Probiotics are living microorganisms that can exert diverse health benefits on the host through interacting with host-driven immune responses. The immunomodulatory effects on host immune systems is quite different depending on probiotic strains. Besides, many recent studies have reported that certain probiotic strains or multi-strain mixtures have potent immunomodulatory capacity in diverse immune-related disorders including autoimmune and allergic diseases. Here we evaluated the immunomodulatory properties and their underlying mechanisms of two different probiotic strains, Leuconostoc citreum LC and Lactobacillus sakei LS, isolated from Kimchi. We first conducted several in vitro assays and found that they have modulatory activities both on innate and adaptive immunity. Then, ameliorating effects of probiotics on immune disorders were evaluated in animal models of rheumatoid arthritis (RA) and atopic dermatitis (AD). Oral administration of Leu. citreum LC lowered the incidence of arthritis, attenuated symptom severity, and inhibited RA progression in the mice. Leu. citreum LC decreased serum levels of collagen-specific IgG and IgG2a, and reduced the collagen-specific Th17 immune response by enhancing the proportion and function of regulatory T cells in spleen. Next, we found that oral administration of L. sakei LS significantly reduced AD-like skin lesions and serum immunoglobulin E and IL-4 levels while decreasing the number of CD4+ T cells and B cells and the levels of Th2 cytokines (IL-4, IL-5, and IL-13) in peripheral lymph nodes and enhancing Treg differentiation and IL-10 secretion in mesenteric lymph nodes. Additionally, L. sakei LS modulated gut microbiome profiles that were altered in AD mice, which showed changes of microbiota proportion correlated with Treg-related responses may contribute to the alleviation of AD responses. Together, these results suggest that beneficial effects of probiotic strains from kimchi on host health may be attributed to their direct and indirect immunoregularoty properties and thereby influence the host immune responses with potential application for disease prevention and treatment.

Hyo Kyeong Park

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