells, and type 2 dendritic cells; and lower serum IgE levels were observed in both groups. Notably, only M40 reduced eosinophils in BALF. In healthy mice, M40 effectively induced IL-10 production and regulatory T (Treg) cells in Peyer's patches compared to M53, indicating a stronger systemic immunomodulatory effect.

CONCLUSION

Orally administered canine-derived L. acidophilus significantly inhibited the development of allergic asthma and AD in murine models. The significant enhancement of IL-10 production in antigen-presenting cells and Treg cells by L. acidophilus may be considered a factor in immune modulation.