Anti-inflammatory potential of a heat-killed Lactobacillus strain isolated from Kimchi on house dust mite-induced atopic dermatitis in NC/Nga mice

Aims: Atopic dermatitis (AD) is an allergic skin disease driven by the Th2-prone immune response. Therefore, a fundamental approach to restoring the Th1/Th2 balance is needed to treat AD. Methods and Results: Eighteen different Lactobacillus strains isolated from Kimchi were screened to identify those that stimulated immune cells to secret Th1-type or Th2-type cytokines. Lactobacillus brevis NS1401 induced the greatest IFN-γ and IL-12 secretion and the least IL-4 production among the tested Lactobacillus strains. Furthermore, oral administration of heat-killed NS1401 ameliorated the symptoms of dust mite-induced AD in NC/Nga mice by decreasing the serum IgE level and reducing the number of mast cells and eosinophils in lesions. Also, the size and number of cells in the draining lymph nodes of NS1401-administered mice were significantly reduced. In agreement with these results, secretion of a Th1-type cytokine (IFN-γ) and allergen-specific IgG2a were increased, whereas secretion of Th2-type cytokines (IL-4, IL-5, and IL-10) and allergen-specific IgG1 were decreased upon administration of NS1401 in mice. Conclusions: Lactobacillus brevis NS1401 alleviates the symptoms of AD by restoring the Th1/Th2 balance through enhancing Th1-prone immunity. Significance and Impact of the Study: The immunomodulatory function of L. brevis NS1401 may provide effective new therapeutics against AD.