Leuconostoc citreum isolated from kimchi suppresses the development of collagen-induced arthritis in DBA/1 mice

[Display omitted] •Leuconostoc citreum WiKim56 modulates cytokine production by splenocytes in vitro.•Leu. citreum WiKim56 ameliorates symptoms in a mouse model of rheumatoid arthritis.•WiKim56 enhances regulatory T cell response and inhibits Th1 and Th17 responses.•Leu. citreum WiKim56 may lessen damage due to inflammatory autoimmune reactions. Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation, which can cause severe bone and joint damage. Leuconostoc citreum WiKim56 is a lactic acid bacterium isolated from gatkimchi, fermented mustard leaves. We evaluated the ability of Leu. citreum WiKim56 to modulate T cell responses and suppress RA in a mouse model of collagen-induced arthritis. Leu. citreum WiKim56 lowered the incidence of arthritis, attenuated symptom severity, and inhibited RA progression in the mice. Leu. citreum WiKim56 decreased serum levels of collagen-specific IgG and IgG2a, and reduced the expression of collagen-specific pro-inflammatory cytokines in the spleen and peripheral lymph nodes. Moreover, the proportion and function of regulatory T cells in splenocytes was significantly enhanced by WiKim56 treatment. These data suggest that Leu. citreum ameliorates RA symptoms by suppressing inflammatory responses, and that Leu. citreum WiKim56 may prevent or lessen damage due to inflammatory autoimmune reactions, including those associated with RA.